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Sample records for svoc water haze

  1. Detection of semi-volatile organic compounds (SVOCs) in surface water, soil, and groundwater in a chemical industrial park in Eastern China.

    Science.gov (United States)

    Liu, Benhua; Li, Yuehua; Ma, Jianfeng; Huang, Linxian; Chen, Liang

    2016-01-01

    China is suffering from serious water and soil pollution, especially in the North China Plain. This work investigated semi-volatile organic compounds (SVOCs) in surface water, groundwater and soil within a chemical industrial park in Eastern China, for which the volatile organic compound (VOC) results have been previously reported. A total of 20 samples were collected from the field, and analyzed in the laboratory. A 100% detection frequency of SVOCs in samples from this chemical industrial park was observed (same as VOCs). Moreover, the detection frequency of 113 SVOCs in each sample reached 15.93, 12.39 and 20.35% for surface water, groundwater and soil, respectively. The most detected SVOCs in the park included N-containing SVOCs, polycyclic aromatic hydrocarbons, phthalates, organic pesticides and polychlorodiphenyls. The elevated detecting frequencies and concentration levels of SVOCs identified in the groundwater were attributed to the intensive chemical production activities in the park. In addition, the agricultural activities in the area might also have contributed to the SVOCs to the groundwater. The results of VOCs and SVOCs from this and previous studies suggest that the groundwater in this industrial park has been severely contaminated, and the contamination likely spreads beyond the park. Imminent hydrogeological assessments and remedial actions are warranted to eliminate the source and mitigate the potential plume expansion beyond the park boundary.

  2. Ice haze, snow, and the Mars water cycle

    Science.gov (United States)

    Kahn, Ralph

    1990-01-01

    Light curves and extinction profiles derived from Martian limb observations are used to constrain the atmospheric temperature structure in regions of the atmosphere with thin haze and to analyze the haze particle properties and atmospheric eddy mixing. Temperature between 170 and 190 K are obtained for three cases at levels in the atmosphere ranging from 20 to 50 km. Eddy diffusion coefficients around 100,000 sq cm/s, typical of a nonconvecting atmosphere, are derived in the haze regions at times when the atmosphere is relatively clear of dust. This parameter apparently changes by more than three orders of magnitude with season and local conditions. The derived particle size parameter varies systematically by more than an order of magnitude with condensation level, in such a way that the characteristic fall time is always about one Martian day. Ice hazes provide a mechanism for scavenging water vapor in the thin Mars atmosphere and may play a key role in the seasonal cycle of water on Mars.

  3. Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China

    Science.gov (United States)

    Cheng, Yafang; Zheng, Guangjie; Wei, Chao; Mu, Qing; Zheng, Bo; Wang, Zhibin; Gao, Meng; Zhang, Qiang; Wang, Kebin; Carmichael, Gregory; Pöschl, Ulrich; Su, Hang

    2017-04-01

    Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in the North China Plain. Sulfate is a major component of fine haze particles. Record sulfate concentrations of up to 300 μg m-3 were observed during the January 2013 winter haze event in Beijing. State-of-the-art air quality models that rely on sulfate production mechanisms requiring photochemical oxidants cannot predict these high levels because of the weak photochemistry activity during haze events. We find that the missing source of sulfate and particulate matter can be explained by reactive nitrogen chemistry in aerosol water. The aerosol water serves as a reactor, where the alkaline aerosol components trap SO2, which is oxidized by NO2 to form sulfate, whereby high reaction rates are sustained by the high neutralizing capacity of the atmosphere in northern China. This mechanism is self-amplifying because higher aerosol mass concentration corresponds to higher aerosol water content, leading to faster sulfate production and more severe haze pollution. Reference: Cheng, Y., Zheng, G., Wei, C., Mu, Q., Zheng, B., Wang, Z., Gao, M., Zhang, Q., He, K., Carmichael, G., Pöschl, U., and Su, H.: Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China, Science Advances, 2, 10.1126/sciadv.1601530, 2016.

  4. Severe haze episodes and seriously polluted fog water in Ji'nan, China.

    Science.gov (United States)

    Wang, Xinfeng; Chen, Jianmin; Sun, Jianfeng; Li, Weijun; Yang, Lingxiao; Wen, Liang; Wang, Wenxing; Wang, Xinming; Collett, Jeffrey L; Shi, Yang; Zhang, Qingzhu; Hu, Jingtian; Yao, Lan; Zhu, Yanhong; Sui, Xiao; Sun, Xiaomin; Mellouki, Abdelwahid

    2014-09-15

    Haze episodes often hit urban cities in China recently. Here, we present several continuous haze episodes with extremely high PM2.5 levels that occurred over several weeks in early 2013 and extended across most parts of the northern and eastern China-far exceeding the Beijing-Tianjin-Hebei region. Particularly, the haze episode covered ~1 million km(2) on January 14, 2013 and the daily averaged PM2.5 concentration exceeded 360 μg m(-3) in Ji'nan. The observed maximum hourly PM2.5 concentration in urban Ji'nan reached 701 μg m(-3) at 7:00 am (local time) in January 30. During these haze episodes, several fog events happened and the concurrent fog water was found to be seriously polluted. For the fog water collected in Ji'nan from 10:00 pm in January 14 to 11:00 am in January 15, sulfate, nitrate, and ammonium were the major ions with concentrations of 1.54 × 10(6), 8.98 × 10(5), and 1.75 × 10(6) μeq L(-1), respectively, leading to a low in-situ pH of 3.30. The sulfate content in the fog sample was more than 544 times as high as those observed in other areas. With examination of the simultaneously observed data on PM2.5 and its chemical composition, the fog played a role in scavenging and removing fine particles from the atmosphere during haze episodes and thus was seriously contaminated. However, the effect was not sufficient to obviously cleanse air pollution and block haze episodes. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Spatial distributions, source apportionment and ecological risk of SVOCs in water and sediment from Xijiang River, Pearl River Delta.

    Science.gov (United States)

    Tang, Jiao; An, Taicheng; Li, Guiying; Wei, Chaohai

    2017-03-09

    Xijiang River is an important drinking water source in Guangxi Province, China. Along the Xijiang River and surrounding tributary, the pollution profile of three important groups of semi-volatile organic compounds, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and phthalate esters (PAEs), was analyzed. Relatively low levels of PAHs (64-3.7 × 10(2) ng L(-1)) and OCPs (16-70 ng L(-1)), but high levels of PAEs (7.9 × 10(2)-6.8 × 10(3) ng L(-1)) occurred in the water. Comparatively, low levels of OCPs (39-1.8 × 10(2) ng g(-1)) and PAEs (21-81 ng g(-1)), but high levels of PAHs (41-1.1 × 10(3) ng g(-1)) were found in sediment. Principal component analyses for source identification indicated petroleum-derived residues or coal and biomass combustion, and vehicular emission was the main sources for PAHs. The OCPs sources of each category were almost independent, whereas the new input of HCHs and p,p'-DDTs probably existed in some areas. PAEs were mainly originated from personal care products of urban sewage, plastic and other industrial sources. Ecological risk through the risk quotient analysis indicated a small or significant potential adverse effect on fish, daphnia and green algae. Nevertheless, the integrated risk of all pollutants should be taken into account in future study.

  6. [Characteristics of mass size distributions of water-soluble, inorganic ions during summer and winter haze days of Beijing].

    Science.gov (United States)

    Huang, Yi-Min; Liu, Zi-Rui; Chen, Hong; Wang, Yue-Si

    2013-04-01

    To investigate the size distribution characteristics of water soluble inorganic ions in haze days, the particle samples were collected by two Andersen cascade impactors in Beijing during summer and winter time and each sampling period lasted two weeks. Online measurement of PM10 and PM2.5 using TEOM were also conducted at the same time. Sources and formation mechanism of water soluble inorganic ions were analyzed based on their size distributions. The results showed that average concentrations of PM10 and PM 2.5 were (245.5 +/- 8.4) microg x m(-3) and (120.2 +/- 2.0) microg x m(-3) during summer haze days (SHD), and were (384.2 +/- 30.2) microg x m(-3) and (252.7 +/- 47.1) microg x m(-3) during winter haze days (WHD), which suggested fine particles predominated haze pollution episode in both seasons. Total water-soluble inorganic ions concentrations were higher in haze days than those in non-haze days, especially in fine particles. Furthermore, concentrations of secondary inorganic ions (SO4(2-), NO3(-) and NH4(+)) increased quicker than other inorganic ions in fine particles during haze days, indicating secondary inorganic ions played an important role in the formation of haze pollution. Similar size distributions were found for all Sinorganic water soluble ions except for NO3(-), during SHD and WHD. SO4(2-) and NH4(+) dominated in the fine mode (PM1.0) while Mg2+ and Ca2+ accumulated in coarse fraction, Na+, Cl- and K+ showed a bimodal distribution. For NO3(-), however, it showed a bimodal distribution during SHD and a unimodal distribution dominated in the fine fraction was found during WHD. The average mass median aerodynamic diameter (MMAD) of SO4(2-) was 0.64 microm in SHD, which suggested the formation of SO4(2-) was mainly attributed to in-cloud processes. Furthermore, a higher apparent conversion rate of sulfur dioxide (SOR) was found in SHD, indicating more fine particles were produced by photochemical reaction in haze days than that in non-haze days. The

  7. Influence of haze pollution on water-soluble chemical species in PM2.5 and size-resolved particles at an urban site during fall.

    Science.gov (United States)

    Yu, Geun-Hye; Zhang, Yan; Cho, Sung-Yong; Park, Seungshik

    2017-07-01

    To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles, PM2.5 and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju, Korea. During the study period, the total concentration of secondary ionic species (SIS) contributed an average of 43.9% to the PM2.5, whereas the contribution of SIS to the PM2.5 during the haze period was 62.3%. The NO3(-) and SO4(2-) concentrations in PM2.5 during the haze period were highly elevated, being 13.4 and 5.0 times higher than those during non-haze period, respectively. The PM, NO3(-), SO4(2-), oxalate, water-soluble organic carbon (WSOC), and humic-like substances (HULIS) had tri-modal size distributions peaks at 0.32, 1.0, and 5.2μm during the non-haze and haze periods. However, during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32μm, while on October 21 when the heaviest haze event occurred, they had predominant droplet mode size distributions peaking at 1.00μm. Moreover, strong correlations of WSOC and HULIS with SO4(2-), oxalate, and K(+) at particle sizes of <1.8μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS formations. It was found that the factors affecting haze formation could be the local stable synoptic conditions, including the weak surface winds and high surface pressures, the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula, as well as the locally emitted and produced aerosol particles. Copyright © 2016. Published by Elsevier B.V.

  8. SVOC exposure indoors: fresh look at dermal pathways

    DEFF Research Database (Denmark)

    Weschler, Charles J.; Nazaroff, W. W.

    2012-01-01

    Abstract This paper critically examines indoor exposure to semivolatile organic compounds (SVOCs) via dermal pathways. First, it demonstrates that - in central tendency - an SVOC's abundance on indoor surfaces and in handwipes can be predicted reasonably well from gas-phase concentrations, assumi...

  9. Predicting SVOC Emissions into Air and Foods in Support of ...

    Science.gov (United States)

    The release of semi-volatile organic compounds (SVOCs) from consumer articles may be a critical human exposure pathway. In addition, the migration of SVOCs from food packaging materials into foods may also be a dominant source of exposure for some chemicals. Here we describe recent efforts to characterize emission-related parameters for these exposure pathways to support prediction of aggregate exposures for thousands of chemicals For chemicals in consumer articles, Little et al. (2012) developed a screening-level indoor exposure prediction model which, for a given SVOC, principally depends on steady-state gas-phase concentrations (y0). We have developed a model that predicts y0 for SVOCs in consumer articles, allowing exposure predictions for 274 ToxCast chemicals. Published emissions data for 31 SVOCs found in flooring materials, provided a training set where both chemical-specific physicochemical properties, article specific formulation properties, and experimental design aspects were available as modeling descriptors. A linear regression yielded R2- and p- values of approximately 0.62 and 3.9E-05, respectively. A similar model was developed based upon physicochemical properties alone, since article information is often not available for a given SVOC or product. This latter model yielded R2 - and p- values of approximately 0.47 and 1.2E-10, respectively. Many SVOCs are also used as additives (e.g. plasticizers, antioxidants, lubricants) in plastic food pac

  10. SVOC partitioning between the gas phase and settled dust indoors

    DEFF Research Database (Denmark)

    Weschler, Charles J.; Nazaroff, W. W.

    2010-01-01

    Semivolatile organic compounds (SVOCs) are a major class of indoor pollutants. Understanding SVOC partitioning between the gas phase and settled dust is important for characterizing the fate of these species indoors and the pathways by which humans are exposed to them. Such knowledge also helps...... than a thousand buildings, mostly residences, in seven countries. In aggregate, measured median data are reported in these studies for 66 different SVOCs whose octanol-air partition coefficients (K-oa) span more than five orders of magnitude. We use these data to test a simple equilibrium model...

  11. Haze over Beijing

    Science.gov (United States)

    2007-01-01

    Thick haze collected over the Beijing region in late March 2007. Earlier that month, the BBC News reported that an international team of scientists had documented how increasing pollution in China led to decreasing rainfall over the region. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard the Aqua satellite captured these images of the Beijing region on March 22, 2007. The top image is a 'true-color' picture, similar to a digital photo. The bottom, 'false-color,' image uses a combination of visible and infrared light to more clearly show vegetation, water, and clouds. Even sparse vegetation appears bright green, while water appears deep blue (bright blue when tinged with sediment). Clouds dominated by water droplets appear white, while clouds made of ice crystals appear light blue. The false-color image highlights water bodies, perhaps aqua-culture ponds, that are all but invisible in the true-color image, especially along the shores of the Bo Hai. While vegetation and water show up more clearly in the false-color image, haze is much more transparent. Although dingy gray haze dominates the true-color picture, it is all but invisible in the false-color view. The haze 'disappears' in the infrared-enhanced image because tiny haze particles do not reflect longer-wavelength infrared light very well, making this type of image useful for distinguishing haze from clouds. The bank of clouds in the upper right corner shows up clearly in both pictures. As China industrializes, factories, power plants, and automobiles all contribute to pollution in the region. In examining pollutants and rainfall, the team of scientists examined records covering more than 50 years, concluding that pollution decreased precipitation at Mount Hua near Xi'an in central China. They concluded that when conditions are so hazy that visibility is reduced to less than 8 kilometers (5 miles), hilly precipitation can drop by 30 to 50 percent. When moist air passes over mountains

  12. Indoor Semi-volatile Organic Compounds (i-SVOC) Version 1.0

    Science.gov (United States)

    i-SVOC Version 1.0 is a general-purpose software application for dynamic modeling of the emission, transport, sorption, and distribution of semi-volatile organic compounds (SVOCs) in indoor environments.

  13. Further advances in modeling transdermal uptake of SVOCs

    DEFF Research Database (Denmark)

    Morrison, Glenn; Weschler, Charles J.; Bekö, Gabriel

    2016-01-01

    To better simulate dermal uptake of SVOCs from air, we develop an enhanced transport model that includes skin surface lipids (SSL). As modeled, clothing can remove SSL by contact transfer and it can act as a source or sink for gas-phase transfer to and from SSL. Addition of SSL increases the over......To better simulate dermal uptake of SVOCs from air, we develop an enhanced transport model that includes skin surface lipids (SSL). As modeled, clothing can remove SSL by contact transfer and it can act as a source or sink for gas-phase transfer to and from SSL. Addition of SSL increases...... the overall resistance to uptake of SVOCs from air but also allows for more rapid release of SVOCs to sinks like clothing or clean air. We compare the model results to reported experimental uptake of di-ethyl phthalate (DEP) and di-n-butyl phthalate (DnBP), normalized by exposed skin area and the phthalate...... air concentration during exposure (Weschler et al., 2015). Overall, the model predicts total uptake values that are consistent with those observed in the experiments. The model predicts a normalized mass uptake of DEP of 3.1 (µg/m2)/(µg/m3) whereas the experimental results range from 1.0 to 4.3 (µg/m2...

  14. SVOC emissions from diesel trucks operating on biodiesel fuels

    Science.gov (United States)

    This study measured semivolatile organic compounds (SVOCs) in particle matter (PM) emitted from three heavy-duty trucks equipped with modern after-treatment technologies. Emissions testing was conducted as described by the George et al. VOC study also presented as part of this se...

  15. Haze in Pluto's atmosphere

    Science.gov (United States)

    Cheng, A. F.; Summers, M. E.; Gladstone, G. R.; Strobel, D. F.; Young, L. A.; Lavvas, P.; Kammer, J. A.; Lisse, C. M.; Parker, A. H.; Young, E. F.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Ennico, K.

    2017-07-01

    Haze in Pluto's atmosphere was detected in images by both the Long Range Reconnaissance Imager (LORRI) and the Multispectral Visible Imaging Camera (MVIC) on New Horizons. LORRI observed haze up to altitudes of at least 200 km above Pluto's surface at solar phase angles from ∼20° to ∼169°. The haze is structured with about ∼20 layers, and the extinction due to haze is greater in the northern hemisphere than at equatorial or southern latitudes. However, more haze layers are discerned at equatorial latitudes. A search for temporal variations found no evidence for motions of haze layers (temporal changes in layer altitudes) on time scales of 2 to 5 hours, but did find evidence of changes in haze scale height above 100 km altitude. An ultraviolet extinction attributable to the atmospheric haze was also detected by the ALICE ultraviolet spectrograph on New Horizons. The haze particles are strongly forward-scattering in the visible, and a microphysical model of haze is presented which reproduces the visible phase function just above the surface with 0.5 μm spherical particles, but also invokes fractal aggregate particles to fit the visible phase function at 45 km altitude and account for UV extinction. A model of haze layer generation by orographic excitation of gravity waves is presented. This model accounts for the observed layer thickness and distribution with altitude. Haze particles settle out of the atmosphere and onto Pluto's surface, at a rate sufficient to alter surface optical properties on seasonal time scales. Pluto's regional scale albedo contrasts may be preserved in the face of the haze deposition by atmospheric collapse.

  16. SPME-Based Ca-History Method for Measuring SVOC Diffusion Coefficients in Clothing Material.

    Science.gov (United States)

    Cao, Jianping; Liu, Ningrui; Zhang, Yinping

    2017-08-15

    Clothes play an important role in dermal exposure to indoor semivolatile organic compounds (SVOCs). The diffusion coefficient of SVOCs in clothing material (Dm) is essential for estimating SVOC sorption by clothing material and subsequent dermal exposure to SVOCs. However, few studies have reported the measured Dm for clothing materials. In this paper, we present the solid-phase microextraction (SPME) based Ca-history method. To the best of our knowledge, this is the first try to measure Dm with known relative standard deviation (RSD). A thin sealed chamber is formed by a circular ring and two pieces of flat SVOC source materials that are tightly covered by the targeted clothing materials. Dm is obtained by applying an SVOC mass transfer model in the chamber to the history of gas-phase SVOC concentrations (Ca) in the chamber measured by SPME. Dm's of three SVOCs, di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and tris(1-chloro-2-propyl) phosphate (TCPP), in a cotton T-shirt can be obtained within 16 days, with RSD less than 3%. This study should prove useful for measuring SVOC Dm in various sink materials. Further studies are expected to facilitate application of this method and investigate the effects of temperature, relative humidity, and clothing material on Dm.

  17. HST ROTATIONAL SPECTRAL MAPPING OF TWO L-TYPE BROWN DWARFS: VARIABILITY IN AND OUT OF WATER BANDS INDICATES HIGH-ALTITUDE HAZE LAYERS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hao; Apai, Dániel; Karalidi, Theodora [Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Marley, Mark S. [NASA Ames Research Center, Naval Air Station, Moffett Field, Mountain View, CA 94035 (United States); Saumon, Didier [Los Alamos National Lab, Los Alamos, NM 87545 (United States); Morley, Caroline V. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Buenzli, Esther [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Artigau, Étienne [Département de Physique, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montréal, QC H3C 3J7 (Canada); Radigan, Jacqueline [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Metchev, Stanimir [Department of Physics and Astronomy, Western University, 1151 Richmond Street, London, ON N6A 3K7 (Canada); Burgasser, Adam J. [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States); Mohanty, Subhanjoy [Imperial College London, 1010 Blackett Lab, Prince Consort Road, London SW7 2AZ (United Kingdom); Lowrance, Patrick J. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Showman, Adam P.; Flateau, Davin [Department of Planetary Sciences, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States); Heinze, Aren N., E-mail: haoyang@email.arizona.edu [Department of Physics and Astronomy, State University of New York, Stony Brook, NY 11794-3800 (United States)

    2015-01-01

    We present time-resolved near-infrared spectroscopy of two L5 dwarfs, 2MASS J18212815+1414010 and 2MASS J15074759–1627386, observed with the Wide Field Camera 3 instrument on the Hubble Space Telescope (HST). We study the wavelength dependence of rotation-modulated flux variations between 1.1 μm and 1.7 μm. We find that the water absorption bands of the two L5 dwarfs at 1.15 μm and 1.4 μm vary at similar amplitudes as the adjacent continuum. This differs from the results of previous HST observations of L/T transition dwarfs, in which the water absorption at 1.4 μm displays variations of about half of the amplitude at other wavelengths. We find that the relative amplitude of flux variability out of the water band with respect to that in the water band shows a increasing trend from the L5 dwarfs toward the early T dwarfs. We utilize the models of Saumon and Marley and find that the observed variability of the L5 dwarfs can be explained by the presence of spatially varying high-altitude haze layers above the condensate clouds. Therefore, our observations show that the heterogeneity of haze layers—the driver of the variability—must be located at very low pressures, where even the water opacity is negligible. In the near future, the rotational spectral mapping technique could be utilized for other atomic and molecular species to probe different pressure levels in the atmospheres of brown dwarfs and exoplanets and uncover both horizontal and vertical cloud structures.

  18. Analysis of the dynamic interaction between SVOCs and airborne particles

    DEFF Research Database (Denmark)

    Liu, Cong; Shi, Shanshan; Weschler, Charles J.

    2013-01-01

    A proper quantitative understanding of the dynamic interaction between gas-phase semivolatile organic compounds (SVOCs) and airborne particles is important for human exposure assessment and risk evaluation. Questions regarding how to properly address gas/particle interactions have introduced...... of aerosols) is negligible compared with the external one (from bulk air to aerosol surfaces) is presented. The analysis is applicable regardless of the phase state of particles (either liquid or amorphous semisolid/solid). It is found that for both porous and nonporous particles, the internal resistance can...... cause a two orders of magnitude error in the estimation of the gas-phase concentration and a factor of two error in the estimation of the particle-phase concentration. Copyright © American Association for Aerosol Research....

  19. The evolution of pollution profile and health risk assessment for three groups SVOCs pollutants along with Beijiang River, China.

    Science.gov (United States)

    Tang, Jiao; An, Taicheng; Xiong, Jukun; Li, Guiying

    2017-12-01

    Three important groups of semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), organic chlorinated pesticides (OCPs) and phthalate esters (PAEs), were produced by various human activities and entered the water body. In this study, the pollution profiles of three species including 16 PAHs, 20 OCPs and 15 PAEs in water along the Beijiang River, China were investigated. The concentrations of Σ16PAHs in the dissolved and particulate phases were obtained as 69-1.5 × 102 ng L-1 and 2.3 × 103-8.6 × 104 ng g-1, respectively. The levels of Σ20OCPs were 23-66 ng L-1 (dissolved phase) and 19-1.7 × 103 ng g-1 (particulate phase). Nevertheless, higher levels of PAEs were found both in the dissolved and particulate phases due to abuse use of plastic products. Furthermore, non-cancer and cancer risks caused by these SVOCs through the ingestion absorption and dermal absorption were also assessed. There was no non-cancer risk existed through two kinds of exposure of them at current levels, whereas certain cancer risk existed through dermal absorption of PAHs in the particulate phase in some sampling sites. The results will show scientific insights into the evaluation of the status of combined pollution in river basins, and the determination of strategies for incident control and pollutant remediation.

  20. Clouds and Hazes in Exoplanets and Brown Dwarfs

    OpenAIRE

    Morley, Caroline Victoria

    2016-01-01

    The formation of clouds significantly alters the spectra of cool substellar atmospheres from terrestrial planets to brown dwarfs. In cool planets like Earth and Jupiter, volatile species like water and ammonia condense to form ice clouds. In hot planets and brown dwarfs, iron and silicates instead condense, forming dusty clouds. Irradiated methane-rich planets may have substantial hydrocarbon hazes. During my dissertation, I have studied the impact of clouds and hazes in a variety of substell...

  1. Direct and Air-Mediated Transfer of Labeled SVOCs from Indoor Sources to Dust.

    NARCIS (Netherlands)

    Sukiene, Vilma; von Goetz, Natalie; Gerecke, Andreas C; Bakker, Martine I; Delmaar, Christiaan J E; Hungerbühler, Konrad

    2017-01-01

    Two small-scale field studies were conducted to investigate the transfer of substances from products into dust due to direct and air-mediated transfer. The project focused on semivolatile organic compounds (SVOCs), which are frequently found in and re-emitted from dust. For the field studies, four

  2. Desorption of SVOCs from Heated Surfaces in the Form of Ultrafine Particles

    DEFF Research Database (Denmark)

    Wallace, Lance A.; Ott, Wayne R.; Weschler, Charles J.

    2017-01-01

    of the accumulation rate of SVOCs on surfaces were similar to those in studies of organic film buildup on indoor windows. Transfer of skin oils by touching the glass or foil surfaces, or after washing the glass surface with detergent and bare hands, was also observed, with measured particle production comparable...

  3. Sulfur Hazes in Giant Exoplanet Atmospheres: Impacts on Reflected Light Spectra

    Science.gov (United States)

    Gao, Peter; Marley, Mark S.; Zahnle, Kevin; Robinson, Tyler D.; Lewis, Nikole K.

    2017-03-01

    Recent work has shown that sulfur hazes may arise in the atmospheres of some giant exoplanets, due to the photolysis of H2S. We investigate the impact such a haze would have on an exoplanet’s geometric albedo spectrum and how it may affect the direct imaging results of the Wide Field Infrared Survey Telescope (WFIRST), a planned NASA space telescope. For temperate (250 K production of ˜1 ppmv of S8 between 100 and 0.1 mbar, which, if cool enough, will condense to form a haze. Nominal haze masses are found to drastically alter a planet’s geometric albedo spectrum: whereas a clear atmosphere is dark at wavelengths between 0.5 and 1 μm, due to molecular absorption, the addition of a sulfur haze boosts the albedo there to ˜0.7, due to scattering. Strong absorption by the haze shortward of 0.4 μm results in albedos orange. The existence of a sulfur haze masks the molecular signatures of methane and water, thereby complicating the characterization of atmospheric composition. Detection of such a haze by WFIRST is possible, though discriminating between a sulfur haze and any other highly reflective, high-altitude scatterer will require observations shortward of 0.4 μm, which is currently beyond WFIRST’s design.

  4. Identification of sensitive parameters in the modeling of SVOCs reemission processes from soil to atmosphere

    Science.gov (United States)

    Loizeau, Vincent; Ciffroy, Philippe; Musson Genon, Luc; Roustan, Yelva

    2013-04-01

    Many studies have shown that semi-volatile organic compounds (SVOCs) are subject to Long-Range Atmospheric Transport (LRAT) and that such a transport may occur through a series of deposition-reemission events at the soil surface-air interface. This periodic movement of pollutants between soil and atmosphere is called the 'grasshopper effect'. Thus, it appears necessary to take into account the exchange between soil and atmosphere to properly simulate the fate of these pollutants at regional or global scale. The prediction of reemission from soils is however associated with large uncertainties, which can be schematically classified into three main sources : (i) natural variability, including nature of soil (organic matter content, porosity, water content) and meteorological conditions ; (ii) uncertainty about intrinsic properties of chemicals, like degradation rate or partitioning between environmental components, which govern the dynamics of chemicals in air and soils ; (iii) model structure, and particularly the discretization of soil compartment. Considering this background, a major challenge is to identify the most sensitive sources of uncertainty in modelling the reemission of chemicals from soils, in order to know where the priority has to be set for upgrading SVOC dispersion estimation. To answer this question, we studied a multi-layer soil model, including exchanges between soil and atmosphere. A sensitivity analysis was conducted by affecting probability density functions for each of model parameters. Four chemicals were selected (Benzo(a)Pyrene, PCB-28, Lindane and Hexachlorobenzene) because of their contrasted behaviors in soils, as expected by their partition and degradation properties. For this first exercise, simple emission scenarii were considered, i.e. a period of constant concentration in air (where realistic concentrations were estimated for each chemical from monitoring data provided by EMEP) followed by a zero-concentration in air. Although

  5. The impact of mass transfer limitations on size distributions of particle associated SVOCs in outdoor and indoor environments

    DEFF Research Database (Denmark)

    Liu, Cong; Zhang, Yinping; Weschler, Charles J.

    2014-01-01

    Semi-volatile organic compounds (SVOCs) partition between the gas phase and airborne particles. The size distribution of particle-associated SVOCs impacts their fate in outdoor and indoor environments, as well as human exposure to these compounds and subsequent health risks. Allen et al. (1996......) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC....../particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas-particle equilibrium relative to the residence time...

  6. Using GC×GC-ToF-MS to characterise SVOC from diesel exhaust emissions

    Science.gov (United States)

    Alam, M. S.; Ramadhas, A. S.; Stark, C. P.; Liu, D.; Xu, H.; Harrison, R. M.

    2014-12-01

    Despite intensive research over the last 20 years, a number of major research questions remain concerning the sources and properties of road traffic-generated particulate matter. There are major knowledge gaps concerning the composition of primary vehicle exhaust aerosol, and its contribution to secondary organic aerosol (SOA) formation. These uncertainties relate especially to the semi-volatile component of the particles. Semi-Volatile Organic Compounds (SVOC) are compounds which partition directly between the gas and aerosol phases under ambient conditions, and include compounds with saturation concentrations roughly between 0.1 and 104 μg m-3. The SVOC in engine exhaust are typically hydrocarbons in the C15-C35 range. They are largely uncharacterised, other than the n-alkanes, because they are unresolved by traditional gas chromatography and form a large hump in the chromatogram referred to as Unresolved Complex Mixture (UCM). In this study, samples were collected from the exhaust of a diesel engine with and without abatement devices fitted. Engine exhaust was diluted with air and collected using both filter and impaction (MOUDI), to resolve total mass and size resolved mass respectively. Particle size distribution was evaluated by sampling simultaneously with a Scanning Mobility Particle Sizer (SMPS). 2D Gas-Chromatography Time-of-Flight Mass-Spectrometry (GC×GC-ToF-MS) was exploited to characterise and quantify the composition of SVOC from the exhaust emission. The SVOC was observed to contain predominantly n-alkanes, alkyl-cyclohexanes and aromatics; similar to both fresh lubricating oil and fuel. Preliminary results indicate that the contribution of diesel fuel to the exhaust SVOC composition is dominant at high speeds, and a more pronounced contribution from lubricating oil is observed at low speeds. Differences were also observed in the SVOC composition when using different fuel types, engine lubricants, starting temperatures and collecting samples with

  7. The impact of mass transfer limitations on size distributions of particle associated SVOCs in outdoor and indoor environments.

    Science.gov (United States)

    Liu, Cong; Zhang, Yinping; Weschler, Charles J

    2014-11-01

    Semi-volatile organic compounds (SVOCs) partition between the gas phase and airborne particles. The size distribution of particle-associated SVOCs impacts their fate in outdoor and indoor environments, as well as human exposure to these compounds and subsequent health risks. Allen et al. (1996) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC/particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas-particle equilibrium relative to the residence time of particles. The higher this ratio, the greater the influence of mass transfer limitations on the size distribution of particle-associated SVOCs. The influence of such constraints is largest on the fraction of particle-associated SVOCs in the coarse mode (>2 μm). Predictions from the model have been found to be in reasonable agreement with size distributions measured for PAHs at roadside and suburban locations in Japan. The model also quantitatively explains shifts in the size distributions of particle associated SVOCs compared to those for particle mass, and the manner in which these shifts vary with temperature and an SVOC's molecular weight. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. HAZE AT OCCATOR CRATER ON DWARF PLANET CERES

    Energy Technology Data Exchange (ETDEWEB)

    Thangjam, G.; Hoffmann, M.; Nathues, A.; Platz, T. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077, Goettingen (Germany); Li, J.-Y., E-mail: thangjam@mps.mpg.de, E-mail: hoffmann@mps.mpg.de, E-mail: nathues@mps.mpg.de, E-mail: platz@mps.mpg.de, E-mail: jyli@psi.edu [Planetary Science Institute, 1700 East Fort Lowell Rd., Suite 106, Tucson, AZ 85719-2395 (United States)

    2016-12-20

    A diurnal varying haze layer at the bright spots of Occator on dwarf planet Ceres has been reported from images of the Dawn Framing Camera. This finding is supported by ground-based observations revealing diurnal albedo changes at Occator’s longitude. In the present work, we further investigate the previously reported haze phenomenon in more detail using additional Framing Camera images. We demonstrate that the light scattering behavior at the central floor of Occator is different compared to a typical cerean surface and is likely inconsistent with a pure solid surface scatterer. The identified deviation is best explained by an additional component to the scattered light of the surface, i.e., a haze layer. Our results support the water vapor detection by Herschel observations though the existence of a tenuous cerean exosphere is not yet confirmed.

  9. The Persistence of Hazing in the Military

    Science.gov (United States)

    2013-04-25

    young boys he observed; ca. 530, Justinian, the Byzantine emperor who codified Roman law, creed that the hazing of first-year law students must be ended...levels of hazing. Every kind of high school group was involved in hazing including 24% of the students involved in church groups. 10% of all

  10. Comparison of physical and chemical properties of ambient aerosols during the 2009 haze and non-haze periods in Southeast Asia.

    Science.gov (United States)

    Xu, Jingsha; Tai, Xuhong; Betha, Raghu; He, Jun; Balasubramanian, Rajasekhar

    2015-10-01

    Recurrent smoke-haze episodes that occur in Southeast Asia (SEA) are of much concern because of their environmental and health impacts. These haze episodes are mainly caused by uncontrolled biomass and peat burning in Indonesia. Airborne particulate matter (PM) samples were collected in the southwest coast of Singapore from 16 August to 9 November in 2009 to assess the impact of smoke-haze episodes on the air quality due to the long-range transport of biomass and peat burning emissions. The physical and chemical characteristics of PM were investigated during pre-haze, smoke-haze, and post-haze periods. Days with PM2.5 mass concentrations of ≥35 μg m(-3) were considered as smoke-haze events. Using this criterion, out of the total 82 sampling days, nine smoke-haze events were identified. The origin of air masses during smoke-haze episodes was studied on the basis of HYSPLIT backward air trajectory analysis for 4 days. In terms of the physical properties of PM, higher particle surface area concentrations and particle gravimetric mass concentrations were observed during the smoke-haze period, but there was no consistent pattern for particle number concentrations during the haze period as compared to the non-haze period except that there was a significant increase at about 08:00, which could be attributed to the entrainment of PM from aloft after the breakdown of the nocturnal inversion layer. As for the chemical characteristics of PM, among the six key inorganic water-soluble ions (Cl(-), NO3(-), nss-SO4(2-), Na(+), NH4(+), and nss-K(+)) measured in this study, NO3(-), nss-SO4(2-), and NH4(+) showed a significant increase in their concentrations during the smoke-haze period together with nss-K(+). These observations suggest that the increased atmospheric loading of PM with higher surface area and increased concentrations of optically active secondary inorganic aerosols [(NH4)2SO4 or NH4HSO4 and NH4NO3] resulted in the atmospheric visibility reduction in SEA due to

  11. Understanding the Southeast Asian haze

    Science.gov (United States)

    G, Karthik K. R.; Baikie, T.; T, Mohan Dass E.; Huang, Y. Z.; Guet, C.

    2017-08-01

    The Southeast Asian region had been subjected to a drastic reduction in air quality from the biomass burnings that occurred in 2013 and 2015. The smoke from the biomass burnings covered the entire region including Brunei, Indonesia, Malaysia, Singapore and Thailand, with haze particulate matter (PM) reducing the air quality to hazardous levels. Here we report a comprehensive size-composition-morphology characterization of the PM collected from an urban site in Singapore during the two haze events. The two haze events were a result of biomass burning and occurred in two different geographical source regions. We show the similarities and variations of particle size distribution during hazy and clear days during the two haze events. Sub-micron particles (composed of carbon (˜51%) and other elements pertaining to the earth’s crust. The complexity of the mixing state of the PM is highlighted and the role of the capture mode is addressed. We also present the morphological characterization of all the classified PM. The box counting method is used to determine the fractal dimensions of the PM, and the dimensionality varied for every classification from 1.79 to 1.88. We also report the complexities of particles and inconsistencies in the existing approaches to understand them.

  12. The exchange of SVOCs across the air-sea interface in Singapore's coastal environment

    Directory of Open Access Journals (Sweden)

    J. He

    2010-02-01

    Full Text Available Coastal areas are vulnerable to the accumulation of semivolatile organic compounds, such as PAHs, OCPs and PCBs from atmospheric inputs. Dry particulate and wet depositions, and air-water diffusive exchange in the Singapore's south coastal area, where most of chemical and oil refinery industries are situated in, were estimated. Based on a yearly dataset, the mean annual dry particulate deposition fluxes of ∑16-PAHs, ∑7 OCPs and ∑21 PCBs were 1328.8±961.1 μg m−2 y−1, 5421.4±3426.7 ng m−2 y−1 and 811.8±578.3 ng m−2 y−1, and the wet deposition of ∑16-PAHs and ∑7 OCPs were 6667.1±1745.2 and 115.4±98.3 μg m−2 y−1, respectively. Seasonal variation of atmospheric depositions was influenced by meteorological conditions. Air-water gas exchange fluxes were shown to be negative values for PAHs, HCHs and DDXs, indicating Singapore's south coast as a sink for the above-mentioned SVOCs. The relative contribution of each depositional process to the total atmospheric input was assessed by annual fluxes. The profile of dry particulate deposition, wet deposition and gas exchange fluxes seemed to be correlated with individual pollutant's properties such as molecular weight and Henry's law constant, etc. For the water column partitioning, the organic carbon-normalized partition coefficients between particulate and dissolved phases (KOC for both PAHs and OCPs were obtained. The relationships between KOC of PAHs and OCPs and their respective octanol-water partition coefficient (KOW were examined. In addition, both adsorption onto combustion-derived soot carbon and absorption into natural organic matter for PAHs in marine water column were investigated. Enrichment factors in the sea-surface microlayer (SML of the particulate phase were 1.2

  13. Effects of fuels, engine load and exhaust after-treatment on diesel engine SVOC emissions and development of SVOC profiles for receptor modeling

    Science.gov (United States)

    Huang, Lei; Bohac, Stanislav V.; Chernyak, Sergei M.; Batterman, Stuart A.

    2015-01-01

    Diesel exhaust emissions contain numerous semivolatile organic compounds (SVOCs) for which emission information is limited, especially for idling conditions, new fuels and the new after-treatment systems. This study investigates exhaust emissions of particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and sterane and hopane petroleum biomarkers from a heavy-duty (6.4 L) diesel engine at various loads (idle, 600 and 900 kPa BMEP), with three types of fuel (ultra-low sulfur diesel or ULSD, Swedish low aromatic diesel, and neat soybean biodiesel), and with and without a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF). Swedish diesel and biodiesel reduced emissions of PM2.5, Σ15PAHs, Σ11NPAHs, Σ5Hopanes and Σ6Steranes, and biodiesel resulted in the larger reductions. However, idling emissions increased for benzo[k]fluoranthene (Swedish diesel), 5-nitroacenaphthene (biodiesel) and PM2.5 (biodiesel), a significant result given the attention to exposures from idling vehicles and the toxicity of high-molecular-weight PAHs and NPAHs. The DOC + DPF combination reduced PM2.5 and SVOC emissions during DPF loading (>99% reduction) and DPF regeneration (83–99%). The toxicity of diesel exhaust, in terms of the estimated carcinogenic risk, was greatly reduced using Swedish diesel, biodiesel fuels and the DOC + DPF. PAH profiles showed high abundances of three and four ring compounds as well as naphthalene; NPAH profiles were dominated by nitro-naphthalenes, 1-nitropyrene and 9-nitroanthracene. Both the emission rate and the composition of diesel exhaust depended strongly on fuel type, engine load and after-treatment system. The emissions data and chemical profiles presented are relevant to the development of emission inventories and exposure and risk assessments. PMID:25709535

  14. Chemical characteristics of PM2.5 during haze episodes in Beijing

    Science.gov (United States)

    Shen, Rongrong; Schaefer, Klaus; Suppan, Peter; Wang, Yuesi; Schnelle-Kreis, Jürgen; Shao, Longyi; Emeis, Stefan

    2014-05-01

    Haze episodes have become much more frequent in Beijing and have received more attention during the past decade because of its influences on visibility and human health. Due to the chemical characteristics and sources of haze, which are different from the normal urban aerosols, studies of haze pollution become more important for the control of air pollution in Beijing. This study aims to investigate the chemical characteristics of PM2.5 during haze episodes in Beijing in 2013 spring and the possible sources of chemical compounds during haze episodes. Two sequential High-Volume Samplers (Digitel DHA-80, Hegnau, Switzerland) were used to collect PM2.5 samples in Beijing automatically from 10 April to 8 June 2013. The inorganic elements, inorganic water-soluble ions, EC and OC of PM2.5 were analyzed by ICP-MS, IC and thermal/optical carbon analyzers respectively. Three haze episodes were found: 18 to 25 April, 3 to 9 May and 1 to 8 June. The average PM2.5 mass concentration during haze days was 140 µg m-3 while 45 µg m-3 during clear days. SO42-, NO3-, NH4+, Cl-, K+, Cu, Ni, Zn, As, Cd, Tl, Pb, EC and OC, mass concentrations increased during haze days, compared with concentrations during clear days. The main increase is that secondary inorganic pollutant mass concentrations (NO3-, SO42- and NH4+) were 6 times higher and mass percentages were 2 times higher. This indicates that the major chemical species of PM2.5 during haze episodes are originated from anthropogenic sources. NO3-, SO42- and NH4+ are basically formed by a gas-to-particle formation processes on the basis of chemical reactions of precursor gases. Mass ratio of NO3-/SO42- is widely used as an indicator to determine the importance of mobile sources and stationary sources of sulphur and nitrogen. The mass ratio of NO3-/SO42- during haze days (0.82) was higher than during clear days (0.68) suggesting that vehicle emission is an important reason for haze in Beijing. OC/EC mass ratio higher than 2 indicates

  15. Hazing in the U.S. Armed Forces: Recommendations for Hazing Prevention Policy and Practice

    Science.gov (United States)

    2015-01-01

    Preventing Hazing: How Parents , Teachers , and Coaches Can Stop the Violence, Harassment, and Humiliation, San Francisco, Calif.: Jossey-Bass, 2006. 120...which actions may be identied as hazing, and this subjectivity may contribute to subsequent disagreement and confusion regarding hazing (Pelletier...to enlist their aid in creating a no- hazing culture. Because of legal liability, national-level parent orga- nizations have a high stake in

  16. Arctic Haze: Natural or Pollution?

    Science.gov (United States)

    1986-11-01

    Atmospheric Environmet 15, 1407-1419. Barrie et al. (1985) have extended the original Berg W, W., Heidt L E, Pollock W, Sperry P. D., Cicerone R. historical...much more ive influences upon the surface-troposphere radiation widely than it was a few years ago, and is generally budget. Atmoshric Environmet 27...contributing to the March 1983 Arctic haze Alaskan Arctic, spring 1983. Atmospheric Environmet 19. episode. Atmospheric Environment 19, 2121-2126. 2159

  17. Role of clothing in both accelerating and impeding dermal absorption of airborne SVOCs.

    Science.gov (United States)

    Morrison, Glenn C; Weschler, Charles J; Bekö, Gabriel; Koch, Holger M; Salthammer, Tunga; Schripp, Tobias; Toftum, Jørn; Clausen, Geo

    2016-01-01

    To assess the influence of clothing on dermal uptake of semi-volatile organic compounds (SVOCs), we measured uptake of selected airborne phthalates for an individual wearing clean clothes or air-exposed clothes and compared these results with dermal uptake for bare-skinned individuals under otherwise identical experimental conditions. Using a breathing hood to isolate dermal from inhalation uptake, we measured urinary metabolites of diethylphthalate (DEP) and di-n-butylphthalate (DnBP) from an individual exposed to known concentrations of these compounds for 6 h in an experimental chamber. The individual wore either clean (fresh) cotton clothes or cotton clothes that had been exposed to the same chamber air concentrations for 9 days. For a 6-h exposure, the net amounts of DEP and DnBP absorbed when wearing fresh clothes were, respectively, 0.017 and 0.007 μg/kg/(μg/m(3)); for exposed clothes the results were 0.178 and 0.261 μg/kg/(μg/m(3)), respectively (values normalized by air concentration and body mass). When compared against the average results for bare-skinned participants, clean clothes were protective, whereas exposed clothes increased dermal uptake for DEP and DnBP by factors of 3.3 and 6.5, respectively. Even for non-occupational environments, wearing clothing that has adsorbed/absorbed indoor air pollutants can increase dermal uptake of SVOCs by substantial amounts relative to bare skin.

  18. The status of soil contamination by semivolatile organic chemicals (SVOCs) in China: A review

    Energy Technology Data Exchange (ETDEWEB)

    Cai Quanying [College of Resources and Environment, South China Agricultural University, Guangzhou 510642 (China)], E-mail: cai_quanying@yahoo.com; Mo Cehui [Department of Environmental Engineering, Jinan University, Guangzhou 510632 (China)], E-mail: tchmo@jnu.edu.cn; Wu Qitang [College of Resources and Environment, South China Agricultural University, Guangzhou 510642 (China); Katsoyiannis, Athanasios [European Commission, Joint Research Centre, Institute for Health and Consumer Protection (IHCP), Physical and Chemical Exposure Unit, Ispra (Vatican City State, Holy See,), TP-281, Via E. Fermi 1, I-21020 (Italy)], E-mail: athanasios.katsogiannis@jrc.it; Zeng Qiaoyun [College of Resources and Environment, South China Agricultural University, Guangzhou 510642 (China)

    2008-01-25

    This paper summarizes the published scientific data on the soil contamination by semivolatile organic chemicals (SVOCs) in China. Data has been found for more than 150 organic compounds which were grouped into six classes, namely, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and phthalic acid esters (PAEs). An overview of data collected from the literature is presented in this paper. The Chinese regulation and/or other maximum acceptable values for SVOCs were used for the characterization of soils. In general, the compounds that are mostly studied in Chinese soils are OCPs, PAHs and PCBs. According to the studies reviewed here, the most abundant compounds were PAEs and PAHs (up to 46 and 28 mg kg{sup -1} dry weight, respectively); PCBs and OCPs occurred generally at concentrations lower than 100 {mu}g kg{sup -1} dry weight. Nevertheless, quite high concentrations of PCDD/Fs, PCBs and PBDEs were observed in contaminated sites (e.g., the sites affected by electronic waste activities). The average concentrations of PAHs and OCPs in soils of North China were higher than those in South China. The principal component analysis demonstrated different distribution patterns for PAH, PCB and PCDD/F congeners and for the various sites/regions examined. The isomer ratios of DDTs and hexachlorocyclohexanes (HCHs) indicated different sources and residue levels in soils. Finally, this review has highlighted several areas where further research is considered necessary.

  19. Uncertainties in monitoring of SVOCs in air caused by within-sampler degradation during active and passive air sampling

    Science.gov (United States)

    Melymuk, Lisa; Bohlin-Nizzetto, Pernilla; Prokeš, Roman; Kukučka, Petr; Přibylová, Petra; Vojta, Šimon; Kohoutek, Jiří; Lammel, Gerhard; Klánová, Jana

    2017-10-01

    Degradation of semivolatile organic compounds (SVOCs) occurs naturally in ambient air due to reactions with reactive trace gases (e.g., ozone, NOx). During air sampling there is also the possibility for degradation of SVOCs within the air sampler, leading to underestimates of ambient air concentrations. We investigated the possibility of this sampling artifact in commonly used active and passive air samplers for seven classes of SVOCs, including persistent organic pollutants (POPs) typically covered by air monitoring programs, as well as SVOCs of emerging concern. Two active air samplers were used, one equipped with an ozone denuder and one without, to compare relative differences in mass of collected compounds. Two sets of passive samplers were also deployed to determine the influence of degradation during longer deployment times in passive sampling. In active air samplers, comparison of the two sampling configurations suggested degradation of particle-bound polycyclic aromatic hydrocarbons (PAHs), with concentrations up to 2× higher in the denuder-equipped sampler, while halogenated POPs did not have clear evidence of degradation. In contrast, more polar, reactive compounds (e.g., organophosphate esters and current use pesticides) had evidence of losses in the sampler with denuder. This may be caused by the denuder itself, suggesting sampling bias for these compounds can be created when typical air sampling apparatuses are adapted to limit degradation. Passive air samplers recorded up to 4× higher concentrations when deployed for shorter consecutive sampling periods, suggesting that within-sampler degradation may also be relevant in passive air monitoring programs.

  20. [The monitoring of haze from HJ-1].

    Science.gov (United States)

    Wang, Zhong-ting; Li, Qing; Li, Shen-shen; Chen, Liang-fu; Zhou, Chun-yan; Wang, Zi-feng; Zhang, Li-juan

    2012-03-01

    With the urbanizing in China, haze days occur frequently, which have largely impacted air quality. In the present paper, based on haze physical properties, haze optical properties were calculated by Mie theory and apparent reflectance of haze in Environment Satellite 1 (HJ-1) channels was simulated by Radiative Transfer (RT) 3. Simulated results show that it is reasonable to extract the haze from apparent reflectance in the first and second channels. By Deep Blue algorithm, Haze Optical Depth (HOD) was retrieved from HJ-1 data supported by reflectance database from MODIS product. From HJ-1 data in 2009 over Beijing area, the haze days were monitored and validated by AERONET/PHOTONS Beijing site. The validation shows that the correlation coefficient of HOD is greater than 0.9, but HOD from HJ-1 is greater than that from ground-based measurements. The discussions show that the error from reflectance database is less than 0.1 and radiance resolution of HJ-1 needs to advance for haze monitoring.

  1. Determinations of Titan's Methane and Haze Variability

    Science.gov (United States)

    Penteado, Paulo F.; Griffith, C.; Tomasko, M.; Engel, S.; See, C.; Doose, L.; VIMS Team

    2009-09-01

    Titan's atmosphere presents a complex and variable meteorology, with a variety of methane clouds detected in ground-based and Cassini near-IR observations. Its thick haze has been observed to vary seasonally, producing a strong variable effect on the radiative balance, dynamics and chemistry of the atmosphere. To understand how the methane cycle and the atmospheric variability, it becomes necessary to measure the methane and haze distribution. In this work, we analyze complementary observations to constrain the variation of the methane and haze: 1) ground-based spectra that resolve the variation of the CH3D band at 1600 nm, obtained with the Near Infrared Spectrograph (NIRSPEC) with adaptive optics at the Keck II telescope, constrain the methane abundance in the lowest 10 kmof the atmosphere. 2) Cassini VIMS (Visual and Infrared Mapping Spectrometer) observations at 400-1600 nm sampleregions of varied methane and haze optical depths, enough to partially constrain the profiles of the haze, and the upper tropospheric (20-50 km altitude) methane. The CH3D observations show no methane variation larger than 20% below 10 km altitude over 32S-32N latitudes. In the VIMS observations there is an ambiguity between the methane and haze abundances. The observations can be reproduced with no methane variation, and a haze density increase of 60% between 20S and 10S. The largest methane variation allowed by the data, derived assuming no haze variation with latitude, is a drop of 60% over latitudes 27S to 19N. To further constrain the range of possible methane and haze profiles, we also present an initial analysis of VIMS limb observations, which resolve the vertical structure of the atmosphere, and thus separate the spectral changes that originate at the troposphere (mostaffected by the methane) from those that originate at the stratosphere (most affected by the haze). Work supported by NASA, CAPES and FAPESP.

  2. Desorption of SVOCs from Heated Surfaces in the Form of Ultrafine Particles

    DEFF Research Database (Denmark)

    Wallace, Lance A.; Ott, Wayne R.; Weschler, Charles J.

    2017-01-01

    Ultrafine particles (UFP) produced by electric heating of stoves and metal cooking pans, absent food, have been hypothesized to be created from a surface film of semivolatile organic compounds (SVOCs) sorbed from the surrounding air. This study tests that hypothesis by size-resolved measurements...... extending the lower range of the UFP studied from 10 to 2.3 nm, and including other surfaces (glass, aluminum, and porcelain). Heating glass Petri dishes or squares of aluminum foil to about 350-400 degrees C for 4-6 min removed all sorbed organic substances completely. Subsequent exposure of these "clean......" Petri dishes and foil squares to indoor air in two different residences for successively longer periods (1 h to 281 days), followed by heating the materials for 4-6 min, indicated a strong relationship of the number, size distribution, and mass of the UFP to the time exposed. Estimates...

  3. Phase shift improvement in ArF/KrF haze-free mask cleaning

    Science.gov (United States)

    Liu, Cathy; Zhao, Shirley; Guo, Eric; Hasegawa, Shinichi; Nemoto, Keiichi; Kuwajima, Tsuneaki

    2008-10-01

    The continuous evolution of LSI design rules has created an increased demand for the use of KrF and ArF phase-shift photomasks (EPSMs). One of the critical issues in the use of those photomasks, especially ArF half-tone photomasks, has been the generation of optical hazes known as (NH4)2SO4. The other critical issue has been a relatively large phase shift of those ArF and KrF photomasks caused by so-called haze-free mask cleaning.. In the present study we used an SPM integrated clean (as a reference) consisting of heated SPM, diluted SC-1 and heated UPW (widely known for rinsing), and a haze-free integrated mask clean consisting of Ozonated-water with a simultaneous 222nm Excimer UV irradiation, diluted SC-1 and heated UPW. We found that both Ozonated-water with a simultaneous 222nm Excimer UV irradiation and the diluted SC-1 (the components of the haze-free integrated clean) caused a sizable phase shift during the mask clean. We also found that the other component of the haze-free integrated clean, the heated UPW developed a relatively large phase shift in those photomasks. We have confirmed that the more we repeat the use of the 172nm Excimer UV light irradiation treatment before the clean, the less (more improved) phase shift has been realized in the haze-free clean. We found that the haze-free integrated clean also developed the CD shifts of the above photomasks and that those CD shifts could be recovered (reduced) drastically by the use of the 172nm Excimer UV light irradiation before the clean.

  4. Insights into a historic severe haze weather in Shanghai: synoptic situation, boundary layer and pollutants

    Science.gov (United States)

    Leng, C.; Duan, J.; Xu, C.; Zhang, H.; Zhang, Q.; Wang, Y.; Li, X.; Kong, L.; Tao, J.; Cheng, T.; Zhang, R.; Chen, J.

    2015-11-01

    A historic winter haze weather, characterized by long duration, large scale and strong pollution intensity, occurred in the Yangtze River Delta (YRD) region of China during the time frame of 1 to 10 December 2013. This severe haze event constituted of several hazy episodes and significantly influenced air quality throughout the region, especially in urban areas. Aerosol physical, chemical and optical properties were measured in Shanghai, where the instantaneous particulate mass burden per volume (e.g. PM2.5) exceeded 600 μg m-3 in some time, breaking the existing historical observation records, and examined to give insights into severe haze weathers. Inorganic water-soluble ions in particles, trace gases and aerosol scattering/absorption coefficients had the same tendency to increase evidently from clear episodes to hazy episodes. A combination of various factors contributed to the formation and evolution of the severe haze, among which meteorological conditions, local anthropogenic emissions and aerosol properties played the major roles. During the haze weather, the YRD region was under the control of a high-pressure system with extremely small surface pressure gradients. The calm surface wind and subsidence airflow were responsible for decreasing planetary boundary layer (PBL) height and constructive to the build-up of air pollutants wandering inside the region, and ultimately induced the haze occurrence. Nonlinear regression analyses indicated that single water-soluble ion did not correlated with the atmospheric visibility degradation so strong, while high ambient relative humidity (RH) indeed exerted a great impact with a correlation coefficient (R2) of 0.41. Moreover, the close relationship was derived between atmospheric visibility and aerosols in size of 600-1400 nm with R2 of 0.70, which further improved to 0.73 when combined aerosol hygroscopicity. This study may provide supports for the public and authorities to recognize severe haze weathers in urban

  5. Planetary science: Haze cools Pluto's atmosphere

    Science.gov (United States)

    West, Robert A.

    2017-11-01

    Modelling suggests that Pluto's atmospheric temperature is regulated by haze, unlike the other planetary bodies in the Solar System. The finding has implications for our understanding of exoplanetary atmospheres. See Letter p.352

  6. Regional Haze Plan for Texas and Oklahoma

    Science.gov (United States)

    EPA partially approved and partially disapproved the Texas regional haze plan. EPA also finalized a plan to limit sulfur dioxide emissions from eight Texas coal-fired electricity generating facilities

  7. Speciated atmospheric mercury on haze and non-haze days in an inland city in China

    Directory of Open Access Journals (Sweden)

    Q. Hong

    2016-11-01

    Full Text Available Long-term continuous measurements of speciated atmospheric mercury were conducted from July 2013 to June 2014 in Hefei, a midlatitude inland city in eastern central China that experiences frequent haze pollution. The mean concentrations (±standard deviation of gaseous elemental mercury (GEM, gaseous oxidized mercury (GOM and particle-bound mercury (PBM were 3.95 ± 1.93 ng m−3, 2.49 ± 2.41 and 23.3 ± 90.8 pg m−3, respectively, on non-haze days, and 4.74 ± 1.62 ng m−3, 4.32 ± 8.36 and 60.2 ± 131.4 pg m−3, respectively, on haze days. Potential source contribution function (PSCF analysis suggested that atmospheric mercury pollution on haze days was caused primarily by local emissions, instead of via long-range transport. The poorer mixing conditions on haze days also favored the accumulation of atmospheric mercury. Compared to GEM and GOM, PBM was especially sensitive to haze pollution. The mean PBM concentration on haze days was 2.5 times that on non-haze days due to elevated concentrations of particulate matter. PBM also showed a clear seasonal trend; its concentration was the highest in fall and winter, decreased rapidly in spring and was the lowest in summer, following the same order in the frequency of haze days in different seasons. On both non-haze and haze days, GOM concentrations remained low at night, but increased rapidly just before sunrise, which could be due to diurnal variation in air exchange between the boundary layer and free troposphere. However, non-haze and haze days showed different trends in daytime GEM and GOM concentrations. On non-haze days, GEM and GOM declined synchronously through the afternoon, probably due to the retreat of the free tropospheric air as the height of the atmospheric boundary layer increases. In contrast, on haze days, GOM and GEM showed opposite trends with the highest GOM and lowest GEM observed in the afternoon, suggesting the occurrence of

  8. The Impact of Clouds and Hazes in Substellar Atmospheres

    Science.gov (United States)

    Morley, Caroline; Fortney, Jonathan J.; Marley, Mark S.

    2016-01-01

    The formation of clouds significantly alters the spectra of cool substellar atmospheres from terrestrial planets to brown dwarfs. In cool planets like Earth and Jupiter, volatile species like water and ammonia condense to form ice clouds. In hot planets and brown dwarfs, iron and silicates instead condense, forming dusty clouds. Irradiated methane-rich planets may have substantial hydrocarbon hazes. During my thesis, I have studied the impact of clouds and hazes in a variety of substellar objects. First, I present results for cool brown dwarfs including clouds previously neglected in model atmospheres. Model spectra that include sulfide and salt clouds can match the spectra of T dwarf atmospheres; water ice clouds will alter the spectra of the newest and coldest brown dwarfs, the Y dwarfs. These sulfide/salt and ice clouds potentially drive spectroscopic variability in these cool objects, and this variability should be distinguishable from variability caused by hot spots.Next, I present results for small, cool exoplanets between the size of Earth and Neptune, so-called super Earths. They likely have sulfide and salt clouds and also have photochemical hazes caused by stellar irradiation. Vast resources have been dedicated to characterizing the handful of super Earths accessible to current telescopes, yet of the planets smaller than Neptune studied to date, all have radii in the near-infrared consistent with being constant in wavelength, likely showing that these small planets are consistently enshrouded in thick hazes and clouds. Very thick, lofted clouds of salts or sulfides in high metallicity (1000× solar) atmospheres create featureless transmission spectra in the near-infrared. Photochemical hazes with a range of particle sizes also create featureless transmission spectra at lower metallicities. I show that despite these challenges, there are promising avenues for understanding this class of small planets: by observing the thermal emission and reflectivity of

  9. Clouds and hazes in exoplanets and brown dwarfs

    Science.gov (United States)

    Morley, Caroline Victoria

    The formation of clouds significantly alters the spectra of cool substellar atmospheres from terrestrial planets to brown dwarfs. In cool planets like Earth and Jupiter, volatile species like water and ammonia condense to form ice clouds. In hot planets and brown dwarfs, iron and silicates instead condense, forming dusty clouds. Irradiated methane-rich planets may have substantial hydrocarbon hazes. During my dissertation, I have studied the impact of clouds and hazes in a variety of substellar objects. First, I present results for cool brown dwarfs including clouds previously neglected in model atmospheres. Model spectra that include sulfide and salt clouds can match the spectra of T dwarf atmospheres; water ice clouds will alter the spectra of the newest and coldest brown dwarfs, the Y dwarfs. These sulfide/salt and ice clouds potentially drive spectroscopic variability in these cool objects, and this variability should be distinguishable from variability caused by hot spots. Next, I present results for small, cool exoplanets between the size of Earth and Neptune. They likely have sulfide and salt clouds and also have photochemical hazes caused by stellar irradiation. Vast resources have been dedicated to characterizing the handful of super Earths and Neptunes accessible to current telescopes, yet of the planets smaller than Neptune studied to date, all have radii in the near-infrared consistent with being constant in wavelength, likely showing that these small planets are consistently enshrouded in thick hazes and clouds. For the super Earth GJ 1214b, very thick, lofted clouds of salts or sulfides in high metallicity (1000x solar) atmospheres create featureless transmission spectra in the near-infrared. Photochemical hazes also create featureless transmission spectra at lower metallicities. For the Neptune-sized GJ 436b, its thermal emission and transmission spectra combine indicate a high metallicity atmosphere, potentially heated by tides and affected by

  10. Haze episodes at Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    Keiichiro Hara

    2010-12-01

    Full Text Available During our aerosol measurement program at Syowa Station, Antarctica in 2004-2007, some low visibility (haze phenomena were observed under conditions with weak wind and without drifting snow and fog in winter-spring. In the "Antarctic haze" phenomenon, the number concentration of aerosol particles and black carbon concentration increased by one-two orders higher relative to background conditions at Syowa Station, while surface O_3 concentration simultaneously dropped especially after polar sunrise. Major aerosol constituents in the haze phenomenon were sea-salts (e.g., Na^+ and Cl^-. From the trajectory analysis and NAAPS model, the plumes from biomass burning in South America and southern Africa were transported to Syowa Station, Antarctic coast, during eastward (occasionally westward approach of cyclones in the Southern Ocean. Thus, poleward flow of the plume from mid-latitudes and injection of sea-salt particles during the transport may lead to the Antarctic haze phenomenon at Syowa Station. The difference of O_3 concentration between the background and the haze conditions tended to be larger in spring (polar sunrise relative to that in winter. Because enhancement of sea-salt particles can play an important role as an additional source of reactive halogen species, the haze episodes might make a significant contribution to surface O_3 depletion during the polar sunrise on the Antarctic coast.

  11. Role of secondary aerosols in haze formation in summer in the Megacity Beijing.

    Science.gov (United States)

    Han, Tingting; Liu, Xingang; Zhang, Yuanhang; Qu, Yu; Zeng, Limin; Hu, Min; Zhu, Tong

    2015-05-01

    A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibilityhaze episodes, which accounted for ~60% of the time during the whole campaign, were characterized by increases of SNA (sulfate, nitrate, and ammonium) and SOA (secondary organic aerosol) concentrations. The average values with standard deviation of SO4(2-), NO3-, NH4+ and SOA were 49.8 (±31.6), 31.4 (±22.3), 25.8 (±16.6) and 8.9 (±4.1)μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO4(2-), NO3-, NH4+, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about 27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR (sulfur oxidation ratio) and NOR (nitrogen oxidation ratio) increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO4(2-) and NO2 to NO3-, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing. Copyright © 2015. Published by Elsevier B.V.

  12. Role of clothing in both accelerating and impeding dermal absorption of airborne SVOCs

    DEFF Research Database (Denmark)

    Morrison, Glenn C.; Weschler, Charles J.; Bekö, Gabriel

    2016-01-01

    To assess the influence of clothing on dermal uptake of semi-volatile organic compounds (SVOCs), we measured uptake of selected airborne phthalates for an individual wearing clean clothes or air-exposed clothes and compared these results with dermal uptake for bare-skinned individuals under....... The individual wore either clean (fresh) cotton clothes or cotton clothes that had been exposed to the same chamber air concentrations for 9 days. For a 6-h exposure, the net amounts of DEP and DnBP absorbed when wearing fresh clothes were, respectively, 0.017 and 0.007 μg/kg/(μg/m3); for exposed clothes...... the results were 0.178 and 0.261 μg/kg/(μg/m3), respectively (values normalized by air concentration and body mass). When compared against the average results for bare-skinned participants, clean clothes were protective, whereas exposed clothes increased dermal uptake for DEP and DnBP by factors of 3.3 and 6...

  13. Theory and Simulation of Exoplanetary Atmospheric Haze: Giant Spectral Line Broadening

    Science.gov (United States)

    Sadeghpour, Hossein; Felfeli, Zineb; Kharchenko, Vasili; Babb, James; Vrinceanu, Daniel

    2018-01-01

    Prominent spectral features in observed transmission spectra of exoplanets are obscured. Atmospheric haze is the leading candidate for the flattening of spectral transmission of expolanetray occultation, but also for solar system planets, Earth and cometary atmospheres. Such spectra which carry information about how the planetary atmospheres become opaque to stellar light in transit, show broad absorption where strong absorption lines from sodium or potassium and water are predicted to exist. In this work, we develop a detailed atomistic theoretical model, taking into account interaction between an atomic or molecular radiator with dust and haze particulates. Our model considers a realistic structure of haze particulates from small seed particles up to sub-micron irregularly shaped aggregates. This theory of interaction between haze and radiator particles allows to consider nearly all realistic structure, size and chemical composition of haze particulates. The computed shift and broadening of emission spectra will include both quasi-static (mean field) and collisional (pressure) shift and broadening. Our spectral calculations will be verified with available laboratory experimental data on spectra of alkali atoms in liquid droplet, solid ice, dust and dense gaseous environments. The simplicity, elegance and generality of the proposed model makes it amenable to a broad community of users in astrophysics and chemistry. The verified models can be used for analysis of emission and absorption spectra of alkali atoms from exoplanets, solar system planets, satellites and comets.

  14. The pollution levels of BTEX and carbonyls under haze and non-haze days in Beijing, China.

    Science.gov (United States)

    Zhang, Yujie; Mu, Yujing; Meng, Fan; Li, Hong; Wang, Xuezhong; Zhang, Weiqi; Mellouki, Abdelwahid; Gao, Jian; Zhang, Xinmin; Wang, Shulan; Chai, Fahe

    2014-08-15

    The North China Plain including Beijing is frequently suffering from serious haze days in recent years. To best recognize the influence of haze days on regional air quality, the pollution levels of deleterious gases of BTEX (benzene, toluene, ethylbenzene, m,p-xylene and o-xylene) and carbonyls (formaldehyde, acetaldehyde and acetone) under haze and non-haze days were contrastively investigated during the period of September 2008-August 2010 in Beijing. In comparison with non-haze days, remarkable enhancement of BTEX and the carbonyls under haze days in winter was found, with enhancement factors of 1.9-5.7 for BTEX and of 1.5-4.2 for the carbonyls. Whereas the enhancement factors for both BTEX (1.0-3.0) and the carbonyls (1.2-1.9) under haze days in summer were relatively small. The ratios of each BTEX to CO under both haze days and non-haze days exhibited a minimal value in the afternoon, whereas maximal values for the ratios of the carbonyls to CO were usually found in the afternoon. The ratios of each BTEX to CO were extremely greater under haze days than those under non-haze days in winter, but no evident difference was found in summer. The ratios of each carbonyl under both haze days and non-haze days in summer were at least a factor of 2 greater than those in winter and only enhancement of the ratios under haze days was found in winter. The remarkably higher ratios of ethylbenzene to m,p-xylene under haze days than non-haze days in both winter and summer revealed high reactivity of photochemical reactions initiated by OH radicals under haze days. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Insights into a historic severe haze event in Shanghai: synoptic situation, boundary layer and pollutants

    OpenAIRE

    Leng, Chunpeng; Duan, Junyan; Xu, Chen; Zhang, Hefeng; Wang, Yifan; Wang, Yanyu; Li, Xiang; Kong, Lingdong; Tao, Jun; Zhang, Renjian; Cheng, Tiantao; Zha, Shuping; Yu, Xingna

    2016-01-01

    A historic haze event, characterized by lengthy, large-scale and severe pollution, occurred in the Yangtze River Delta (YRD) of China from 1 to 10 December 2013. This haze event significantly influenced air quality throughout the region, especially in urban areas. Aerosol physical, chemical and optical properties were measured in Shanghai. Sometimes the 1 h average particle concentration (e.g., PM2.5) exceeded 600 µg m−3. Inorganic water-soluble ions in particles, trace gase...

  16. Mt. Kelud haze removal using color attenuation prior

    Science.gov (United States)

    Fresy, N.; Yuniarno, Eko M.; Supeno, M. S. N.; Hariadi, M.

    2017-03-01

    Kelud crater observation using closed-circuit television (CCTV) has not been used as the main guide in the world of volcanology. This is caused by observations manually by volcanologist who is not certain and depends on their ability and experience. In practice, there is still obstacles haze in the image taken from CCTV record. This paper present color attenuation prior method to eliminate haze on the digital image. The results obtained showed that the selected method is capable of eliminating sparse haze and moderate haze but not dense haze.

  17. CORRECTION OF ATMOSPHERIC HAZE IN RESOURCESAT-1 LISS-4 MX DATA FOR URBAN ANALYSIS: AN IMPROVED DARK OBJECT SUBTRACTION APPROACH

    Directory of Open Access Journals (Sweden)

    S. Mustak

    2013-09-01

    Full Text Available The correction of atmospheric effects is very essential because visible bands of shorter wavelength are highly affected by atmospheric scattering especially of Rayleigh scattering. The objectives of the paper is to find out the haze values present in the all spectral bands and to correct the haze values for urban analysis. In this paper, Improved Dark Object Subtraction method of P. Chavez (1988 is applied for the correction of atmospheric haze in the Resoucesat-1 LISS-4 multispectral satellite image. Dark object Subtraction is a very simple image-based method of atmospheric haze which assumes that there are at least a few pixels within an image which should be black (% reflectance and such black reflectance termed as dark object which are clear water body and shadows whose DN values zero (0 or Close to zero in the image. Simple Dark Object Subtraction method is a first order atmospheric correction but Improved Dark Object Subtraction method which tends to correct the Haze in terms of atmospheric scattering and path radiance based on the power law of relative scattering effect of atmosphere. The haze values extracted using Simple Dark Object Subtraction method for Green band (Band2, Red band (Band3 and NIR band (band4 are 40, 34 and 18 but the haze values extracted using Improved Dark Object Subtraction method are 40, 18.02 and 11.80 for aforesaid bands. Here it is concluded that the haze values extracted by Improved Dark Object Subtraction method provides more realistic results than Simple Dark Object Subtraction method.

  18. Hygroscopic analysis of individual Beijing haze aerosol particles by environmental scanning electron microscopy

    Science.gov (United States)

    Bai, Zhangpeng; Ji, Yuan; Pi, Yiqun; Yang, Kaixiang; Wang, Li; Zhang, Yinqi; Zhai, Yadi; Yan, Zhengguang; Han, Xiaodong

    2018-01-01

    Investigating the hygroscopic behavior of haze aerosol particles is essential for understanding their physicochemical properties and their impacts on regional weather and visibility. An environmental scanning electron microscope equipped with a home-made transmission-scattering electron imaging setup and an energy dispersive spectrometer was used for in-situ observations of pure water-soluble (WS) salts and Beijing haze particles. This imaging setup showed obvious advantages for improving the resolution and acquiring internal information of mixed particles in hydrated environments. We measured the deliquescence relative humidity of pure NaCl, NH4NO3, and (NH4)2SO4 by deliquescence-crystallization processes with an accuracy of up to 0.3% RH. The mixed haze particles showed hygroscopic activation like water uptake and morphological changes when they included WS components such as nitrates, sulfates, halides, ammoniums, and alkali metal salts. In addition, the hygroscopic behavior provides complementary information for analyzing possible phases in mixed haze particles.

  19. Polycyclic aromatic hydrocarbons - fate and long-range atmospheric transport studied using a global model, EMAC-SVOC

    Science.gov (United States)

    Octaviani, Mega; Tost, Holger; Lammel, Gerhard

    2017-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are emitted by incomplete combustion from fossil fuel, vehicles, and biomass burning. They may persist in environmental compartments, pose a health hazard and may bio accumulate along food chains. The ECHAM/MESSy Atmospheric Chemistry (EMAC) model had been used to simulate global tropospheric, stratospheric chemistry and climate. In this study, we improve the model to include simulations of the transport and fate of semi-volatile organic compounds (SVOC). The EMAC-SVOC model takes into account essential environmental processes including gas-particle partitioning, dry and wet deposition, chemical and bio-degradation, and volatilization from sea surface, soils, vegetation, and snow. The model was evaluated against observational data in the Arctic, mid-latitudes, and tropics, and further applied to study total environmental lifetime and long-range transport potential (LRTP) of PAHs. We selected four compounds for study, spanning a wide range of volatility, i.e., phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene. Several LRTP indicators were investigated, including the Arctic contamination potential, meridional spreading, and zonal and meridional fluxes to remote regions.

  20. Archean Earth Atmosphere Fractal Haze Aggregates: Light Scattering Calculations and the Faint Young Sun Paradox

    Science.gov (United States)

    Boness, D. A.; Terrell-Martinez, B.

    2010-12-01

    As part of an ongoing undergraduate research project of light scattering calculations involving fractal carbonaceous soot aggregates relevant to current anthropogenic and natural sources in Earth's atmosphere, we have read with interest a recent paper [E.T. Wolf and O.B Toon,Science 328, 1266 (2010)] claiming that the Faint Young Sun paradox discussed four decades ago by Carl Sagan and others can be resolved without invoking heavy CO2 concentrations as a greenhouse gas warming the early Earth enough to sustain liquid water and hence allow the origin of life. Wolf and Toon report that a Titan-like Archean Earth haze, with a fractal haze aggregate nature due to nitrogen-methane photochemistry at high altitudes, should block enough UV light to protect the warming greenhouse gas NH3 while allowing enough visible light to reach the surface of the Earth. To test this hypothesis, we have employed a rigorous T-Matrix arbitrary-particle light scattering technique, to avoid the simplifications inherent in Mie-sphere scattering, on haze fractal aggregates at UV and visible wavelenths of incident light. We generate these model aggregates using diffusion-limited cluster aggregation (DLCA) algorithms, which much more closely fit actual haze fractal aggregates than do diffusion-limited aggregation (DLA) algorithms.

  1. Investigation of the sources and evolution processes of severe haze pollution in Beijing in January 2013

    National Research Council Canada - National Science Library

    Sun, Yele; Jiang, Qi; Wang, Zifa; Fu, Pingqing; Li, Jie; Yang, Ting; Yin, Yan

    2014-01-01

    China experienced severe haze pollution in January 2013. Here we have a detailed characterization of the sources and evolution mechanisms of this haze pollution with a focus on four haze episodes that occurred during 10...

  2. Aerosol Optical Properties Based on Ground and Satellite Retrievals during a Serious Haze Episode in December 2015 over Beijing

    Directory of Open Access Journals (Sweden)

    Ke Gui

    2016-05-01

    Full Text Available An extreme haze event occurred in the Beijing area from 17 to 23 December 2015. Ground-based measurements and satellite observations during this event were used to further our understanding of the formation process of haze pollution and aerosol optical properties. The results suggest that high relative humidity, poor diffusion conditions (low wind speed and stable stratification and favorable secondary transformation conditions under the hygroscopic growth of aerosol and high emissions led to this serious haze episode. During the haze period, the daily average value was 1.15 and 0.42 for aerosol optical depth (AOD500nm and columnar water-vapor (CWV, in cm, respectively. On 19 December, the correlation coefficient between CWV and AOD500nm was 0.91, indicating the effect of hygroscopic growth of fine-mode articles. The daily average values for Ångström exponent, fine-mode fraction, aerosol absorption optical depth, and Ångström absorption exponent were 1.19, 0.81, 0.11 and 1.47, respectively, which suggests that fine aerosol particles were dominant in the atmosphere and fine-mode particles were the dominant contributor to atmospheric extinction during the haze period. Moreover, it also reflects that there were more absorbing aerosol particles during the haze period. Compared with other polluted periods with a bimodal distribution, there was an obvious trimodal distribution on 19 December. There were three peaks at radii of about 0.1 μm, 0.5–0.8 μm and 4 μm. Satellite observations show that there was an obvious aerosol layer in the Beijing area during the haze period, concentrated at ground level to within 2 km in the upper layers. The types of aerosol were mainly composed of mixed pollution aerosols.

  3. Hazing practices in higher education : a study with portuguese students

    OpenAIRE

    Caldeira, Suzana Nunes; Silva, Osvaldo; Mendes, Maria; Botelho, Susana P.

    2015-01-01

    Hazing practices in higher education institutions are perceived controversially. This study looked at the perception towards hazing practices of students from the University of the Azores in first cycle (n=247). It analyses if their perception was positive, emphasizing the integrative aspects of hazing practices, or if it was negative, inclining to define those practises like being violent and humiliating. The applied questionnaire measures 3 factors to define individual’s perception with haz...

  4. A Commander’s Guide to Hazing Prevention

    Science.gov (United States)

    2015-01-01

    of recent deaths, including suicides , have put a spotlight on military hazing, causing public outcry, congressional action, and military...from bullying ? Bullying is meant to exclude someone from a group, while hazing is meant to bring someone into it. In another context, hazing is...typically ritualized, passed down from previous generations, and ends when the target is accepted into the group. In contrast, bullying has no standard

  5. Using resident-based hazing programs to reduce human-coyote conflicts in urban environments

    OpenAIRE

    Bonnell, Mary Ann; Breck, Stewart W.

    2017-01-01

    Abstract The concept of hazing (aversive conditioning) is often promoted as a tool for reducing human-coyote (Canis latrans) conflicts in urban environments. Little scientific evidence exists on the effectiveness of hazing, particularly hazing applied by residents (i.e., community-level hazing). Wildlife professionals question if residents will properly and consistently apply hazing techniques and if hazing impacts coyote behavior over short- and long-term periods. We describe two separate ef...

  6. Vehicle exhaust: An overstated cause of haze in China.

    Science.gov (United States)

    Zhao, Yi-Bo; Gao, Pan-Pan; Yang, Wan-Dong; Ni, Hong-Gang

    2018-01-15

    Overall, total exhaust emissions of NOX, VOC and particulate matter (PM) declined, though vehicles in use continued to increase in China. This suggested that contribution of motor vehicle exhaust to haze in China may be exaggerated. A higher frequency of haze episodes in China with lower total emissions fraction from vehicle exhaust compared with those in the USA confirmed that there exists no strict causality between vehicle and haze. No significant correlation (pvehicles to airborne PM2.5 (particulates that are aerodynamic diameter) or car ownerships. All results revealed again that vehicle exhaust is an overstated cause for haze formation in China. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Cassini ISS Observations of Titan's Haze 2012-2016

    Science.gov (United States)

    West, Robert; Rannou, Paascal; Lavvas, Panayotis; Ovanessian, Aida

    2016-06-01

    Since approximately late 2012 the 'Detached' haze layer that was so prominent in short-wavelength Cassini ISS (Imaging Science Subsystem) images from 2004 to 2012 and also seen in Voyager images has not been detected in Cassini images. This development provides an important clue to the nature of processes responsible for the haze and its structure, although it is unclear yet how to interpret this as well as the evolution of the haze prior to its disappearance. Here we provide details on the time evolution of the haze as it disappeared and as it has been observed by the Cassini ISS from 2012 to the present.

  8. The nature and extent of college student hazing.

    Science.gov (United States)

    Allan, Elizabeth J; Madden, Mary

    2012-01-01

    This study explored the nature and extent of college student hazing in the USA. Hazing, a form of interpersonal violence, can jeopardize the health and safety of students. Using a web-based survey, data were collected from 11,482 undergraduate students, aged 18-25 years, who attended one of 53 colleges and universities. Additionally, researchers interviewed 300 students and staff at 18 of the campuses. Results reveal hazing among USA college students is widespread and involves a range of student organizations and athletic teams. Alcohol consumption, humiliation, isolation, sleep-deprivation and sex acts are hazing practices common across student groups. Furthermore, there is a large gap between the number of students who report experience with hazing behaviors and those that label their experience as hazing. To date, hazing prevention efforts in post-secondary education have focused largely on students in fraternities/sororities and intercollegiate athletes. Findings from this study can inform development of more comprehensive and research-based hazing prevention efforts that target a wider range of student groups. Further, data can serve as a baseline from which to measure changes in college student hazing over time.

  9. Laboratory Simulation of Haze/Aerosol formation in warm and hot Jupiters

    Science.gov (United States)

    Gharib-Nezhad, Ehsan; Lyons, James R.; Wright, David P.

    2016-10-01

    During the transit of an exoplanet across its host star, transmitted starlight through exoplanet atmosphere is absorbed and scattered, and the recorded transit spectra reveal important chemical information. There are many detected exoplanets in which hazes/aerosols obscure the incident photons, and consequently, fewer photons are transmitted through the atmosphere, contributing to a flat/nearly flat transit spectrum. Here, we have carried out two complementary approaches to address haze formation. First, laboratory simulations of haze condensation in exoplanet atmospheres are carried out using an electric discharge tube. A mixture of likely gas species (i.e. H2, He, H2O, CH4, N2 and H2S) is inserted into a glass manifold on a vacuum line, at a pressure ~100-10 mbar, and depending on the exoplanet category (e.g., warm or hot Jupiters), the temperature is set. Applying a few kilovolts produces plasma in the discharge tube, and as a result, particles are formed. We use spectroscopic ellipsometry to measure the optical constants (complex refractive index) of the collected laboratory hazes. Then, chemical characterization is made using RBS (Rutherford Backscattering Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy). Second, we developed a transit modeling code by which the transit spectra are generated using observational and laboratory data as an input. The model accounts for Mie scattering from haze particles in the vis-NIR spectral region, and Rayleigh scattering which comes from gases and particles (effective in UV-vis). The measured refractive indexes (real and imaginary part) describe the absorption and scattering in the vis-NIR transmission region, and, by generating transit spectra close to the observed ones from exoplanets, constraints on atmospheric chemical characterization can be revealed. Our laboratory results show that haze particles formed in the presence of water and with the solar C/O ratio = 0.5. The other outcome of our experiment is that

  10. Characterization of major pollution events (dust, haze, and two festival events) at Agra, India.

    Science.gov (United States)

    Pachauri, Tripti; Singla, Vyoma; Satsangi, Aparna; Lakhani, Anita; Kumari, K Maharaj

    2013-08-01

    Total suspended particulate (TSP) samples were collected during dust, haze, and two festival events (Holi and Diwali) from February 2009 to June 2010. Pollutant gases (NO2, SO2, and O3) along with the meteorological parameters were also measured during the four pollution events at Agra. The concentration of pollutant gases decreases during dust events (DEs), but the levels of the gases increase during other pollution events indicating the impact of anthropogenic emissions. The mass concentrations were about two times higher during pollution events than normal days (NDs). High TSP concentrations during Holi and Diwali events may be attributed to anthropogenic activities while increased combustion sources in addition to stagnant meteorological conditions contributed to high TSP mass during haze events. On the other hand, long-range transport of atmospheric particles plays a major role during DEs. In the dust samples, Ca(2+), Cl(-), NO3 (-), and SO4 (2-) were the most abundant ions and Ca(2+) alone accounted for 22 % of the total ionic mass, while during haze event, the concentrations of secondary aerosols species, viz., NO3 (-), SO4 (2-), and NH4 (+), were 3.6, 3.3, and 5.1 times higher than the normal days. During Diwali, SO4 (2-) concentration (17.8 μg m(-3)) was highest followed by NO3 (-), K(+), and Cl(-) while the Holi samples were strongly enriched with Cl(-) and K(+) which together made up 32.7 % of the total water-soluble ions. The ion balances indicate that the haze samples were acidic. On the other hand, Holi, Diwali, and DE samples were enriched with cations. The carbonaceous aerosol shows strong variation with the highest concentration during Holi followed by haze, Diwali, DEs, and NDs. However, the secondary organic carbon concentration follows the order haze > DEs > Diwali > Holi > NDs. The scanning electron microscope/EDX results indicate that KCl and carbon-rich particles were more dominant during Holi and haze events while DE samples were enriched

  11. Characteristics of aerosol pollution during heavy haze events in Suzhou, China

    Directory of Open Access Journals (Sweden)

    M. Tian

    2016-06-01

    Full Text Available Extremely severe haze weather events occurred in many cities in China, especially in the east part of the country, in January 2013. Comprehensive measurements including hourly concentrations of PM2.5 and its major chemical components (water-soluble inorganic ions, organic carbon (OC, and elemental carbon (EC and related gas-phase precursors were conducted via an online monitoring system in Suzhou, a medium-sized city in Jiangsu province, just east of Shanghai. PM2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less frequently exceeded 150 µg m−3 on hazy days, with the maximum reaching 324 µg m−3 on 14 January 2013. Unfavorable weather conditions (high relative humidity (RH, and low rainfall, wind speed, and atmospheric pressure were conducive to haze formation. High concentrations of secondary aerosol species (including SO42−, NO3−, NH4+, and SOC and gaseous precursors were observed during the first two haze events, while elevated primary carbonaceous species emissions were found during the third haze period, pointing to different haze formation mechanisms. Organic matter (OM, (NH42SO4, and NH4NO3 were found to be the major contributors to visibility impairment. High concentrations of sulfate and nitrate might be explained by homogeneous gas-phase reactions under low RH conditions and by heterogeneous processes under relatively high RH conditions. Analysis of air mass trajectory clustering and potential source contribution function showed that aerosol pollution in the studied areas was mainly caused by local activities and surrounding sources transported from nearby cities.

  12. Characteristics of aerosol pollution during heavy haze events in Suzhou, China

    Science.gov (United States)

    Tian, Mi; Wang, Huanbo; Chen, Yang; Yang, Fumo; Zhang, Xiaohua; Zou, Qiang; Zhang, Renquan; Ma, Yongliang; He, Kebin

    2016-06-01

    Extremely severe haze weather events occurred in many cities in China, especially in the east part of the country, in January 2013. Comprehensive measurements including hourly concentrations of PM2.5 and its major chemical components (water-soluble inorganic ions, organic carbon (OC), and elemental carbon (EC)) and related gas-phase precursors were conducted via an online monitoring system in Suzhou, a medium-sized city in Jiangsu province, just east of Shanghai. PM2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less) frequently exceeded 150 µg m-3 on hazy days, with the maximum reaching 324 µg m-3 on 14 January 2013. Unfavorable weather conditions (high relative humidity (RH), and low rainfall, wind speed, and atmospheric pressure) were conducive to haze formation. High concentrations of secondary aerosol species (including SO42-, NO3-, NH4+, and SOC) and gaseous precursors were observed during the first two haze events, while elevated primary carbonaceous species emissions were found during the third haze period, pointing to different haze formation mechanisms. Organic matter (OM), (NH4)2SO4, and NH4NO3 were found to be the major contributors to visibility impairment. High concentrations of sulfate and nitrate might be explained by homogeneous gas-phase reactions under low RH conditions and by heterogeneous processes under relatively high RH conditions. Analysis of air mass trajectory clustering and potential source contribution function showed that aerosol pollution in the studied areas was mainly caused by local activities and surrounding sources transported from nearby cities.

  13. Perceived haze, stress, and negative emotions: An ecological momentary assessment study of the affective responses to haze.

    Science.gov (United States)

    Xu, Wei; Ding, Xu; Zhuang, Yulu; Yuan, Guangzhe; An, Yuanyuan; Shi, Zhiqiang; Hwa Goh, Pei

    2017-07-01

    The aim of this study was to examine the mediating role of stress in the association between people's perceived haze and negative emotions in daily life. Using ecological momentary assessment, 95 college students reported their perceived haze, stress, and negative emotions twice a day over the course of 2 weeks. The results showed a positive relationship between perceived haze and negative emotions. More importantly, this association was significantly mediated by levels of stress. Findings suggested that people who perceived more severe haze may report higher stress levels, which in turn may lead to increases in negative emotions.

  14. Hazing in orientation programmes in boys-only secondary schools ...

    African Journals Online (AJOL)

    Hazing, associated with initiation, aims at taking newcomers from novice status to a status of functional and acknowledged members of a new group. However, the process is often dangerous, injurious, and usually secretive. Hazing may occur as an unauthorised component of institutionally sanctioned orientation ...

  15. Light Scatter in Optical Materials: Advanced Haze Modeling

    Science.gov (United States)

    2017-03-31

    glare. Haze can be inherent in the material, a result of the molding process, or a result of surface texture. Haze can also be a result of...detector (10 mm diameter silicon photodiode) located 1000 mm from the sample. A partially-collimated probe beam of 532 nm laser light was used to

  16. Climate modulation of the Tibetan Plateau on haze in China

    Directory of Open Access Journals (Sweden)

    X. Xu

    2016-02-01

    Full Text Available Rapid increases in pollutant emissions in conjunction with stagnant meteorological conditions result in haze pollution in China. Recent frequent haze in China has attracted worldwide attention. Here we show a relationship between the haze events and Tibetan Plateau (TP's environment and climate changes. Based on observational data taken over recent decades, we identify central-eastern China (CEC as a climatological large-scale “susceptible region” of frequent haze, which is harbored by the TP with its impact on midlatitude westerly winds. The observational and modeling studies demonstrate that the interannual variations in the thermal forcing of TP are positively correlated with the incidences of wintertime haze over CEC. Further analysis indicates that the climate warming of the TP induced changes in atmospheric circulation, driving frequent haze events in CEC. The frequent haze occurrences in CEC are consistent with decreasing winter monsoon winds, intensifying downward air flows and increasing atmospheric stability in the lower troposphere over the CEC in association with upstream plateau's thermal anomalies. Therefore, variations of haze in China are related to mechanical and thermal forcing by the TP. Our results also suggest that implications of the large TP topography for environment and climate changes should be taken into account for air pollution mitigation policies in China.

  17. Evaluation and guidelines for using polyurethane foam (PUF) passive air samplers in double-dome chambers to assess semi-volatile organic compounds (SVOCs) in non-industrial indoor environments.

    Science.gov (United States)

    Bohlin, Pernilla; Audy, Ondřej; Škrdlíková, Lenka; Kukučka, Petr; Vojta, Šimon; Přibylová, Petra; Prokeš, Roman; Čupr, Pavel; Klánová, Jana

    2014-11-01

    Indoor air pollution has been recognized as an important risk factor for human health, especially in areas where people tend to spend most of their time indoors. Many semi-volatile organic compounds (SVOCs) have primarily indoor sources and are present in orders of magnitude higher concentrations indoors than outdoors. Despite this, awareness of SVOCs in indoor air and assessment of the link between indoor concentrations and human health have lagged behind those of outdoor air. This is partially related to challenges associated with indoor sampling of SVOCs. Passive air samplers (PASs), which are widely accepted in established outdoor air monitoring networks, have been used to fill the knowledge gaps on indoor SVOCs distribution. However, their applicability for indoor environments and the assessment of human health risks lack sufficient experimental data. To address this issue, we performed an indoor calibration study of polyurethane foam (PUF) PAS deployed in a double-dome chamber, covering both legacy and new SVOC classes. PUF-PAS and a continuous low-volume active air sampler (AAS) were co-deployed for a calibration period of twelve weeks. Based on the results from this evaluation, PUF-PAS in a double-bowl chamber is recommended for indoor sampling and health risk assessment of gas phase SVOCs, including novel brominated flame retardants (nBFR) providing sufficient exposure time is applied. Data for particle associated SVOCs suffered from significant uncertainties caused by low level of detection and low precision in this study. A more open chamber design for indoor studies may allow for higher sampling rates (RS) and better performance for the particle associated SVOCs.

  18. A sporting chance to fight haze

    Science.gov (United States)

    Showstack, Randy

    Sometimes sports can open up the way for politicians to take action. Several decades ago, ping-pong diplomacy helped to ease tensions between China and the United States. Now, it appears that the upcoming Southeast Asia Games (SEA Games) also may be wielding some influence in policy making.Environment ministers from countries in the region and officials from the Association of South East Asian Nations (ASEAN), hoping to keep the skies clear during the sporting competition in Brunei in August, on July 6 announced a plan to try to prevent forest fires and avert the dangerous levels of smog and haze that enveloped the region 2 years ago.

  19. Haze Removal Based on a Fully Automated and Improved Haze Optimized Transformation for Landsat Imagery over Land

    Directory of Open Access Journals (Sweden)

    Lixin Sun

    2017-09-01

    Full Text Available Optical satellite imagery is often contaminated by the persistent presence of clouds and atmospheric haze. Without an effective method for removing this contamination, most optical remote sensing applications are less reliable. In this research, a methodology has been developed to fully automate and improve the Haze Optimized Transformation (HOT-based haze removal. The method is referred to as AutoHOT and characterized with three notable features: a fully automated HOT process, a novel HOT image post-processing tool and a class-based HOT radiometric adjustment method. The performances of AutoHOT in haze detection and compensation were evaluated through three experiments with one Landsat-5 TM, one Landsat-7 ETM+ and eight Landsat-8 OLI scenes that encompass diverse landscapes and atmospheric haze conditions. The first experiment confirms that AutoHOT is robust and effective for haze detection. The average overall, user’s and producer’s accuracies of AutoHOT in haze detection can reach 96.4%, 97.6% and 97.5%, respectively. The second and third experiments demonstrate that AutoHOT can not only accurately characterize the haze intensities but also improve dehazed results, especially for brighter targets, compared to traditional HOT radiometric adjustment.

  20. Insights into a historic severe haze event in Shanghai: synoptic situation, boundary layer and pollutants

    Directory of Open Access Journals (Sweden)

    C. Leng

    2016-07-01

    Full Text Available A historic haze event, characterized by lengthy, large-scale and severe pollution, occurred in the Yangtze River Delta (YRD of China from 1 to 10 December 2013. This haze event significantly influenced air quality throughout the region, especially in urban areas. Aerosol physical, chemical and optical properties were measured in Shanghai. Sometimes the 1 h average particle concentration (e.g., PM2.5 exceeded 600 µg m−3. Inorganic water-soluble ions in particles, trace gases and aerosol optical coefficients had a similar tendency to increase evidently from clear to hazy episodes. A combination of various factors contributed to the formation and evolution of the haze event, among which meteorological conditions, local anthropogenic emissions and pollutants are the major factors. High pressure system, calm surface wind and subsidence airflow were responsible for the decrease of planetary boundary layer (PBL and the accumulation of pollutants. Atmospheric visibility correlated strongly with relative humidity (RH, particle number in size of 600–1400 nm other than particulate water-soluble species and particle mass (PM2.5. The particle hygroscopicity plays an important role in atmospheric visibility reduction. The results are somewhat helpful to forecast and eliminate regional atmospheric pollution in China.

  1. Haze heats Pluto’s atmosphere yet explains its cold temperature

    Science.gov (United States)

    Zhang, Xi; Strobel, Darrell F.; Imanaka, Hiroshi

    2017-11-01

    Pluto’s atmosphere is cold and hazy. Recent observations have shown it to be much colder than predicted theoretically, suggesting an unknown cooling mechanism. Atmospheric gas molecules, particularly water vapour, have been proposed as a coolant; however, because Pluto’s thermal structure is expected to be in radiative-conductive equilibrium, the required water vapour would need to be supersaturated by many orders of magnitude under thermodynamic equilibrium conditions. Here we report that atmospheric hazes, rather than gases, can explain Pluto’s temperature profile. We find that haze particles have substantially larger solar heating and thermal cooling rates than gas molecules, dominating the atmospheric radiative balance from the ground to an altitude of 700 kilometres, above which heat conduction maintains an isothermal atmosphere. We conclude that Pluto’s atmosphere is unique among Solar System planetary atmospheres, as its radiative energy equilibrium is controlled primarily by haze particles instead of gas molecules. We predict that Pluto is therefore several orders of magnitude brighter at mid-infrared wavelengths than previously thought—a brightness that could be detected by future telescopes.

  2. Effects of meteorology and secondary particle formation on visibility during heavy haze events in Beijing, China.

    Science.gov (United States)

    Zhang, Qiang; Quan, Jiannong; Tie, Xuexi; Li, Xia; Liu, Quan; Gao, Yang; Zhao, Delong

    2015-01-01

    The causes of haze formation in Beijing, China were analyzed based on a comprehensive measurement, including PBL (planetary boundary layer), aerosol composition and concentrations, and several important meteorological parameters such as visibility, RH (relative humidity), and wind speed/direction. The measurement was conducted in an urban location from Nov. 16, 2012 to Jan. 15, 2013. During the period, the visibility varied from >20 km to less than a kilometer, with a minimum visibility of 667 m, causing 16 haze occurrences. During the haze occurrences, the wind speeds were less than 1m/s, and the concentrations of PM2.5 (particle matter with radius less than 2.5 μm) were often exceeded 200 μg/m(3). The correlation between PM2.5 concentration and visibility under different RH values shows that visibility was exponentially decreased with the increase of PM2.5 concentrations when RH was less than 80%. However, when RH was higher than 80%, the relationship was no longer to follow the exponentially decreasing trend, and the visibility maintained in very low values, even with low PM2.5 concentrations. Under this condition, the hygroscopic growth of particles played important roles, and a large amount of water vapor acted as particle matter (PM) for the reduction of visibility. The variations of meteorological parameters (RH, PBL heights, and WS (wind speed)), chemical species in gas-phase (CO, O3, SO2, and NOx), and gas-phase to particle-phase conversions under different visibility ranges were analyzed. The results show that from high visibility (>20 km) to low visibility (<2 km), the averaged PBL decreased from 1.24 km to 0.53 km; wind speeds reduced from 1m/s to 0.5m/s; and CO increased from 0.5 ppmv to 4.0 ppmv, suggesting that weaker transport/diffusion caused the haze occurrences. This study also found that the formation of SPM (secondary particle matter) was accelerated in the haze events. The conversions between SO2 and SO4 as well as NOx to NO3(-) increased

  3. Factors Contributing to Haze Pollution: Evidence from Macao, China

    Directory of Open Access Journals (Sweden)

    Wai-Ming To

    2017-09-01

    Full Text Available Haze is a major environmental concern in many cities because it adversely affects people’s physiological and psychological well-being. This paper examines the extent of haze in Macao during the period 1986–2016. It identifies the relationships between haze, energy use, and meteorological conditions directly. The haze in Macao changed over the period 1986–2016 with air pollution getting worse and then improving after 2007. Specifically, the number of haze hours increased from 3 in 1986 to 766 in 2007, and then dropped to 57 in 2016, while the total energy use increased from 12,246 TJ in 1986 to 37,144 TJ in 2007, and then to 42,405 TJ in 2016. As per primary energy, Macao used 12,096 TJ in 1986, 21,388 TJ in 2007, and 16,647 TJ in 2016 excluding aviation kerosene. Bivariate correlations show that haze was most positively and significantly associated with annual primary energy use. Multiple regression analysis indicates that the number of hours with haze was significantly, positively related to the consumption of gas oil/diesel, fuel oil, and natural gas in Macao and aviation kerosene. Nevertheless, the improvement in Macao could come at a cost to areas in downwind of Zhuhai’s coal power stations supplying Macao’s electricity energy.

  4. Role of atmospheric circulations in haze pollution in December 2016

    Science.gov (United States)

    Yin, Zhicong; Wang, Huijun

    2017-09-01

    In the east of China, recent haze pollution has been severe and damaging. In addition to anthropogenic emissions, atmospheric circulations and local meteorological conditions were conducive factors. The number of December haze days over North China and the Huanghuai area has increased sharply since 2010 and was greatest in 2016. During 2016, the most aggressive control measures for anthropogenic emissions were implemented from 16 to 21 December, but the most severe haze pollution still occurred, covering approximately 25 % of the land area of China and lasting for 6 days. The atmospheric circulations must play critical roles in the sub-seasonal haze events. Actually, the positive phase of the East Atlantic-West Russia pattern in the middle troposphere strengthened the anomalous anti-cyclone over the NH area that confined vertical motion below. The associated southerly anomalies made the cold air and surface wind speed weaker, but enhanced the humid flow. Thus, the horizontal and vertical dispersion of atmospheric particulates was suppressed and the pollutants gathered within a narrow space. In December 2016, these key indices were strongly beneficial for haze occurrence and combined to result in the severest haze pollution. The influences of the preceding autumn sea surface temperature near the Gulf of Alaska and the subtropical eastern Pacific, October-November snow cover in western Siberia, and associated physical processes on haze pollution are also discussed.

  5. Tropospheric haze and colors of the clear daytime sky.

    Science.gov (United States)

    Lee, Raymond L

    2015-02-01

    To casual observers, haze's visible effects on clear daytime skies may seem mundane: significant scattering by tropospheric aerosols visibly (1) reduces the luminance contrast of distant objects and (2) desaturates sky blueness. However, few published measurements of hazy-sky spectra and chromaticities exist to compare with these naked-eye observations. Hyperspectral imaging along sky meridians of clear and hazy skies at one inland and two coastal sites shows that they have characteristic colorimetric signatures of scattering and absorption by haze aerosols. In addition, a simple spectral transfer function and a second-order scattering model of skylight reveal the net spectral and colorimetric effects of haze.

  6. Polarization of Hazes and Aurorae on Jupiter

    Science.gov (United States)

    Yanamandra-Fisher, Padma A.; McLean, Will; PACA_Jupiter

    2017-10-01

    Our solar system planets show a large variety of atmospheric polarization properties, from the thick, highly polarizing haze on Titan and the poles of Jupiter, Rayleigh scattering by molecules on Uranus and Neptune, to clouds in the equatorial region of Jupiter or on Venus. Changes in the clouds/thermal filed can be brought about by endogenic dynamical processes such merger of vortices; global, planetary scale upheavals, and external factors such as celestial collisions (such as D/Shoemaker-Levy 9 impact with Jupiter in 1994, etc.). Although the range of phase angles available from Earth for outer planets is restricted to a narrow range, limb polarization measurements provide constraints on the polarimetric properties. For example, at the equator, much of the observed reflected radiation is due to the presence of clouds and therefore, low polarization. Polar asymmetry exists between the two poles, while the planetary disk is unpolarized. Jupiter is known to exhibit a strong polar limb polarization and a low equatorial limb polarization due to the presence of haze particles and Rayleigh scattering at the poles. In contrast, at the equator, the concentration of particulates in the high atmosphere might change, changing the polarimetric signature and aurorae at both poles. The polarimetric maps, in conjunction with thermal maps and albedo maps, can provide constraints on modeling efforts to understand the nature of the aerosols/hazes in Jovian atmosphere. With Jupiter experiencing morphological changes at many latitudes, we have initiated a polarimetric observing campaign of Jupiter, in conjunction with The PACA Project. With NASA/Juno mission in a 53-day orbit around Jupiter, and recent outbreaks in the atmosphere, changes in the polarimetric signature will provide insight to the changes occurring in the atmosphere. Some of our observations are acquired by a team of professional/amateur planetary imagers astronomers based in the U.K., Australia and Europe. France

  7. Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

    Science.gov (United States)

    Xie, Yuanyuan; Ye, Xingnan; Ma, Zhen; Tao, Ye; Wang, Ruyu; Zhang, Ci; Yang, Xin; Chen, Jianmin; Chen, Hong

    2017-06-01

    We characterize a representative particulate matter (PM) episode that occurred in Shanghai during winter 2014. Particle size distribution, hygroscopicity, effective density, and single particle mass spectrometry were determined online, along with offline analysis of water-soluble inorganic ions. The mass ratio of SNA / PM1. 0 (sulfate, nitrate, and ammonium) fluctuated slightly around 0.28, suggesting that both secondary inorganic compounds and carbonaceous aerosols contributed substantially to the haze formation, regardless of pollution level. Nitrate was the most abundant ionic species during hazy periods, indicating that NOx contributed more to haze formation in Shanghai than did SO2. During the representative PM episode, the calculated PM was always consistent with the measured PM1. 0, indicating that the enhanced pollution level was attributable to the elevated number of larger particles. The number fraction of the near-hydrophobic group increased as the PM episode developed, indicating the accumulation of local emissions. Three banana-shaped particle evolutions were consistent with the rapid increase of PM1. 0 mass loading, indicating that the rapid size growth by the condensation of condensable materials was responsible for the severe haze formation. Both hygroscopicity and effective density of the particles increased considerably with growing particle size during the banana-shaped evolutions, indicating that the secondary transformation of NOx and SO2 was one of the most important contributors to the particle growth. Our results suggest that the accumulation of gas-phase and particulate pollutants under stagnant meteorological conditions and subsequent rapid particle growth by secondary processes were primarily responsible for the haze pollution in Shanghai during wintertime.

  8. Atmospheric Prebiotic Chemistry and Organic Hazes

    Science.gov (United States)

    Trainer, Melissa G.

    2012-01-01

    Earth's atmospheric composition at the time of the origin of life is not known, but it has often been suggested that chemical transformation of reactive species in the atmosphere was a significant source of pre biotic organic molecules. Experimental and theoretical studies over the past half century have shown that atmospheric synthesis can yield molecules such as amino acids and nucleobases, but these processes are very sensitive to gas composition and energy source. Abiotic synthesis of organic molecules is more productive in reduced atmospheres, yet the primitive Earth may not have been as reducing as earlier workers assumed, and recent research has reflected this shift in thinking. This work provides a survey of the range of chemical products that can be produced given a set of atmospheric conditions, with a particular focus on recent reports. Intertwined with the discussion of atmospheric synthesis is the consideration of an organic haze layer, which has been suggested as a possible ultraviolet shield on the anoxic early Earth. Since such a haze layer - if formed - would serve as a reservoir for organic molecules, the chemical composition of the aerosol should be closely examined. The results highlighted here show that a variety of products can be formed in mildly reducing or even neutral atmospheres, demonstrating that contributions of atmospheric synthesis to the organic inventory on early Earth should not be discounted. This review intends to bridge current knowledge of the range of possible atmospheric conditions in the prebiotic environment and pathways for synthesis under such conditions by examining the possible products of organic chemistry in the early atmosphere.

  9. About hazing, vampires and relationships at the medical school

    OpenAIRE

    Maria Cristina Pereira Lima

    2012-01-01

    The students’ relationships with one another and their teachers can become difficult at different times. However, entrance into the university seems to be a particularly tense moment, due to the hazing suffered this stage of their academic lives. This study presents a review of the literature on the hazing, especially that have happen in medical schools, trying to identify the characteristics and maintaining factors of those ritual. In parallel, constructs a metaphor of the vampire myth, prop...

  10. Triton, Pluto, and Titan: A Comparison of Haze Photometry

    Science.gov (United States)

    Buratti, Bonnie J.; Hillier, John K.; Abgarian, Mary; Kutsop, Nicholas; Devins, Spencer; Mosher, Joel A.; Stern, S. Alan; Weaver, Harold A.; Olkin, Catherine; Young, Leslie; Ennico, Kimberly; New Horizons Science Team

    2017-10-01

    As Kuiper Belt Objects of similar size and albedo, Triton and Pluto were thought to be kindred bodies exhibiting like geologic histories and features, with possible seasonal volatile transport in their polar regions. During the flyby of Pluto in July 2015, active geological processes were observed on the planet (Stern et al., 2015), and a substantial haze layer that was more akin to Titan’s was observed (Gladstone et. al., 2016). Multiple haze layers were discovered surrounding the dwarf planet (Cheng et al. 2017).Using a radiative transfer model based on Chandrasekhar’s “Planetary Problem” of an optically thin atmosphere and a surface of arbitrary single scattering albedo and single particle phase function (Chandrasekhar, 1960; Hillier et al., 1990, 1991; Buratti et al., 2011), we have characterized the optical depth and surface properties of Pluto, Triton, and Titan. The forward-scattering properties of the haze can also be quantified by this model. Optical imaging data was analyzed for Triton and Pluto. For Titan we made use of published data on Titan (Tomasko and West, 2009) plus new Cassini Visual Infrared Mapping Spectrometer (VIMS) data, which spans the wavelength range between 0.35 and 5.2 microns, and which has several channels in the mid-infrared where both the haze opacity is relatively low and the atmosphere is optically thin. Pluto’s atmosphere is more optically thick than Triton’s but both are far thinner than Titan’s. The composition of Triton’s haze layer differs markedly from Titan’s. Observations of Pluto’s haze reveal a bluish color (Gladstone et al., 2016), but the reddish tint of possible haze deposits on the surface (Stern et al., 2015; Buratti et al., 2015) suggest Pluto’s haze composition is Titan-like. Institute of Technology. Government sponsorship acknowledged.

  11. Characteristics and formation of heavy winter haze pollution during 2014-2015 in Tianjin, China

    Science.gov (United States)

    Sun, Zhenli; Ma, Tao; Zhu, Lidan; Duan, Fengkui; He, Kebin

    2017-04-01

    With the rapid increase in the amount of vehicles and energy consumption during the past two decades, China faces a serious air pollution in urban areas, which has produced negative impact on the society development and human health. Tianjin, locating on the southeast of Beijing-Tianjin-Hebei region in north China, has been one of the heavy polluted cities during 2013-2016 of which the haze occurred frequently in particular in winter while the knowledge on its sources and formation mechanism are limited. For better understanding of the characteristics and the formation mechanisms of PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), especially secondary water-soluble inorganic species in these haze events, continuous and online hourly field observations in Tianjin urban area were carried out during 2014-2015 winter, that were, hourly concentrations of PM2.5, sulfate, nitrate, and ammonium (SNA) as well as the concentrations of gaseous pollutants and meteorological parameters. PM2.5 concentrations ranged from 5.6 μgṡm-3 to 495.5 μgṡm-3, with an average of 112.1 (±96.1) μgṡm-3. In general, SNA (sulfate, nitrate and ammonium) was the most abundant secondary water-soluble inorganic species and contributed to 35% of PM2.5 mass concentration. The most severe PM2.5 pollution was observed in January 2015 with four haze episodes observed. The chemical composition of four episodes was characterized by high level of SO42- (22%˜38%), together with high concentration of NO3- (22%˜34%), suggesting the contribution of secondary conversion. NOR and SOR increased with elevated PM2.5levels and heterogeneous processes seemed to be the most plausible explanation of this increase. Nitrogen oxidation ratio (NOR) was much higher than sulfur oxidation ratio (SOR), indicating the NO2 was easily oxidized in low temperature condition than that of SO2. Relative humidity (RH) played a considerable role in the formation of secondary inorganic aerosols, accelerated

  12. Potential climatic impact of organic haze on early Earth.

    Science.gov (United States)

    Hasenkopf, Christa A; Freedman, Miriam A; Beaver, Melinda R; Toon, Owen B; Tolbert, Margaret A

    2011-03-01

    We have explored the direct and indirect radiative effects on climate of organic particles likely to have been present on early Earth by measuring their hygroscopicity and cloud nucleating ability. The early Earth analog aerosol particles were generated via ultraviolet photolysis of an early Earth analog gas mixture, which was designed to mimic possible atmospheric conditions before the rise of oxygen. An analog aerosol for the present-day atmosphere of Saturn's moon Titan was tested for comparison. We exposed the early Earth aerosol to a range of relative humidities (RHs). Water uptake onto the aerosol was observed to occur over the entire RH range tested (RH=80-87%). To translate our measurements of hygroscopicity over a specific range of RHs into their water uptake ability at any RH 100%, we relied on the hygroscopicity parameter κ, developed by Petters and Kreidenweis. We retrieved κ=0.22 ±0.12 for the early Earth aerosol, which indicates that the humidified aerosol (RH Earth atmosphere than previously modeled with dry aerosol. Such effects would have been of significance in regions where the humidity was larger than 50%, because such high humidities are needed for significant amounts of water to be on the aerosol. Additionally, Earth organic aerosol particles could have activated into CCN at reasonable-and even low-water-vapor supersaturations (RH > 100%). In regions where the haze was dominant, it is expected that low particle concentrations, once activated into cloud droplets, would have created short-lived, optically thin clouds. Such clouds, if predominant on early Earth, would have had a lower albedo than clouds today, thereby warming the planet relative to current-day clouds. © Mary Ann Liebert, Inc.

  13. Modeling analysis of the seasonal characteristics of haze formation in Beijing

    Science.gov (United States)

    Han, X.; Zhang, M.; Gao, J.; Wang, S.; Chai, F.

    2014-09-01

    The air quality modeling system RAMS-CMAQ (Regional Atmospheric Modeling System-Community Multiscale Air Quality), coupled with an aerosol optical property scheme, was applied to simulate the meteorological field, major aerosol components (sulfate, nitrate, ammonium, black carbon, organic carbon, dust, and sea salt), and surface visibility over the North China Plain (NCP) in 2011. The modeled results in February and July 2011 were selected and analyzed to obtain an in-depth understanding of the haze formation mechanism in Beijing for different seasons. The simulation results showed that the visibility was below 10 km for most regions of the NCP, and dropped to less than 5 km over the megacities of Beijing and Tianjin, the whole of Hebei Province, and the northwest part of Shandong Province during pollution episodes in February and July. The heavy mass concentration of PM2.5 ranged from 120 to 300 μg m-3 and was concentrated in the areas with low visibility. The haze formation mechanism in Beijing in winter was different from that in summer. The mass concentration of PM2.5 was higher, and the components more complicated, in winter. While the mass concentration of PM2.5 in summer was lower than that in winter, the mass concentrations of hygroscopic inorganic salts were comparable with those in winter, and the relative humidity was, as expected, higher. Therefore, the water uptake of hygroscopic aerosols played a key role in summer. Moreover, the analysis showed that the influence of the PM2.5 mass burden on visibility was very weak when its value was larger than 100 μg m-3. Only when the mass burden of PM2.5 decreased to a certain threshold interval did the visibility increase rapidly. This indicates that, when emission reduction measures are taken to control haze occurrence, the mass burden of PM2.5 must be cut to below this threshold interval. The relationship between the threshold of haze occurrence and the relative humidity in Beijing was fitted by an

  14. Regional Haze Evolved from Peat Fires - an Overview

    Science.gov (United States)

    Hu, Yuqi; Rein, Guillermo

    2016-04-01

    This work provides an overview of haze episodes, their cause, emissions and health effects found in the scientific literature. Peatlands, the terrestrial ecosystems resulting from the accumulation of partially decayed vegetation, become susceptible to smouldering fires because of natural droughts or anthropogenic-induced drainages. Once ignited, smouldering peat fires persistently consume large amounts of soil carbon in a flameless form. It is estimated that the average annual carbon gas emissions (mainly CO2 and CO) from peat fires are equivalent to 15% of manmade emissions, representing influential perturbation of global carbon circle. In addition to carbon emissions, smouldering peat fires emit substantial quantities of heterogeneous smoke, which is responsible for haze phenomena, has not yet been fully studied. Peat-fire-derived smoke is characterized by high concentration of particulate matter (PM), ranging from nano-scale ultrafine fraction (PM1, particle diameter smoke could be blocked due to the stagnant weather condition, and then low buoyant smoke plume could accumulate and migrate long distances, leading to regional haze. Apart from air quality deterioration, haze leads to severe reduction in visibility, which strongly affects local transportation, construction, tourism and agriculture-based industries. For example, an unprecedented peatland mega-fire burst on the Indonesian islands Kalimantan and Sumatra during the 1997 El-Niño event, resulting in transboundary smoke-haze disaster. Severe haze events continue to appear in Southeast Asia every few years due to periodical peat fires in this region. In addition, smouldering peat fires have been frequently reported in tropical, temperate and boreal regions (Botswana in 2000, North America in 2004, Scotland in 2006 and Central Russia in 2010 et al.), peat-fire-induced haze has become a regional seasonal phenomenon. Exposure to smoky haze results in deleterious physiologic responses, predominantly to the

  15. Size-resolved source apportionment of particulate matter in urban Beijing during haze and non-haze episodes

    Directory of Open Access Journals (Sweden)

    S. L. Tian

    2016-01-01

    Full Text Available Additional size-resolved chemical information is needed before the physicochemical characteristics and sources of airborne particles can be understood; however, this information remains unavailable in most regions of China due to lacking measurement data. In this study, we report observations of various chemical species in size-segregated particle samples that were collected over 1 year in the urban area of Beijing, a megacity that experiences severe haze episodes. In addition to fine particles, high concentrations of coarse particles were measured during the periods of haze. The abundance and chemical compositions of the particles in this study were temporally and spatially variable, with major contributions from organic matter and secondary inorganic aerosols. The contributions of organic matter to the particle mass decreased from 37.9 to 31.2 %, and the total contribution of sulfate, nitrate and ammonium increased from 19.1 to 33.9 % between non-haze and haze days, respectively. Due to heterogeneous reactions and hygroscopic growth, the peak concentrations of the organic carbon, cadmium and sulfate, nitrate, ammonium, chloride and potassium shifted from 0.43 to 0.65 µm on non-haze days to 0.65–1.1 µm on haze days. Although the size distributions of lead and thallium were similar during the observation period, their concentrations increased by a factor of more than 1.5 on haze days compared with non-haze days. We observed that sulfate and ammonium, which have a size range of 0.43–0.65 µm, sulfate and nitrate, which have a size range of 0.65–1.1 µm, calcium, which has a size range of 5.8–9 µm, and the meteorological factors of relative humidity and wind speed were responsible for haze pollution when the visibility was less than 10 km. Source apportionment using Positive Matrix Factorization showed six PM2.1 sources and seven PM2.1–9 common sources: secondary inorganic aerosol (25.1 % for fine particles vs. 9.8

  16. Haze in Apple-Based Beverages: Detailed Polyphenol, Polysaccharide, Protein, and Mineral Compositions.

    Science.gov (United States)

    Millet, Melanie; Poupard, Pascal; Le Quéré, Jean-Michel; Bauduin, Remi; Guyot, Sylvain

    2017-08-09

    Producers of apple-based beverages are confronted with colloidal instability. Haze is caused by interactions between molecules that lead to the formation of aggregates. Haze composition in three apple-based beverages, namely, French sparkling cider, apple juice, and pommeau, was studied. Phenolic compounds, proteins, polysaccharides, and minerals were analyzed using global and detailed analytical methods. The results explained <75% (w/w) of haze dry mass. Polyphenols, represented mainly by procyanidins, were the main compounds identified and accounted for 10-31% of haze. However, oxidized phenolic compounds were probably underestimated and may represent a high proportion of haze. Proteins were present in all of the samples in proportions of <6% of haze except in two apple juice hazes, where they were the main constituents (18 and 24%). Polysaccharides accounted for 0-30% of haze. Potassium and calcium were the main minerals.

  17. Regionality of Dust Haze Transport in the Mars Atmosphere Revealed by Ensemble Simulations

    Science.gov (United States)

    Ogohara, K.

    2017-06-01

    Regionality of dust haze transport in the Mars atmosphere is investigated by ensemble simulations using a GCM. It is turned out that processes of dust haze dispersion by advection are categorized into a few cases.

  18. Formation and evolution mechanism of regional haze: a case study in the megacity Beijing, China

    National Research Council Canada - National Science Library

    Liu, X. G; Li, J; Qu, Y; Han, T; Hou, L; Gu, J; Chen, C; Yang, Y; Liu, X; Yang, T; Zhang, Y; Tian, H; Hu, M

    2013-01-01

      The main objective of this study is to investigate the formation and evolution mechanism of the regional haze in megacity Beijing by analyzing the process of a severe haze that occurred 20-27 September 2011...

  19. The impact of haze on the adolescent's acute respiratory disease: A single institution study

    Directory of Open Access Journals (Sweden)

    Wan Fairos Wan Yaacob

    2016-05-01

    Conclusions: Student with haze effect documented much higher symptoms during haze especially female students. Symptoms such as headache, wheezing and mucus were noted among the normal secondary school children in Kota Bharu.

  20. 77 FR 24385 - Approval and Promulgation of Air Quality Implementation Plans; Maine; Regional Haze

    Science.gov (United States)

    2012-04-24

    ... approve Maine's Regional Haze SIP submittal. Comments were received from the citizen's group Credo Action... members of Credo Action stating ``As a Maine resident, I urge you to greatly reduce haze pollution at...

  1. Laboratory Simulations on Haze Formation in Cool Exoplanet Atmospheres

    Science.gov (United States)

    He, Chao; Horst, Sarah; Lewis, Nikole; Yu, Xinting; McGuiggan, Patricia; Moses, Julianne I.

    2017-10-01

    The Kepler mission has shown that the most abundant types of planets are super-Earths and mini-Neptunes among ~3500 confirmed exoplanets, and these types of exoplanets are expected to exhibit a wide variety of atmospheric compositions. Recent transit spectra have demonstrated that clouds and/or hazes could play a significant role in these planetary atmospheres (Deming et al. 2013, Knutson et al. 2014, Kreidberg et al. 2014, Pont, et al. 2013). However, very little laboratory work has been done to understand the formation of haze over a broad range of atmospheric compositions. Here we conducted a series of laboratory simulations to investigate haze formation in a range of planetary atmospheres using our newly built Planetary HAZE Research (PHAZER) chamber (He et al. 2017). We ran experimental simulations for nine different atmospheres: three temperatures (300 K, 400 K, and 600 K) and three metallicities (100, 1000, and 10000 times solar metallicity) using AC glow discharge as an energy source to irradiate gas mixtures. We found that haze particles are formed in all nine experiments, but the haze production rates are dramatically different for different cases. We investigated the particle sizes of the haze particles deposited on quartz discs using atomic force microscopy (AFM). The AFM images show that the particle size varies from 30 nm to 200 nm. The haze particles are more uniform for 100x solar metallicity experiments (30 nm to 40 nm) while the particles sizes for 1000x and 10000x solar metallicity experiments have wider distributions (30 nm to 200 nm). The particle size affects the scattering of light, and thus the temperature structure of planetary atmospheres. The haze production rates and particle size distributions obtained here can serve as critical inputs to atmospheric physical and chemical tools to understand the exoplanetary atmospheres and help guide future TESS and JWST observations of super-Earths and mini-Neptunes.Ref:Deming, D., et al. 2013, Ap

  2. Dehazed Image Quality Assessment by Haze-Line Theory

    Science.gov (United States)

    Song, Yingchao; Luo, Haibo; Lu, Rongrong; Ma, Junkai

    2017-06-01

    Images captured in bad weather suffer from low contrast and faint color. Recently, plenty of dehazing algorithms have been proposed to enhance visibility and restore color. However, there is a lack of evaluation metrics to assess the performance of these algorithms or rate them. In this paper, an indicator of contrast enhancement is proposed basing on the newly proposed haze-line theory. The theory assumes that colors of a haze-free image are well approximated by a few hundred distinct colors, which form tight clusters in RGB space. The presence of haze makes each color cluster forms a line, which is named haze-line. By using these haze-lines, we assess performance of dehazing algorithms designed to enhance the contrast by measuring the inter-cluster deviations between different colors of dehazed image. Experimental results demonstrated that the proposed Color Contrast (CC) index correlates well with human judgments of image contrast taken in a subjective test on various scene of dehazed images and performs better than state-of-the-art metrics.

  3. Haze Heating and Cooling in Pluto’s Atmosphere

    Science.gov (United States)

    Zhang, Xi; Strobel, Darrell F.; Imanaka, Hiroshi

    2017-10-01

    During the Pluto flyby, an ultraviolet imaging spectrometer ALICE onboard New Horizon spacecraft revealed an unexpected cold atmosphere on Pluto (Gladstone et al., 2016). The missing cooling agent is still a mystery. Here we show that hazes in the atmosphere could explain Pluto’s temperature profile. Haze particles are likely formed via hydrocarbon and nitrile chemistry in Pluto’s atmosphere. Numerous global haze layers have been discovered in the New Horizons images obtained from the LOng Range Reconnaissance Imager (LORRI) (Gladstone et al. 2016). Based on the vertical profile of haze opacity derived from ALICE observations (Gao et al. 2017; Young et al. 2017), we calculate the UV and visible heating and infrared cooling rates on Pluto. We found that the haze heating and cooling effects are large compared with the heating from methane and cooling from CO, HCN and C2 hydrocarbons. We predict that Pluto is much brighter than a conventionally assumed blackbody in the mid-infrared, which can be tested by future observations.

  4. 77 FR 30454 - Approval and Promulgation of Implementation Plans; State of Oregon; Regional Haze State...

    Science.gov (United States)

    2012-05-23

    ... Proposed Action A. Definition of Regional Haze B. Regional Haze Rules and Regulations C. Roles of Agencies... Reasonable Progress Goals (RPGs) and the Long Term Strategy (LTS). A. Definition of Regional Haze Regional... electrostatic precipitation system. The BART rule for this facility requires that the Foster Wheeler boiler at...

  5. 76 FR 43963 - Regional Haze State Implementation Plan; State of Nevada; Extension of Comment Period

    Science.gov (United States)

    2011-07-22

    ... (SIP) to implement the regional haze program for the first planning period through July 31, 2018. The... for more time to review the technical materials that form the basis of Nevada's Regional Haze SIP and... Regional Haze Rule requirements and EPA's proposed approval of the technical analyses presented in Nevada's...

  6. A Case of High School Hazing: Applying Restorative Justice to Promote Organizational Learning

    Science.gov (United States)

    DeWitt, Douglas M.; DeWitt, Lori J.

    2012-01-01

    While collegiate fraternity and sorority hazing are well documented problems that receive prominent attention, hazing at the high school level is also a serious issue. Across the nation, media headlines offer a continual reminder that high school hazing is not a phenomenon of the past. As high school principals seek ways to discourage and…

  7. 76 FR 1579 - Approval and Promulgation of Implementation Plans; State of Idaho; Regional Haze State...

    Science.gov (United States)

    2011-01-11

    ... address regional haze. The regional haze program, as reflected in the RHR, recognizes the importance of..., meteorology and atmospheric chemistry for aerosol formation to predict pollutant concentrations in the Class I... contribute to haze at specific Class I areas. WEP does not account for atmospheric chemistry (secondary...

  8. Developing Tighter Constraints on Exoplanet Biosignatures by Modeling Atmospheric Haze

    Science.gov (United States)

    Felton, Ryan; Neveu, Marc; Domagal-Goldman, Shawn David; Desch, Steven; Arney, Giada

    2018-01-01

    As we increase our capacity to resolve the atmospheric composition of exoplanets, we must continue to refine our ability to distinguish true biosignatures from false positives in order to ultimately distinguish a life-bearing from a lifeless planet. Of the possible true and false biosignatures, methane (CH4) and carbon dioxide (CO2) are of interest, because on Earth geological and biological processes can produce them on large scales. To identify a biotic, Earth-like exoplanet, we must understand how these biosignatures shape their atmospheres. High atmospheric abundances of CH4 produce photochemical organic haze, which dramatically alters the photochemistry, climate, and spectrum of a planet. Arney et al. (2017) have suggested that haze-bearing atmospheres rich in CO2 may be a type of biosignature because the CH4 flux required to produce the haze is similar to the amount of biogenic CH4 on modern Earth. Atmospheric CH4 and CO2 both affect haze-formation photochemistry, and the potential for hazes to form in Earth-like atmospheres at abiotic concentrations of these gases has not been well studied. We will explore a wide range of parameter space of abiotic concentration levels of these gases to determine what spectral signatures are possible from abiotic environments and look for measurable differences between abiotic and biotic atmospheres. We use a 1D photochemical model with an upgraded haze production mechanism to compare Archean and modern Earth atmospheres to abiotic versions while varying atmospheric CH4 and CO2 levels and atmospheric pressure. We will vary CO2 from a trace gas to an amount such that it dominates atmospheric chemistry. For CH4, there is uncertainty regarding the amount of abiotic CH4 that comes from serpentinizing systems. To address this uncertainty, we will model three cases: 1) assume all CH4 comes from photochemistry; 2) use estimates of modern-day serpentinizing fluxes, assuming they are purely abiotic; and 3) assume serpentinizing

  9. Hazing in orientation programmes in boys-only secondary schools

    Directory of Open Access Journals (Sweden)

    C Huysamer

    2013-01-01

    Full Text Available Hazing, associated with initiation, aims at taking newcomers from novice status to a status of functional and acknowledged members of a new group. However, the process is often dangerous, injurious, and usually secretive. Hazing may occur as an unauthorised component of institutionally sanctioned orientation programmes commonly held for new students at educational institutions at the beginning of the academic year. This study focuses on the occurrence of hazing elements in orientation programmes (OP for Grade 8 boys primarily run by Grade 12 learners in boys-only secondary schools in South Africa. A cross-sectional survey was conducted by administering a researcher-designed questionnaire to a non-probabilistic sample of 296 Grade 12 learners enrolled at three boys-only secondary schools in Johannesburg. The computer assisted analysis strategy included frequency distributions, exploratory factor analysis, and analysis of variance. Findings indicated that respondents generally agreed with regard to the structure, aims, and behaviours common to orientation programmes. Respondents strongly disagreed about the occurrence of physical and sexual abuse and activities aimed at discomfort in the OP; however, respondents showed ambivalence about the occurrence of certain activities, which may deteriorate into hazing. Prior experience of an orientation programme when in Grade 8; length of enrolment in the school, and boarder status affected respondents' perceptions of certain aspects of orientation programmes.

  10. Urban heat islands in China enhanced by haze pollution.

    Science.gov (United States)

    Cao, Chang; Lee, Xuhui; Liu, Shoudong; Schultz, Natalie; Xiao, Wei; Zhang, Mi; Zhao, Lei

    2016-08-23

    The urban heat island (UHI), the phenomenon of higher temperatures in urban land than the surrounding rural land, is commonly attributed to changes in biophysical properties of the land surface associated with urbanization. Here we provide evidence for a long-held hypothesis that the biogeochemical effect of urban aerosol or haze pollution is also a contributor to the UHI. Our results are based on satellite observations and urban climate model calculations. We find that a significant factor controlling the nighttime surface UHI across China is the urban-rural difference in the haze pollution level. The average haze contribution to the nighttime surface UHI is 0.7±0.3 K (mean±1 s.e.) for semi-arid cities, which is stronger than that in the humid climate due to a stronger longwave radiative forcing of coarser aerosols. Mitigation of haze pollution therefore provides a co-benefit of reducing heat stress on urban residents.

  11. Hazing in orientation programmes in boys-only secondary schools

    African Journals Online (AJOL)

    Art. #809, 22 pages, http://www.sajournalofeducation.co.za. Hazing in orientation programmes in boys-only secondary schools. C Huysamer. St Mary's School for Girls, Johannesburg. E M Lemmer ... The computer assisted analysis strategy included frequency distributions, exploratory ...... South African Journal of Science,.

  12. Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike Exoplanets

    Energy Technology Data Exchange (ETDEWEB)

    Arney, Giada N.; Meadows, Victoria S.; Tovar, Guadalupe; Schwieterman, Edward [University of Washington Astronomy Department, Box 351580, U.W. Seattle, WA 98195 (United States); Domagal-Goldman, Shawn D.; Deming, Drake; Robinson, Tyler D. [NASA Astrobiology Institute Virtual Planetary Laboratory, Box 351580, U.W. Seattle, WA 98195 (United States); Wolf, Eric T., E-mail: giada.n.arney@nasa.gov [University of Colorado at Boulder Laboratory for Astrophysics and Space Physics, 1234 Innovation Drive, Boulder, CO 80303 (United States)

    2017-02-10

    Hazes are common in known planetary atmospheres, and geochemical evidence suggests that early Earth occasionally supported an organic haze with significant environmental and spectral consequences. The UV spectrum of the parent star drives organic haze formation through methane photochemistry. We use a 1D photochemical-climate model to examine production of fractal organic haze on Archean Earth-analogs in the habitable zones of several stellar types: the modern and early Sun, AD Leo (M3.5V), GJ 876 (M4V), ϵ Eridani (K2V), and σ Boötis (F2V). For Archean-like atmospheres, planets orbiting stars with the highest UV fluxes do not form haze because of the formation of photochemical oxygen radicals that destroy haze precursors. Organic hazes impact planetary habitability via UV shielding and surface cooling, but this cooling is minimized around M dwarfs, whose energy is emitted at wavelengths where organic hazes are relatively transparent. We generate spectra to test the detectability of haze. For 10 transits of a planet orbiting GJ 876 observed by the James Webb Space Telescope , haze makes gaseous absorption features at wavelengths < 2.5 μ m 2–10 σ shallower than a haze-free planet, and methane and carbon dioxide are detectable at >5 σ . A haze absorption feature can be detected at 5 σ near 6.3 μ m, but a higher signal-to-noise ratio is needed to distinguish haze from adjacent absorbers. For direct imaging of a planet at 10 pc using a coronagraphic 10 m class ultraviolet–visible–near-infrared telescope, a UV–blue haze absorption feature would be strongly detectable at >12 σ in 200 hr.

  13. Public Sector Responses to Sustainable Haze Management in Upper Northern Thailand

    Directory of Open Access Journals (Sweden)

    Yongyut Tiyapairat

    2012-06-01

    Full Text Available This research focuses on urban haze in Upper Northern Thailand (UNT, where smoke haze often produce impacts on human health, tourism, and transportation. The objective was to better understand how the public sector responded to the haze impacts in policy review interviews and analyses of compiled haze-related data during 2007-2011. Moreover, integration of haze adaptation policy and coherency was also explored. The results revealed that Thailand has mainly implemented three National Haze Action Plans since 1997, together with laws and regulations for haze management. Further examination of haze policy at all levels of governance disclosed only vertical integration, whereas cross-boundary integration was reported only with the data and budget. Practically, manpower and function have not yet brought satisfactory outcomes. Moreover, the extent of state responses has been centralized –not decentralized from their centralized political structure. Low participation of people living in both urban and rural areas and cooperative efforts were identified as the main factors contributing to failures in combating smoke haze. Therefore, individuals are of utmost importance for effective solutions. There is a continuous need for prevention campaigns to enhance local people's understanding and participation as well as local communities' networking for solutions to the haze problem.

  14. Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike Exoplanets

    Science.gov (United States)

    Arney, Giada N.; Meadows, Victoria S.; Domagal-Goldman, Shawn D.; Deming, Drake; Robinson, Tyler D.; Tovar, Guadalupe; Wolf, Eric T.; Schwieterman, Edward

    2017-02-01

    Hazes are common in known planetary atmospheres, and geochemical evidence suggests that early Earth occasionally supported an organic haze with significant environmental and spectral consequences. The UV spectrum of the parent star drives organic haze formation through methane photochemistry. We use a 1D photochemical-climate model to examine production of fractal organic haze on Archean Earth-analogs in the habitable zones of several stellar types: the modern and early Sun, AD Leo (M3.5V), GJ 876 (M4V), ɛ Eridani (K2V), and σ Boötis (F2V). For Archean-like atmospheres, planets orbiting stars with the highest UV fluxes do not form haze because of the formation of photochemical oxygen radicals that destroy haze precursors. Organic hazes impact planetary habitability via UV shielding and surface cooling, but this cooling is minimized around M dwarfs, whose energy is emitted at wavelengths where organic hazes are relatively transparent. We generate spectra to test the detectability of haze. For 10 transits of a planet orbiting GJ 876 observed by the James Webb Space Telescope, haze makes gaseous absorption features at wavelengths methane and carbon dioxide are detectable at >5σ. A haze absorption feature can be detected at 5σ near 6.3 μm, but a higher signal-to-noise ratio is needed to distinguish haze from adjacent absorbers. For direct imaging of a planet at 10 pc using a coronagraphic 10 m class ultraviolet-visible-near-infrared telescope, a UV-blue haze absorption feature would be strongly detectable at >12σ in 200 hr.

  15. Urbanization and industrialization effects on haze in China: take Jinagsu for example

    Science.gov (United States)

    Liu, Duanyang; Wei, Jiansu; Kang, Zhiming; Yan, Wenlian; Cao, Lu; Chen, Hao

    2017-04-01

    Since the policy of ''Reform and Open to the Outside World'' was implemented from 1978, urbanization and industrialization have been rapid in China, leading to the expansion of urban areas, industrial district and population synchronous with swift advances in economy. With urban industrialization development underway, the urban heat island (UHI) and air pollution are being enhanced, together with vegetation coverage and relative humidity on the decrease. Based on the surface meteorological data of Jiangsu Province during 1980-2012, the climatic characteristics and the trends of haze were analyzed. The results indicated that during 1980-2012 haze days increased; in particular, severe and moderate haze days significantly increased. In the northern and coastal cities of Jiangsu Province China, haze days showed a significant increase. Haze often appeared in fall and winter, and rare in summer in the study area. It also occurred more often inland, and less along the coast. Haze occurred more often in June due to straw burning in the harvest time. The haze day increased during the 1990's over southern and southwestern Jiangsu Province; in central and northern Jiangsu, haze day increased after 2000. The continuous, regional and regional continuous haze days all showed increasing trends. As the urban area expanded each year, industrial emissions, coal consumption and car ownership increased accordingly, resulting in regional temperature increase and relative humidity decrease, which formed the urban heat island and dry island effects. Hence, haze formation and maintenance conditions became more favorable for more haze days, which led to the increase of haze days, and the significant increases of continuous, regional and regional continuous haze days.

  16. Titan-Like Exoplanets: Variations in Geometric Albedo and Effective Transit Height with Haze Production Rate

    Science.gov (United States)

    Checlair, Jade; McKay, Christopher P.; Imanaka, Hiroshi

    2016-01-01

    Extensive studies characterizing Titan present an opportunity to study the atmospheric properties of Titan-like exoplanets. Using an existing model of Titan's atmospheric haze, we computed geometric albedo spectra and effective transit height spectra for six values of the haze production rate (zero haze to twice present) over a wide range of wavelengths (0.2-2 microns). In the geometric albedo spectra, the slope in the UV-visible changes from blue to red when varying the haze production rate values from zero to twice the current Titan value. This spectral feature is the most effective way to characterize the haze production rates. Methane absorption bands in the visible-NIR compete with the absorbing haze, being more prominent for smaller haze production rates. The effective transit heights probe a region of the atmosphere where the haze and gas are optically thin and that is thus not effectively probed by the geometric albedo. The effective transit height decreases smoothly with increasing wavelength, from 376 km to 123 km at 0.2 and 2 microns, respectively. When decreasing the haze production rate, the methane absorption bands become more prominent, and the effective transit height decreases with a steeper slope with increasing wavelength. The slope of the geometric albedo in the UV-visible increases smoothly with increasing haze production rate, while the slope of the effective transit height spectra is not sensitive to the haze production rate other than showing a sharp rise when the haze production rate increases from zero. We conclude that geometric albedo spectra provide the most sensitive indicator of the haze production rate and the background Rayleigh gas. Our results suggest that important and complementary information can be obtained from the geometric albedo and motivates improvements in the technology for direct imaging of nearby exoplanets.

  17. Aerosol Optical Properties During Haze Event in Wuhan, Center China

    Science.gov (United States)

    MA, Y.; Zhang, M.; Gong, W.; Wang, L.; Yang, J.

    2016-12-01

    In recent years, an increasing occurrence of haze events has been reported in China. Wuhan City is a megalopolis in central China, which is faced with many aspects of environmental pressures from demographic explosion and industrial development. Except for Beijing-Tianjin-Hebei, the Yangtze Delta region, and the Pearl River Delta region, the number of haze events has been gradually increasing in central China. However, there are few study in this area. To further understand the mechanism of haze formation and diffusion, it is very important to analyze multiple atmospheric parameters. For example, Aerosol volume size distribution is an important atmospheric parameter to understand the physical and chemical properties of aerosols. Complex refractive index is an important parameter in determining the scattering and absorption properties of light, and is closely related to the hygroscopic properties and chemical compositions of the aerosol particles. Further, it is also required for performing radiative calculations and to understand the radiative effects of aerosols. Therefore, we will observe the haze aerosol by using sun-photometer CE-318, multifilter rotating shadowband radiometer, PM monitor and scanning mobility particle sizers which fitted at Wuhan University. Fall and winter records from 2015 to 2016 were used in this study. The volume concentration of fine particles is greater than those of coarse particles, being 0.1083 and 0.0863, respectively. The proportion of fine particulate is larger on haze days than on common days, obviously. Monthly average mass concentrations of PM1, PM2.5, and PM10 reaching 128 μg/m3, 146 μg/m3, and 202 μg/m3, respectively. The averaged columnar mass concentration of BC is 4.732 mg/m2 while that of BrC is 15.605 mg/m2, The BrC/BC ratio in Wuhan is about 3. Observation results show, the main source of city pollution come from large vehicle emissions caused heavy traffic, exogenous pollutants, and shallow Planetary Boundary Layer

  18. Source apportionment of Beijing air pollution during a severe winter haze event and associated pro-inflammatory responses in lung epithelial cells

    Science.gov (United States)

    Liu, Qingyang; Baumgartner, Jill; Zhang, Yuanxun; Schauer, James J.

    2016-02-01

    Air pollution is a leading risk factor for the disease burden in China and globally. Few epidemiologic studies have characterized the particulate matter (PM) components and sources that are most responsible for adverse health outcomes, particularly in developing countries. In January 2013, a severe haze event occurred over 25 days in urban Beijing, China. Ambient fine particulate matter (PM2.5) was collected at a central urban site in Beijing from January 16-31, 2013. We analyzed the samples for water soluble ions, metals, elemental carbon (EC), organic carbon (OC), and individual organic molecular markers including n-alkanes, hopanes, PAHs and sterols. Chemical components were used to quantify the source contributions to PM2.5 using the chemical mass balance (CMB) model by the conversion of the OC estimates combined with inorganic secondary components (e.g. NH4+, SO42-, NO3-). Water extracts of PM were exposed to lung epithelial cells, and supernatants recovered from cell cultures were assayed for the pro-inflammatory cytokines by a quantitative ELLSA method. Linear regression models were used to estimate the associations between PM sources and components with pro-inflammatory responses in lung epithelial cells following 24-hrs and 48-hrs of exposure. The largest contributors to PM2.5 during the monitoring period were inorganic secondary ions (53.2% and 54.0% on haze and non-haze days, respectively). Other organic matter (OM) contributed to a larger proportion of PM2.5 during haze days (16.9%) compared with non-haze days (12.9%), and coal combustion accounted for 10.9% and 8.7% on haze and non-haze days, respectively. We found PM2.5 mass and specific sources (e.g. coal combustion, traffic emission, dust, other OM, and inorganic secondary ions) were highly associated with inflammatory responses of lung epithelial cells. Our results showed greater responses in the exposure to 48-hr PM2.5 mass and its sources compared to 24-hr PM exposure, and that secondary and coal

  19. Haze growth on reticles: What's the RigHT thing to do?

    Science.gov (United States)

    McDonald, Steven M.; Chalom, Daniel V.; Green, Michael J.; McMurran, Jeffrey A.; Garrett, Michael B.; Dlouhy, David W.

    2009-04-01

    The authors are reporting on the comparison of various industry methods of managing, controlling and limiting haze growth on 193nm reticles. This comparison includes reporting on the results from the Reticle Haze Treatment (RigHT) process developed at Micron / Photronics Mask Technology Center and transferred to Photronics, Inc. This process provides 193nm PSM reticles that have shown no haze growth after excessive wafer exposures and are usable for the life of the reticle.

  20. Investigating the impact of haze on MODIS cloud detection

    Science.gov (United States)

    Mao, Feiyue; Duan, Miaomiao; Min, Qilong; Gong, Wei; Pan, Zengxin; Liu, Guangyi

    2015-12-01

    The cloud detection algorithm for passive sensors is usually based on a fuzzy logic system with thresholds determined from previous observations. In recent years, haze and high aerosol concentrations with high aerosol optical depth (AOD) occur frequently in China and may critically impact the accuracy of the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud detection. Thus, we comprehensively explore this impact by comparing the results from MODIS/Aqua (passive sensor), Cloud-Aerosol Lidar with Orthogonal Polarization/CALIPSO (lidar sensor), and Cloud Profiling Radar/CloudSat (microwave sensor) of the A-Train suite of instruments using an averaged AOD as an index for an aerosol concentration value. Case studies concerning the comparison of the three sensors indicate that MODIS cloud detection is reduced during haze events. In addition, statistical studies show that an increase in AOD creates an increase in the percentage of uncertain flags and a decrease in hit rate, a consistency index between consecutive sets of cloud retrievals. On average, AOD values lower than 0.1 give hit rate values up to 80.0% and uncertainty values lower than 16.8%, while AOD values greater than 1.0 reduce the hit rate below to 66.6% and increase the percentage of uncertain flags up to 46.6%. Therefore, we can conclude that the ability of MODIS cloud detection is weakened by large concentrations of aerosols. This suggests that use of the MODIS cloud mask, and derived higher-level products, in situations with haze requires caution. Further improvement of this retrieval algorithm is desired as haze studies based on MODIS products are of great interest in a number of related fields.

  1. [Aerosol Optical Properties in the Northern Suburb of Nanjing During Haze Days in January 2013].

    Science.gov (United States)

    Wang, Li-peng; Ma, Yan; Zheng, Jun; Cui, Fen-ping; Zhou, Yao-yao

    2016-03-15

    In January 2013 large-scale, continuous and severe haze occurred in Nanjing. Three-wavelength photoacoustic soot spectrometer (PASS-3) was used for real-time, online and situ measurements of aerosol absorption and scattering coefficients in the northern suburb of Nanjing during January 2013. The results indicated that the average aerosol absorption and scattering coefficients were (83.20 ± 35.24) Mm⁻¹ and (670.16 ± 136.44) Mm⁻¹ during haze days, which were 3.85 and 3.45 times higher than those on clean days, respectively. The diurnal variation of absorption and scattering coefficients showed a bimodal distribution. The mean single scattering albedo and scattering Angstrom exponent were (0.89 ± 0.04) and (1.30 ± 0.27) respectively, indicating the predominance of scattering fine particles during haze days in Nanjing. Aerosols could be significantly removed by precipitation. The absorption and scattering coefficients showed negative correlations with surface wind speed, and the single scattering albedo and Angstrom exponent showed positive correlations with wind speed. Aerosol scattering coefficient was highest under southeasterly wind, whereas the absorption coefficient was highest under the southwesterly wind. In the three haze pollution events, Haze 1 and Haze 2 were mainly affected by long-range transportation of pollutants. Haze 1 was mainly affected by aging air mass from north Nanjing, Haze 2 was mainly affected by biomass burning air mass from southwest Nanjing, while Haze 3 was mainly caused by the high sulfate.

  2. A spectral haze diagnostic feature for normalizing Landsat Thematic Mapper data

    Science.gov (United States)

    Crist, E. P.

    1985-01-01

    The effects of atmospheric haze on Thematic Mapper data, transformed to TM Tasseled Cap features, are illustrated by means of simulation. A spectral feature by which the amount of atmospheric haze may be inferred is derived and described for both simulated and actual TM data. Results presented for two actual TM scenes illustrate the diagnostic feature's sensitivity to changes in haze level as well as its insensitivity to scene-class-related variability. The method by which such a diagnostic feature might be incorporated into a haze normalization procedure is also discussed.

  3. The three-micron spectral feature of the Saturnian haze: Implications for the haze composition and formation process

    Science.gov (United States)

    Kim, S. J.; Sim, C. K.; Lee, D. W.; Courtin, R.; Moses, J. I.; Minh, Y. C.

    2012-05-01

    We retrieve a 3.4-μm spectral feature pertaining to the Saturnian haze from Cassini/VIMS Procyon occultation data obtained at 12 different altitudes from approximately 0.7 to 0.0018 mbar (Nicholson et al., 2006; Bellucci, 2008; Bellucci et al., 2009). The occultation occurred at 55°N latitude, at the edge of the “polar hood” region, where the extinction from stratospheric aerosols becomes strongest. The improved retrieval procedure eliminates the influence of strong adjacent CH4 absorption bands. We derive optical-depth spectra (hereafter called τ-spectra) of the haze on a relative scale and find that the τ-spectra exhibit a broad opacity peak at 3.36-3.41 μm. At the 0.7-0.025 mbar levels, the opacity is maximum at 3.41 μm, which approximately coincides with the 3.4-μm aliphatic C-H stretching bands typical of the solid state of hydrocarbons such as C5H12, C6H12, C6H14 and C7H14, but not limited to these molecules. At the 0.015-0.0018 mbar levels, however, maximum opacity occurs at 3.36 μm, similarly to the τ-spectra of Titan's haze (Kim et al., 2011), suggesting similar chemical composition and possibly a similar formation mechanism occurring in the upper stratospheres of Saturn and Titan. We also find that with mole fractions on the order of 1 ppb, C6H12, C6H14 and C7H14 can be saturated near the lower levels of the occultation, suggesting that condensation of these or other heavier hydrocarbons could contribute to the formation of the stratospheric haze particles at these altitudes on Saturn.

  4. Characteristics of bacterial and fungal aerosols during the autumn haze days in Xi'an, China

    Science.gov (United States)

    Li, Yanpeng; Fu, Honglei; Wang, Wei; Liu, Jun; Meng, Qinglong; Wang, Wenke

    2015-12-01

    In recent years, haze pollution has become one of the most critical environmental issues in Xi'an, China, with particular matter (PM) being one of the top pollutants. As an important fraction of PM, bioaerosols may have adverse effects on air quality and human health. In this study, to better understand the characteristics of such biological aerosols, airborne microbial samples were collected by using an Andersen six-stage sampler in Xi'an from October 8th to 22nd, 2014. The concentration, size distribution and genera of airborne viable bacteria and fungi were comparably investigated during the haze days and non-haze days. Correlations of bioaerosol levels with meteorological parameters and PM concentrations were also examined. The results showed that the daily average concentrations of airborne viable bacteria and fungi during the haze days, 1102.4-1736.5 and 1466.2-1703.9 CFU/m3, respectively, were not only much higher than those during the non-haze days, but also exceeded the recommended permissible limit values. Comparing to size distributions during the non-haze days, slightly different patterns for bacterial aerosols and similar single-peak distribution pattern for fungal aerosols were observed during the haze days. Moreover, more allergic and infectious genera (e.g. Neisseria, Aspergillus, and Paecilomyces) in bioaerosols were identified during the haze days than during non-haze days. The present results reveal that bioaerosols may have more significant effects on public health and urban air quality during the haze days than during non-haze days.

  5. Tourists’ Perception of Haze Pollution and the Potential Impacts on Travel: Reshaping the Features of Tourism Seasonality in Beijing, China

    OpenAIRE

    Aiping Zhang; Linsheng Zhong; Yong Xu; Hui Wang; Lijuan Dang

    2015-01-01

    Haze pollution has worsened and has received close attention by news agencies in the past two years. This type of environmental pollution might have a great effect on tourism image and the entire tourism industry of a destination. This study aimed to reveal the potential impacts of haze pollution on the tourism industry. Based on a case study in Beijing using questionnaires for potential tourists, awareness of haze pollution, impacts of haze pollution on travel and attitudes toward the impact...

  6. 76 FR 42557 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Regional Haze State...

    Science.gov (United States)

    2011-07-19

    ... progress goals for the first planning period, through 2018. Delaware's Regional Haze Plan contains the... regional planning process. Other specific requirements of the CAA and EPA's Regional Haze Rule and the... needed to achieve Delaware's share of emission reductions agreed upon through the regional planning...

  7. Male Team Sport Hazing Initiations in a Culture of Decreasing Homohysteria

    Science.gov (United States)

    Anderson, Eric; McCormack, Mark; Lee, Harry

    2012-01-01

    In this longitudinal ethnographic research, we report on 7 years of hazing rituals on two separate men's sports teams at one university in the United Kingdom. Using 38 in-depth interviews alongside naturalistic observations of the initiation rituals, we demonstrate that hazing activities have changed from being centered around homophobic same-sex…

  8. Indonesia's Fires and Haze: The Cost of Catastrophe (with a 2006 ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    1999-01-01

    Indonesia's Fires and Haze: The Cost of Catastrophe (with a 2006 update). Book cover Indonesia's Fires and Haze: The Cost of Catastrophe (with a 2006 update. Editor(s):. David Glover and Timothy Jessup. Publisher(s):. ISEAS, IDRC. January 1, 1999. ISBN: 9812300066. 160 pages. e-ISBN: 1552503321. Download PDF.

  9. It Happens, Just Not to Me: Hazing on a Canadian University Campus

    Science.gov (United States)

    Massey, Kyle D.; Massey, Jennifer

    2017-01-01

    Research on hazing in higher education has primarily focused on Greek-letter organizations and athletes, with little research beyond these two subsets of college students. The purpose of this qualitative study was to explore the attitudes of students from the general student population at a Canadian university with regard to hazing and identify…

  10. Quantifying the relationship between PM2.5 concentration, visibility and planetary boundary layer height for long-lasting haze and fog–haze mixed events in Beijing

    Directory of Open Access Journals (Sweden)

    T. Luan

    2018-01-01

    Full Text Available Air quality and visibility are strongly influenced by aerosol loading, which is driven by meteorological conditions. The quantification of their relationships is critical to understanding the physical and chemical processes and forecasting of the polluted events. We investigated and quantified the relationship between PM2.5 (particulate matter with aerodynamic diameter is 2.5 µm and less mass concentration, visibility and planetary boundary layer (PBL height in this study based on the data obtained from four long-lasting haze events and seven fog–haze mixed events from January 2014 to March 2015 in Beijing. The statistical results show that there was a negative exponential function between the visibility and the PM2.5 mass concentration for both haze and fog–haze mixed events (with the same R2 of 0.80. However, the fog–haze events caused a more obvious decrease of visibility than that for haze events due to the formation of fog droplets that could induce higher light extinction. The PM2.5 concentration had an inversely linear correlation with PBL height for haze events and a negative exponential correlation for fog–haze mixed events, indicating that the PM2.5 concentration is more sensitive to PBL height in fog–haze mixed events. The visibility had positively linear correlation with the PBL height with an R2 of 0.35 in haze events and positive exponential correlation with an R2 of 0.56 in fog–haze mixed events. We also investigated the physical mechanism responsible for these relationships between visibility, PM2.5 concentration and PBL height through typical haze and fog–haze mixed event and found that a double inversion layer formed in both typical events and played critical roles in maintaining and enhancing the long-lasting polluted events. The variations of the double inversion layers were closely associated with the processes of long-wave radiation cooling in the nighttime and short-wave solar radiation reduction in the

  11. Arctic sea ice, Eurasia snow, and extreme winter haze in China.

    Science.gov (United States)

    Zou, Yufei; Wang, Yuhang; Zhang, Yuzhong; Koo, Ja-Ho

    2017-03-01

    The East China Plains (ECP) region experienced the worst haze pollution on record for January in 2013. We show that the unprecedented haze event is due to the extremely poor ventilation conditions, which had not been seen in the preceding three decades. Statistical analysis suggests that the extremely poor ventilation conditions are linked to Arctic sea ice loss in the preceding autumn and extensive boreal snowfall in the earlier winter. We identify the regional circulation mode that leads to extremely poor ventilation over the ECP region. Climate model simulations indicate that boreal cryospheric forcing enhances the regional circulation mode of poor ventilation in the ECP region and provides conducive conditions for extreme haze such as that of 2013. Consequently, extreme haze events in winter will likely occur at a higher frequency in China as a result of the changing boreal cryosphere, posing difficult challenges for winter haze mitigation but providing a strong incentive for greenhouse gas emission reduction.

  12. Episode-Based Evolution Pattern Analysis of Haze Pollution: Method Development and Results from Beijing, China.

    Science.gov (United States)

    Zheng, Guangjie; Duan, Fengkui; Ma, Yongliang; Zhang, Qiang; Huang, Tao; Kimoto, Takashi; Cheng, Yafang; Su, Hang; He, Kebin

    2016-05-03

    Haze episodes occurred in Beijing repeatedly in 2013, resulting in 189 polluted days. These episodes differed in terms of sources, formation processes, and chemical composition and thus required different control policies. Therefore, an overview of the similarities and differences among these episodes is needed. For this purpose, we conducted one-year online observations and developed a program that can simultaneously divide haze episodes and identify their shapes. A total of 73 episodes were identified, and their shapes were linked with synoptic conditions. Pure-haze events dominated in wintertime, whereas mixed haze-dust (PM2.5/PM10 pollution level increased. The only OM-driven episode observed was associated with intensive biomass-burning activities. In comparison, haze evolution generally coincided with increasing sulfur and nitrogen oxidation ratios (SOR and NOR), indicating the enhanced production of secondary inorganic species. Applicability of these conclusions required further tests with simultaneously multisite observations.

  13. Distribution profile, health risk and elimination of model atmospheric SVOCs associated with a typical municipal garbage compressing station in Guangzhou, South China

    Science.gov (United States)

    Li, Guiying; Sun, Hongwei; Zhang, Zhengyong; An, Taicheng; Hu, Jianfang

    2013-09-01

    Semi-volatile organic compounds (SVOCs) air pollution caused by municipal garbage compressing process was investigated at a garbage compressing station (GCS). The most abundant contaminants were phthalate esters (PAEs), followed by polycyclic aromatic hydrocarbons (PAHs) and organic chlorinated pesticides (OCPs). ∑16PAHs concentrations ranged from 58.773 to 68.840 ng m-3 in gas and from 6.489 to 17.291 ng m-3 in particulate phase; ∑20OCPs ranged from 4.181 to 5.550 ng m-3 and from 0.823 to 2.443 ng m-3 in gas and particulate phase, respectively; ∑15PAEs ranged from 46.498 to 87.928 ng m-3 and from 414.765 to 763.009 ng m-3 in gas and particulate phase. Lung-cancer risk due to PAHs exposure was 1.13 × 10-4. Both non-cancer and cancer risk levels due to OCPs exposure were acceptable. Non-cancer hazard index of PAEs was 4.57 × 10-3, suggesting safety of workers as only exposure to PAEs at GCS. At pilot scale, 60.18% of PAHs, 70.89% of OCPs and 63.2% of PAEs were removed by an integrated biotrickling filter-photocatalytic reactor at their stable state, and health risk levels were reduced about 50%, demonstrating high removal capacity of integrated reactor.

  14. Titan's Oxygen Chemistry and its Impact on Haze Formation

    Science.gov (United States)

    Vuitton, Veronique; Carrasco, Nathalie; Flandinet, Laurene; Horst, Sarah; Klippenstein, Stephen; Lavvas, Panayotis; Orthous-Daunay, Francois-Regis; Quirico, Eric; Thissen, Roland; Yelle, Roger V.

    2016-10-01

    Though Titan's atmosphere is reducing with its 98% N2, 2% CH4 and 0.1% H2, CO is the fourth most abundant molecule with a uniform mixing ratio of ~50 ppm. Two other oxygen bearing molecules have also been observed in Titan's atmosphere: CO2 and H2O, with a mixing ratio of ~15 and ~1 ppb, respectively. The physical and chemical processes that determine the abundances of these species on Titan have been at the centre of a long-standing debate as they place constraints on the origin and evolution of its atmosphere [1]. Moreover, laboratory experiments have shown that oxygen can be incorporated into complex molecules, some of which are building blocks of life [2]. Finally, the presence of CO modifies the production rate and size of tholins [3, 4], which transposed to Titan's haze may have some strong repercussions on the temperature structure and dynamics of the atmosphere.We present here our current understanding of Titan's oxygen chemistry and of its impact on the chemical composition of the haze. We base our discussion on a photochemical model that describes the first steps of the chemistry and on state-of-the-art laboratory experiments for the synthesis and chemical analysis of aerosol analogues. We used a very-high resolution mass spectrometer (LTQ-Orbitrap XL instrument) to characterize the soluble part of tholin samples generated from N2/CH4/CO mixtures at different mixing ratios and with two different laboratory set-ups. These composition measurements provide some understanding of the chemical mechanisms by which CO affects particle formation and growth. Our final objective is to obtain a global picture of the fate and impact of oxygen on Titan, from its origin to prebiotic molecules to haze particles to material deposited on the surface.[1] S.M. Hörst et al., The origin of oxygen species in Titan's atmosphere, J. Geophys. Res., 113, E10006 (2008).[2] S.M. Hörst et al., Formation of amino acids and nucleotide bases in a Titan atmosphere simulation experiment

  15. Chemical composition, source, and process of urban aerosols during winter haze formation in Northeast China.

    Science.gov (United States)

    Zhang, Jian; Liu, Lei; Wang, Yuanyuan; Ren, Yong; Wang, Xin; Shi, Zongbo; Zhang, Daizhou; Che, Huizheng; Zhao, Hujia; Liu, Yanfei; Niu, Hongya; Chen, Jianmin; Zhang, Xiaoye; Lingaswamy, A P; Wang, Zifa; Li, Weijun

    2017-12-01

    The characteristics of aerosol particles have been poorly evaluated even though haze episodes frequently occur in winter in Northeast China. OC/EC analysis, ion chromatography, and transmission electron microscopy (TEM) were used to investigate the organic carbon (OC) and elemental carbon (EC), and soluble ions in PM 2.5 and the mixing state of individual particles during a severe wintertime haze episode in Northeast China. The organic matter (OM), NH 4 + , SO 4 2- , and NO 3 - concentrations in PM 2.5 were 89.5 μg/m 3 , 24.2 μg/m 3 , 28.1 μg/m 3 , and 32.8 μg/m 3 on the haze days, respectively. TEM observations further showed that over 80% of the haze particles contained primary organic aerosols (POAs). Based on a comparison of the data obtained during the haze formation, we generate the following synthetic model of the process: (1) Stable synoptic meteorological conditions drove the haze formation. (2) The early stage of haze formation (light or moderate haze) was mainly caused by the enrichment of POAs from coal burning for household heating and cooking. (3) High levels of secondary organic aerosols (SOAs), sulfates, and nitrates formation via heterogeneous reactions together with POAs accumulation promoted to the evolution from light or moderate to severe haze. Compared to the severe haze episodes over the North China Plain, the PM 2.5 in Northeast China analyzed in the present study contained similar sulfate, higher SOA, and lower nitrate contents. Our results suggest that most of the POAs and secondary particles were likely related to emissions from coal-burning residential stoves in rural outskirts and small boilers in urban areas. The inefficient burning of coal for household heating and cooking should be monitored during wintertime in Northeast China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Source characterization of ambient fine aerosol in Singapore during a haze episode in 2015

    Science.gov (United States)

    Hapsari Budisulistiorini, Sri; Riva, Matthieu; Williams, Michael; Miyakawa, Takuma; Komazaki, Yuichi; Chen, Jing; Surratt, Jason; Kuwata, Mikinori

    2017-04-01

    Recurring transboundary haze from Indonesia peatland fires in the previous decades has significantly elevated particulate matter (PM) concentration in Southeast Asia, particularly during the 2015 El Niño event. Previous studies have investigated chemical composition of particles emitted during haze episodes; however, they were limited to time-integrated samples and the number of identified compounds. Low time-resolution measurement results in co-variance of PM sources; therefore, higher time-resolution measurement is important in PM source apportionment. Between October 10-31, 2015, Aerodyne Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) was deployed for real-time chemical characterization of ambient submicron PM (NR-PM1) in Singapore. Simultaneously, PM2.5 filter samples were collected for molecular-level organic aerosol (OA) constituents, organic carbon (OC), elemental carbon (EC) and water-soluble OC (WSOC) analyses. OA constituents were quantified by gas chromatography interfaced to electron ionization mass spectrometry (GC/EI-MS) and ultra-performance liquid chromatography interfaced to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer operated in the negative ion mode (UPLC/(-)ESI-HR-Q-TOFMS). OA and SO42- are dominant components of the haze particles, accounting for ˜77% and ˜12% of the total NR-PM1 mass, respectively. OC/EC ratio of 4.8 might indicate formation of secondary OA (SOA) and aerosols from biomass burning, including those from peat burning. OA fraction from ToF-ACSM measurements was analyzed for source apportionment using a bilinear model through multi-linear engine algorithm (ME-2) in graphical user interface SoFi (Source Finder). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), peat burning OA (PBOA), low-volatility oxygenated OA (LV-OOA), and semi-volatile oxygenated OA (SV-OOA). The HOA factor shows a distinct diurnal profile peaking in the morning and

  17. Size-resolved aerosol chemical analysis of extreme haze pollution events during early 2013 in urban Beijing, China.

    Science.gov (United States)

    Tian, Shili; Pan, Yuepeng; Liu, Zirui; Wen, Tianxue; Wang, Yuesi

    2014-08-30

    Using size-resolved filter sampling and chemical characterization, high concentrations of water-soluble ions, carbonaceous species and heavy metals were found in both fine (PM2.1) and coarse (PM2.1-9) particles in Beijing during haze events in early 2013. Even on clear days, average mass concentration of submicron particles (PM1.1) was several times higher than that previously measured in most of abroad urban areas. A high concentration of particulate matter on haze days weakens the incident solar radiation, which reduces the generation rate of secondary organic carbon in PM1.1. We show that the peak mass concentration of particles shifted from 0.43-0.65μm on clear days to 0.65-1.1μm on lightly polluted days and to 1.1-2.1μm on heavily polluted days. The peak shifts were also found for the following species: organic carbon, elemental carbon, NH4(+), SO4(2-), NO3(-), K, Cu, Zn, Cd and Pb. Our findings demonstrate that secondary inorganic aerosols (36%) and organic matter (26%) dominated the fine particle mass on heavily polluted days, while their contribution reduced to 29% and 18%, respectively, on clear days. Besides fine particles, anthropogenic chemical species also substantially accumulated in the coarse mode, which suggests that particles with aerodynamic diameter larger than 2.1μm cannot be neglected during severe haze events. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Impact of regional haze towards air quality in Malaysia: A review

    Science.gov (United States)

    Latif, Mohd Talib; Othman, Murnira; Idris, Nurfathehah; Juneng, Liew; Abdullah, Ahmad Makmom; Hamzah, Wan Portia; Khan, Md Firoz; Nik Sulaiman, Nik Meriam; Jewaratnam, Jegalakshimi; Aghamohammadi, Nasrin; Sahani, Mazrura; Xiang, Chung Jing; Ahamad, Fatimah; Amil, Norhaniza; Darus, Mashitah; Varkkey, Helena; Tangang, Fredolin; Jaafar, Abu Bakar

    2018-03-01

    Haze is a common phenomenon afflicting Southeast Asia (SEA), including Malaysia, and has occurred almost every year within the last few decades. Haze is associated with high level of air pollutants; it reduces visibility and affects human health in the affected SEA countries. This manuscript aims to review the potential origin, chemical compositions, impacts and mitigation strategies of haze in Malaysia. "Slash and burn" agricultural activities, deforestation and oil palm plantations on peat areas, particularly in Sumatra and Kalimantan, Indonesia were identified as the contributing factors to high intensity combustions that results in transboundary haze in Malaysia. During the southwest monsoon (June to September), the equatorial SEA region experiences a dry season and thus an elevated number of fire events. The prevailing southerly and south-westerly winds allow the cross-boundary transportation of pollutants from the burning areas in Sumatra and Kalimantan in Indonesia, to Peninsular Malaysia and Malaysian Borneo, respectively. The dry periods caused by the El Niño - Southern Oscillation (ENSO) prolong the duration of poor air quality. The size range of particulate matter (PM) in haze samples indicates that haze is dominated by fine particles. Secondary inorganic aerosols (SIA, such as SO42- and NH4+) and organic substances (such as levoglucosan, LG) were the main composition of PM during haze episodes. Local vehicular emissions and industrial activities also contribute to the amount of pollutants and can introduce toxic material such as polyaromatic hydrocarbons (PAHs). Haze episodes have contributed to increasing hospital visits for treatments related to chronic obstructive pulmonary diseases, upper respiratory infections, asthma and rhinitis. Respiratory mortality increased 19% due to haze episodes. Children and senior citizens are more likely to suffer the health impacts of haze. The inpatient cost alone from haze episodes was estimated at around USD 91

  19. Assessment of semi-volatile organic compounds in drinking water sources in Jiangsu, China.

    Science.gov (United States)

    Wu, Yifeng; Jia, Yongzhi; Lu, Xiwu

    2013-08-01

    Many xenobiotic compounds, especially organic pollutants in drinking water, can cause threats to human health and natural ecosystems. The ability to predict the level of pollutants and identify their source is crucial for the design of pollutant risk reduction plans. In this study, 25 semi-volatile organic compounds (SVOCs) were assessed at 16 monitoring sites of drinking water sources in Jiangsu, east China, to evaluate water quality conditions and source of pollutants. Four multivariate statistical techniques were used for this analysis. The correlation test indicated that 25 SVOCs parameters variables had a significant spatial variability (Psources, i.e., agricultural residual pesticides, industrial sewage, water transportation vehicles and miscellaneous sources, were responsible for the presence of SVOCs in the drinking water sites examined, accounting for 89.6% of the total variance in the dataset. The analysis of site similarity showed that 16 sites could be divided into high, moderate, and low pollutant level groups at (D(link)/D(max))×25water sources. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Violence in youth sports: hazing, brawling and foul play.

    Science.gov (United States)

    Fields, S K; Collins, C L; Comstock, R D

    2010-01-01

    By separating hazing, brawling, and foul play and failing to recognise that their connection to sport binds them together into a cohesive subset of sport injury and youth violence, past research has failed to show how sports-related violence is a broad example of interpersonal violence. The acceptance of violence within the sporting culture may, in part, explain why sports-related violence has not yet been widely recognised as a public health concern. This review shows that sports-related violence, including hazing, brawling and foul play, occurs among youth athletes of all ages and in a variety of different sports. The few studies to address this issue have all acknowledged the dangers of sports-related violence; however, no incident tracking method has been developed. Future research must provide accurate national estimates of the incidence of sports-related violence among youth, identify associated risk factors, evaluate preventive interventions and identify effective methods of distributing and implementing evidence-based interventions. Monitoring the magnitude and distribution of the burden of sports-related violence and building the scientific infrastructure necessary to support the development and widespread application of effective sports-related prevention interventions are essential first steps toward a reduction in the incidence of sports-related violence.

  1. Proteome-Based Analysis of Colloidal Instability Enables the Detection of Haze-Active Proteins in Beer.

    Science.gov (United States)

    Schulte, Fabian; Flaschel, Erwin; Niehaus, Karsten

    2016-09-07

    Colloidal haze is a serious quality defect of bright beers that considerably reduces their shelf life and is thought to be triggered by hordeins, a class of proline-rich barley proteins. In this work, the proteomes of fresh and old beers were investigated in bottled pilsners and compared to the protein inventory of haze to identify specific haze-active proteins. Haze isolates dissolved in rehydration buffer contained high concentrations of proteins and sugars but provided protein gels with weak spot signals. Consequently, a treatment for the chemical deglycation with trifluoromethanesulfonic acid was applied, which resulted in the identification of protein Z4, LTP1, CMb, CMe, pUP13, 3a, and Bwiph as constituents of the haze proteome. Because only one hordein was detectable and the proline content in haze hydrolysates was lower than those of barley prolamins, our results suggest that this class of proteins is of minor importance for haze development.

  2. A High-Fidelity Haze Removal Method Based on HOT for Visible Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Hou Jiang

    2016-10-01

    Full Text Available Spatially varying haze is a common feature of most satellite images currently used for land cover classification and mapping and can significantly affect image quality. In this paper, we present a high-fidelity haze removal method based on Haze Optimized Transformation (HOT, comprising of three steps: semi-automatic HOT transform, HOT perfection and percentile based dark object subtraction (DOS. Since digital numbers (DNs of band red and blue are highly correlated in clear sky, the R-squared criterion is utilized to search the relative clearest regions of the whole scene automatically. After HOT transform, spurious HOT responses are first masked out and filled by means of four-direction scan and dynamic interpolation, and then homomorphic filter is performed to compensate for loss of HOT of masked-out regions with large areas. To avoid patches and halo artifacts, a procedure called percentile DOS is implemented to eliminate the influence of haze. Scenes including various land cover types are selected to validate the proposed method, and a comparison analysis with HOT and Background Suppressed Haze Thickness Index (BSHTI is performed. Three quality assessment indicators are selected to evaluate the haze removed effect on image quality from different perspective and band profiles are utilized to analyze the spectral consistency. Experiment results verify the effectiveness of the proposed method for haze removal and the superiority of it in preserving the natural color of object itself, enhancing local contrast, and maintaining structural information of original image.

  3. Particle number concentration, size distribution and chemical composition during haze and photochemical smog episodes in Shanghai.

    Science.gov (United States)

    Wang, Xuemei; Chen, Jianmin; Cheng, Tiantao; Zhang, Renyi; Wang, Xinming

    2014-09-01

    The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and photochemical smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibilitydistributed in winter and spring. The mean particle number concentration was about 17,000/cm(3) in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5-1μm and 1-10μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100nm and 100-200nm fractions during photochemical smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, photochemical smog and clean days were 102, 49, 15μm(3)/cm(3) and 949, 649, 206μm(2)/cm(3), respectively. As haze events got more severe, the number concentration of particles smaller than 50nm decreased, but the particles of 50-200nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4(+), SO4(2-) and NO3(-) increased greatly, followed by Na(+), K(+), Ca(2+) and Cl(-). These ions were very different in size-resolved particles during haze and photochemical smog episodes. Copyright © 2014. Published by Elsevier B.V.

  4. Latitudinal variations in Titan's methane and haze from Cassini VIMS observations

    Science.gov (United States)

    Penteado, P.F.; Griffith, C.A.; Tomasko, M.G.; Engel, S.; See, C.; Doose, L.; Baines, K.H.; Brown, R.H.; Buratti, B.J.; Clark, R.; Nicholson, P.; Sotin, Christophe

    2010-01-01

    We analyze observations taken with Cassini's Visual and Infrared Mapping Spectrometer (VIMS), to determine the current methane and haze latitudinal distribution between 60??S and 40??N. The methane variation was measured primarily from its absorption band at 0.61 ??m, which is optically thin enough to be sensitive to the methane abundance at 20-50 km altitude. Haze characteristics were determined from Titan's 0.4-1.6 ??m spectra, which sample Titan's atmosphere from the surface to 200 km altitude. Radiative transfer models based on the haze properties and methane absorption profiles at the Huygens site reproduced the observed VIMS spectra and allowed us to retrieve latitude variations in the methane abundance and haze. We find the haze variations can be reproduced by varying only the density and single scattering albedo above 80 km altitude. There is an ambiguity between methane abundance and haze optical depth, because higher haze optical depth causes shallower methane bands; thus a family of solutions is allowed by the data. We find that haze variations alone, with a constant methane abundance, can reproduce the spatial variation in the methane bands if the haze density increases by 60% between 20??S and 10??S (roughly the sub-solar latitude) and single scattering absorption increases by 20% between 60??S and 40??N. On the other hand, a higher abundance of methane between 20 and 50 km in the summer hemisphere, as much as two times that of the winter hemisphere, is also possible, if the haze variations are minimized. The range of possible methane variations between 27??S and 19??N is consistent with condensation as a result of temperature variations of 0-1.5 K at 20-30 km. Our analysis indicates that the latitudinal variations in Titan's visible to near-IR albedo, the north/south asymmetry (NSA), result primarily from variations in the thickness of the darker haze layer, detected by Huygens DISR, above 80 km altitude. If we assume little to no latitudinal methane

  5. Tropospheric haze and colors of the clear twilight sky.

    Science.gov (United States)

    Lee, Raymond L; Mollner, Duncan C

    2017-07-01

    At the earth's surface, clear-sky colors during civil twilights depend on the combined spectral effects of molecular scattering, extinction by tropospheric aerosols, and absorption by ozone. Molecular scattering alone cannot produce the most vivid twilight colors near the solar horizon, for which aerosol scattering and absorption are also required. However, less well known are haze aerosols' effects on twilight sky colors at larger scattering angles, including near the antisolar horizon. To analyze this range of colors, we compare 3D Monte Carlo simulations of skylight spectra with hyperspectral measurements of clear twilight skies over a wide range of aerosol optical depths. Our combined measurements and simulations indicate that (a) the purest antisolar twilight colors would occur in a purely molecular, multiple-scattering atmosphere, whereas (b) the most vivid solar-sky colors require at least some turbidity. Taken together, these results suggest that multiple scattering plays an important role in determining the redness of the antitwilight arch.

  6. A New Perspective on Formation of Haze-Fog: The Fuzzy Cognitive Map and Its Approaches to Data Mining

    Directory of Open Access Journals (Sweden)

    Zhen Peng

    2017-02-01

    Full Text Available Haze-fog has seriously hindered the sustainable development of the ecological environment and caused great harm to the physical and mental health of residents in China. Therefore, it is important to probe the formation of haze-fog for its early warning and prevention. The formation of haze-fog is, in fact, a fuzzy nonlinear process. The formation of haze-fog is such a complex process that it is difficult to simulate its dynamic evolution using traditional methods, mainly because of the lack of their consideration of the nonlinear relationships. It is, therefore, essential to explore new perspectives on the formation of haze-fog. In this work, previous research on haze-fog formation is summarized first. Second, a new perspective is proposed on the application of fuzzy cognitive map to the formation of haze-fog. Third, a data mining method based on the genetic algorithm is used to discover the causality values of a fuzzy cognitive map (FCM for hazefog formation. Finally, simulation results are obtained through an experiment using the fuzzy cognitive map and its data mining method for the formation of haze-fog. The validity of this approach is determined by definition of a simple rule and the Kappa values. Thus, this research not only provides a new idea using FCM modeling the formation of haze-fog, but also uses an effective method of FCM for solving the nonlinear dynamics of the haze-fog formation.

  7. Do Photochemical Hazes Cloud the Atmosphere of 51 Eri b?

    Science.gov (United States)

    Marley, Mark; Zahnle, Kevin; Moses, Julianne; Morley, Caroline

    2015-12-01

    The first young giant planet to be discovered by the Gemini Planet Imager was the ~ 2MJ planet 51 Eri b. This ~20 Myr old young Jupiter is the first directly imaged planet to show unmistakable methane in H band. To constrain the planet’s mass, atmospheric temperature, and composition, the GPI J and H band spectra as well as some limited photometric points were compared to the predictions of substellar atmosphere models. The best fitting models reported in the discovery paper (Macintosh et al. 2015) relied upon a combination of clear and cloudy atmospheric columns to reproduce the data. In the atmosphere of an object as cool as 700 K the global silicate and iron clouds would be expected to be found well below the photosphere, although strong vertical mixing in the low gravity atmosphere is a possibility. Instead, clouds of Na2S, as have been detected in brown dwarf atmospheres, are a likely source of particle opacity. As a third explanation we have explored whether atmospheric photochemistry, driven by the UV flux from the primary star, may yield hazes that also influence the observed spectrum of the planet. To explore this possibility we have modeled the atmospheric photochemistry of 51 Eri b using two state-of-the-art photochemical models, both capable of predicting yields of complex hydrocarbons under various atmospheric conditions. We also have explored whether photochemical products can alter the equilibrium temperature profile of the atmosphere. In our presentation we will summarize the modeling approach employed to characterize 51 Eri b, explaining constraints on the planet’s effective temperature, gravity, and atmospheric composition and also present results of our studies of atmospheric photochemistry. We will discuss whether photochemical hazes could indeed be responsible for the particulate opacity that apparently sculpts the spectrum of the planet.

  8. Transboundary smoke haze pollution in Malaysia: inpatient health impacts and economic valuation.

    Science.gov (United States)

    Othman, Jamal; Sahani, Mazrura; Mahmud, Mastura; Ahmad, Md Khadzir Sheikh

    2014-06-01

    This study assessed the economic value of health impacts of transboundary smoke haze pollution in Kuala Lumpur and adjacent areas in the state of Selangor, Malaysia. Daily inpatient data from 2005, 2006, 2008, and 2009 for 14 haze-related illnesses were collected from four hospitals. On average, there were 19 hazy days each year during which the air pollution levels were within the Lower Moderate to Hazardous categories. No seasonal variation in inpatient cases was observed. A smoke haze occurrence was associated with an increase in inpatient cases by 2.4 per 10,000 populations each year, representing an increase of 31 percent from normal days. The average annual economic loss due to the inpatient health impact of haze was valued at MYR273,000 ($91,000 USD). Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Typical types and formation mechanisms of haze in an Eastern Asia megacity, Shanghai

    National Research Council Canada - National Science Library

    Huang, K; Zhuang, G; Lin, Y; Fu, J. S; Wang, Q; Liu, T; Zhang, R; Jiang, Y; Deng, C; Fu, Q; Hsu, N. C; Cao, B

    2012-01-01

    .... This study provided a complementary picture of typical haze types and the formation mechanisms in megacities over China by using a synergy of ground-based monitoring, satellite and lidar observations...

  10. Structure of haze forming proteins in white wines: Vitis vinifera thaumatin-like proteins.

    Directory of Open Access Journals (Sweden)

    Matteo Marangon

    Full Text Available Grape thaumatin-like proteins (TLPs play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. Different isoforms of TLPs have different hazing potential and aggregation behavior. Here we present the elucidation of the molecular structures of three grape TLPs that display different hazing potential. The three TLPs have very similar structures despite belonging to two different classes (F2/4JRU is a thaumatin-like protein while I/4L5H and H2/4MBT are VVTL1, and having different unfolding temperatures (56 vs. 62°C, with protein F2/4JRU being heat unstable and forming haze, while I/4L5H does not. These differences in properties are attributable to the conformation of a single loop and the amino acid composition of its flanking regions.

  11. The Link between Knowledge, Attitudes and Practices in Relation to Atmospheric Haze Pollution in Peninsular Malaysia

    National Research Council Canada - National Science Library

    De Pretto, Laura; Acreman, Stephen; Ashfold, Matthew J; Mohankumar, Suresh K; Campos-Arceiz, Ahimsa

    2015-01-01

    .... Here we present a cross-sectional survey conducted among people in Kuala Lumpur and surrounds to assess the links between knowledge, attitudes, and practices in relation to the transboundary haze episodes...

  12. Characterization of size-resolved urban haze particles collected in summer and winter at Taiyuan City, China using quantitative electron probe X-ray microanalysis

    Science.gov (United States)

    Geng, Hong; Jin, Chun-Song; Zhang, Dong-Peng; Wang, Shu-Rong; Xu, Xiao-Tian; Wang, Xu-Ran; Zhang, Yuan; Wu, Li; Ro, Chul-Un

    2017-07-01

    The aim of the study is to characterize the size-resolved urban haze particles and investigate their modification in morphology and composition in summer and winter using the semi-quantitative electron probe X-ray microanalysis (EPMA) based on both scanning and transmission electron microscopies equipped with ultrathin-window energy dispersive X-ray spectrometers (SEM-EDX and TEM-EDX). The haze and non-haze particles were collected through a seven-stage May cascade impactor on Dec. 29-30, 2009 and Jan. 8-9 and July 11-14, 2010 in Taiyuan, a typical inland city in the North China Plain. Approximately 3752 atmospheric particles in the size ranges of 4-2 μm, 2-1 μm, 1-0.5 μm, and 0.5-0.25 μm in aerodynamic diameter were measured and identified according to their secondary electron or TEM images and elemental atomic concentrations calculated through a Monte Carlo simulation program. Results show that on the haze days many reacted or aged mineral dust particles were encountered, in which the sulfate-containing ones outnumbered the nitrate-containing ones in the winter samples while it was on the contrary in the summer samples, suggesting different haze formation and evolution mechanisms in summer and winter. Furthermore, in the haze events (especially in summer), many CNOS-rich particles, likely mixtures of water-soluble organic carbon with (NH4)2SO4 or NH4HSO4, were observed not only in the submicron but also in the super-micron fractions. The simultaneous observation of the fresh and aged CNOS-rich particles in the same SEM or TEM images implied that the status and components of secondary particles were complicated and changeable. The significant increase of both elemental concentration ratios of [N]/[S] and [C]/[S] in the aged ones compared to the fresh ones indicated that NH4NO3 and secondary organic matter were likely absorbed onto (NH4)2SO4 or NH4HSO4 particles and mixed with them. K-rich, Fe-rich, and heavy metal-containing particles in TEM-EDX measurement

  13. Application of the Junge- and Pankow-equation for estimating indoor gas/particle distribution and exposure to SVOCs

    Science.gov (United States)

    Salthammer, Tunga; Schripp, Tobias

    2015-04-01

    In the indoor environment, distribution and dynamics of an organic compound between gas phase, particle phase and settled dust must be known for estimating human exposure. This, however, requires a detailed understanding of the environmentally important compound parameters, their interrelation and of the algorithms for calculating partitioning coefficients. The parameters of major concern are: (I) saturation vapor pressure (PS) (of the subcooled liquid); (II) Henry's law constant (H); (III) octanol/water partition coefficient (KOW); (IV) octanol/air partition coefficient (KOA); (V) air/water partition coefficient (KAW) and (VI) settled dust properties like density and organic content. For most of the relevant compounds reliable experimental data are not available and calculated gas/particle distributions can widely differ due to the uncertainty in predicted Ps and KOA values. This is not a big problem if the target compound is of low (10-2 Pa) volatility, but in the intermediate region even small changes in Ps or KOA will have a strong impact on the result. Moreover, the related physical processes might bear large uncertainties. The KOA value can only be used for particle absorption from the gas phase if the organic portion of the particle or dust is high. The Junge- and Pankow-equation for calculating the gas/particle distribution coefficient KP do not consider the physical and chemical properties of the particle surface area. It is demonstrated by error propagation theory and Monte-Carlo simulations that parameter uncertainties from estimation methods for molecular properties and variations of indoor conditions might strongly influence the calculated distribution behavior of compounds in the indoor environment.

  14. The role of fog in haze episode in Tianjin, China: A case study for November 2015

    Science.gov (United States)

    Hao, Tianyi; Han, Suqin; Chen, Shucheng; Shan, Xiaolin; Zai, Ziying; Qiu, Xiaobin; Yao, Qing; Liu, Jingle; Chen, Jing; Meng, Lihong

    2017-09-01

    A severe haze episode that heavy fog appeared in its later stage emerged in Tianjin, east-central China, from November 27 to December 2, 2015. With meteorological data and pollutants monitoring data, the characteristics of this event and the role of fog in haze were investigated. During this process, the visibility was less than 600 m, especially in the haze and fog coexisting period (below 100 m). The peak value of PM2.5 mass concentration appeared in the haze only period was 446 μg/m3. The fog played a role in scavenging and removing PM2.5 during haze and fog coexisting period. The surface high humidity province can match well with the high PM2.5 concentration region in pollutants removal period. The fog top height was reduced to about 200 m by cold air. Although the cold air has arrived in Tianjin high altitude, the saturated layer below 200 m maintained for nearly 12 h. The heavy fog prevented the momentum in upper atmosphere from transmitting downward and caused the high altitude cold air difficult to reach the ground. The latent heat flux was transmitted upward ahead of sensible heat flux in pollutants removal period, indicating the increasing tendency of mechanical turbulence after fog dissipation. Turbulent kinetic energy (Etk) and the surface mean kinetic energy (E) also enhanced after fog dissipation. It demonstrates that the termination of haze was delayed by heavy fog.

  15. Singapore’s willingness to pay for mitigation of transboundary forest-fire haze from Indonesia

    Science.gov (United States)

    Lin, Yuan; Wijedasa, Lahiru S.; Chisholm, Ryan A.

    2017-02-01

    Haze pollution over the past four decades in Southeast Asia is mainly a result of forest and peatland fires in Indonesia. The economic impacts of haze include adverse health effects and disruption to transport and tourism. Previous studies have used a variety of approaches to assess the economic impacts of haze and the forest fires more generally. But no study has used contingent valuation to assess non-market impacts of haze on individuals. Here we apply contingent valuation to estimate impacts of haze on Singapore, one of most severely affected countries. We used a double-bounded dichotomous-choice survey design and the Kaplan-Meier-Turnbull method to infer the distribution of Singaporeans’ willingness to pay (WTP) for haze mitigation. Our estimate of mean individual WTP was 0.97% of annual income (n = 390). To calculate total national WTP, we stratified by income, the demographic variable most strongly related to individual WTP. The total WTP estimate was 643.5 million per year (95% CI [527.7 million, 765.0 million]). This estimate is comparable in magnitude to previously estimated impacts of Indonesia’s fires and also to the estimated costs of peatland protection and restoration. We recommend that our results be incorporated into future cost-benefit analyses of the fires and mitigation strategies.

  16. Understanding the recent trend of haze pollution in eastern China: roles of climate change

    Directory of Open Access Journals (Sweden)

    H.-J. Wang

    2016-04-01

    Full Text Available In this paper, the variation and trend of haze pollution in eastern China for winter of 1960–2012 were analyzed. With the overall increasing number of winter haze days in this period, the 5 decades were divided into three sub-periods based on the changes of winter haze days (WHD in central North China (30–40° N and eastern South China (south of 30° N for east of 109° E mainland China. Results show that WHD kept gradually increasing during 1960–1979, remained stable overall during 1980–1999, and increased fast during 2000–2012. The author identified the major climate forcing factors besides total energy consumption. Among all the possible climate factors, variability of the autumn Arctic sea ice extent, local precipitation and surface wind during winter is most influential to the haze pollution change. The joint effect of fast increase of total energy consumption, rapid decline of Arctic sea ice extent and reduced precipitation and surface winds intensified the haze pollution in central North China after 2000. There is a similar conclusion for haze pollution in eastern South China after 2000, with the precipitation effect being smaller and spatially inconsistent.

  17. Calibration of polydimethylsiloxane and XAD-Pocket passive air samplers (PAS) for measuring gas- and particle-phase SVOCs

    Science.gov (United States)

    Okeme, Joseph O.; Saini, Amandeep; Yang, Congqiao; Zhu, Jiping; Smedes, Foppe; Klánová, Jana; Diamond, Miriam L.

    2016-10-01

    Polydimethylsiloxane (PDMS) has seen wide use as the stationary phase of gas chromatographic columns, a passive sampler in water, and recently as a personal exposure sampler, while styrene divinyl-benzene copolymer (XAD) has been used extensively as a passive air sampler outdoors and indoors. We have introduced PDMS and XAD-Pocket as new indoor passive air samplers (PASs). The XAD-Pocket was designed to maximize the surface area-to-volume ratio of XAD and to minimize obstruction of air flow by the sampler housing. Methods were developed to expedite the use of these PASs for measuring phthalates, novel brominated flame-retardants (NFRs) and polybrominated diphenyl ethers (PBDEs) indoors. Sampling rates, Rs, (m3 day-1), were measured during a 7-week calibration study. Variability within and between analyte groups was not statistically significant. As a result, generic values of 0.8 ± 0.4 and 0.5 ± 0.3 m3 day-1 dm-2 are recommended for PDMS and XAD-Pocket for a 50-day deployment time, respectively. PDMS has a higher uptake rate and is easier to use than XAD-Pocket.

  18. Classification and its scale analysis of Severe Haze recently observed in Korea

    Science.gov (United States)

    Lee, K. M.; Eun, S. H.; Kim, B. G.; Kim, S. W.; Park, J. S.

    2015-12-01

    Cloud-aerosol-precipitation interactions mechanism is heavily dependent upon scale problems, and thus the first thing to understand its mechanism is to quantify the time (or spatial) scale of forcing driver, aerosols. This study is focused on recently occurring dense haze episodes accompanied with severe visibility impairment from 2011 to 2013 at two adjacent monitoring stations (Baengnyeongdo and Seoul) in Korea. Baengnyeongdo is an island being located 200 km west from Seoul. First of all, we have tested various flow charts to classify the various categories of heavy haze events by making use of aerosol scattering coefficient, PM2.5, and time lag difference of PM2.5 increase time at both stations, backward trajectories, and the ratio of PM2.5 to PM10 specifically in the quantitative perspective. One of them is selected for this study. Long range transported haze (LH) and Yellow Sand (YS) show very distinctive time lags of both PM2.5 and PM10 between both stations, but much higher ratio of PM2.5 to PM10 for LH in comparison with YS. Meanwhile urban haze (UH) has a significant increase in PM2.5 only at Seoul as easily expected. Time scales (e-folding time) of aerosol light scattering coefficients for LH and UH are 6-12 hrs and 7-16 hrs, respectively calculated for several episodes according to the criteria developed, which eventually corresponds to spatial scale of 120 - 240 km, 140 - 320 km, respectively by assuming average boundary wind speed, 5.6 m/s (Anderson et al., 2003). In general, long-range transported hazes have larger temporal and spatial dimension (about meso-a scale) than domestic hazes, after carefully designed classification of haze episodes. These results can be an useful basis for the estimation of regional aerosol radiative forcings in East Asia.

  19. Identification of two key genes controlling chill haze stability of beer in barley (Hordeum vulgare L).

    Science.gov (United States)

    Ye, Lingzhen; Huang, Yuqing; Dai, Fei; Ning, Huajiang; Li, Chengdao; Zhou, Meixue; Zhang, Guoping

    2015-06-11

    In bright beer, haze formation is a serious quality problem, degrading beer quality and reducing its shelf life. The quality of barley (Hordeum vulgare L) malt, as the main raw material for beer brewing, largely affects the colloidal stability of beer. In this study, the genetic mechanism of the factors affecting beer haze stability in barley was studied. Quantitative trait loci (QTL) analysis of alcohol chill haze (ACH) in beer was carried out using a Franklin/Yerong double haploid (DH) population. One QTL, named as qACH, was detected for ACH, and it was located on the position of about 108 cM in chromosome 4H and can explain about 20 % of the phenotypic variation. Two key haze active proteins, BATI-CMb and BATI-CMd were identified by proteomics analysis. Bioinformatics analysis showed that BATI-CMb and BATI-CMd had the same position as qACH in the chromosome. It may be deduced that BATI-CMb and BATI-CMd are candidate genes for qACH, controlling colloidal stability of beer. Polymorphism comparison between Yerong and Franklin in the nucleotide and amino acid sequence of BATI-CMb and BATI-CMd detected the corresponding gene specific markers, which could be used in marker-assisted selection for malt barley breeding. We identified a novel QTL, qACH controlling chill haze of beer, and two key haze active proteins, BATI-CMb and BATI-CMd. And further analysis showed that BATI-CMb and BATI-CMd might be the candidate genes associated with beer chill haze.

  20. An International Haze-Monitoring Network for Students.

    Science.gov (United States)

    Mims, Forrest M., III

    1999-07-01

    The Global Learning and Observations to Benefit the Environment (GLOBE) Program is an international network of schools in 71 countries that monitors up to 20 environmental parameters. Recently GLOBE added a haze-monitoring program to its measurement protocols. This network has the potential of providing important data about changes in the aerosol optical depth of the atmosphere caused by weather fronts, industrial and automobile pollution, and smoke from forest and brush fires and volcanic eruptions. Initially, monitoring will be conducted with an inexpensive, single-channel (520 nm) sun photometer. Unlike conventional sun photometers that use interference filters that are subject to unpredictable and rapid degradation, the GLOBE instrument uses a common light-emitting diode (LED) as a spectrally selective detector. Annual calibrations of two LED sun photometers at Mauna Loa Observatory since 1992 show that these instruments have insignificant degradation when compared to filter sun photometers. Some 175 prototype versions of a kit LED sun photometer have been assembled and tested by students from 16 countries at the University of the Nations and by more than 130 high school teachers in various pilot studies. These studies have demonstrated that even inexperienced students and teachers can quickly assemble a sun photometer from a kit of parts and perform a reliable angley calibration. The pilot studies have also demonstrated that sun photometery provides a convenient means for allowing students to perform hands-on science while they learn about various topics in history, electronics, algebra, statistics, graphing, and meteorology.

  1. [Spatial distribution characteristics of NMHCs during winter haze in Beijing].

    Science.gov (United States)

    Duan, Jing-Chun; Peng, Yan-Chun; Tan, Ji-Hua; Hao, Ji-Ming; Chai, Fa-He

    2013-12-01

    NMHCs and NOx samples were simultaneously collected and analyzed in six urban and suburban representative sampling sites (Sihuan, Tian'anmen, Pinguoyuan, Fatou, Beijing Airport and Miyun) during a typical haze period in winter 2005, Beijing. The concentrations of NMHCs during the sampling period in descending order were: Sihuan (1101.29 microg x m(-3)) > Fatou (692.40 microg x m(-3)) >Tian'anmen (653.28 microg x m(-3)) >Pinguoyuan (370.27 microg x m(-3)) > Beijing Airport (350.36 microg x m(-3)) > Miyun (199.97 microg x m(-3)). Atmospheric benzene pollution in Beijing was rather serious. The ratio of NMHCs/NOx ranged from 2.1 to 6.3, indicating that the peak ozone concentrations in urban Beijing were controlled by VOCs during the sampling period. Analysis of propylene equivalent concentration and ozone formation potential showed that the NMHCs reactivity descended in the order of Sihuan > Fatou > Tian'anmen > Pinguoyuan > Beijing Airport > Miyun. B/T values (0.52 to 0.76) indicated that besides motor vehicle emission, coal combustion and other emission sources were also the sources of NHMCs in Beijing in winter. The spatial variations of isoprene in Beijing indicated that the contribution of anthropogenic sources to isoprene increased and the emissions by biogenic sources decreased in winter. The spatial variations of propane and butane indicated that LPG emissions existed in the urban region of Beijing.

  2. Disequilibrium Chemistry and Photochemical Hazes in Temperate Jupiter Atmospheres

    Science.gov (United States)

    Gao, Peter; Zahnle, Kevin; Marley, Mark; Morley, Caroline

    2018-01-01

    Probing the chemical composition and aerosol content of "temperate Jupiters" - young, Jupiter-like worlds with effective temperatures between 400 and 800 K with no direct analogues in our own Solar System - may be possible with the James Webb Space Telescope and its direct imaging capabilities. The relatively low temperatures of these exoplanets, as compared to hot Jupiters, means that disequilibrium processes such as eddy mixing and photochemistry could play a dominant role in determining the composition of their atmospheres. In this work we use a photochemical model and a cloud microphysics model to investigate the impact of disequilibrium processes. We find that the resulting model atmospheres may be significantly different from one predicted by equilibrium chemistry. For example, upward transport of CO from depth leads to the formation of large amounts of CO2, such that observed CO2 abundances may not scale with metallicity the same way as in equilibrium models. In addition, formation of sulfur hazes from H2S loss could lead to UV heating of the atmosphere, and increased albedos at red-optical wavelengths. Our results show that disequilibrium models may be necessary to interpret future observations of these cool objects.

  3. Chemical partitioning of fine particle-bound metals on haze-fog and non-haze-fog days in Nanjing, China and its contribution to human health risks

    Science.gov (United States)

    Li, Huiming; Wu, Hongfei; Wang, Qin'geng; Yang, Meng; Li, Fengying; Sun, Yixuan; Qian, Xin; Wang, Jinhua; Wang, Cheng

    2017-01-01

    Information on chemical partitioning and associated risk of airborne metals, particularly during a haze-fog episode, is limited. Fine particulate matter (PM2.5) was collected during a severe haze-fog event in winter and non-haze-fog periods in summer and fall from an urban region of a typical Chinese mega-city, Nanjing. The particulate-bound metals (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sr, Ti, V, and Zn) were chemically fractionated in a four-step sequential extraction procedure and human health risk was assessed. During the haze-fog episode, PM2.5 was extremely elevated with a mean concentration of 281 μg/m3 (range: 77-431 μg/m3), whereas the mean PM2.5 concentrations in summer and fall periods were 86 μg/m3 (range: 66-111 μg/m3) and 77 μg/m3 (range: 42-131 μg/m3), respectively. All elements had significantly higher concentrations and many metals exceeded relevant limits on haze-fog days. K, Na, Sr, Zn, Mo, Ca, Cd, Mg, Mn, Cu, Ba, Cr and As all showed relatively high proportions of the soluble and exchangeable fraction and strong bio-accessible potential. High temperature and humidity may increase the bio-accessible fraction of many airborne metals. The hazard index for potential toxic metals was 0.115, which was lower than the safe limit (1). However, the combined carcinogenic risk was 1.32 × 10- 6 for children and 5.29 × 10- 6 for adults, with both values being higher than the precautionary criterion (10- 6). Results of this study provide information for the behavior and risk mitigation of airborne metals.

  4. A case-crossover analysis of forest fire haze events and mortality in Malaysia

    Science.gov (United States)

    Sahani, Mazrura; Zainon, Nurul Ashikin; Wan Mahiyuddin, Wan Rozita; Latif, Mohd Talib; Hod, Rozita; Khan, Md Firoz; Tahir, Norhayati Mohd; Chan, Chang-Chuan

    2014-10-01

    The Southeast Asian (SEA) haze events due to forest fires are recurrent and affect Malaysia, particularly the Klang Valley region. The aim of this study is to examine the risk of haze days due to biomass burning in Southeast Asia on daily mortality in the Klang Valley region between 2000 and 2007. We used a case-crossover study design to model the effect of haze based on PM10 concentration to the daily mortality. The time-stratified control sampling approach was used, adjusted for particulate matter (PM10) concentrations, time trends and meteorological influences. Based on time series analysis of PM10 and backward trajectory analysis, haze days were defined when daily PM10 concentration exceeded 100 μg/m3. The results showed a total of 88 haze days were identified in the Klang Valley region during the study period. A total of 126,822 cases of death were recorded for natural mortality where respiratory mortality represented 8.56% (N = 10,854). Haze events were found to be significantly associated with natural and respiratory mortality at various lags. For natural mortality, haze events at lagged 2 showed significant association with children less than 14 years old (Odd Ratio (OR) = 1.41; 95% Confidence Interval (CI) = 1.01-1.99). Respiratory mortality was significantly associated with haze events for all ages at lagged 0 (OR = 1.19; 95% CI = 1.02-1.40). Age-and-gender-specific analysis showed an incremental risk of respiratory mortality among all males and elderly males above 60 years old at lagged 0 (OR = 1.34; 95% CI = 1.09-1.64 and OR = 1.41; 95% CI = 1.09-1.84 respectively). Adult females aged 15-59 years old were found to be at highest risk of respiratory mortality at lagged 5 (OR = 1.66; 95% CI = 1.03-1.99). This study clearly indicates that exposure to haze events showed immediate and delayed effects on mortality.

  5. UV–Vis Light-induced Aging of Titan’s Haze and Ice

    Science.gov (United States)

    Couturier-Tamburelli, Isabelle; Piétri, Nathalie; Le Letty, Vincent; Chiavassa, Thierry; Gudipati, Murthy

    2018-01-01

    The study of the photochemical aging of aerosols is an important tool for understanding Titan’s stratosphere/troposphere composition and evolution, particularly the haze. Laboratory simulations of the photoreactivity of the haze aerosol analogs provide insight into the photochemical evolution of Titan’s atmosphere at and below the haze layers. Here we use experimental simulations to investigate the evolution of the laboratory analogs of these organic aerosols under ultraviolet (UV)–visible (Vis) photons, which make it through the haze layers during their sedimentation process. We present experimental results for the aging of Titan’s aerosol analogs obtained from two dominant nitrogen-containing organics, HC3N and HCN, under simulated Titan atmospheric conditions (photons and temperature). We report that volatile nitriles condensed on haze particles could be incorporated through photochemistry and provide one such sink mechanism for nitrile compounds. We provide laboratory evidence that the organic aerosols could photochemically evolve during their sedimentation through Titan’s atmosphere.

  6. Study on storage components and application performance for mask haze prevention

    Science.gov (United States)

    Chen, Shu Li; Fang, T. Y.; Lai, Ryan; Lee, Chun Der; Yeh, Shang Hao; Chen, Timmy

    2012-06-01

    The amount of sulfate ion on mask surface will increase haze defect growing once exposed by an ArF laser. And then the storage conditions influence amount of sulfate ion was investigated. Therefore, our evaluations used extraction method and IC (Ion Chromatography) test to examine the amount of ions for current mask pods and storage cabinet. The pods included the different material of ABS (Amber and Violet Acrylonitrile Butadiene Styrene), PMMA (Polymethyl meth acrylate), PEEK (Polyether ether ketone), Metal case, LCP (Liquid Crystal Plastic), PC+CF (Polycarbonate with carbon fiber) and PC+CNT (Polycarbonate with Carbon nano-tubes). Moreover, PSM (Phase shift Mask) haze life time and dosage was strongly interrelated with the amount of chemical contaminant aggregation for storage pods. The other factor to impact haze generation of ArF PSM masks is the condition of storage environment; therefore, we're comparing the different structure of cabinet from different vendors to extend mask life time. They included 3 types of storage system: cabinet with XCDA, purge cabinet and purge stocker. According to this point of view, we used the impinger and Cr Blank IC test to verify the best storage system and remove some of the polluted parts for cabinet to ensure haze free. Resulting from our investigations, we setup storage BKM (Best Known Method) and monitor haze performance to record their results. Consequently, the optimization components of storages will contribute the enormously economical benefit.

  7. Instrument for the in situ measurement of haze in aircraft windscreens

    Science.gov (United States)

    Gallagher, Frank W., III; Brock, Fred V.

    1996-06-01

    Current instruments for the measurement of haze in aircraft windscreens generally require the removal, and possible destruction, of the windscreen to conduct the test. Most instruments available for haze measurement of samples taken from a windscreen cannot be used in situ. This is because the standard definition of haze requires measurement of light scattered in transmission through the sample so the instrument must have a light source and a light detector on opposite sides of the sample. One portable instrument has been reported in the literature; however, it is not readily available and, in the reported form, is subject to errors due to orientation of the instrument with respect to the sample under test, and due to background light. The orientation error arises from the typically more or less parallel orientation of scratches in the windscreen. If haze is measured in just one orientation through the sample, the haze value will depend upon whether the measurement plane is parallel to scratches or not. Background light will also affect the reading if the instrument has not been designed to eliminate most ambient light and to compensate for the remaining illumination. We report on the development of a new prototype instrument that is portable, easy to use, is relatively insensitive to ambient light, and will be less influenced by scratch orientation.

  8. Towards maximizing the haze effect of electrodes for high efficiency hybrid tandem solar cell

    Science.gov (United States)

    Vincent, Premkumar; Song, Dong-Seok; Kwon, Hyeok Bin; Kim, Do-Kyung; Jung, Ji-Hoon; Kwon, Jin-Hyuk; Choe, Eunji; Kim, Young-Rae; Kim, Hyeok; Bae, Jin-Hyuk

    2018-02-01

    In this study, we executed optical simulations to compute the optimum power conversion efficiency (PCE) of a-Si:H/organic photovoltaic (OPV) hybrid tandem solar cell. The maximum ideal short circuit current density (Jsc,max) of the tandem solar cell is initially obtained by optimizing the thickness of the active layer of the OPV subcell for varying thickness of the a-Si:H bottom subcell. To investigate the effect of Haze parameter on the ideal short-circuit current density (Jsc,ideal) of the solar cells, we have varied the haze ratio for the TCO electrode of the a-Si:H subcell in the tandem structure. The haze ratio was obtained for various root mean square (RMS) roughness of the TCO of the front cell. The effect of haze ratio on the Jsc,ideal on the tandem structured solar cell was studied, and the highest Jsc,ideal was obtained at a haze of 55.5% when the thickness of the OPV subcell was 150 nm and that of the a-Si:H subcell was 500 nm.

  9. Reformulating atmospheric aerosol thermodynamics and hygroscopic growth into fog, haze and clouds

    Directory of Open Access Journals (Sweden)

    S. Metzger

    2007-06-01

    Full Text Available Modeling atmospheric aerosol and cloud microphysics is rather complex, even if chemical and thermodynamical equilibrium is assumed. We show, however, that the thermodynamics can be considerably simplified by reformulating equilibrium to consistently include water, and transform laboratory-based concepts to atmospheric conditions. We generalize the thermodynamic principles that explain hydration and osmosis – merely based on solute solubilities – to explicitly account for the water mass consumed by hydration. As a result, in chemical and thermodynamical equilibrium the relative humidity (RH suffices to determine the saturation molality, including solute and solvent activities (and activity coefficients, since the water content is fixed by RH for a given aerosol concentration and type. As a consequence, gas/liquid/solid aerosol equilibrium partitioning can be solved analytically and non-iteratively. Our new concept enables an efficient and accurate calculation of the aerosol water mass and directly links the aerosol hygroscopic growth to fog, haze and cloud formation.

    We apply our new concept in the 3rd Equilibrium Simplified Aerosol Model (EQSAM3 for use in regional and global chemistry-transport and climate models. Its input is limited to the species' solubilities from which a newly introduced stoichiometric coefficient for water is derived. Analogously, we introduce effective stoichiometric coefficients for the solutes to account for complete or incomplete dissociation. We show that these coefficients can be assumed constant over the entire activity range and calculated for various inorganic, organic and non-electrolyte compounds, including alcohols, sugars and dissolved gases. EQSAM3 calculates the aerosol composition and gas/liquid/solid partitioning of mixed inorganic/organic multicomponent solutions and the associated water uptake for almost 100 major compounds. It explicitly accounts for particle hygroscopic growth by

  10. Semi-volatile organic pollutants in Jordanian surface water

    Directory of Open Access Journals (Sweden)

    Yahya R. Tahboub

    2017-05-01

    Full Text Available Jordan relies heavily on rainwater stored in reservoirs because it has extremely limited alternative water resources. These reservoirs are essential for drinking water and irrigation, so monitoring their water quality is extremely important. In this study we monitored 55 semi-volatile organic chemicals (SVOCs in monthly samples from the Zarqa River and three reservoirs between April and August 2010, and also screened the samples for non-target pollutants. Twelve SVOCs were detected and quantified at King Talal Dam followed by ten at Zarqa River and four each at Wadi Al-Arab and Mujib dams. Phenol and phthalate esters were detected at wide range concentrations (0.01–25 μg/L in all water samples. Phenol has the highest level at the Zarqa River (18.5 ± 5.5 μg/L followed by King Talal (12.5 ± 2.5 μg/L and Wadi Al-Arab (2.5 ± 0.63 μg/L. Phthalate esters (total were detected at the Zarqa River, King Talal, Wadi Al-Arab, and Mujib dams at levels 3.85, 3.75, 1.03 and 0.12 μg/L. Other contaminants, including polyaromatic hydrocarbons (PAHs, were detected at low concentrations in the King Talal Dam reservoir and Zarqa River samples. Two non-targeted phosphate plasticizers, tri-n-butylphosphate and tris(2-chloroethylphosphate were identified in the July and August Zarqa River samples. A comparison study reveals that SVOC pollution of surface water in Jordan is within acceptable international limits, but long-term monitoring programs should be implemented.

  11. Haze image enhancement based on space fractional-order partial differential equation

    Science.gov (United States)

    Xue, Wendan; Zhao, Fengqun

    2017-07-01

    Based on good amplitude frequency characteristics and the spatial global correlation of fractional-order differential, an energy functional of haze image enhancement is established by taking fractional derivative on both sides of the atmospheric physics scattering model, and a haze image enhancement model based on space fractional-order partial differential equation is obtained by using steepest descent method. Based on fast wavelet transform, the low-frequency part of patch transmission and the high-frequency part of point transmission are fused to estimate the transmission. Finally, the numerical solution of the fractional-order partial differential equation is obtained by the finite difference method. The experimental results show that the algorithm can improve the contrast, brightness and clarity of the image, and it is an effective image enhancement method for haze images.

  12. The research on aging failure rate and optimization estimation of protective relay under haze conditions

    Science.gov (United States)

    Wang, Ying-kang; Zhou, Meng-ran; Yang, Jie; Zhou, Pei-qiang; Xie, Ying

    2017-01-01

    In the fog and haze, the air contains large amounts of H2S, SO2, SO3 and other acids, air conductivity is greatly improved, the relative humidity is also greatly increased, Power transmission lines and electrical equipment in such an environment will increase in the long-running failure ratedecrease the sensitivity of the detection equipment, impact protection device reliability. Weibull distribution is widely used in component failure distribution fitting. It proposes a protection device aging failure rate estimation method based on the least squares method and the iterative method,.Combined with a regional power grid statistics, computing protective equipment failure rate function. Binding characteristics of electrical equipment operation status under haze conditions, optimization methods, get more in line with aging protection equipment failure under conditions of haze characteristics.

  13. What Causes Haze Pollution? An Empirical Study of PM2.5 Concentrations in Chinese Cities

    Directory of Open Access Journals (Sweden)

    Jiannan Wu

    2016-01-01

    Full Text Available In recent years, many areas of China have suffered from serious haze pollution, which greatly affects human health and daily life. It is of policy importance to understand the factors that influence the spatial concentration of PM2.5. Based on data from 74 cities with PM2.5 monitoring stations in 2013 and 2014, this study presents the overall haze situation in China and explores the determinants of PM2.5 using a random-effects model, as well as a set of OLS regressions. The results indicate that PM2.5 is significantly correlated with the industrial proportion, the number of motor vehicles, and household gas consumption, while public financial expenditure on energy saving and environmental protection does not show statistically significant effects. The analysis implies that China should adjust its economic structure and optimizes environmental governance to effectively respond to haze pollution.

  14. Assessing the Performance of the Photovoltaic Cells on the Effects of Yellow Dust Events and Haze in Seoul, Korea

    Science.gov (United States)

    Choi, Jiyeon; Kim, Yong Pyo; Wee, DaeHyun

    2016-04-01

    We analyze the potential effects of the Asian yellow dust Events and haze on the performance of Korean photovoltaic systems. Particulate matters from the Asian yellow dust outbreaks in the deserts of Mongolia and northern China are typically transported to Korea. Haze is an atmospheric phenomenon where dust, smoke and other dry particles obscure the clarity of the sky. Hence, we conjecture that the effects of the Asian yellow dust and haze block the incident solar irradiance. The potential reduction of the solar spectral irradiance due to Asian yellow dust events and haze in Korea is investigated using a clear-sky spectral radiation model, and the performance of photovoltaic systems under reduced irradiance is estimated by using a simple analytic model representing typical photovoltaic cells. Comparison of photovoltaic performance under Asian dust events, haze and that under a clear condition is made to evaluate overall influence of the particulate air pollution, respectively.

  15. Slicing The 2010 Saturn's Storm: Upper Clouds And Hazes

    Science.gov (United States)

    Perez-Hoyos, Santiago; Sanz-Requena, J. F.; Sanchez-Lavega, A.; Hueso, R.

    2012-10-01

    At the end of 2010 a small storm erupted in Saturn's northern mid-latitudes. Starting from a localized perturbation, it grew up to be a global-scale disturbance and cover the whole latitude band by February, 2011 (Fletcher et al. 2011, Science 332; Sánchez-Lavega et al. 2011, Nature 475; Fischer et al. 2011, Nature 475). By June, 2011 the storm was facing its end and gradually disappeared (Sánchez-Lavega et al. 2012, Icarus 220). In this work we use the observations acquired by the Cassini ISS instrument during the whole process to investigate the vertical cloud and haze structure above the ammonia condensation level (roughly 1 bar). Cassini ISS observations cover visual wavelengths from the blue to the near-infrared including two methane absorption bands. Such observations have been modeled using a radiative transfer code which reproduces the atmospheric reflectivity as a function of observation/illumination geometry and wavelength together with a retrieval technique to find maximum likelihood atmospheric models. This allows to investigate some atmospheric parameters: cloud-top pressures, aerosol optical thickness and particle absorption, among others. We will focus on two aspects: (1) maximum likelihood models for the undisturbed reference atmosphere in the 15°N to 45°N band before and after the disturbance; (2) models for particular structures during the development of the global-scale phenomenon. Our results show a general increase of particle density and single-scattering albedo inside the storm. However, some discrete features showing anomalous structure and related to the storm peculiar dynamics will also be discussed. Acknowledgments: This work was supported by the Spanish MICIIN project AYA2009-10701 with FEDER funds, by Grupos Gobierno Vasco IT-464-07 and by Universidad País Vasco UPV/EHU through program UFI11/55.

  16. A campaign for investigating aerosol optical properties during winter hazes over Shijiazhuang, China

    Science.gov (United States)

    Qin, Kai; Wang, Luyao; Wu, Lixin; Xu, Jian; Rao, Lanlan; Letu, Husi; Shi, Tiewei; Wang, Runfeng

    2017-12-01

    As the capital of the most air-polluted Hebei province in China, Shijiazhuang has been suffering serious haze pollutions especially during wintertime. An integrated campaign for investigating aerosol optical properties under haze conditions over Shijiazhuang were carried out using a sunphotometer, an aethalometer and a lidar in the winter from late 2013 to early 2014. The results indicated that the haze episodes during the measurement period were severer and more frequent over Shijiazhuang than Beijing. Under heavy pollution conditions (PM2.5 > 150 μg/m3) over Shijiazhuang, fine-mode fractions of AOD500nm were larger than 0.80 with more dispersive angstrom exponent due to hygroscopic growth. The mean values of SSA over Shijiazhuang were smaller than those over Beijing both in this study and the severe haze episodes in January 2013, suggesting that there were more fine-mode absorbing particles over Shijiazhuang. More significant spectrally-dependence of imaginary part of refractive index over Shijiazhuang implies larger relative magnitude of brown carbon (BrC) as compared to Beijing. The black carbon (BC) measurement displayed extremely high records with a larger ratio of BC to PM2.5 (12.11% in average) comparing with other cities in China. The high carbonaceous aerosols (BC and BrC) should be attributed to large amounts of coal consumption. During the hazes with high BC concentrations, the daily maximal planetary boundary layer (PBL) heights were consistently lower than 500 m, implying the impacts of BC aerosols on the PBL development and hence enhance the surface haze pollution.

  17. Geospatial Analysis of Atmospheric Haze Effect by Source and Sink Landscape

    Science.gov (United States)

    Yu, T.; Xu, K.; Yuan, Z.

    2017-09-01

    Based on geospatial analysis model, this paper analyzes the relationship between the landscape patterns of source and sink in urban areas and atmospheric haze pollution. Firstly, the classification result and aerosol optical thickness (AOD) of Wuhan are divided into a number of square grids with the side length of 6 km, and the category level landscape indices (PLAND, PD, COHESION, LPI, FRAC_MN) and AOD of each grid are calculated. Then the source and sink landscapes of atmospheric haze pollution are selected based on the analysis of the correlation between landscape indices and AOD. Next, to make the following analysis more efficient, the indices selected before should be determined through the correlation coefficient between them. Finally, due to the spatial dependency and spatial heterogeneity of the data used in this paper, spatial autoregressive model and geo-weighted regression model are used to analyze atmospheric haze effect by source and sink landscape from the global and local level. The results show that the source landscape of atmospheric haze pollution is the building, and the sink landscapes are shrub and woodland. PLAND, PD and COHESION are suitable for describing the atmospheric haze effect by source and sink landscape. Comparing these models, the fitting effect of SLM, SEM and GWR is significantly better than that of OLS model. The SLM model is superior to the SEM model in this paper. Although the fitting effect of GWR model is more unsuited than that of SLM, the influence degree of influencing factors on atmospheric haze of different geography can be expressed clearer. Through the analysis results of these models, following conclusions can be summarized: Reducing the proportion of source landscape area and increasing the degree of fragmentation could cut down aerosol optical thickness; And distributing the source and sink landscape evenly and interspersedly could effectively reduce aerosol optical thickness which represents atmospheric haze

  18. Identification of chemical compositions and sources of atmospheric aerosols in Xi'an, inland China during two types of haze events.

    Science.gov (United States)

    Li, Jianjun; Wang, Gehui; Ren, Yanqin; Wang, Jiayuan; Wu, Can; Han, Yanni; Zhang, Lu; Cheng, Chunlei; Meng, Jingjing

    2016-10-01

    High time resolution (1h) of TSP filter samples was collected in Xi'an in inland China from December 5 to 13, 2012, during which a 9-day long of haze episode occurred. The hazy days were classified as two types, i.e., Light-haze period with moderate degradation in visibility (5-10km) and relatively dry conditions (RH: 53±19%) and Severe-haze period with a daily visibility less than 5km and humid conditions (RH: 73±14%). TSP in the two periods (415±205 and 530±180μgm(-3) in Light-haze and Severe-haze periods, respectively) was comparable, but crustal Fe and Ca elements presented higher concentrations and strong correlation (R(2)=0.72) with TSP in Light-haze period. SO4(2-), NO3(-) and NH4(+) in Light-haze period were 16±5.9, 12±6.7 and 4.1±2.8μgm(-3), respectively, and increased dramatically to 51±15, 44±9.7 and 23±5.6μgm(-3) in Severe-haze period. Contributions of Fe and Ca to TSP decreased from 9.2% in Light-haze period to 5.3% in Severe-haze period, but those of SO4(2-), NO3(-) and NH4(+) increased from 3.8%, 2.9% and 1.0% in Light-haze period to 9.6%, 8.3% and 4.4% in Severe-haze period, respectively. These results suggest that dust-derived particles were more significant in Light-haze period while secondary aerosols were more important in Severe-haze period. Hopanes (33±24 and 38±29ngm(-3) in Light-haze and Severe-haze periods, respectively) during the two types of haze periods are comparable, indicating that differences in contribution of primary organic aerosols from fossil fuel combustions to TSP were insignificant. In contrast, the ratio of secondary organic aerosols (e.g., o-phthalic acid) to EC was much higher in Severe-haze period (5.8±2.7ngμg(-1)) than in Light-haze period (3.4±2.1ngμg(-1)), probably indicating that the humid conditions in Severe-haze period are favorable for secondary organic aerosol formation. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Indoor airborne particle sources and outdoor haze days effect in urban office areas in Guangzhou.

    Science.gov (United States)

    Zhang, Manwen; Zhang, Sukun; Feng, Guixian; Su, Hui; Zhu, Fengzhi; Ren, Mingzhong; Cai, Zongwei

    2017-04-01

    To identify the sources of PM2.5 pollutants in work environments and determine whether the air quality inside an office was affected by a change in outdoor pollution status, concurrent indoor and outdoor measurements of PM2.5 were conducted at five different office spaces in the urban center of Guangzhou on low pollution days (non-episode days, NEDs), and high pollution days (haze episode days, EDs). Indoor-outdoor relationships between the PM2.5 mass and its chemical constituents, which included water-soluble ions, carbonaceous species, and metal elements, were investigated. A principle component analysis (PCA) was performed to further confirm the relationship between the indoor and outdoor PM2.5 pollution. The results reveal that (1) Printing and ETS (Environmental tobacco smoking) were found to be important office PM2.5 sources and associated with the enrichment of SO42-, OC, EC and some toxic metals indoors; (2) On EDs, serious outdoor pollution and higher air exchange rate greatly affected all studied office environments, masking the original differences of the indoor characteristics (3) Fresh air system could efficiently filter out most of the outside pollutants on both NEDs and EDs. Overall, the results of our study suggest that improper human behavior is associated with the day-to-day generation of indoor PM2.5 levels and sporadic outdoor pollution events can lead to poor indoor air quality in urban office environments. Moreover, fresh air system has been experimentally proved with data as an effective way to improve the air quality in office. Copyright © 2016. Published by Elsevier Inc.

  20. The Link between Knowledge, Attitudes and Practices in Relation to Atmospheric Haze Pollution in Peninsular Malaysia.

    Directory of Open Access Journals (Sweden)

    Laura De Pretto

    Full Text Available Transboundary haze episodes caused by seasonal forest fires have become a recurrent phenomenon in Southeast Asia, with serious environmental, economic, and public health implications. Here we present a cross-sectional survey conducted among people in Kuala Lumpur and surrounds to assess the links between knowledge, attitudes, and practices in relation to the transboundary haze episodes. Of 305 respondents, 125 were amateur athletes participating in a duathlon event and the remainder were surveyed in an inner-city shopping mall. Across the whole sample, people who possessed more factual information about the haze phenomenon showed significantly higher levels of concern. Duathletes were more knowledgeable than non-duathletes and also more concerned about the negative effects of haze, especially on health. For all people who regularly practice outdoor sports (including people interviewed at the shopping mall, higher levels of knowledge and concerned attitudes translated into a greater likelihood of engaging in protective practices, such as cancelling their outdoor training sessions, while those with greater knowledge were more likely to check the relevant air pollution index on a daily basis. Our results indicate that the provision of accurate and timely information about air quality to residents will translate into beneficial practices, at least among particularly exposed individuals, such as amateur athletes who regularly practice outdoor sports.

  1. 77 FR 12770 - Approval, Disapproval and Promulgation of Implementation Plans; Nebraska; Regional Haze State...

    Science.gov (United States)

    2012-03-02

    ... and related issues. The RPOs first evaluated technical information to better understand how their... referred to as the ``regional haze program''). States are required to ensure reasonable progress toward the... of sources until monitoring, modeling and scientific knowledge about the relationships between...

  2. 76 FR 76646 - Approval and Promulgation of Implementation Plans; South Dakota; Regional Haze State...

    Science.gov (United States)

    2011-12-08

    ... identify the best available type and level of control for reducing emissions. \\7\\ BART-eligible sources are... calculations presented in Table 1 and elsewhere in section III.B represent corrections EPA made to minor math... Haze Levels II: Application of the New IMPROVE Algorithm to Natural Species Concentrations Estimates...

  3. 77 FR 48061 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Regional Haze State...

    Science.gov (United States)

    2012-08-13

    ... number 2 is revised to read as follows: ``2. In Sec. 52.2020, the table in paragraph (e)(1) is amended by adding an entry for Regional Haze Plan at the end of the table to read as follows:'' 0 2. On page 41284... drafting errors and ambiguity, minimize potential litigation, and provide a clear legal standard for...

  4. Effect of onion extract on corneal haze suppression after air assisted lamellar keratectomy

    Science.gov (United States)

    KIM, Soohyun; PARK, Young Woo; LEE, Euiri; PARK, Sang Wan; PARK, Sungwon; NOH, Hyunwoo; KIM, Jong Whi; SEONG, Je Kyung; SEO, Kangmoon

    2015-01-01

    This study evaluated the effect of onion extract on corneal haze suppression after applying the air assisted lamellar keratectomy. The air assisted lamellar keratectomy was performed on 24 canine eyes. They were treated with an artificial tear (group C), prednisolone acetate (group P), onion extract (group O) and TGF-β1 (group T) three times per day from 7 to 28 days after the surgery. Corneal haze occurred on the all eyes and was observed beginning 7 days after the surgery. The haze was significantly decreased in groups P and O from day 14 compared with the group C using the clinical (group P; P=0.021, group O; P=0.037) and objective evaluation method (group P; P=0.021, group O; P=0.039). In contrast, it was significantly increased in group T from day 14 compared with group C based on the clinical (P=0.002) and objective evaluation method (P<0.001). Subsequently, these eyes were enucleated after euthanasia, and immunohistochemistry with α-SMA antibodies was done. The total green intensity for α-SMA was significantly more expressed in group T and significantly less expressed in groups P and O than in group C. Onion extract could have potential as a therapeutic in preventing corneal haze development by suppressing the differentiation of fibroblasts into myofibroblasts. PMID:26607134

  5. 77 FR 39177 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Regional Haze

    Science.gov (United States)

    2012-07-02

    ..., 2012 (77 FR 3712). The proposal notice described the nature of the regional haze problem and the...- term strategy for addressing reasonable progress requirements is based more on the collective set of... economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62...

  6. 76 FR 12651 - Approval and Promulgation of Implementation Plans; State of Oregon; Regional Haze State...

    Science.gov (United States)

    2011-03-08

    ..., meteorology and atmospheric chemistry for aerosol formation to predict pollutant concentrations in the Class I... contribute to haze at specific Class I areas. WEP does not account for atmospheric chemistry (secondary... sources in Washington, Oregon, and marine shipping in the Pacific offshore region (see Oregon Regional...

  7. Wireless real-time haze monitoring device | Ya'acob | Journal of ...

    African Journals Online (AJOL)

    controller to control the transmission process of measured data taken via wireless data network to the MySQL database. The reading, which is real-time reading and more accurate compared to pollutant PM10, can provide haze awareness and guidance to people to plan their activities. Keywords: PSI; PM10; PM2.5; ...

  8. Indonesia's Fires and Haze: The Cost of Catastrophe (with a 2006 ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    From September to November of 1997, raging fires in Indonesia pumped enough smoke into the air to blanket the entire region in haze, reaching as far north as southern Thailand and the Philippines, with Malaysia and Singapore being particularly affected. An area the size of Costa Rica was completely devastated.

  9. 77 FR 11809 - Approval and Promulgation of Air Quality Implementation Plans; New Hampshire; Regional Haze

    Science.gov (United States)

    2012-02-28

    ... designated as mandatory Class I Federal areas consist of national parks exceeding 6000 acres, wilderness... Hampshire Department of Environmental Services (NHDES) on January 29, 2010, with supplemental submittals on... mandatory Class I areas (also referred to as the ``regional haze program''). States are required to assure...

  10. Filtration, haze and foam characteristics of fermented wort mediated by yeast strain.

    Science.gov (United States)

    Douglas, P; Meneses, F J; Jiranek, V

    2006-01-01

    To investigate the influence of the choice of yeast strain on the haze, shelf life, filterability and foam quality characteristics of fermented products. Twelve strains were used to ferment a chemically defined wort and hopped ale or stout wort. Fermented products were assessed for foam using the Rudin apparatus, and filterability and haze characteristics using the European Brewing Convention methods, to reveal differences in these parameters as a consequence of the choice of yeast strain and growth medium. Under the conditions used, the choice of strain of Saccharomyces cerevisiae effecting the primary fermentation has an impact on all of the parameters investigated, most notably when the fermentation medium is devoid of macromolecular material. The filtration of fermented products has a large cost implication for many brewers and wine makers, and the haze of the resulting filtrate is a key quality criterion. Also of importance to the quality of beer and some wines is the foaming and head retention of these beverages. The foam characteristics, filterability and potential for haze formation in a fermented product have long been known to be dependant on the raw materials used, as well as other production parameters. The choice of Saccharomyces cerevisiae strain used to ferment has itself been shown here to influence these parameters.

  11. 77 FR 72742 - Approval and Promulgation of State Implementation Plans: State of Washington; Regional Haze State...

    Science.gov (United States)

    2012-12-06

    ... for NO X for the TransAlta Centralia Generation LLC coal-fired power plant in Centralia, Washington (TransAlta). The Washington State Department of Ecology (Ecology) submitted its Regional Haze State... at 40 CFR 50.308. On December 29, 2011 Ecology submitted an update to the SIP submittal containing a...

  12. 77 FR 34218 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Regional Haze

    Science.gov (United States)

    2012-06-11

    ... the requirements of the Clean Air Act (CAA) and EPA's rules for states to prevent and remedy future... satisfy the requirements for best available retrofit technology (BART). DATES: This final rule is... the nature of the regional haze problem and the statutory and regulatory background for EPA's review...

  13. 77 FR 50611 - Approval and Promulgation of Implementation Plans; State of Oregon; Regional Haze State...

    Science.gov (United States)

    2012-08-22

    ... requirements of Clean Air Act (CAA or the Act) section 169A and B and the regional haze regulations in 40 CFR... retrofit technology (BART). 76 FR 38997. On May 23, 2012, EPA proposed approving the remaining portion of.... Information is organized as follows: Table of Contents I. Background II. Final Action III. Scope of Action IV...

  14. The Link between Knowledge, Attitudes and Practices in Relation to Atmospheric Haze Pollution in Peninsular Malaysia.

    Science.gov (United States)

    De Pretto, Laura; Acreman, Stephen; Ashfold, Matthew J; Mohankumar, Suresh K; Campos-Arceiz, Ahimsa

    2015-01-01

    Transboundary haze episodes caused by seasonal forest fires have become a recurrent phenomenon in Southeast Asia, with serious environmental, economic, and public health implications. Here we present a cross-sectional survey conducted among people in Kuala Lumpur and surrounds to assess the links between knowledge, attitudes, and practices in relation to the transboundary haze episodes. Of 305 respondents, 125 were amateur athletes participating in a duathlon event and the remainder were surveyed in an inner-city shopping mall. Across the whole sample, people who possessed more factual information about the haze phenomenon showed significantly higher levels of concern. Duathletes were more knowledgeable than non-duathletes and also more concerned about the negative effects of haze, especially on health. For all people who regularly practice outdoor sports (including people interviewed at the shopping mall), higher levels of knowledge and concerned attitudes translated into a greater likelihood of engaging in protective practices, such as cancelling their outdoor training sessions, while those with greater knowledge were more likely to check the relevant air pollution index on a daily basis. Our results indicate that the provision of accurate and timely information about air quality to residents will translate into beneficial practices, at least among particularly exposed individuals, such as amateur athletes who regularly practice outdoor sports.

  15. 77 FR 17334 - Approval and Promulgation of Air Quality Implementation Plans; State of Nevada; Regional Haze...

    Science.gov (United States)

    2012-03-26

    ... ) and volatile organic compounds (VOC). Fine particle precursors react in the atmosphere to form fine particulate matter (PM 2.5 ), primarily sulfates, nitrates, organic carbon, elemental carbon, and soil dust... regional haze. This legislation established the Grand Canyon Visibility Transport Commission (GCVTC), which...

  16. 77 FR 11937 - Approval and Promulgation of Air Quality Implementation Plans; State of Alabama; Regional Haze...

    Science.gov (United States)

    2012-02-28

    ... consider to be CBI or otherwise protected. The www.regulations.gov Web site is an ``anonymous access... http://www.epa.gov/ttn/caaa/t1/memoranda/siproc.pdf . In a separate action, EPA has proposed a limited... which a dark object can be viewed against the sky. B. Requirements of the CAA and EPA's Regional Haze...

  17. Crossing the Line: Rites of Passage, Team Aspects, and Ambiguity of Hazing

    Science.gov (United States)

    Waldron, Jennifer J.; Kowalski, Christopher L.

    2009-01-01

    Framed within the psychosocial context of the sport ethic and social-approval goal orientation, 10 female and 11 male current collegiate or former high school athletes participated in individual interviews about their hazing experiences. Data analysis resulted in seven lower order themes and two higher order themes. The higher order theme of the…

  18. 77 FR 14603 - Approval and Promulgation of Implementation Plans; Arkansas; Regional Haze State Implementation...

    Science.gov (United States)

    2012-03-12

    ... BART Analysis for White Bluff 7. Other Comments Related to BART D. Comments on the Arkansas Pollution... Implementation Plan To Address Pollution Affecting Visibility and Regional Haze; Final Rule #0;#0;Federal... State Implementation Plan; Interstate Transport State Implementation Plan To Address Pollution Affecting...

  19. 76 FR 41158 - Approval and Promulgation of Air Quality Implementation Plans; West Virginia; Regional Haze State...

    Science.gov (United States)

    2011-07-13

    ... techniques for agricultural and forestry management purposes including plans as currently exist within the...) Revisions, EPA Memorandum from John Calcagni, Director, Air Quality Management Division, OAQPS, to Air... activities associated with the management of regional haze, visibility and other air quality issues in the...

  20. 77 FR 11928 - Approval and Promulgation of Air Quality Implementation Plans; Wisconsin; Regional Haze

    Science.gov (United States)

    2012-02-28

    ... and forestry management purposes including plans as currently exist within the state for these... tribes and Federal land management agencies on discussions of regional haze and visibility in the Midwest... emissions management strategies. 40 CFR 51.308(d)(3)(i). In such cases, the contributing state must...

  1. 77 FR 3712 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Regional Haze

    Science.gov (United States)

    2012-01-25

    ... and forestry management purposes including plans as currently exist within the state for these... agencies established to initiate and coordinate activities associated with the management of regional haze... develop coordinated emissions management strategies. 40 CFR 51.308(d)(3)(i). In such cases, the...

  2. 76 FR 36329 - Approval and Promulgation of Implementation Plans; State of Idaho; Regional Haze State...

    Science.gov (United States)

    2011-06-22

    ... consider TASCO's shutdown and replacement of three coal-fired pulp dryers in the Regional Haze SIP... alternative crop). EPA also refers to the Patterson study (2009) which compared sugar beets, at different price and yield levels, to alternative crops. Affordability Analysis, p. 27. Furthermore, the analysis...

  3. Modeling study of the 2010 regional haze event in the North China Plain

    Directory of Open Access Journals (Sweden)

    M. Gao

    2016-02-01

    Full Text Available The online coupled Weather Research and Forecasting-Chemistry (WRF-Chem model was applied to simulate a haze event that happened in January 2010 in the North China Plain (NCP, and was validated against various types of measurements. The evaluations indicate that WRF-Chem provides reliable simulations for the 2010 haze event in the NCP. This haze event was mainly caused by high emissions of air pollutants in the NCP and stable weather conditions in winter. Secondary inorganic aerosols also played an important role and cloud chemistry had important contributions. Air pollutants outside Beijing contributed about 64.5 % to the PM2.5 levels in Beijing during this haze event, and most of them are from south Hebei, Tianjin city, Shandong and Henan provinces. In addition, aerosol feedback has important impacts on surface temperature, relative humidity (RH and wind speeds, and these meteorological variables affect aerosol distribution and formation in turn. In Shijiazhuang, Planetary Boundary Layer (PBL decreased about 278.2 m and PM2.5 increased more than 20 µg m−3 due to aerosol feedback. It was also shown that black carbon (BC absorption has significant impacts on meteorology and air quality changes, indicating more attention should be paid to BC from both air pollution control and climate change perspectives.

  4. Aspartic Acid Protease from Botrytis cinerea Removes Haze-Forming Proteins during White Winemaking

    NARCIS (Netherlands)

    Sluyter, Van S.C.; Warnock, N.I.; Schmidt, S.; Anderson, P.; Kan, van J.A.L.; Bacic, A.; Waters, E.J.

    2013-01-01

    White wines suffer from heat-induced protein hazes during transport and storage unless the proteins are removed prior to bottling. Bentonite fining is by far the most commonly used method, but it is inefficient and creates several other process challenges. An alternative to bentonite is the

  5. 77 FR 3966 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Regional Haze

    Science.gov (United States)

    2012-01-26

    ... address mercury emissions from EGUs, Illinois adopted Part 225 of Illinois's air pollution regulations... AGENCY 40 CFR Part 52 Approval and Promulgation of Air Quality Implementation Plans; Illinois; Regional... approve revisions to the Illinois State Implementation Plan (SIP) addressing regional haze for the first...

  6. Qualitative review of hazing in collegiate and school sports: consequences from a lack of culture, knowledge and responsiveness.

    Science.gov (United States)

    Diamond, Alex B; Callahan, S Todd; Chain, Kelly F; Solomon, Gary S

    2016-02-01

    As with most mental health disorders, the topic of hazing is not exclusive to the student athlete. However, it is also clear that the unique set of situations faced by athletes create a set of additional and difficult challenges to their mental and physical well-being. A deep-rooted culture, a lack of knowledge about hazing and its causal relationships, and a failure to act by teammates and adults all play a role in the propagation of this danger. Also, in an era where the popular press similarly celebrates and chastises episodes of hazing, it is increasingly crucial to turn to the scientific literature for guidance. To provide a comprehensive review of the scientific research on hazing in sports and to make recommendations for enhancing the approach and assistance to those in need on an individual and societal level. Qualitative literature review of hazing in collegiate and school sports. Databases including PubMed, Google Scholar, SPORTDiscus, EMBASE and MEDLINE were searched using standardised terms, alone and in combination, including 'hazing', 'bullying', 'sport', 'athlete', 'college', 'school' and 'youth'. Despite increased attention to its dangers, hazing remains pervasive throughout the sports world. However, many do not recognise those actions as consistent with hazing. A change in culture, increased education and awareness, along with methodologically sound strategies for action must occur in order to reduce the ill effects and cycle of hazing. To date, current information and efforts are lacking. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  7. Cassini limb images of hazes in Saturn’s northern hemisphere

    Science.gov (United States)

    Sanchez-Lavega, Agustin M.; Garcia, Daniel; del Rio-Gaztelurrutia, Teresa; Garcia-Muñoz, Antonio; Perez-Hoyos, Santiago; Hueso, Ricardo

    2017-10-01

    We have used high resolution Cassini ISS images of the limb of Saturn to study the vertical distribution, altitude location, thickness and optical properties of the haze layers in the northern hemisphere (1°S to 82°N) in 2013 and 2015. The images cover an ample spectral range from the ultraviolet (UV1 filter, 264 nm) to the near infrared (CB3 filter, 938 nm) including methane absorption bands at 619 nm, 724 nm and 890 nm. Spatial resolution ranges from 1.6 to 13 km/pixel depending on wavelength and latitude. Three latitude bands were selected for the analysis according to the background zonal wind profile measured at cloud level and known dynamical activity: (a) North Polar Region encompassing the Hexagon latitude (74°N) (b) Mid-latitudes (45°N-52°N), and (3) Equator (1°N-3°S). The best defined haze structures and most extended haze layers were found at the latitude of the Hexagon. Up to 6-8 haze layers extending up to 400 km in altitude above clouds (in the pressure range from about 0.7 bar to 0.1 mbar) were detected. The vertical thickness of the layers is in the range 3-15 km compared to the scale height which is about 40 km. The spectral reflectivity is relatively uniform between the layers in the blue and red continuum wavelengths coming from the backward light scattering from the haze particles, while the brightness in the methane bands (relative to red continuum) and in the ultraviolet shows the effects of methane absorption and Rayleigh scattering by the gas, respectively. At mid-latitudes 3-4 haze layers are found spanning up to altitudes 200 km above the clouds. At the Equator 5-6 layers are found extending up to altitudes 250 km above the clouds (up to 2 mbar in pressure level) in a region of great dynamical interest because of the particular structure of the zonal winds and their known oscillations. We comment on the possible nature of the haze layers on the basis of condensing species and photochemistry.

  8. Large-scale weather dynamics during the 2015 haze event in Singapore

    Science.gov (United States)

    Djamil, Yudha; Lee, Wen-Chien; Tien Dat, Pham; Kuwata, Mikinori

    2017-04-01

    The 2015 haze event in South East Asia is widely considered as a period of the worst air quality in the region in more than a decade. The source of the haze was from forest and peatland fire in Sumatra and Kalimantan Islands, Indonesia. The fires were mostly came from the practice of forest clearance known as slash and burn, to be converted to palm oil plantation. Such practice of clearance although occurs seasonally but at 2015 it became worst by the impact of strong El Nino. The long period of dryer atmosphere over the region due to El Nino makes the fire easier to ignite, spread and difficult to stop. The biomass emission from the forest and peatland fire caused large-scale haze pollution problem in both Islands and further spread into the neighboring countries such as Singapore and Malaysia. In Singapore, for about two months (September-October, 2015) the air quality was in the unhealthy level. Such unfortunate condition caused some socioeconomic losses such as school closure, cancellation of outdoor events, health issues and many more with total losses estimated as S700 million. The unhealthy level of Singapore's air quality is based on the increasing pollutant standard index (PSI>120) due to the haze arrival, it even reached a hazardous level (PSI= 300) for several days. PSI is a metric of air quality in Singapore that aggregate six pollutants (SO2, PM10, PM2.5, NO2, CO and O3). In this study, we focused on PSI variability in weekly-biweekly time scales (periodicity < 30 days) since it is the least understood compare to their diurnal and seasonal scales. We have identified three dominant time scales of PSI ( 5, 10 and 20 days) using Wavelet method and investigated their large-scale atmospheric structures. The PSI associated large-scale column moisture horizontal structures over the Indo-Pacific basin are dominated by easterly propagating gyres in synoptic (macro) scale for the 5 days ( 10 and 20 days) time scales. The propagating gyres manifest as cyclical

  9. Impact Test Analysis of the Aging Property of Power Plant Running Silicone Rubber Insulators in the Fog and Haze Days

    Directory of Open Access Journals (Sweden)

    Liu He

    2016-01-01

    Full Text Available The current fog and haze days are increasingly serious. The pollution level in various regions of our country is increasing. With all kinds of dust and acid gas pollution in the fog and haze weather, the polluted surface of the silicone rubber insulators is slowly and evenly damp aging in the open operation. Here, the aging degree of the silicone rubber insulators which ran for different years under actual fog and haze environment has been analyzed, such as surface topography, hydrophilic/hydrophobic, thermal performance, mechanical properties and so on.

  10. Laboratory studies of butane nucleation on organic haze particles: application to Titan's clouds.

    Science.gov (United States)

    Curtis, Daniel B; Glandorf, David L; Toon, Owen B; Tolbert, Margaret A; McKay, Christopher P; Khare, Bishun N

    2005-02-24

    Titan, Saturn's largest satellite, has a thick nitrogen/methane atmosphere with various hydrocarbons present in minor amounts. Recent observations suggest that CH4 may condense to form clouds near the moon's tropopause. Titan's methane cloud formation is probably triggered by a sequential nucleation of hydrocarbons onto Titan's haze material as tropospheric convection occurs due to differential heating of the surface or as the haze settles through the lower stratosphere. To better constrain Titan's cloud formation mechanism, investigations of the nucleation of several hydrocarbons will be necessary. Butane was chosen for this study because it has a relatively high freezing point and is estimated to be present at 200 part per billion levels. If this amount of butane were to condense on each haze particle, a visible cloud would be observed. Laboratory measurements at T = 125 K were performed to determine the relative ease of solid butane nucleation onto laboratory-produced tholin particles having an elemental composition of C5H5N, and solid films of hexane and acetonitrile. We find that butane nucleation onto the haze particles requires a relatively high saturation ratio of S > 1.30. Because butane nucleation is difficult, it may occur on only a very small subset of the total haze particles available. Such selective nucleation of butane would lead to those particles becoming coated with significant amounts of butane. Requiring a high saturation ratio for butane nucleation will reduce the optical depth of butane clouds by a factor of 100 because the particles will be fewer in number for a given condensed mass.

  11. [Pollution characteristics of organic acids in atmospheric particles during haze periods in autumn in Guangzhou].

    Science.gov (United States)

    Tan, Ji-hua; Zhao, Jing-ping; Duan, Jing-chun; Ma, Yong-liang; He, Ke-bin; Yang, Fu-mo

    2013-05-01

    Total suspended particles (TSP), collected during a typical haze period in Guangzhou, were analyzed for the fatty acids (C12-C30) and low molecular weight dicarboxylic acids (C3-C9) using gas chromatography/mass spectrometry (GC/MS). The results showed that the concentration of total fatty and carboxylic acids was pretty high during the haze episode. The ratios of fatty acids and carboxylic acids in haze to those in normal days were 1.9 and 2.5, respectively. During the episode of the increasing pollution, the fatty acids and carboxylic acids at night (653 ng x m(-3)) was higher than that (487 ng x m(-3)) in days. After that, the level of fatty acids and carboxylic acids in days (412 ng x m(-3)) was higher than that (336 ng x m(-3)) at night. In general, the time-series of fatty acids and carboxylic acids was similar to that of the air particle and carbonaceous species, however, the trend of the ratio of fatty acids and carboxylic acids to organic carbon was opposite to that of air particle and carbonaceous species. This ratio decreased with the increase of the concentration of air particle and after the night of 27th, the ratio increased with the decrease in the concentration of air particle. The results showed that haze pollution had a significant inhibitory effect on the enrichment of fatty and carboxylic acids. Based on the ratio of malonate to succinate (C3/C4), it could be found that primary sources contribute more to the atmospheric fatty and carboxylic acids during the autumn haze pollution periods in Guangzhou.

  12. Projected changes in haze pollution potential in China: an ensemble of regional climate model simulations

    Science.gov (United States)

    Han, Zhenyu; Zhou, Botao; Xu, Ying; Wu, Jia; Shi, Ying

    2017-08-01

    Based on the dynamic downscaling by the regional climate model RegCM4 from three CMIP5 global models under the historical and the RCP4.5 simulations, this article evaluated the performance of the RegCM4 downscaling simulations on the air environment carrying capacity (AEC) and weak ventilation days (WVDs) in China, which are applied to measure haze pollution potential. Their changes during the middle and the end of the 21st century were also projected. The evaluations show that the RegCM4 downscaling simulations can generally capture the observed features of the AEC and WVD distributions over the period 1986-2005. The projections indicate that the annual AEC tends to decrease and the annual WVDs tend to increase over almost the whole country except central China, concurrent with greater change by the late 21st century than by the middle of the 21st century. It suggests that annual haze pollution potential would be enlarged under the RCP4.5 scenario compared to the present. For seasonal change in the four main economic zones of China, it is projected consistently that there would be a higher probability of haze pollution risk over the Beijing-Tianjin-Hebei (BTH) region and the Yangtze River Delta (YRD) region in winter and over the Pearl River Delta (PRD) region in spring and summer in the context of the warming scenario. Over Northeast China (NEC), future climate change might reduce the AEC or increase the WVDs throughout the whole year, which favours the occurrence of haze pollution and thus the haze pollution risk would be aggravated. The relative contribution of different components related to the AEC change further indicates that changes in the boundary layer depth and the wind speed play leading roles in the AEC change over the BTH and NEC regions. In addition to those two factors, the precipitation change also exerts important impacts on the AEC change over the YRD and PRD zones.

  13. Formation and evolution mechanism of regional haze: a case study in the megacity Beijing, China

    Directory of Open Access Journals (Sweden)

    X. G. Liu

    2013-05-01

    Full Text Available The main objective of this study is to investigate the formation and evolution mechanism of the regional haze in megacity Beijing by analyzing the process of a severe haze that occurred 20–27 September 2011. Mass concentration and size distribution of aerosol particles as well as aerosol optical properties were concurrently measured at the Beijing urban atmospheric environment monitoring station. Gaseous pollutants (SO2, NO-NO2-NOx, O3, CO and meteorological parameters (wind speed, wind direction, and relative humidity were simultaneously monitored. Meanwhile, aerosol spatial distribution and the height of planetary boundary layer (PBL were retrieved from the signal of satellite and LIDAR (light detection and ranging. Concentrations of NO, NO2, SO2, O3, and CO observed during 23–27 September had exceeded the national ambient air quality standards for residents. The mass concentration of PM2.5 gradually accumulated during the measurement and reached at 220 μg m−3 on 26 September, and the corresponding atmospheric visibility was only 1.1 km. The daily averaged AOD in Beijing increased from ~ 0.16 at λ = 500 nm on 22 September and reached ~ 3.5 on 26 September. The key factors that affected the formation and evolution of this haze episode were stable anti-cyclone synoptic conditions at the surface, decreasing of the height of PBL, heavy pollution emissions from urban area, number and size evolution of aerosols, and hygroscopic growth for aerosol scattering. This case study may provide valuable information for the public to recognize the formation mechanism of the regional haze event over the megacity, which is also useful for the government to adopt scientific approach to forecast and eliminate the occurrence of regional haze in China.

  14. Depolarized haze of nano-porous AAO film via porosity and aspect control

    Science.gov (United States)

    Tseng, Chun-Wei; Lin, Yung-Hsiang; Cheng, Chih-Hsien; Lin, Gong-Ru

    2018-01-01

    Multiple scattering induced haze and depolarization effects of nano-porous AAO films controlled by detuning the porosity and aspect ratio of the nano holes are investigated. The nano-porous AAO film with its porosity increasing from 12.6% to 19.3% enhances the scattering of the incident laser beam with its maximal scattering angle enlarged from 5° to 8° under TM-mode incidence and from 6° to 10° under TE-mode incidence. Because of multiple scattering within the porous holes of the AAO, the depolarization on the reflected beam by transferring its electric field from horizontal to the vertical such that the polarization ratio is degraded with a randomized haze. The porosity of AAO surface broadens from 12.6% to 19.3% when increasing the bias voltage from 40 to 60 V during the second-step of the electro-chemical anodization process, which essentially adjusts the polarization ratio under TM-mode and TE-mode incidences raise from 0.31 to 0.35 and from 0.32 to 0.48, respectively. The depolarized haze of the nano-porous AAO film is correlated with its porosity and aspect ratio controlled by the pore size and etched depth of the AAO. Under TM-mode incidence, the simulated polarization ratio increases from 0.35 to 0.38, which correlates well with experimental results. In contrast, the experiment result slightly deviates from the theoretical prediction as the TE-mode field interacts more surface area than the TM-mode field does. Such a nano-porous AAO exhibits tunable depolarized haze via the control porosity and aspect ratio, which is particularly suitable to serve as the catalytic buffer for synthesizing the hydrophobic and hazed solar energy converters.

  15. The Link between Knowledge, Attitudes and Practices in Relation to Atmospheric Haze Pollution in Peninsular Malaysia: e0143655

    National Research Council Canada - National Science Library

    Laura De Pretto; Stephen Acreman; Matthew J Ashfold; Suresh K Mohankumar; Ahimsa Campos-Arceiz

    2015-01-01

    .... Here we present a cross-sectional survey conducted among people in Kuala Lumpur and surrounds to assess the links between knowledge, attitudes, and practices in relation to the transboundary haze episodes...

  16. DOD and Coast Guard: Actions Needed to Increase Oversight and Management Information on Hazing Incidents Involving Servicemembers

    Science.gov (United States)

    2016-02-01

    Venturous from 2007 through 2009. In 2011, while serving in Afghanistan, an Army private committed suicide after reportedly being subjected to verbal ...Corps officials subsequently told us that these incidents in their services may be better defined as bullying rather than hazing. According to the...Army, while hazing and bullying can include both physical and nonphysical interactions, bullying is always committed with the intent to exclude or

  17. Increase in winter haze over eastern China in recent decades: Roles of variations in meteorological parameters and anthropogenic emissions: INCREASE IN WINTER HAZE IN EASTERN CHINA

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Liao, Hong [School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing China; Joint International Research Laboratory of Climate and Environment Change, Nanjing University of Information Science and Technology, Nanjing China; Lou, Sijia [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2016-11-05

    The increase in winter haze over eastern China in recent decades due to variations in meteorological parameters and anthropogenic emissions was quantified using observed atmospheric visibility from the National Climatic Data Center Global Summary of Day database for 1980–2014 and simulated PM2.5 concentrations for 1985–2005 from the Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). Observed winter haze days averaged over eastern China (105–122.5°E, 20–45°N) increased from 21 d in 1980 to 42 d in 2014, and from 22 to 30 d between 1985 and 2005. The GEOS-Chem model captured the increasing trend of winter PM2.5 concentrations for 1985–2005, with concentrations averaged over eastern China increasing from 16.1 μg m-3 in 1985 to 38.4 μg m-3 in 2005. Considering variations in both anthropogenic emissions and meteorological parameters, the model simulated an increase in winter surface-layer PM2.5 concentrations of 10.5 (±6.2) μg m-3 decade-1 over eastern China. The increasing trend was only 1.8 (±1.5) μg m-3 decade-1 when variations in meteorological parameters alone were considered. Among the meteorological parameters, the weakening of winds by -0.09 m s-1 decade-1 over 1985–2005 was found to be the dominant factor leading to the decadal increase in winter aerosol concentrations and haze days over eastern China during recent decades.

  18. Source appointment of fine particle number and volume concentration during severe haze pollution in Beijing in January 2013.

    Science.gov (United States)

    Liu, Zirui; Wang, Yuesi; Hu, Bo; Ji, Dongsheng; Zhang, Junke; Wu, Fangkun; Wan, Xin; Wang, Yonghong

    2016-04-01

    Extreme haze episodes repeatedly shrouded Beijing during the winter of 2012-2013, causing major environmental and health problems. To better understand these extreme events, particle number size distribution (PNSD) and particle chemical composition (PCC) data collected in an intensive winter campaign in an urban site of Beijing were used to investigate the sources of ambient fine particles. Positive matrix factorization (PMF) analysis resolved a total of eight factors: two traffic factors, combustion factors, secondary aerosol, two accumulation mode aerosol factors, road dust, and long-range transported (LRT) dust. Traffic emissions (54%) and combustion aerosol (27%) were found to be the most important sources for particle number concentration, whereas combustion aerosol (33%) and accumulation mode aerosol (37%) dominated particle volume concentrations. Chemical compositions and sources of fine particles changed dynamically in the haze episodes. An enhanced role of secondary inorganic species was observed in the formation of haze pollution. Regional transport played an important role for high particles, contribution of which was on average up to 24-49% during the haze episodes. Secondary aerosols from urban background presented the largest contributions (45%) for the rapid increase of fine particles in the severest haze episode. In addition, the invasion of LRT dust aerosols further elevated the fine particles during the extreme haze episode. Our results showed a clear impact of regional transport on the local air pollution, suggesting the importance of regional-scale emission control measures in the local air quality management of Beijing.

  19. Tourists’ Perception of Haze Pollution and the Potential Impacts on Travel: Reshaping the Features of Tourism Seasonality in Beijing, China

    Directory of Open Access Journals (Sweden)

    Aiping Zhang

    2015-02-01

    Full Text Available Haze pollution has worsened and has received close attention by news agencies in the past two years. This type of environmental pollution might have a great effect on tourism image and the entire tourism industry of a destination. This study aimed to reveal the potential impacts of haze pollution on the tourism industry. Based on a case study in Beijing using questionnaires for potential tourists, awareness of haze pollution, impacts of haze pollution on travel and attitudes toward the impacts were discussed. The results indicated that haze pollution has a considerable potential impact on travel, and there are distinct differences among travel elements and tourism market segments. Due to its impacts, haze pollution could be taken into account in tourists’ decision-making processes, causing a portion of potential tourists to cancel tourism plans. As a result, tourist arrivals to similar destinations could decrease by a small margin, but the most significant impact could be on the temporal distribution of tourist arrivals, namely tourism seasonality, due to tourists’ “avoiding” psychology.

  20. Planck Intermediate Results. IX. Detection of the Galactic haze with Planck

    DEFF Research Database (Denmark)

    Planck Collaboration,; Ade, P. A. R.; Aghanim, N.

    2013-01-01

    is consistent with power-law emission with a spectral index of -2.55 +/- 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ~ E^-2.1. At Galactic latitudes |b|......Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterize the emission from the Galactic "haze" at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre......, and extends to |b| ~35 deg in Galactic latitude and |l| ~15 deg in longitude. By combining the Planck data with observations from the WMAP we are able to determine the spectrum of this emission to high accuracy, unhindered by the large systematic biases present in previous analyses. The derived spectrum...

  1. The Shift from Acceptance to Prevention: Hazing Behaviors in the U.S. Military

    Science.gov (United States)

    2016-10-31

    Graphical representations of all results can be found in the results section of this report. Conclusion: These data suggest there is a gap in knowledge...prior literature (Parks et al., 2014; Svec, 2014), five hypotheses were developed for this study. Hypothesis 1 predicted that when presented with real...Hughey, M. W. (2015). White Boys Drink, Black Girls Yell: A Racialized and Gendered Analysis of Violent Hazing and the Law. J. Gender Race & Just., 18

  2. Perceptions of Hazing and Bullying among U.S. Military Service Members

    Science.gov (United States)

    2016-10-18

    RESEARCH, DEVELOPMENT, AND STRATEGIC INITIATIVES DR. DANIEL P. MCDONALD, EXECUTIVE DIRECTOR 18 October 2016 Dr. Richard Oliver Hope Human...Institute (DEOMI) Organizational Climate Survey (DEOCS), perceptions of hazing and bullying among SMs of all branches of the U.S. Armed Forces (except... change of station moves. Because of this, there may be multiple responses from the same individuals, influencing reported perception rates. It is

  3. Public concerns about transboundary haze: a comparison of Indonesia, Singapore, and Malaysia

    OpenAIRE

    Tim Forsyth

    2014-01-01

    Public concerns about environmental problems create narrative structures that influence policy by allocating roles of blame, responsibility, and appropriate behavior. This paper presents an analysis of public concerns about transboundary haze resulting from forest fires in Indonesia, Singapore, and Malaysia for crises experienced in 1997, 2005 and 2013. The source of the information is content analysis of 2231 articles from representative newspapers in each country. The study shows that newsp...

  4. Highly transparent, low-haze, hybrid cellulose nanopaper as electrodes for flexible electronics

    KAUST Repository

    Xu, Xuezhu

    2016-06-01

    Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are still characterized by high diffuse transmittance and small direct transmittance, resulting in high optical haze of the substrates. In this study, we proposed a simple methodology for large-scale production of high-transparency, low-haze CNP comprising both long cellulose nanofibrils (CNFs) and short cellulose nanocrystals (CNCs). By varying the CNC/CNF ratio in the hybrid CNP, we could tailor its total transmittance, direct transmittance and diffuse transmittance. By increasing the CNC content, the optical haze of the hybrid CNP could be decreased and its transparency could be increased. The direct transmittance and optical haze of the CNP were 75.1% and 10.0%, respectively, greatly improved from the values of previously reported CNP (31.1% and 62.0%, respectively). Transparent, flexible electrodes were fabricated by coating the hybrid CNP with silver nanowires (AgNWs). The electrodes showed a low sheet resistance (minimum 1.2 Ω sq-1) and a high total transmittance (maximum of 82.5%). The electrodes were used to make a light emitting diode (LED) assembly to demonstrate their potential use in flexible displays. © 2016 The Royal Society of Chemistry.

  5. Characterisation of individual aerosol particles collected during a haze episode in Incheon, Korea using the quantitative ED-EPMA technique

    Directory of Open Access Journals (Sweden)

    H. Geng

    2011-02-01

    Full Text Available A quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA, called low-Z particle EPMA, was used to analyse individual aerosol particles collected in Incheon, Korea on 13–18 October 2008 (a typical haze episode occurred from 15 to 18 October. Overall 3600 individual particles in PM2.5-10 and PM1.0-2.5 fractions from 12 aerosol samples collected on haze and non-haze days were analysed. The analysed particles were classified, based on their X-ray spectral data together with their secondary electron images. The major particle types included organic carbon (OC, elemental carbon (EC, sea-salt, mineral dust (such as aluminosilicate, SiO2, CaCO3/CaMgCO3, etc., (NH42SO4/NH4HSO4-containing, K-containing, Fe-rich and fly ash particles. Their relative number abundance results showed that OC particles were significantly increased while sea-salts and mineral dust particles were significantly decreased (especially in PM1.0-2.5 fraction when haze occurred. For the other particle types (except Fe-rich particles in PM2.5-10 fraction, there were no significant differences in their relative abundances between haze and non-haze samples. On non-haze days, the nitrate-containing reacted sea-salt and mineral dust particles in PM1.0-2.5 fraction significantly outnumbered the sulfate-containing ones, whereas it was the reverse on haze days, implying that on haze days there were special sources or formation mechanisms for fine aerosol particles (≤2.5 μm in aerodynamic diameter. The emission of air pollutants from motor vehicles and stagnant meteorological conditions, such as low wind speed and high relative humidity, might be responsible for the elevated level of OC particles on haze days.

  6. On the latitudinal distribution of Titan's haze at the Voyager epoch

    Science.gov (United States)

    Negrao, A.; Roos-Serote, M.; Rannou, P.; Rages, K.; McKay, C.

    2002-09-01

    In this work, we re-analyse a total of 10 high phase angle images of Titan (2 from Voyager 1 and 8 from Voyager 2). The images were acquired in different filters of the Voyager Imaging Sub System in 1980 - 1981. We apply a model, developed and used by Rannou etal. (1997) and Cabane etal. (1992), that calculates the vertical (1-D) distribution of haze particles and the I/F radial profiles as a function of a series of parameters. Two of these parameters, the haze particle production rate (P) and imaginary refractive index (xk), are used to obtain fits to the observed I/F profiles at different latitudes. Differerent from previous studies is that we consider all filters simultaneously, in an attempt to better fix the parameter values. We also include the filter response functions, not considered previously. The results show that P does not change significantly as a function of latitude, eventhough somewhat lower values are found at high northern latitudes. xk seems to increase towards southern latitudes. We will compare our results with GCM runs, that can give the haze distribution at the epoch of the observations. Work financed by portuguese Foundation for Science and Tecnology (FCT), contract ESO/PRO/40157/2000

  7. Wavelength-Scale Structures as Extremely High Haze Films for Efficient Polymer Solar Cells.

    Science.gov (United States)

    Ham, Juyoung; Dong, Wan Jae; Jung, Gwan Ho; Lee, Jong-Lam

    2016-03-09

    Wavelength-scale inverted pyramid structures with low reflectance and excellent haze have been designed for application to polymer solar cells (PSCs). The wavelength-scale structured haze films are fabricated on the back surface of glass without damages to organic active layer by using a soft lithographic technique with etched GaN molds. With a rigorous coupled-wave analysis of optical modeling, we find the shift of resonance peaks with the increase of pattern's diameter. Wavelength-scale structures could provide the number of resonances at the long wavelength spectrum (λ = 650-800 nm), yielding enhancement of power conversion efficiency (PCE) in the PSCs. Compared with a flat device (PCE = 7.12%, Jsc = 15.6 mA/cm(2)), improved PCE of 8.41% is achieved in a haze film, which is mainly due to the increased short circuit current density (Jsc) of 17.5 mA/cm(2). Hence, it opens up exciting opportunities for a variety of PSCs with wavelength-scale structures to further improve performance, simplify complicated process, and reduce costs.

  8. Evaluation of the Components Released by Wine Yeast Strains on Protein Haze Formation in White Wine

    Directory of Open Access Journals (Sweden)

    Ellen Cristine Giese

    2016-12-01

    Full Text Available Cultures of 23 indigenous yeast strains (22 Saccharomyces cerevisiae and a non-Saccharomyces, Torulaspora delbrueckii, isolated from fermentation tanks at wineries in Castilla-La Mancha (Spain, and were performed under winemaking conditions using a synthetic must. Polysaccharide analysis and turbidity assays were conducted so as to observe the capacity of the released mannoproteins against protein haze formation in white wine, and 3 strains (2 Saccharomyces cerevisiae and T. delbrueckii were chosen for further experiments. The action of a commercial b-glucanolytic enzyme preparation (Lallzyme BETA®, and a β-(1→3-glucanase preparation from Trichoderma harzianum Rifai were evaluated to release polysaccharides from the different yeast strains’ cell walls. Protection against protein haze formation was strain dependent, and only two strains (Sc2 and Sc4 presented >50% stabilization in comparison to controls. Addition of β-glucanases did not increase the concentrations of polysaccharides in the fermentation musts; however, a significant increase of polymeric mannose (mannoproteins was detected using an enzymatic assay following total acid hydrolysis of the soluble polysaccharides. Enzymatic treatment presented positive effects and decreased protein haze formation in white wine. DOI http://dx.doi.org/10.17807/orbital.v8i6.869

  9. Net effect of wort osmotic pressure on fermentation course, yeast vitality, beer flavor, and haze.

    Science.gov (United States)

    Sigler, K; Matoulková, D; Dienstbier, M; Gabriel, P

    2009-04-01

    The net effect of increased wort osmolarity on fermentation time, bottom yeast vitality and sedimentation, beer flavor compounds, and haze was determined in fermentations with 12 degrees all-malt wort supplemented with sorbitol to reach osmolarity equal to 16 degrees and 20 degrees. Three pitchings were performed in 12 degrees/12 degrees/12 degrees, 16 degrees/16 degrees/12 degrees, and 20 degrees/20 degrees/12 degrees worts. Fermentations in 16 degrees and 20 degrees worts decreased yeast vitality measured as acidification power (AP) by a maximum of 10%, lowered yeast proliferation, and increased fermentation time. Repitching aggravated these effects. The 3rd "back to normal" pitching into 12 degrees wort restored the yeast AP and reproductive abilities while the extended fermentation time remained. Yeast sedimentation in 16 degrees and 20 degrees worts was delayed but increased about two times at fermentation end relative to that in 12 degrees wort. Third "back-to-normal" pitching abolished the delay in sedimentation and reduced its extent, which became nearly equal in all variants. Beer brewed at increased osmolarity was characterized by increased levels of diacetyl and pentanedione and lower levels of dimethylsulfide and acetaldehyde. Esters and higher alcohols displayed small variations irrespective of wort osmolarity or repitching. Increased wort osmolarity had no appreciable effect on the haze of green beer and accelerated beer clarification during maturation. In all variants, chill haze increased with repitching.

  10. Silver nanowires decorated with silver nanoparticles for low-haze flexible transparent conductive films.

    Science.gov (United States)

    Menamparambath, Mini Mol; Ajmal, C Muhammed; Kim, Kwang Hee; Yang, Daejin; Roh, Jongwook; Park, Hyeon Cheol; Kwak, Chan; Choi, Jae-Young; Baik, Seunghyun

    2015-11-17

    Silver nanowires have attracted much attention for use in flexible transparent conductive films (TCFs) due to their low sheet resistance and flexibility. However, the haze was too high for replacing indium-tin-oxide in high-quality display devices. Herein, we report flexible TCFs, which were prepared using a scalable bar-coating method, with a low sheet resistance (24.1 Ω/sq at 96.4% transmittance) and a haze (1.04%) that is comparable to that of indium-tin-oxide TCFs. To decrease the haze and maintain a low sheet resistance, small diameter silver nanowires (~20 nm) were functionalized with low-temperature surface-sintering silver nanoparticles (~5 nm) using bifunctional cysteamine. The silver nanowire-nanoparticle ink stability was excellent. The sheet resistance of the TCFs was decreased by 29.5% (from 34.2 to 24.1 Ω/sq) due to the functionalization at a low curing temperature of 85 °C. The TCFs were highly flexible and maintained their stability for more than 2 months and 10,000 bending cycles after coating with a protective layer.

  11. Weather conditions conducive to Beijing severe haze more frequent under climate change

    Science.gov (United States)

    Cai, Wenju; Li, Ke; Liao, Hong; Wang, Huijun; Wu, Lixin

    2017-03-01

    The frequency of Beijing winter severe haze episodes has increased substantially over the past decades, and is commonly attributed to increased pollutant emissions from China’s rapid economic development. During such episodes, levels of fine particulate matter are harmful to human health and the environment, and cause massive disruption to economic activities, as occurred in January 2013. Conducive weather conditions are an important ingredient of severe haze episodes, and include reduced surface winter northerlies, weakened northwesterlies in the midtroposphere, and enhanced thermal stability of the lower atmosphere. How such weather conditions may respond to climate change is not clear. Here we project a 50% increase in the frequency and an 80% increase in the persistence of conducive weather conditions similar to those in January 2013, in response to climate change. The frequency and persistence between the historical (1950-1999) and future (2050-2099) climate were compared in 15 models under Representative Concentration Pathway 8.5 (RCP8.5). The increased frequency is consistent with large-scale circulation changes, including an Arctic Oscillation upward trend, weakening East Asian winter monsoon, and faster warming in the lower troposphere. Thus, circulation changes induced by global greenhouse gas emissions can contribute to the increased Beijing severe haze frequency.

  12. Planck intermediate results. IX. Detection of the Galactic haze with Planck

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Bernard, J.-P.; Bersanelli, M.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Burigana, C.; Cabella, P.; Cardoso, J.-F.; Catalano, A.; Cayón, L.; Chary, R.-R.; Chiang, L.-Y.; Christensen, P. R.; Clements, D. L.; Colombo, L. P. L.; Coulais, A.; Crill, B. P.; Cuttaia, F.; Danese, L.; D'Arcangelo, O.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dobler, G.; Dole, H.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, T. R.; Jagemann, T.; Jewell, J.; Jones, W. C.; Juvela, M.; Keihänen, E.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lawrence, C. R.; Leach, S.; Leonardi, R.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Mitra, S.; Moneti, A.; Montier, L.; Morgante, G.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Natoli, P.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pearson, T. J.; Perdereau, O.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Savini, G.; Schaefer, B. M.; Scott, D.; Smoot, G. F.; Spencer, L.; Stivoli, F.; Sudiwala, R.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Türler, M.; Umana, G.; Valenziano, L.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; White, M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2013-06-01

    Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission from the Galactic "haze" at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to | b | ~ 35-50° in Galactic latitude and | l | ~ 15-20° in longitude. By combining the Planck data with observations from the Wilkinson Microwave Anisotropy Probe, we were able to determine the spectrum of this emission to high accuracy, unhindered by the strong systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of -2.56 ± 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ∝ E-2.1. At Galactic latitudes | b | spatially coincident with the edge in the gamma-ray bubbles. Taken together, this indicates that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new astrophysical mechanism for cosmic-ray acceleration in the inner Galaxy is implied.

  13. Uso de la mitomicina C en la prevención del haze corneal Use of mitomycin-C in prevention of corneal haze

    Directory of Open Access Journals (Sweden)

    Oslay Mijail Tirado Martínez

    2011-06-01

    Full Text Available OBJETIVOS: Evaluar resultados visuales y aparición de haze en pacientes sometidos a LASEK con Mitomicina C intraoperatoria. MÉTODOS: Se realizó un estudio longitudinal prospectivo, tipo serie de casos, en el servicio de cirugía refractiva del Instituto Cubano de Oftalmología "Ramón Pando Ferrer", con pacientes operados entre septiembre y diciembre de 2008, y seguimiento por 12 meses. La muestra fue de 92 ojos con miopía o astigmatismo miópico. Se analizó la agudeza visual mejor corregida y sin corrección, así como la refracción manifiesta pre y posoperatoria. Se cuantificó el haze corneal y se determinaron los índices de efectividad, seguridad, predictibilidad y estabilidad. Se utilizaron técnicas de estadísticas descriptivas para el análisis de los resultados. RESULTADOS: La edad promedio fue 30,11 ± 7,00 años. El sexo femenino representó el 58,82 %. La mejor agudeza visual sin corrección media preoperatoria fue 0,12 ± 0,07 y la mejor agudeza visual corregida media fue 0,89 ± 0,15. Al año de operados, la mejor agudeza visual sin corrección y la mejor corregida fueron 0,9 ± 0,01 (R: 0,5 a 1,0. El haze corneal grado 1 apareció en dos ojos (2,17 %. El índice de efectividad fue 1,01; el índice de seguridad: 1,02; el índice de predictibilidad: 90,22 % de los ojos en±0,50 dioptrías. Hubo estabilidad de la refracción después del tercer mes posoperatorio. CONCLUSIONES: Hubo mejoría de agudeza visual sin corrección en posoperatorio con mantenimiento de agudeza visual mejor corregida preoperatoria. La aparición del haze corneal fue mínima. Los índices de efectividad, seguridad, predictibilidad y estabilidad mostraron valores similares a estándares internacionales.OBJECTIVES: To assess the visual results and the appearance of haze in patients underwent LASEK with intraoperative mitomycin-c. METHODS: A prospective and longitudinal and cases series type was conducted in the service of refractive surgery of the "Ram

  14. The development of Haze Events observed by multi-satellite retrievals and Meteorological Analysis: A Case Study over Eastern China in December 2013

    Science.gov (United States)

    Zhang, Xiaoyu; Jiang, Binbin; Du, Yong; Yao, Lingling; Huang, Dasong

    2015-04-01

    With the rapid development of national economy and urbanization, the haze has been one of the environment disasters in eastern China. It is necessary that building a model of monitoring the haze for preventing and solving it in the future. In this study, NPP/AOT(550nm) >1and GOCI/AOT(555nm) >1 are adopted to dynamically monitor severe haze events in December 2013 over eastern China. Meanwhile, wind field data from CDAS-NCEP/DOE Reanalysis data and air temperature data from CDAS-NCEP/FNL are adopted to study the mechanism of the occurrence, migration and decay of the haze events. The haze event is composed of two consecutive cases. The first case occurred during 4-9 December is an exogenous haze for Yangtze River Delta, whereas the second case appeared during 11-15 December is an endogenous haze. This result shows:1) With the improved two-stream approximation model, GOCI is successful used to retrieve AOT with compared AERONET AOT, which demonstrates to be feasible in monitoring severe haze events. 2)Because of the large-scale observation capacity of NPP/AOT(550nm) product (×6km) and the high temporal resolution of GOCI/AOT(555nm), this study establishes a framework that detect the large-scale haze events using both data sets. 3)Weak wind speed of less than 5 m*s-1 is important for the development of the haze but the inversion is not a necessary condition for the haze. The strong cold air mass from the northern Siberia area and from East China Sea is the main force for the immigration, diffusion and decay of this haze event. 4)The air quality around Yangtze River Delta in winter is apt to suffer widely divergent influences including exogenous hazes carried by winter northwestward monsoon flows from northern Asia, and endogenous hazes induced by the rapid development of urbanization. The hit of multiple hazes over Yangtze River Delta lead to one of the most severe polluted regions of haze in China. Key words: NPP/AOT;GOCI/AOT; Haze;dynamic monitoring

  15. Retrieval and tentative indentification of the 3 μm spectral feature in Titan's haze

    Science.gov (United States)

    Kim, Sang J.; Jung, A.; Sim, C. K.; Courtin, R.; Bellucci, A.; Sicardy, B.; Song, I. O.; Minh, Y. C.

    2011-06-01

    Recently, an unidentified 3.3-3.4 μm feature found in the solar occultation spectra of the atmosphere of Titan observed by Cassini/VIMS was tentatively attributed to the C-H stretching mode of aliphatic hydrocarbon chains attached to large organic molecules, but without properly extracting the feature from adjacent influences of strong CH4 and weak C2H6 absorptions (Bellucci et al., 2009). In this work, we retrieve the detailed spectral feature using a radiative transfer program including absorption and fluorescent emission of both molecules, as well as absorption and scattering by haze particles. The spectral features of the haze retrieved from the VIMS data at various altitudes are similar to each other, indicating relatively uniform spectral properties of the haze with altitude. However, slight deviations observed near 127 km and above 300 km suggest inhomogeneity at these altitudes. We find that the positions of the major spectral peaks occur at 3.33-3.37 μm, which are somewhat different from the typical 3.3 μm aromatic or 3.4 μm aliphatic C-H stretches usually seen in the spectra of dust particles of the interstellar medium and comets. The peaks, however, coincide with those of the solid state spectra of C2H6, CH4, and CH3CN; and a broad shoulder from 3.37 to 3.50 μm coincides with those of C5H12 and C6H12 as well as those of typical aliphatic C-H stretches. This result combined with high-altitude (∼1000 km) haze formation process recently reported by Waite et al. (2007) opens a new question on the chemical composition of the haze particles. We discuss the possibility that the 3 μm feature may be due to the solid state absorption bands of these molecules (or some other molecules) and we advocate additional laboratory measurements for the ices of hydrocarbon and nitrogen-bearing molecules present in Titan's atmosphere for the identification of this 3 μm feature.

  16. Projected changes in haze pollution potential in China: an ensemble of regional climate model simulations

    Directory of Open Access Journals (Sweden)

    Z. Han

    2017-08-01

    Full Text Available Based on the dynamic downscaling by the regional climate model RegCM4 from three CMIP5 global models under the historical and the RCP4.5 simulations, this article evaluated the performance of the RegCM4 downscaling simulations on the air environment carrying capacity (AEC and weak ventilation days (WVDs in China, which are applied to measure haze pollution potential. Their changes during the middle and the end of the 21st century were also projected. The evaluations show that the RegCM4 downscaling simulations can generally capture the observed features of the AEC and WVD distributions over the period 1986–2005. The projections indicate that the annual AEC tends to decrease and the annual WVDs tend to increase over almost the whole country except central China, concurrent with greater change by the late 21st century than by the middle of the 21st century. It suggests that annual haze pollution potential would be enlarged under the RCP4.5 scenario compared to the present. For seasonal change in the four main economic zones of China, it is projected consistently that there would be a higher probability of haze pollution risk over the Beijing–Tianjin–Hebei (BTH region and the Yangtze River Delta (YRD region in winter and over the Pearl River Delta (PRD region in spring and summer in the context of the warming scenario. Over Northeast China (NEC, future climate change might reduce the AEC or increase the WVDs throughout the whole year, which favours the occurrence of haze pollution and thus the haze pollution risk would be aggravated. The relative contribution of different components related to the AEC change further indicates that changes in the boundary layer depth and the wind speed play leading roles in the AEC change over the BTH and NEC regions. In addition to those two factors, the precipitation change also exerts important impacts on the AEC change over the YRD and PRD zones.

  17. The aerosol radiative effect on a severe haze episode in the Yangtze River Delta

    Science.gov (United States)

    Sun, Kai; Liu, Hongnian; Wang, Xueyuan; Peng, Zhen; Xiong, Zhe

    2017-10-01

    Due to increased aerosol emissions and unfavorable weather conditions, severe haze events have occurred frequently in China in the last 10 years. In addition, the interaction between the boundary layer and the aerosol radiative effect may be another important factor in haze formation. To better understand the effect of this interaction, the aerosol radiative effect on a severe haze episode that took place in December 2013 was investigated by using two WRF-Chem model simulations with different aerosol configurations. The results showed that the maximal reduction of regional average surface shortwave radiation, latent heat, and sensible heat during this event were 88, 12, and 37 W m-2, respectively. The planetary boundary layer height, daytime temperature, and wind speed dropped by 276 m, 1°C, and 0.33 m s-1, respectively. The ventilation coefficient dropped by 8%-24% for in the central and northwestern Yangtze River Delta (YRD). The upper level of the atmosphere was warmed and the lower level was cooled, which stabilized the stratification. In a word, the dispersion ability of the atmosphere was weakened due to the aerosol radiative feedback. Additional results showed that the PM2.5 concentration in the central and northwestern YRD increased by 6-18 μg m-3, which is less than 15% of the average PM2.5 concentration during the severely polluted period in this area. The vertical profile showed that the PM2.5 and PM10 concentrations increased below 950 hPa, with a maximum increase of 7 and 8 μg m-3, respectively. Concentrations reduced between 950 and 800 hPa, however, with a maximum reduction of 3.5 and 4.5 μg m-3, respectively. Generally, the aerosol radiative effect aggravated the level of pollution, but the effect was limited, and this haze event was mainly caused by the stagnant meteorological conditions. The interaction between the boundary layer and the aerosol radiative effect may have been less important than the large-scale static weather conditions for

  18. Development of a daytime cloud and haze detection algorithm for Himawari-8 satellite measurements over central and eastern China

    Science.gov (United States)

    Shang, Huazhe; Chen, Liangfu; Letu, Husi; Zhao, Meng; Li, Shenshen; Bao, Shanhu

    2017-03-01

    Cloud detection by passive satellite sensors is very challenging in hazy weather over China because the reflective characteristics of haze and clouds are very similar. Consequently, hazy areas tend to be mistaken as cloudy or clear areas by current cloud mask algorithms. The Advanced Himawari Imager (AHI) aboard Himawari-8 is a multispectral Earth observation sensor with high temporal and spatial resolutions. A cloud and haze detection algorithm for AHI measurements is urgently needed for monitoring atmospheric pollution and its transport over China. This study presents the new Himawari-8 Cloud and Haze Mask (HCHM) algorithm that classifies image pixels from central and eastern China into one of three categories: clear, cloudy, or hazy. Based on the observations that haze occurs near the ground and accumulates in low-elevation plains and basins while clouds form at high altitudes, the proposed HCHM algorithm incorporates altitude information to adjust the thresholds used in the selected threshold tests to separate haze and cloud pixels. We find that combining auxiliary digital elevation model data with traditional indicators, such as the R0.86/R0.64, R0.86/R1.6, and BT11-BT3.9, improves the accuracy of cloud and haze discrimination. The HCHM algorithm is applied to Himawari-8 observations from August 2015, November 2015, January 2016, and May 2016 and validated against the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation vertical feature mask results. The validation shows that the average leakage rate, false alarm rate, and haze missing rate of the HCHM algorithm are 3.95%, 5.88%, and 4.17%, respectively.

  19. Effect of post crosslinking haze on the repeatability of Scheimpflug-based and slit-scanning imaging devices

    Directory of Open Access Journals (Sweden)

    Rohit Shetty

    2017-01-01

    Full Text Available Purpose: The aim of this study was to analyze the effect of postcollagen crosslinking (CXL haze on the measurement and repeatability of pachymetry and mean keratometry (Km of four corneal topographers. Materials and Methods: Sixty eyes of sixty patients with progressive keratoconus who had undergone accelerated CXL (ACXL underwent imaging with a scanning slit imaging device (Orbscan II and three Scheimpflug imaging devices (Pentacam HR, Sirius, and Galilei. Post-ACXL haze was measured using the densitometry software on the Pentacam HR. Readings of the thinnest corneal thickness (TCT and Km from three scans of each device were analyzed. Effect of haze on the repeatability of TCT and Km measurements was evaluated using regression models. Repeatability was assessed by coefficient of variation. Results: Corneal densitometry in different zones affected the repeatability of TCT measurement of Orbscan (P < 0.05 significantly but not the repeatability of TCT with Pentacam HR and Sirius (P = 0.03 and 0.05, respectively. Km values were affected by haze when measured with the Pentacam HR (P < 0.05. The repeatability of Km readings for all devices was unaffected by haze. In the anterior 0–2 mm and 2–6 mm zone, TCT (P = 0.43 and 0.45, respectively, Km values (P = 0.4 and 0.6, respectively, repeatability of TCT (P = 0.1 in both zones, and Km (P = 0.5 and 0.1, respectively with Galilei were found to be the most reliable. Conclusion: Galilei measurements appear to be least affected by post-ACXL haze when compared with other devices. Hence, topography measurements in the presence of haze need to be interpreted with caution.

  20. Clouds and Hazes in Saturn's North Polar Vortex: New Results from Cassini/VIMS High-Spatial Resolution Spectral Imagery on the First Grand Finale Pass

    Science.gov (United States)

    Baines, Kevin H.; Sromovsky, Lawrence A.; Fry, Patrick M.; Momary, Thomas W.; Brown, Robert H.; Buratti, Bonnie J.; Clark, Roger Nelson; Nicholson, Philip D.; Sotin, Christophe

    2017-10-01

    High-spatial-resolution spectral images of Saturn's polar region obtained during the first Grand Finale pass on April 26, 2017 by the Cassini/Visual Infrared Mapping Spectrometer (VIMS) reveal a variety of cloud/haze structures exhibiting distinctively different colors in the near-infrared, corresponding to a variety of cloud compositions, altitudes and thicknesses. Two spectral images in particular, obtained from altitudes of 110,000 km and 69,600 km above the cloudtops - corresponding to VIMS pixel resolutions of 55 and 34 km, some five times better than has been obtained by VIMS on any previous orbit - reveal small (~ 200 km across) discrete clouds remarkably enhanced in 3-micron absorption compared to nearby features, indicating enhanced ammonia and/or perhaps ammonia hydrosulfide or water ice absorptions. The ~2000-km-wide eye of the vortex in which these discrete ammonia/water ice clouds are embedded is surprisingly dark, exhibiting reflectivities less than one-third of those displayed by the small discrete clouds at all near-IR continuum wavelengths. However, at 5 microns, this contrast is reversed with the vortex eye emanating eight times the thermal flux of the embedded clouds. Taken together, the small reflectivity and large 5-micron thermal transmission indicate that the eye is an optically-thin haze/cloud region, nearly devoid of aerosols. From a dynamical point of view, the stark contrast between the reflectively dark, nearly-aerosol-free polar "eye" - indicative of downwelling processes - and the clouds of 3-micron absorbers embedded within it - indicative of powerful upwelling of materials from the depths of Saturn perhaps 50-200 km below - is puzzling, revealing that a remarkable range of vertical dynamical processes occur in Saturn's north polar region over relatively small spatial scales. Quantitative results for these various clouds, including their compositional characteristics, altitudes, mass loading, and wavelength-dependent opacities will be

  1. Source apportionment and dynamic changes of carbonaceous aerosols during the haze bloom-decay process in China based on radiocarbon and organic molecular tracers

    Directory of Open Access Journals (Sweden)

    J. Liu

    2016-03-01

    Full Text Available Fine carbonaceous aerosols (CAs is the key factor influencing the currently filthy air in megacities in China, yet few studies simultaneously focus on the origins of different CAs species using specific and powerful source tracers. Here, we present a detailed source apportionment for various CAs fractions, including organic carbon (OC, water-soluble OC (WSOC, water-insoluble OC (WIOC, elemental carbon (EC and secondary OC (SOC in the largest cities of North (Beijing, BJ and South China (Guangzhou, GZ, using the measurements of radiocarbon and anhydrosugars. Results show that non-fossil fuel sources such as biomass burning and biogenic emission make a significant contribution to the total CAs in Chinese megacities: 56 ± 4 in BJ and 46 ± 5 % in GZ, respectively. The relative contributions of primary fossil carbon from coal and liquid petroleum combustions, primary non-fossil carbon and secondary organic carbon (SOC to total carbon are 19, 28 and 54 % in BJ, and 40, 15 and 46 % in GZ, respectively. Non-fossil fuel sources account for 52 in BJ and 71 % in GZ of SOC, respectively. These results suggest that biomass burning has a greater influence on regional particulate air pollution in North China than in South China. We observed an unabridged haze bloom-decay process in South China, which illustrates that both primary and secondary matter from fossil sources played a key role in the blooming phase of the pollution episode, while haze phase is predominantly driven by fossil-derived secondary organic matter and nitrate.

  2. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  3. Characterizing the weathering induced haze formation and gloss loss of poly(ethylene-terephthalate) via MaPd:RTS spectroscopy

    Science.gov (United States)

    Gordon, Devin A.; Gok, Abdulkerim; Meyer, Corey W.; Fagerholm, Cara L.; Sweet, Noah W.; DeNoyer, Lin; Bruckman, Laura S.; French, Roger H.

    2016-09-01

    Poly(ethylene-terephthalate) (PET) film is a widely used material in photovoltaic module backsheets, for its dielectric breakdown strength, and in optical displays for its excellent combination of properties, notably optical clarity. However, PET degrades and loses optical clarity under environmental stressors of heat, moisture, and ultraviolet irradiance. Stabilizers are often included in PET formulation to increase its longevity; however, even these are subject to degradation and further reduce optical clarity. In a previous study, it was found that material yellowing is dominant with UV light exposures while moisture mostly causes hazing of the samples. Lifetime service prediction models were developed for PET from yellowing and hazing responses. To study the loss of optical clarity in PET films, samples of a UV-stabilized grade of PET were exposed to heat, moisture, and UV irradiance as prescribed by ASTM-G154 Cycle 4 and their optical properties were studied over time. Surface gloss loss and bulk haze formation were observed as primary material responses to degradation; after the first 168 hour exposure step an initial three-fold increase in bulk haze and a two-fold reduction in gloss were observed. Multi-Angle, Polarization-Dependent, Reflection, Transmission, and Scattering (MaPd:RTS) spectroscopy was employed to fully characterize the haze formation and gloss loss of the PET films under exposure.

  4. Wintertime haze deterioration in Beijing by industrial pollution deduced from trace metal fingerprints and enhanced health risk by heavy metals.

    Science.gov (United States)

    Lin, Yu-Chi; Hsu, Shih-Chieh; Chou, Charles C-K; Zhang, Renjian; Wu, Yunfei; Kao, Shuh-Ji; Luo, Li; Huang, Chao-Hao; Lin, Shuen-Hsin; Huang, Yi-Tang

    2016-01-01

    Airborne particulate matter (PM) was collected in Beijing between 24 February and 12 March 2014 to investigate chemical characteristics and potential industrial sources of aerosols along with health risk of haze events. Results showed secondary inorganic aerosol was the major contributor to PM2.5 during haze days. Utilizing specific elements, including Fe, La, Tl and As, as fingerprinting tracers, four emission sources, namely iron and steel manufacturing, petroleum refining, cement plant, and coal combustion were explicitly identified; their elevated contributions to PM during haze days were also estimated. The average cancer risk from exposure to inhalable PM toxic metals was 1.53 × 10(-4) on haze days, which is one order of magnitude higher than in other developed cities. These findings suggested heavy industries emit large amounts of not only primary PM but also precursor gas pollutants, leading to secondary aerosol formation and harm to human health during haze days. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Causation mechanism analysis for haze pollution related to vehicle emission in Guangzhou, China by employing the fault tree approach.

    Science.gov (United States)

    Huang, Weiqing; Fan, Hongbo; Qiu, Yongfu; Cheng, Zhiyu; Xu, Pingru; Qian, Yu

    2016-05-01

    Recently, China has frequently experienced large-scale, severe and persistent haze pollution due to surging urbanization and industrialization and a rapid growth in the number of motor vehicles and energy consumption. The vehicle emission due to the consumption of a large number of fossil fuels is no doubt a critical factor of the haze pollution. This work is focused on the causation mechanism of haze pollution related to the vehicle emission for Guangzhou city by employing the Fault Tree Analysis (FTA) method for the first time. With the establishment of the fault tree system of "Haze weather-Vehicle exhausts explosive emission", all of the important risk factors are discussed and identified by using this deductive FTA method. The qualitative and quantitative assessments of the fault tree system are carried out based on the structure, probability and critical importance degree analysis of the risk factors. The study may provide a new simple and effective tool/strategy for the causation mechanism analysis and risk management of haze pollution in China. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Individual particle analysis of aerosols collected under haze and non-haze conditions at a high-elevation mountain site in the North China plain

    Directory of Open Access Journals (Sweden)

    W. J. Li

    2011-11-01

    Full Text Available The North China plain is a region with megacities and huge populations. Aerosols over the highly polluted area have a significant impact on the regional and global climate. In order to investigate the physical and chemical characteristics of aerosol particles in elevated layers there, observations were carried out at the summit of Mt. Tai (1534 m a.s.l. from 19 to 28 April, 2010, when the air masses were advected from the east (phase-I: 19–21 April, from the south (phase-II: 22–25 April, and from the northwest (phase-III: 26–28 April. Individual aerosol particles were identified with transmission electron microscopy (TEM, new particle formation (NPF and growth events were monitored by a wide-range particle spectrometer, and ion concentrations in PM2.5 were analyzed. During phase-I and phase-II, haze layers caused by anthropogenic pollution were observed, and a high percentage of particles were sulfur-rich (47–49%. In phase-III, the haze disappeared due to the intrusion of cold air from the northwest, and mineral dust particles from deserts were dominant (43%. NPF followed by particle growth during daytime was more pronounced on hazy than on clear days. Particle growth during daytime resulted in an increase of particle geometric mean diameter from 10–22 nm in the morning to 56–96 nm in the evening. TEM analysis suggests that sulfuric acid and secondary organic compounds should be important factors for particle nucleation and growth. However, the presence of fine anthropogenic particles (e.g., soot, metal, and fly ash embedded within S-rich particles indicates that they could weaken NPF and enhance particle growth through condensation and coagulation. Abundant mineral particles in phase-III likely suppressed the NPF processes because they supplied sufficient area on which acidic gases or acids condensed.

  7. Bullying, hazing, and workplace harassment: the nexus in professional sports as exemplified by the first NFL Wells report.

    Science.gov (United States)

    Tofler, Ian R

    2016-12-01

    In the sporting context there is a significant nexus between adult workplace harassment and two other critical, developmentally related areas, that of child and adolescent bullying, and college hazing. These are all addressed, albeit obliquely and perhaps inadvertently, in the Miami Dolphins saga and the subsequent NFL Wells Report of 2013-2014. This is a significant document. It is even a brave, if politically expedient milestone. It evaluates the complex inter-personal and inter- and intra-systemic contributions within a sporting organization. Wells also elucidates a case where there is overlapping damage to individuals and systems as a result of malignant bullying, harassment, and hazing within overlapping systems. Constructive approaches to team building, and other positive alternatives to hazing may be the best place to initiate trust and verify institutional change at all these levels.

  8. High haze textured surface B-doped ZnO-TCO films on wet-chemically etched glass substrates for thin film solar cells

    Science.gov (United States)

    Xinliang, Chen; Jieming, Liu; Jia, Fang; Ze, Chen; Ying, Zhao; Xiaodan, Zhang

    2016-08-01

    Textured glass substrates with crater-like feature sizes of ˜5-30 μm were obtained using the chemical etching method through adjusting the treatment round (R). Pyramid-like boron-doped zinc oxide (ZnO:B) films with feature sizes of ˜300-800 nm were deposited on the etched glass substrates by the metal organic chemical deposition (MOCVD) technique using water, diethylzinc and 1%-hydrogen-diluted diborane. The ZnO:B films on the etched glass with micro/nano double textures presented a much stronger light-scattering capability than the conventional ZnO:B on the flat glass and their electrical properties changed little. Typical etched glass-3R/ZnO:B exhibited a high root mean square (RMS) roughness of ˜160 nm. The haze values at the wavelengths of 550 nm and 850 nm for etched glass-3R/ZnO:B sample were 61% and 42%, respectively. Finally, the optimized etched glass/ZnO:B was applied in the silicon (Si) based thin film solar cells. The high haze etched glass/ZnO:B substrates have potential merits for thin film solar cells. Project supported by the State Key Development Program for Basic Research of China (Nos. 2011CBA00706, 2011CBA00707), the Tianjin Applied Basic Research Project and Cutting-Edge Technology Research Plan (No. 13JCZDJC26900), the Tianjin Major Science and Technology Support Project (No. 11TXSYGX22100), the National High Technology Research and Development Program of China (No. 2013AA050302), and the Fundamental Research Funds for the Central Universities (No. 65010341).

  9. An Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Kempton, Eliza M.-R. [Department of Physics, Grinnell College, 1116 8th Avenue, Grinnell, IA 50112 (United States); Bean, Jacob L. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Parmentier, Vivien, E-mail: kemptone@grinnell.edu [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States)

    2017-08-20

    The nature of aerosols in hot exoplanet atmospheres is one of the primary vexing questions facing the exoplanet field. The complex chemistry, multiple formation pathways, and lack of easily identifiable spectral features associated with aerosols make it especially challenging to constrain their key properties. We propose a transmission spectroscopy technique to identify the primary aerosol formation mechanism for the most highly irradiated hot Jupiters (HIHJs). The technique is based on the expectation that the two key types of aerosols—photochemically generated hazes and equilibrium condensate clouds—are expected to form and persist in different regions of a highly irradiated planet’s atmosphere. Haze can only be produced on the permanent daysides of tidally locked hot Jupiters, and will be carried downwind by atmospheric dynamics to the evening terminator (seen as the trailing limb during transit). Clouds can only form in cooler regions on the nightside and morning terminator of HIHJs (seen as the leading limb during transit). Because opposite limbs are expected to be impacted by different types of aerosols, ingress and egress spectra, which primarily probe opposing sides of the planet, will reveal the dominant aerosol formation mechanism. We show that the benchmark HIHJ, WASP-121b, has a transmission spectrum consistent with partial aerosol coverage and that ingress–egress spectroscopy would constrain the location and formation mechanism of those aerosols. In general, using this diagnostic we find that observations with the James Webb Space Telescope and potentially with the Hubble Space Telescope should be able to distinguish between clouds and haze for currently known HIHJs.

  10. Understanding severe winter haze events in the North China Plain in 2014: roles of climate anomalies

    Science.gov (United States)

    Yin, Zhicong; Wang, Huijun; Chen, Huopo

    2017-02-01

    Atmospheric pollution has become a serious environmental and social problem in China. Over the past 30 years, the number of winter (December-February) haze days over the North China Plain (WHDNCP) was greatest in 2014. In addition to anthropogenic influence, climate anomalies also played a role. Thus, it is necessary to analyze the anomalous atmosphere circulations associated with haze pollution of this year in detail. Near the surface, the weaker East Asian winter monsoon pattern, causing southerly winds over the North China Plain, could aggravate the situation of haze. In the lower and middle troposphere, taking the anticyclone circulation over North China as an intermediate system, the positive phases of the eastern Atlantic/western Russia (EA/WR), the western Pacific (WP), and the Eurasia (EU) patterns led to a worse air pollution dispersion condition that contributed to a larger number of WHDNCP. In 2014, these three patterns could be recognized from the wind anomalies in the lower troposphere. The preceding autumn (September-November) Arctic sea ice (ASI) anomalies over the eastern Hemisphere and the warmer winter surface over Eurasia might have induced or intensified the positive EA/WR pattern in 2014. These two external forcings, together with the pre-autumn sea surface temperature anomalies in the Pacific, might have also stimulated or enhanced the positive EU-like patterns. The anomalous surface temperature in autumn 2014 was efficient in intensifying anomalous circulations such as the positive phase of the WP pattern. The opposite case of minimum WHDNCP in 2010 further supports the mechanism of how EA/WR and WP patterns and associated external factors altered the local climate conditions to impact the WHDNCP.

  11. Bacterial characterization in ambient submicron particles during severe haze episodes at Ji'nan, China.

    Science.gov (United States)

    Xu, Caihong; Wei, Min; Chen, Jianmin; Wang, Xinfeng; Zhu, Chao; Li, Jiarong; Zheng, Lulu; Sui, Guodong; Li, Weijun; Wang, Wenxing; Zhang, Qingzhu; Mellouki, Abdelwahid

    2017-02-15

    In January 2014, severe haze episodes which sweep across Chinese cities have attracted public concern and interest at home and abroad. In addition to the physicochemical properties of air pollutants, bacteria are thought to be responsible for the spread of respiratory diseases and various allergies. We attempted the bacterial characterization of submicron particles (PM 0.18-0.32 , PM 0.32-0.56 , and PM 0.56-1 ) under severe haze episodes using high-throughput sequencing and real-time quantitative PCR detecting system based on 21 samples collected from January to March 2014 at Ji'nan, China. The high bacterial concentration in PM 0.32-0.56 (7314cells m -3 ), PM 0.18-0.32 (7212cells m -3 ), and PM 0.56-1 (6982cells m -3 ) showed significant negative correlations with SO 2 , NO 2, and O 3 . Under sufficient sequencing depth, 37 phyla, 71 classes, 137 orders, 236 families, and 378 genera were classified, and the bacterial community structure varied significantly in different size fractions. For example, Holophagaceae (Acidobacteria) in PM 0.32-0.56 showed 6-fold higher abundance than that in PM 0.18-0.32 . Moreover, functional categories and bacterial species (Lactococcus piscium, Pseudomonas fragi, Streptococcus agalactiae, and Pseudomonas cichorii) that may potentially be responsible for infections and allergies were also discovered. Source track analysis showed that the ambient bacteria mainly originated from soils, leaf surfaces, and feces. Our results highlighted the importance of airborne microbial communities by understanding the concentration, structure, ecological and health effects, especially those in submicron particles during haze episodes. Copyright © 2016. Published by Elsevier B.V.

  12. Different senescent HDPE pipe-risk: brief field investigation from source water to tap water in China (Changsha City).

    Science.gov (United States)

    Tang, Jing; Tang, Lin; Zhang, Chang; Zeng, Guangming; Deng, Yaocheng; Dong, Haoran; Wang, Jingjing; Wu, Yanan

    2015-10-01

    Semi-volatile organic compounds (SVOCs) derived from plastic pipes widely used in water distribution definitely influence our daily drinking water quality. There are still few scientific or integrated studies on the release and degradation of the migrating chemicals in pipelines. This investigation was carried out at field sites along a pipeline in Changsha, China. Two chemicals, 2, 4-tert-buthylphenol and 1, 3-diphenylguanidine, were found to be migrating from high density polyethylene (HDPE) pipe material. New pipes released more of these two compounds than older pipes, and microorganisms living in older pipes tended to degrade them faster, indicating that the aged pipes were safer for water transmission. Microorganism degradation in water plays a dominant role in the control of these substances. To minimize the potential harm to human, a more detailed study incorporating assessment of their risk should be carried out, along with seeking safer drinking pipes.

  13. Corneal haze induced by excimer laser photoablation in rabbits is reduced by preserved human amniotic membrane graft

    Science.gov (United States)

    Wang, Ming X.; Gray, Trevor; Prabhasawat, Pinnita; Ma, Xiong; Culbertson, William; Forster, Richard; Hanna, Khalil; Tseng, Scheffer C. G.

    1998-06-01

    We conducted a study to determine if preserved human amniotic membrane can reduce corneal haze induced by excimer laser photoablation. Excimer photoablation was performed bilaterally on 40 New Zealand white rabbits with a 6 mm ablation zone and 120 micrometer depth (PTK) using the VISX Star. One eye was randomly covered with a preserved human amniotic membrane and secured using four interrupted 10 - 0 nylon sutures; the other eye served as control. The amniotic membranes were removed at one week, and the corneal haze was graded with a slit-lamp biomicroscopy by three masked corneal specialists (WC, KH and RF) biweekly for the ensuing 12 weeks. Histology and in situ TUNEL staining (for fragmented DNA as an index for apoptosis) was performed at days 1, 3 and 7 and at 12 weeks. One week after excimer photoablation, the amniotic membrane-covered corneas showed more anterior stromal edema, which resolved at the second week. A consistent grading of organized reticular corneal haze was noted among the three masked observers. Such corneal haze peaked at the seventh week in both groups. The amniotic membrane-covered group showed statistically significant less corneal haze (0.50 plus or minus 0.15) than the control groups (1.25 plus or minus 0.35) (p less than 0.001). The amniotic membrane-covered corneas had less inflammatory response at days 1 and 3, showing nearly nil DNA fragmentation on keratocytes on the ablated anterior stromal and less stromal fibroblast activation. There is less altered epithelial cell morphology and less epithelial hyperplasia at 1 week in these amniotic membrane-treated eyes. We concluded from this study that amniotic membrane matrix is effective in reducing corneal haze induced by excimer photoablation in rabbits and may have clinical applications.

  14. Rapid formation of a severe regional winter haze episode over a mega-city cluster on the North China Plain.

    Science.gov (United States)

    Li, Jie; Du, Huiyun; Wang, Zifa; Sun, Yele; Yang, Wenyi; Li, Jianjun; Tang, Xiao; Fu, Pingqing

    2017-04-01

    The Nested Air Quality Prediction Model System (NAQPMS) was used to investigate an extreme regional haze episode persisting over the Beijing-Tianjin-Hebei megacity cluster from November 26 to December 1, 2015. During this extreme haze event, the regional daily mean PM2.5 exceeded 500 μg/m3. We found that local emissions were the main source of haze over Beijing and Hebei in the early formational stage of this episode. The accumulation of regionally transported, highly aged secondary inorganic aerosols (SIA) along the foot of the mountains was responsible (60%) for the rapid increase of surface PM2.5 in Beijing between November 30 and December 1, although PM2.5 concentrations in the source regions of Hebei province were lower. The height of regional transport ranged from 200 to 700 m above ground level, with a slow increase with increasing distance of the source regions from Beijing. This indicates that more attention should be given to point sources at heights of 200-500 m in order to reduce the contribution of transport. The contribution of local emissions to haze in Beijing was mostly concentrated below 300 m above ground level, and was more significant for black carbon (BC) and organic matter (OM) than SIA. Tagging of pollutants by emission time showed that PM2.5 had been aged before it arrived at Beijing, and PM2.5 formed one or more days prior to arrival was twice that formed on the arrival day. This suggests that control measures would be more effective if they were implemented two days prior to haze episodes. In contrast to Beijing, haze in Tianjin was governed by transport from outside sources, whereas in cities located in Hebei province this episode resulted from local emissions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Characterization of rainwater chemical composition after a Southeast Asia haze event: insight of transboundary pollutant transport during the northeast monsoon.

    Science.gov (United States)

    Nadzir, Mohd Shahrul Mohd; Lin, Chin Yik; Khan, Md Firoz; Latif, Mohd Talib; Dominick, Doreena; Hamid, Haris Hafizal Abdul; Mohamad, Noorlin; Maulud, Khairul Nizam Abdul; Wahab, Muhammad Ikram Abdul; Kamaludin, Nurul Farahana; Lazim, Mohamad Azwani Shah Mat

    2017-06-01

    Open biomass burning in Peninsula Malaysia, Sumatra, and parts of the Indochinese region is a major source of transboundary haze pollution in the Southeast Asia. To study the influence of haze on rainwater chemistry, a short-term investigation was carried out during the occurrence of a severe haze episode from March to April 2014. Rainwater samples were collected after a prolonged drought and analyzed for heavy metals and major ion concentrations using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. The chemical composition and morphology of the solid particulates suspended in rainwater were examined using a scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The dataset was further interpreted using enrichment factors (EF), statistical analysis, and a back trajectory (BT) model to find the possible sources of the particulates and pollutants. The results show a drop in rainwater pH from near neutral (pH 6.54) to acidic (haze to non-haze transitional period, suggesting that the deposition rate of sulfate and nitrate in the atmosphere via the precipitation process was relatively lower compared to the mineral components. Zinc, nitrate, and calcium, which were the predominant elements in the first rainwater samples. Besides, the results of the SEM-EDS indicated that the zinc was possibly originated from anthropogenic activities which are consistent with the results obtained from EF. The BT model showed that pollutants transported from the mainland of Indo-China and the marine region in the South China Sea were responsible for the high pollution event in the study area. These findings can be useful in identifying contributions of pollutants from single or multiple sources in rainwater samples during haze episodes.

  16. 76 FR 80754 - Approval and Promulgation of Implementation Plans; State of Kansas: Regional Haze

    Science.gov (United States)

    2011-12-27

    ... 0.0 0.5 0.0 Gill 3 181.6 452.1 148.6 0.3 33.0 451.8 Gill 4 103.8 333.3 85.2 0.2 18.7 333.1 Neosho 7... regional haze SIP, Westar Energy, EPA, and the State entered into a Federal Consent Decree in resolution of... in resolution of alleged violations of the Clean Air Act. The Consent Decree requires that Jeffrey...

  17. Individual metal-bearing particles in a regional haze caused by firecracker and firework emissions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weijun, E-mail: liweijun@sdu.edu.cn [Environment Research Institute, Shandong University, Jinan, Shandong 250100 (China); State Key of Laboratory of Atmospheric Boundary Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 (China); Shi, Zongbo [School of Geography, Earth and Environmental Sciences, University of Birmingham (United Kingdom); Yan, Chao; Yang, Lingxiao; Dong, Can; Wang, Wenxing [Environment Research Institute, Shandong University, Jinan, Shandong 250100 (China)

    2013-01-15

    Intensive firecracker/firework displays during Chinese New Year (CNY) release fine particles and gaseous pollutants into the atmosphere, which may lead to serious air pollution. We monitored ambient PM{sub 2.5} and black carbon (BC) concentrations at a regional background site in the Yellow River Delta region during the CNY in 2011. Our monitoring data and MOUDI images showed that there was a haze event during the CNY. Daily average PM{sub 2.5} concentration reached 183 μg m{sup −3} during the CNY, which was six times higher than that before and after the CNY. Similarly, the black carbon (BC) concentrations were elevated during the CNY. In order to confirm whether the firecracker/firework related emission is the main source of the haze particles, we further analyzed the morphology and chemical composition of individual airborne particles collected before, during and after the CNY by using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy (TEM/EDS). We found that sulfate and organic-rich particles were dominant in the atmosphere before and after the CNY. In contrast, K-rich sulfates and other metal (e.g., Ba-rich, Al-rich, Mg-rich, and Fe-rich) particles were much more abundant than ammoniated sulfate particles during the CNY. These data suggest that it was the aerosol particles from the firecracker/firework emissions that induced the regional haze episode during the CNY. In individual organic and K-rich particles, we often found more than two types of nano-metal particles. These metal-bearing particles also contained abundant S but not Cl. In contrast, fresh metal-bearing particles from firecrackers generated in the laboratory contained abundant Cl with minor amounts of S. This indicates that the firecracker/firework emissions during the CNY significantly changed the atmospheric transformation pathway of SO{sub 2} to sulfate. - Highlights: ► TEM was used to observe the aged individual particles from firecrackers

  18. Photochemistry in Saturn’s Ring-Shadowed Atmosphere: Photochemistry and Haze Observations

    Science.gov (United States)

    Edgington, Scott G.; Atreya, Sushil K.; Baines, Kevin H.; West, Robert A.; Bjoraker, Gordon L.; Fletcher, Leigh; Momary, Thomas W.; Wilson, Eric; CIRS, ISS, UVIS, VIMS

    2017-10-01

    After 13 years of observing Saturn, Cassini would have ended nearly a half Saturnian year. During this epoch, the ring shadow has moved from covering much of the northern hemisphere to covering a large swath southern hemisphere. The net effect is that the intensity of both ultraviolet and visible sunlight penetrating through the rings to any particular latitude will vary depending on both Saturn’s axis relative to the Sun and the optical thickness of each ring system. In essence, the rings act like semi-transparent venetian blinds. This effect magnifies the effect due to axial tilt alone and acts to turn off photochemistry and haze generation. This effect is seen in both the presence of a bluish Rayleigh-scattering atmosphere in 2004 in the northern hemisphere and color change to blue in the northern hemisphere.Previous work examined the variation of the solar flux as a function of solar inclination, i.e. for each 7.25-year season at Saturn. We report on the impact of the oscillating ring shadow, in addition to variation due to axial tilt, on photolysis and production rates of hydrocarbons and phosphine in Saturn’s stratosphere and upper troposphere. The impact of these production and loss rates on the abundance of long-lived photochemical products leading to haze formation are explored. We assess their impact on a disequilibrium species whose presence in the upper troposphere can be used as a tracer of convective processes in the deeper atmosphere.We will also present our ongoing analysis of Cassini’s CIRS, UVIS, and VIMS datasets that provide an estimate of the evolving haze content. In particular, we will examine how the region inside Saturn’s famous hexagonal jet stream changes over time from a relatively clear atmosphere to a hazy one. We also explore how the hexagon acts like a barrier to transport, isolating Saturn’s north polar region from outside influences of photochemically-generated molecules and haze.The research described in this paper was

  19. Artificial intelligence based approach to forecast PM2.5 during haze episodes: A case study of Delhi, India

    Science.gov (United States)

    Mishra, Dhirendra; Goyal, P.; Upadhyay, Abhishek

    2015-02-01

    Delhi has been listed as the worst performer across the world with respect to the presence of alarmingly high level of haze episodes, exposing the residents here to a host of diseases including respiratory disease, chronic obstructive pulmonary disorder and lung cancer. This study aimed to analyze the haze episodes in a year and to develop the forecasting methodologies for it. The air pollutants, e.g., CO, O3, NO2, SO2, PM2.5 as well as meteorological parameters (pressure, temperature, wind speed, wind direction index, relative humidity, visibility, dew point temperature, etc.) have been used in the present study to analyze the haze episodes in Delhi urban area. The nature of these episodes, their possible causes, and their major features are discussed in terms of fine particulate matter (PM2.5) and relative humidity. The correlation matrix shows that temperature, pressure, wind speed, O3, and dew point temperature are the dominating variables for PM2.5 concentrations in Delhi. The hour-by-hour analysis of past data pattern at different monitoring stations suggest that the haze hours were occurred approximately 48% of the total observed hours in the year, 2012 over Delhi urban area. The haze hour forecasting models in terms of PM2.5 concentrations (more than 50 μg/m3) and relative humidity (less than 90%) have been developed through artificial intelligence based Neuro-Fuzzy (NF) techniques and compared with the other modeling techniques e.g., multiple linear regression (MLR), and artificial neural network (ANN). The haze hour's data for nine months, i.e. from January to September have been chosen for training and remaining three months, i.e., October to December in the year 2012 are chosen for validation of the developed models. The forecasted results are compared with the observed values with different statistical measures, e.g., correlation coefficients (R), normalized mean square error (NMSE), fractional bias (FB) and index of agreement (IOA). The performed

  20. Aerosol radiative effect in UV, VIS, NIR, and SW spectra under haze and high-humidity urban conditions

    Science.gov (United States)

    Zhang, Ming; Ma, Yingying; Gong, Wei; Wang, Lunche; Xia, Xiangao; Che, Huizheng; Hu, Bo; Liu, Boming

    2017-10-01

    Aerosol properties derived from sun-photometric observations at Wuhan during a haze period were analyzed and used as input in a radiative transfer model to calculate the aerosol radiative effect (ARE) in ultraviolet (UV), visible (VIS), near-infrared (NIR), and shortwave (SW) spectra. The results showed that the aerosol optical depth (AOD) at 440 nm increased from 0.32 under clear-air conditions to 0.85 during common haze and 1.39 during severe haze. An unusual inverse relationship was found between the Ångström exponent (AE) and AOD during the haze period at Wuhan. Under high-humidity conditions, the fine-mode median radius of aerosols increased from 0.113 μm to approximately 0.2-0.5 μm as a result of hygroscopic growth, which led to increases in the AOD and decreases in the AE simultaneously. These changes were responsible for the inverse relationship between AE and AOD at Wuhan. The surface ARE in the UV (AREUV), VIS (AREVIS), NIR (ARENIR), and SW (ARESW) spectra changed from -4.46, -25.37, -12.15, and -41.99 W/m2 under clear-air conditions to -9.48, -53.96, -29.81, and -93.25 W/m2 during common hazy days and -12.89, -80.16, -55.17, and -148.22 W/m2 during severe hazy days, respectively, and the percentages of AREUV, AREVIS, and ARENIR in ARESW changed from 11%, 61%, and 28%-9%, 54%, and 37%, respectively. Meanwhile, the ARE efficiencies (REE) in SW varied from -206.5 W/m2 under clear-air conditions to -152.94 W/m2 during the common haze period and -131.47 W/m2 during the severe haze period. The smallest decreasing rate of the REE in NIR was associated with the increase of ARENIR. The weakened REE values were related to the strong forward scattering and weak backward scattering of fine aerosol particles with increasing size resulting from hygroscopic growth, while the variation of the single scattering albedo showed less impact. Source region analysis by back trajectories and the concentration weighted trajectory (CWT) method showed that black carbon came

  1. Organic composition of aerosol particulate matter during a haze episode in Kuala Lumpur, Malaysia

    Science.gov (United States)

    Radzi Bin Abas, M.; Rahman, Noorsaadah A.; Omar, Nasr Yousef M. J.; Maah, M. Jamil; Abu Samah, Azizan; Oros, Daniel R.; Otto, Angelika; Simoneit, Bernd R. T.

    The solvent-extractable compounds of urban airborne particulate matter were analyzed to determine the distributions of homologous and biomarker tracers. Samples were collected by high-volume air filtration during the haze episode of 1997 around the University of Malaya campus near Petaling Jaya, a suburb of Kuala Lumpur, Malaysia. These results show that the samples contain n-alkanes, n-alkan-2-ones, n-alkanols, methyl n-alkanoates, n-alkyl nitriles, n-alkanals, n-alkanoic acids, levoglucosan, PAHs, and UCM as the dominant components, with minor amounts of terpenoids, glyceryl esters and sterols, all derived from natural biogenic sources (vascular plant wax), from burning of biomass, and from anthropogenic utilization of fossil fuel products (lubricating oil, vehicle emissions, etc.). Some compositional differences are observed in the samples and greater atmospheric concentrations were found for almost all organic components in the samples collected near a roadway. The results interpreted in terms of major sources are due to local build-up of organic contaminants from vehicular emissions, smoke from biomass burning, and natural background as a result of the atmospheric stability during the haze episodes. The organic components transported in from areas outside the region, assuming all smoke components are external to the city, amount to about 30% of the total organic particle burden.

  2. Liquid crystal light shutters for simultaneous control of haze and transmittance

    Science.gov (United States)

    Yoon, Tae-Hoon; Heo, Joon; Yu, Byeong-Hun; Huh, Jae-Won

    2016-03-01

    Recently, see-through displays have been attracted much attention as next-generation displays. There are two basic technologies by which we can realize a see-through display: organic light-emitting diodes (OLEDs) and liquid crystal (LC) displays. The pixel structure of a see-through display includes a transparent window area through which the background image can be seen. Therefore, background images are always seen along with the displayed image. In addition, a see-through display using OLEDs cannot provide the black color. As a result, a see-thorough display exhibits poor visibility. This inevitable problem can be solved by placing a light shutter at the back of a see-through display. Light shutter technology can be divided into two types; light absorption and light scattering. Light shutter based on light absorption can be used to control the transmittance, but it cannot block the object behind the display panel completely. Light shutters based on light scattering can be used to control the haze, but it cannot provide black color. To realize a high-visibility see-through display, we need a light shutter by which we can control haze and transmittance simultaneously. In this talk we would like to introduce technologies for LC light shutters by which we can block the background image and provide black color by utilizing light scattering and absorption effects simultaneously.

  3. Seasonal prediction of winter haze days in the north central North China Plain

    Directory of Open Access Journals (Sweden)

    Z. Yin

    2016-11-01

    Full Text Available Recently, the winter (December–February haze pollution over the north central North China Plain (NCP has become severe. By treating the year-to-year increment as the predictand, two new statistical schemes were established using the multiple linear regression (MLR and the generalized additive model (GAM. By analyzing the associated increment of atmospheric circulation, seven leading predictors were selected to predict the upcoming winter haze days over the NCP (WHDNCP. After cross validation, the root mean square error and explained variance of the MLR (GAM prediction model was 3.39 (3.38 and 53 % (54 %, respectively. For the final predicted WHDNCP, both of these models could capture the interannual and interdecadal trends and the extremums successfully. Independent prediction tests for 2014 and 2015 also confirmed the good predictive skill of the new schemes. The predicted bias of the MLR (GAM prediction model in 2014 and 2015 was 0.09 (−0.07 and −3.33 (−1.01, respectively. Compared to the MLR model, the GAM model had a higher predictive skill in reproducing the rapid and continuous increase of WHDNCP after 2010.

  4. Development of engineered yeast for biosorption of beer haze-active polyphenols.

    Science.gov (United States)

    Cejnar, Rudolf; Hložková, Kateřina; Jelínek, Lukáš; Kotrba, Pavel; Dostálek, Pavel

    2017-02-01

    Compared to most other alcoholic beverages, the shelf life of beer is much more limited due to its instability in the bottle. That instability is most likely to appear as turbidity (haze), even sedimentation, during storage. The haze in beer is mostly caused by colloidal particles formed by interactions between proteins and polyphenols within the beer. Therefore, beers are usually stabilized by removing at least one of these components. We developed and constructed a Saccharomyces cerevisiae strain with a proline-rich QPF peptide attached to the cell wall, using the C-terminal anchoring domain of α-agglutinin. The QPF peptide served to bind polyphenols during fermentation and, thus, to decrease their concentration. Strains displaying QPF were able to bind about twice as much catechin and epicatechin as a control strain displaying only the anchoring domain. All these experiments were done with model solutions. Depending on the concentration of yeast, uptake of polyphenols was 1.7-2.5 times higher. Similarly, the uptake of proanthocyanidins was increased by about 20 %. Since the modification of yeasts with QPF did not affect their fermentation performance under laboratory conditions, the display of QPF appears to be an approach to increase the stability of beer.

  5. 2013 Southeast Asian smoke haze: fractionation of particulate-bound elements and associated health risk.

    Science.gov (United States)

    Betha, Raghu; Behera, Sailesh N; Balasubramanian, Rajasekhar

    2014-04-15

    Recurring biomass burning-induced smoke haze is a serious regional air pollution problem in Southeast Asia (SEA). The June 2013 haze episode was one of the worst air pollution events in SEA. Size segregated particulate samples (2.5-1.0 μm; 1.0-0.5 μm; 0.5- 0.2 μm; and 60%) of the elements was present in oxidizable and residual fractions while the bioavailable (exchangeable) fraction accounted for up to 20% for most of the elements except K and Mn. Deposition of inhaled potentially toxic trace elements in various regions of the human respiratory system was estimated using a Multiple-Path Particle Dosimetry model. The particle depositions in the respiratory system tend to be more severe during hazy days than those during nonhazy days. A prolonged exposure to finer particles can thus cause adverse health outcomes during hazy days. Health risk estimates revealed that the excessive lifetime carcinogenic risk to individuals exposed to biomass burning-impacted aerosols (18 ± 1 × 10(-6)) increased significantly (P < 0.05) compared to those who exposed to urban air (12 ± 2 × 10(-6)).

  6. Fractionation of airborne particulate-bound elements in haze-fog episode and associated health risks in a megacity of southeast China.

    Science.gov (United States)

    Li, Huiming; Wang, Qin'geng; Shao, Min; Wang, Jinhua; Wang, Cheng; Sun, Yixuan; Qian, Xin; Wu, Hongfei; Yang, Meng; Li, Fengying

    2016-01-01

    Haze caused by high particulate matter loadings is an important environmental issue. PM2.5 was collected in Nanjing, China, during a severe haze-fog event and clear periods. The particulate-bound elements were chemically fractionated using sequential extractions. The average PM2.5 concentration was 3.4 times higher during haze-fog (96-518 μg/m(3)) than non-haze fog periods (49-142 μg/m(3)). Nearly all elements showed significantly higher concentrations during haze-fog than non-haze fog periods. Zn, As, Pb, Cd, Mo and Cu were considered to have higher bioavailability and enrichment degree in the atmosphere. Highly bioavailable fractions of elements were associated with high temperatures. The integrated carcinogenic risk for two possible scenarios to individuals exposed to metals was higher than the accepted criterion of 10(-6), whereas noncarcinogenic risk was lower than the safe level of 1. Residents of a city burdened with haze will incur health risks caused by exposure to airborne metals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Investigating the impact of haze on cloud detection of passive satellite by comparing MODIS, CloudSat and CALIPSO

    Science.gov (United States)

    Gong, W.; Mao, F.

    2015-12-01

    The cloud detection algorithm for passive sensors is usually based on a fuzzy logic system with thresholds determined from previous observations. In recent years, haze and high aerosol concentrations with high AOD occur frequently in China and may critically impact the accuracy of the MODIS cloud detection. Thus, we comprehensively explore this impact by comparing the results from MODIS/Aqua (passive sensor), CALIOP/CALIPSO (lidar sensor), and CPR/CloudSat (microwave sensor) of the A-Train suite of instruments using an averaged AOD as an index for an aerosol concentration value. Case studies concerning the comparison of the three sensors indicate that MODIS cloud detection is reduced during haze events. In addition, statistical studies show that an increase in AOD creates an increase in the percentage of uncertain flags and a decrease in hit rate, a consistency index between consecutive sets of cloud retrievals. Therefore, we can conclude that the ability of MODIS cloud detection is weakened by large concentrations of aerosols. This suggests that use of the MODIS cloud mask, and derived higher level products, in situations with haze requires caution. Further improvement of this retrieval algorithm, is desired as haze studies based on MODIS products are of great interest in a number of related fields.

  8. Efficiency of enzymatic and other alternative clarification and fining treatments on turbidity and haze in cherry juice

    DEFF Research Database (Denmark)

    Meyer, Anne Boye Strunge; Köser, C.; Adler-Nissen, Jens

    2001-01-01

    function. Individual and interactive effects on turbidity and haze formation in precentrifuged and uncentrifuged cherry juice of treatments with pectinase, acid protease, bromelain, gallic acid, and gelatin-silica sol were investigated in a factorial experimental design with 32 different parameter...

  9. Haze production in the atmospheres of super-Earths and mini-Neptunes: Insight from PHAZER lab

    Science.gov (United States)

    Horst, Sarah; He, Chao; Kempton, Eliza; Moses, Julianne I.; Vuitton, Veronique; Lewis, Nikole

    2017-10-01

    Super-Earths and mini-Neptunes (~1.2-3 Earth radii) comprise a large fraction of planets in the universe and TESS (Transiting Exoplanet Survey Satellite) will increase the number that are amenable to atmospheric characterization with observatories like JWST (James Webb Space Telescope). These atmospheres should span a large range of temperature and atmospheric composition phase space, with no solar system analogues. Interpretation of current and future atmospheric observations of super-Earths and mini-Neptunes requires additional knowledge about atmospheric chemistry and photochemical haze production. We have experimentally investigated haze formation for H2, H2O, and CO2 dominated atmospheres (100x, 1000x, and 10000x solar metallicity) for a range of temperatures (300 K, 400 K, and 600 K) using the PHAZER (Planetary Haze Research) experiment at Johns Hopkins University. This is a necessary step in understanding which, if any, super-Earths and mini-Neptunes possess the conditions required for efficient production of photochemical haze in their atmospheres. We find that the production rates vary over a few orders of magnitudes with some higher than our nominal Titan experiments. We therefore expect that planets in this temperature and atmospheric composition phase space will exhibit a range of particle concentrations and some may be as hazy as Titan.

  10. A Comparison of the AFGL Flash, Draper Dart and AWS Haze Models with the Rand Wetta Model for Calculating Atmospheric Contrast Reduction.

    Science.gov (United States)

    1982-03-01

    and 2-m Surface Visibility. 10 HAZE MODEL COMPARI[SON ALT =12000 FT. 0 SOLAR ZENITH 60 (DEG) SALBEDO = 0.18 e- VSBY = 23 KM. 1988 ELTERMAN MODEL tW UP z...0.18, and 23-km Surface Visibility. 14 HAZE MODEL COMPARISON ALT =12000 FT. SOLAR ZENITH 20 (DEG) SALBEDO = 0.06 SVSBY - 23 KM. S1968 ELTERMAN MODEL...Albedo of 0.06, and 23-km Surface Visibility. 15 21-. HAZE MODEL COMPARISON ALT 12000 FT. SOLAR ZENITH 60 (DEC) SALBEDO - 0.06 SVSBY = 23 KM. , 1968

  11. Microscopia confocal cuantitativa del haze corneal y correlación con la ametropía a tratar en cirugía refractiva de superficie

    Directory of Open Access Journals (Sweden)

    Eduardo Rojas Alvarez

    2016-07-01

    Conclusiones: El grosor del haze corneal obtenido en pacientes intervenidos con excímer láser mediante la técnica LASEK es dependiente de la magnitud de la ametropía a tratar, y adquiere su mayor valor a los 3 meses de posoperatorio. La magnitud de la ametropía no es el único factor influyente en la aparición y grosor del haze. En córneas transparentes en el posoperatorio de LASEK siempre existe algún grado de haze corneal morfométrico.

  12. Process analysis of characteristics of the boundary layer during a heavy haze pollution episode in an inland megacity, China.

    Science.gov (United States)

    Wang, Shan; Liao, Tingting; Wang, Lili; Sun, Yang

    2016-02-01

    Ground observation data from 8 meteorological stations in Xi'an, air mass concentration data from 13 environmental quality monitoring sites in Xi'an, as well as radiosonde observation and wind profile radar data, were used in this study. Thereby, the process, causes and boundary layer meteorological characteristics of a heavy haze episode occurring from 16 to 25 December 2013 in Xi'an were analyzed. Principal component analysis showed that this haze pollution was mainly caused by the high-intensity emission and formation of gaseous pollutants (NO2, CO and SO2) and atmospheric particles (PM2.5 (fine particles) and PM10 (respirable suspended particle). The second cause was the relative humidity and continuous low temperature. The third cause was the allocation of the surface pressure field. The presence of a near-surface temperature inversion at the boundary layer formed favorable stratification conditions for the formation and maintenance of heavy haze pollution. The persistent thick haze layer weakened the solar radiation. Meanwhile, a warming effect in the urban canopy layer and in the transition zone from the urban friction sublayer to the urban canopy was indicated. All these conditions facilitated the maintenance and reinforcement of temperature inversion. The stable atmospheric stratification finally acted on the wind field in the boundary layer, and further weakened the exchange capacity of vertical turbulence. The superposition of a wind field with the horizontal gentle wind induced the typical air stagnation and finally caused the deterioration of air quality during this haze event. Copyright © 2015. Published by Elsevier B.V.

  13. Meteoric Dust as Condensation Nuclei of Small-Mode Particles in the Upper Haze of Venus

    Science.gov (United States)

    Gao, P.; Zhang, X.; Crisp, D.; Bardeen, C.; Yung, Y. L.

    2012-12-01

    Observations by the SPICAV/SOIR instruments aboard Venus Express have revealed that the Upper Haze of Venus is populated by two particle modes, as reported by Wilquet et al. (J. Geophys. Res., 114, E00B42, 2009). In this work, we posit that the large mode is made up of cloud particles that have diffused upwards from the cloud deck below, while the smaller mode is generated by the in situ nucleation of meteoric dust. We test this hypothesis by using version 3.0 of the Community Aerosol and Radiation Model for Atmospheres, first developed by Turco et al. (J. Atmos. Sci., 36, 699-717, 1979) and upgraded to version 3.0 by Bardeen et al. (The CARMA 3.0 microphysics package in CESM, Whole Atmosphere Working Group Meeting, 2011). Using the meteoric dust production profile of Kalashnikova et al. (Geophys. Res. Lett., 27, 3293-3296, 2000), the sulfur/sulfate condensation nuclei production profile of Imamura and Hashimoto (J. Atmos. Sci., 58, 3597-3612, 2001), and sulfuric acid vapor production profile of Zhang et al. (Icarus, 217, 714-739, 2012), we numerically simulate a column of the Venus atmosphere from 40 to 100 km above the surface. Our aerosol number density results agree well with Pioneer Venus data from Knollenberg and Hunten (J. Geophys. Res., 85, 8039-8058, 1980), while our gas distribution results match that of Kolodner and Steffes below 55 km (Icarus, 132, 151-169, 1998). The resulting size distribution of cloud particles shows two distinct modes, qualitatively matching the observations of Pioneer Venus. We also observe a third mode in our results with a size of a few microns at 48 km altitude, which appears to support the existence of the controversial third mode in the Pioneer Venus data. This mode disappears if coagulation is not included in the simulation. The Upper Haze size distribution shows two lognormal-like distributions overlapping each other, possibly indicating the presence of the two distinct modes. We test our hypothesis by simulating the

  14. Typical Types and Formation Mechanisms of Haze in an Eastern Asia Megacity, Shanghai

    Science.gov (United States)

    Huang, K.; Zhuang, G.; Lin, Y.; Fu, J. S.; Wang, Q.; Liu, T.; Zhang, R.; Jiang, Y.; Deng, C.; Fu, Q.; hide

    2012-01-01

    An intensive aerosol and gases campaign was performed at Shanghai in the Yangtze River Delta region over Eastern China from late March to early June 2009. This study provided a complementary picture of typical haze types and the formation mechanisms in megacities over China by using a synergy of ground-based monitoring, satellite and lidar observations. During the whole study period, several extreme low visibility periods were observed with distinct characteristics, and three typical haze types were identified, i.e. secondary inorganic pollution, dust, and biomass burning. Sulfate, nitrate and ammonium accounted for a major part of PM2.5 mass during the secondary inorganic pollution, and the good correlation between SO2/NOx/CO and PM2.5 indicated that coal burning and vehicle emission were the major sources. Large-scale regions with high AOD (aerosol optical depths) and low Angstrom exponent were detected by remote-sensing observation during the dust pollution episode, and this episode corresponded to coarse particles rich in mineral components such as Al and Ca contributing 76.8% to TSP. The relatively low Ca/Al ratio of 0.75 along with the air mass backward trajectory analysis suggested the dust source was from Gobi Desert. Typical tracers for biomass burning from satellite observation (column CO and HCHO) and from ground measurement (CO, particulate K+, OC, and EC) were greatly enhanced during the biomass burning pollution episode. The exclusive linear correlation between CO and PM2.5 corroborated that organic aerosol dominated aerosol chemistry during biomass burning, and the high concentration and enrichment degree of arsenic (As) could be also partly derived from biomass burning. Aerosol optical profile observed by lidar demonstrated that aerosol was mainly constrained below the boundary layer and comprised of spheric aerosol (depolarization ratio <5%) during the secondary inorganic and biomass burning episodes, while thick dust layer distributed at altitudes

  15. Typical types and formation mechanisms of haze in an Eastern Asia megacity, Shanghai

    Directory of Open Access Journals (Sweden)

    K. Huang

    2012-01-01

    Full Text Available An intensive aerosol and gases campaign was performed at Shanghai in the Yangtze River Delta region over Eastern China from late March to early June 2009. This study provided a complementary picture of typical haze types and the formation mechanisms in megacities over China by using a synergy of ground-based monitoring, satellite and lidar observations. During the whole study period, several extreme low visibility periods were observed with distinct characteristics, and three typical haze types were identified, i.e. secondary inorganic pollution, dust, and biomass burning. Sulfate, nitrate and ammonium accounted for a major part of PM2.5 mass during the secondary inorganic pollution, and the good correlation between SO2/NOx/CO and PM2.5 indicated that coal burning and vehicle emission were the major sources. Large-scale regions with high AOD (aerosol optical depths and low Ångström exponent were detected by remote-sensing observation during the dust pollution episode, and this episode corresponded to coarse particles rich in mineral components such as Al and Ca contributing 76.8% to TSP. The relatively low Ca/Al ratio of 0.75 along with the air mass backward trajectory analysis suggested the dust source was from Gobi Desert. Typical tracers for biomass burning from satellite observation (column CO and HCHO and from ground measurement (CO, particulate K+, OC, and EC were greatly enhanced during the biomass burning pollution episode. The exclusive linear correlation between CO and PM2.5 corroborated that organic aerosol dominated aerosol chemistry during biomass burning, and the high concentration and enrichment degree of arsenic (As could be also partly derived from biomass burning. Aerosol optical profile observed by lidar demonstrated that aerosol was mainly constrained below the boundary layer and comprised of spheric aerosol (depolarization ratio <5% during the secondary

  16. Spatial distribution and temporal variability of Harmattan dust haze in sub-Sahel West Africa

    Science.gov (United States)

    Anuforom, Anthony C.

    The distributions of frequency of occurrence (FOO) of 'thick dust haze' (TDH) and of 'light dust haze' (LDH) with respect to latitude, longitude, elevation and distance from source during Harmattan season (from November to February) are investigated, using 30-year visibility data collected from 27 synoptic stations located in Nigeria between the West African Sahel and the coasts of Gulf of Guinea. This region lies along the Harmattan season trajectory of Saharan dust. Also investigated is the temporal variability of TDH and LDH on intra-seasonal and inter-annual timescales spanning three decades from 1971 to 2000. Dust haze distribution over the region is found to correlate with the four geographical variables to different extents, with latitude, distance from source and elevation showing strong correlations with both TDH and LDH. The investigation also shows that while FOO of TDH days increases with latitude (correlation coefficient, rlat,FOO_TDH=0.88), FOO of LDH days decreases with latitude over the region (correlation coefficient, rlat,FOO_LDH=-0.74). The correlation coefficients with longitude over the region are rlon,FOO_TDH=0.44 and rlon,FOO_LDH=-0.25, respectively, indicating weaker dependence of TDH and LDH on longitude. The average number of TDH days per month during the Harmattan season in the region ranges from about 0.5 in the humid coastal zone near the Gulf of Guinea in the south, to approximately 6 in the dry semi-arid zone near the West African Sahel. An empirical equation which shows that FOO of TDH increases exponentially with latitude over the region is derived. The FOO of TDH is found to be most variable in or near the Sahel zone and decreases southwards towards the Gulf of Guinea. The average of the standard deviations is 1.13 for the six northernmost synoptic stations and decreases to 0.51 over the six coastal and southernmost locations. In contrast, the FOO of LDH is most variable in the south (with standard deviation of 2.11 (over the six

  17. Water

    Science.gov (United States)

    ... environment and your health: Green living Sun Water Health effects of water pollution How to protect yourself from water pollution Air Chemicals Noise Quizzes Links to more information girlshealth glossary girlshealth. ...

  18. High secondary aerosol contribution to particulate pollution during haze events in China.

    Science.gov (United States)

    Huang, Ru-Jin; Zhang, Yanlin; Bozzetti, Carlo; Ho, Kin-Fai; Cao, Jun-Ji; Han, Yongming; Daellenbach, Kaspar R; Slowik, Jay G; Platt, Stephen M; Canonaco, Francesco; Zotter, Peter; Wolf, Robert; Pieber, Simone M; Bruns, Emily A; Crippa, Monica; Ciarelli, Giancarlo; Piazzalunga, Andrea; Schwikowski, Margit; Abbaszade, Gülcin; Schnelle-Kreis, Jürgen; Zimmermann, Ralf; An, Zhisheng; Szidat, Sönke; Baltensperger, Urs; El Haddad, Imad; Prévôt, André S H

    2014-10-09

    Rapid industrialization and urbanization in developing countries has led to an increase in air pollution, along a similar trajectory to that previously experienced by the developed nations. In China, particulate pollution is a serious environmental problem that is influencing air quality, regional and global climates, and human health. In response to the extremely severe and persistent haze pollution experienced by about 800 million people during the first quarter of 2013 (refs 4, 5), the Chinese State Council announced its aim to reduce concentrations of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 micrometres) by up to 25 per cent relative to 2012 levels by 2017 (ref. 6). Such efforts however require elucidation of the factors governing the abundance and composition of PM2.5, which remain poorly constrained in China. Here we combine a comprehensive set of novel and state-of-the-art offline analytical approaches and statistical techniques to investigate the chemical nature and sources of particulate matter at urban locations in Beijing, Shanghai, Guangzhou and Xi'an during January 2013. We find that the severe haze pollution event was driven to a large extent by secondary aerosol formation, which contributed 30-77 per cent and 44-71 per cent (average for all four cities) of PM2.5 and of organic aerosol, respectively. On average, the contribution of secondary organic aerosol (SOA) and secondary inorganic aerosol (SIA) are found to be of similar importance (SOA/SIA ratios range from 0.6 to 1.4). Our results suggest that, in addition to mitigating primary particulate emissions, reducing the emissions of secondary aerosol precursors from, for example, fossil fuel combustion and biomass burning is likely to be important for controlling China's PM2.5 levels and for reducing the environmental, economic and health impacts resulting from particulate pollution.

  19. [Exploring the Severe Haze in Beijing During December, 2015: Pollution Process and Emissions Variation].

    Science.gov (United States)

    Xue, Yi-feng; Zhou, Zhen; Nie, Teng; Pan, Tao; Qi, Jun; Nie, Lei; Wang, Zhan-shan; Li, Yun-ting; Li, Xue-feng; Tian, He-zhong

    2016-05-15

    Severe haze episodes shrouded Beijing and its surrounding regions again during December, 2015, causing major environmental and health problems. Beijing authorities had launched two red alerts for atmospheric heavy pollution in this period, adopted a series of emergency control measures to reduce the emissions from major pollution sources. To better understand the pollution process and emissions variation during these extreme pollution events, we performed a model-assisted analysis of the hourly observation data of PM₂.₅, and meteorological parameters combined with the emissions variation of pollution sources. The synthetic analysis indicated that: (1) Compared with the same period of last year, the emissions of atmospheric pollution sources decreased in December 2015. However, the emission levels of primary pollutants were still rather high, which were the main intrinsic causes for haze episodes, and the unfavorable diffusion conditions represented the important external factor. High source emissions and meteorological factors together led to this heavy air pollution process. (2) Emergency control measures taken by the red alert for heavy air pollution could decrease the pollutants emission by about 36% and the PM₂.₅ concentrations by 11% to 21%. Though the implementation of red alert could not reverse the evolution trend of heavier pollution, it indeed played an active role in mitigation of PM₂.₅ pollution aggravating. (3) Under the heavy pollution weather conditions, air pollutants continued to accumulate in the atmosphere, and the maximum effect by taking emergency measures occurred 48-72 hours after starting the implementation; therefore, the best time for executing emergency measures should be 36-48 hours before the rapid rise of PM₂.₅ concentration, which requires a more powerful demand on the accuracy of air quality forecast.

  20. Understanding the Atmosphere of 51 Eri b: Do Photochemical Hazes Cloud the Planets Spectrum?

    Science.gov (United States)

    Marley, Mark Scott; Zahnle, Kevin; Moses, J.; Morley, C.

    2015-01-01

    The first young giant planet to be discovered by the Gemini Planet Imager was the (is) approximately 2MJ planet 51 Eri b. This approximately 20 Myr old young Jupiter is the first directly imaged planet to show unmistakable methane in H band. To constrain the planet's mass, atmospheric temperature, and composition, the GPI J and H band spectra as well as some limited photometric points were compared to the predictions of substellar atmosphere models. The best fitting models reported in the discovery paper (Macintosh et al. 2015) relied upon a combination of clear and cloudy atmospheric columns to reproduce the data. However for an object as cool as 700 K, the origin of the cloud coverage is somewhat puzzling, as the global silicate and iron clouds would be expected to have sunk well below the photosphere by this effective temperature. While strong vertical mixing in these low gravity atmospheres remains a plausible explanation, we have explored whether atmospheric photochemistry, driven by the UV flux from the primary star, may yield hazes that also influence the observed spectrum of the planet. To explore this possibility we have modeled the atmospheric photochemistry of 51 Eri b using two state-of-the-art photochemical models, both capable of predicting yields of complex hydrocarbons under various atmospheric conditions. In our presentation we will summarize the modeling approach employed to characterize 51 Eri b, explaining constraints on the planet's effective temperature, gravity, and atmospheric composition and also present results of our studies of atmospheric photochemistry. We will discuss whether photochemical hazes could indeed be responsible for the particulate opacity that apparently sculpts the spectrum of the planet.

  1. Chitosan and thiolated chitosan: Novel therapeutic approach for preventing corneal haze after chemical injuries.

    Science.gov (United States)

    Zahir-Jouzdani, Forouhe; Mahbod, Mirgholamreza; Soleimani, Masoud; Vakhshiteh, Faezeh; Arefian, Ehsan; Shahosseini, Saeed; Dinarvand, Rasoul; Atyabi, Fatemeh

    2018-01-01

    Corneal haze, commonly caused by deep physical and chemical injuries, can greatly impair vision. Growth factors facilitate fibroblast proliferation and differentiation, which leads to haze intensity. In this study, the potential effect of chitosan (CS) and thiolated-chitosan (TCS) nanoparticles and solutions on inhibition of fibroblast proliferation, fibroblast to myofibroblast differentiation, neovascularization, extracellular matrix (ECM) deposition, and pro-fibrotic cytokine expression was examined. Transforming growth factor beta-1 (TGFβ1) was induced by interleukin-6 (IL6) in human corneal fibroblasts and expression levels of TGFβ1, Platelet-derived growth factor (PDGF), α-smooth muscle actins (α-SMA), collagen type I (Col I), fibronectin (Fn) and vascular endothelial growth factor (VEGF) were quantified using qRT-PCR. To assess wound-healing capacity, TCS-treated mice were examined for α-SMA positive cells, collagen deposition, inflammatory cells and neovascularization through pathological immunohistochemistry. The results revealed that CS and TCS could down-regulate the expression levels of TGFβ1 and PDGF comparable to that of TGFβ1 knockdown experiment. However, down-regulation of TGFβ1 was not regulated through miR29b induction. Neovascularization along with α-SMA and ECM deposition were significantly diminished. According to these findings, CS and TCS can be considered as potential anti-fibrotic and anti-angiogenic therapeutics. Furthermore, TCS, thiolated derivative of CS, will increase mucoadhesion of the polymer at the corneal surface which makes the polymer efficient and non-toxic therapeutic approach for corneal injuries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. After Indonesia’s Ratification: The ASEAN Agreement on Transboundary Haze Pollution and Its Effectiveness As a Regional Environmental Governance Tool

    Directory of Open Access Journals (Sweden)

    Daniel Heilmann

    2015-01-01

    Full Text Available On 20 January 2015 Indonesia deposited its instrument of ratification for the ASEAN Agreement on Transboundary Haze Pollution with the ASEAN Secretariat, becoming the last ASEAN member state to join the treaty. Haze pollution poses a serious health threat to the people of Indonesia, Singapore and Malaysia, and for decades haze pollution has been a highly contentious issue among ASEAN member states. This article argues that Indonesia’s ratification will not be an immediate game changer. The mechanisms of the agreement are too weak to contribute much to a reduction of haze pollution in the region. The agreement is designed according to the ASEAN way: a non-binding approach that is based on the principles of state sovereignty and non-intervention. This makes it unlikely that the agreement itself will bring about change, even now that all ASEAN member states have ratified it.

  3. Heterogeneous chemistry: a mechanism missing in current models to explain secondary inorganic aerosol formation during the January 2013 haze episode in North China

    Science.gov (United States)

    Zheng, B.; Zhang, Q.; Zhang, Y.; He, K. B.; Wang, K.; Zheng, G. J.; Duan, F. K.; Ma, Y. L.; Kimoto, T.

    2015-02-01

    Severe regional haze pollution events occurred in eastern and central China in January 2013, which had adverse effects on the environment and public health. Extremely high levels of particulate matter with aerodynamic diameter of 2.5 μm or less (PM2.5) with dominant components of sulfate and nitrate are responsible for the haze pollution. Although heterogeneous chemistry is thought to play an important role in the production of sulfate and nitrate during haze episodes, few studies have comprehensively evaluated the effect of heterogeneous chemistry on haze formation in China by using the 3-D models due to of a lack of treatments for heterogeneous reactions in most climate and chemical transport models. In this work, the WRF-CMAQ model with newly added heterogeneous reactions is applied to East Asia to evaluate the impacts of heterogeneous chemistry and the meteorological anomaly during January 2013 on regional haze formation. As the parameterization of heterogeneous reactions on different types of particles is not well established yet, we arbitrarily selected the uptake coefficients from reactions on dust particles and then conducted several sensitivity runs to find the value that can best match observations. The revised CMAQ with heterogeneous chemistry not only captures the magnitude and temporal variation of sulfate and nitrate, but also reproduces the enhancement of relative contribution of sulfate and nitrate to PM2.5 mass from clean days to polluted haze days. These results indicate the significant role of heterogeneous chemistry in regional haze formation and improve the understanding of the haze formation mechanisms during the January 2013 episode.

  4. Water

    Science.gov (United States)

    Leopold, Luna Bergere; Baldwin, Helene L.

    1962-01-01

    What do you use water for?If someone asked you this question you would probably think right away of water for drinking. Then you would think of water for bathing, brushing teeth, flushing the toilet. Your list would get longer as you thought of water for cooking, washing the dishes, running the garbage grinder. Water for lawn watering, for play pools, for swimming pools, for washing the car and the dog. Water for washing machines and for air conditioning. You can hardly do without water for fun and pleasure—water for swimming, boating, fishing, water-skiing, and skin diving. In school or the public library, you need water to wash your hands, or to have a drink. If your home or school bursts into flames, quantities of water are needed to put it out.In fact, life to Americans is unthinkable without large supplies of fresh, clean water. If you give the matter a little thought, you will realize that people in many countries, even in our own, may suffer from disease and dirt simply because their homes are not equipped with running water. Imagine your own town if for some reason - an explosion, perhaps - water service were cut off for a week or several weeks. You would have to drive or walk to a neighboring town and bring water back in pails. Certainly if people had to carry water themselves they might not be inclined to bathe very often; washing clothes would be a real chore.Nothing can live without water. The earth is covered by water over three-fourths of its surface - water as a liquid in rivers, lakes and oceans, and water as ice and snow on the tops of high mountains and in the polar regions. Only one-quarter of our bodies is bone and muscle; the other three-fourths is made of water. We need water to live, and so do plants and animals. People and animals can live a long time without food, but without water they die in a few days. Without water, everything would die, and the world would turn into a huge desert.

  5. Water

    Science.gov (United States)

    ... the tap as described). 3. In all situations, drink or cook only with water that comes out of the tap cold. Water that comes out of the tap warm or hot can contain much higher levels of lead. Boiling ...

  6. Radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer and its feedback on the haze formation

    Science.gov (United States)

    Wei, Chao; Su, Hang; Cheng, Yafang

    2016-04-01

    Planetary boundary layer (PBL) plays a key role in air pollution dispersion and influences day-to-day air quality. Some studies suggest that high aerosol loadings during severe haze events may modify PBL dynamics by radiative effects and hence enhance the development of haze. This study mainly investigates the radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer by conducting simulations with Weather Research and Forecasting single-column model (WRF-SCM). We find that high aerosol loading in PBL depressed boundary layer height (PBLH). But the magnitude of the changes of PBLH after adding aerosol loadings in our simulations are small and can't explain extreme high aerosol concentrations observed. We also investigate the impacts of the initial temperature and moisture profiles on the evolution of PBL. Our studies show that the impact of the vertical profile of moisture is comparable with aerosol effects.

  7. Prophylactic Effects of Mitomycin-C on Regression and Haze Formation in Photorefractive Keratectomy

    Directory of Open Access Journals (Sweden)

    Hassan Hashemi

    2008-12-01

    Full Text Available

    PURPOSE: To study the effect of prophylactic application of mitomycin-C on regression and corneal haze formation after photorefractive keratectomy (PRK for high myopia. METHODS: Fifty-four eyes of 28 high myopic patients were enrolled in this prospective study. All eyes underwent PRK with application of 0.02% mitomycin-C for two minutes and irrigation with 15-20 ml of normal saline. Follow-up visits were scheduled for the first 7 days and 1, 3 and 6 months after surgery. Hanna grading (in the scale of 0 to 4+ was used to assess corneal haze. RESULTS: Mean spherical equivalent refraction (SE was -7.08 ± 1.11 diopters (D, preoperatively. All eyes were examined on the first 7 days and one month after surgery; 48 eyes (88.9% were evaluated 3 and 6 months post-surgery. Six months after surgery, all eyes had uncorrected visual acuity (UCVA of 20/40 or better and 37 eyes (77.1 % achieved UCVA of 20/20 or better, 45 eyes (93.7% had SE within ±1.00D of emmetropia. One month postoperatively, 2 eyes (3.7% had grade 0.5 haze, while at 3 and 6 months after surgery no visited eye had haze at all. There was no decrease in best corrected visual acuity after 6 months. In spatial frequencies of 6 and 12 cycle/degree, contrast sensitivity decreased immediately after PRK but increased to the preoperative values by the 6th postoperative month

  8. Analysis of meteorology and emission in haze episode prevalence over mountain-bounded region for early warning.

    Science.gov (United States)

    Kim Oanh, Nguyen Thi; Leelasakultum, Ketsiri

    2011-05-01

    This study investigated the main causes of haze episodes in the northwestern Thailand to provide early warning and prediction. In an absence of emission input data required for chemical transport modeling to predict the haze, the climatological approach in combination with statistical analysis was used. An automatic meteorological classification scheme was developed using regional meteorological station data of 8years (2001-2008) which classified the prevailing synoptic patterns over Northern Thailand into 4 patterns. Pattern 2, occurring with high frequency in March, was found to associate with the highest levels of 24h PM(10) in Chiangmai, the largest city in Northern Thailand. Typical features of this pattern were the dominance of thermal lows over India, Western China and Northern Thailand with hot, dry and stagnant air in Northern Thailand. March 2007, the month with the most severe haze episode in Chiangmai, was found to have a high frequency of occurrence of pattern 2 coupled with the highest emission intensities from biomass open burning. Backward trajectories showed that, on haze episode days, air masses passed over the region of dense biomass fire hotspots before arriving at Chiangmai. A stepwise regression model was developed to predict 24h PM(10) for days of meteorology pattern 2 using February-April data of 2007-2009 and tested with 2004-2010 data. The model performed satisfactorily for the model development dataset (R(2)=87%) and test dataset (R(2)=81%), which appeared to be superior over a simple persistence regression of 24h PM(10) (R(2)=76%). Our developed model had an accuracy over 90% for the categorical forecast of PM(10)>120μg/m(3). The episode warning procedure would identify synoptic pattern 2 and predict 24h PM(10) in Chiangmai 24h in advance. This approach would be applicable for air pollution episode management in other areas with complex terrain where similar conditions exist. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Simulation of Smoke-Haze Dispersion from Wildfires in South East Asia with a Lagrangian Particle Model

    Science.gov (United States)

    Hertwig, D.; Burgin, L.; Gan, C.; Hort, M.; Jones, A. R.; Shaw, F.; Witham, C. S.; Zhang, K.

    2014-12-01

    Biomass burning, often related to agricultural deforestation, not only affects local pollution levels but periodically deteriorates air quality in many South East Asian megacities due to the transboundary transport of smoke-haze. In June 2013, Singapore experienced the worst wildfire related air-pollution event on record following from the escalation of peatland fires in Sumatra. An extended dry period together with anomalous westerly winds resulted in severe and unhealthy pollution levels in Singapore that lasted for more than two weeks. Reacting to this event, the Met Office and the Meteorological Service Singapore have explored how to adequately simulate haze-pollution dispersion, with the aim to provide a reliable operational forecast for Singapore. Simulations with the Lagrangian particle model NAME (Numerical Atmospheric-dispersion Modelling Environment), running on numerical weather prediction data from the Met Office and Meteorological Service Singapore and emission data derived from satellite observations of the fire radiative power, are validated against PM10 observations in South East Asia. Comparisons of simulated concentrations with hourly averages of PM10 measurements in Singapore show that the model captures well the severe smoke-haze event in June 2013 and a minor episode in March 2014. Different quantitative satellite-derived emissions have been tested, with one source demonstrating a consistent factor of two under-prediction for Singapore. Confidence in the skill of the model system has been substantiated by further comparisons with data from monitoring sites in Malaysia, Brunei and Thailand. Following the validation study, operational smoke-haze pollution forecasts with NAME were launched in Singapore, in time for the 2014 fire season. Real-time bias correction and verification of this forecast will be discussed.

  10. Laboratory Studies of Planetary Hazes: composition of cool exoplanet atmospheric aerosols with very high resolution mass spectrometry

    Science.gov (United States)

    Moran, Sarah E.; Horst, Sarah; He, Chao; Flandinet, Laurene; Moses, Julianne I.; Orthous-Daunay, Francois-Regis; Vuitton, Veronique; Wolters, Cedric; Lewis, Nikole

    2017-10-01

    We present first results of the composition of laboratory-produced exoplanet haze analogues. With the Planetary HAZE Research (PHAZER) Laboratory, we simulated nine exoplanet atmospheres of varying initial gas phase compositions representing increasing metallicities (100x, 1000x, and 10000x solar) and exposed them to three different temperature regimes (600, 400, and 300 K) with two different “instellation” sources (a plasma source and a UV lamp). The PHAZER exoplanet experiments simulate a temperature and atmospheric composition phase space relevant to the expected planetary yield of the Transiting Exoplanet Survey Satellite (TESS) mission as well as recently discovered potentially habitable zone exoplanets in the TRAPPIST-1, LHS-1140, and Proxima Centauri systems. Upon exposure to the energy sources, all of these experiments produced aerosol particles, which were collected in a dry nitrogen glove box and then analyzed with an LTQ Orbitrap XL™ Hybrid Ion Trap-Orbitrap Mass Spectrometer utilizing m/z ranging from 50 to 1000. The collected aerosol samples were found to contain complex organics. Constraining the composition of these aerosols allows us to better understand the photochemical and dynamical processes ongoing in exoplanet atmospheres. Moreover, these data can inform our telescope observations of exoplanets, which is of critical importance as we enter a new era of exoplanet atmosphere observation science with the upcoming launch of the James Webb Space Telescope. The molecular makeup of these haze particles provides key information for understanding exoplanet atmospheric spectra, and constraining the structure and behavior of clouds, hazes, and other aerosols is at the forefront of exoplanet atmosphere science.

  11. The Use of Social Media Amid Government, Mass Media, and Non Government Organisations Responsibilities Due to Haze Disaster

    OpenAIRE

    Christantyawati, Nevrettia

    2017-01-01

     The haze disaster that have been devastating many regions in Indonesia from July to October 2015, was stated as national tragedy by the Government. As a consequence, there were many cases of public health deterioration.There were many efforts done to tackle this crisis due to provision of public information. In a contrary, there were also many angry public statements and dissatisfaction.This paper will scrutinize the content of using social media, particularly twitter, as various channels an...

  12. Clinical Study of Mitomycin C in Reducing Haze Formation After Ultraviolet A/Riboflavin Crosslinking for Keratoconus.

    Science.gov (United States)

    Xu, Linlin; Tao, Xiangchen; Li, Zhiwei; Xu, Yanyun; Zhu, Wei; Xu, Huijuan; Pu, Wei; Xie, Yi; Mu, Guoying

    2017-09-21

    To evaluate the safety and efficacy of mitomycin C (MMC) in haze formation after ultraviolet A/riboflavin corneal crosslinking (CXL) for progressive keratoconus. A total of 60 keratoconic eyes of 48 patients were enrolled in this prospective comparative study after obtaining informed consent. In the CXL group, standard corneal CXL was performed, whereas in the CXL+MMC group, 0.02% MMC was used for 30 s soon after CXL. Comprehensive ophthalmologic examinations were performed on all patients before surgery and at 1, 3, 6, and 12 months after surgery. The epithelium recovered within 3 to 4 days after CXL, and the healing time was comparable in the two groups. There was no significant endothelial cell density loss after CXL in both groups. Eyes in both groups showed improvement of uncorrected distance visual acuity (Snellen) and best-corrected visual acuity (Snellen; Pdegree, and central corneal thickness (CCT) (P0.05). Corneal haze scores were significantly higher in the CXL group at 1 and 3 months after CXL (P=0.012 and P=0.028, respectively), but were similar to the MMC group at 6 and 12 months after surgery (P=0.329 and P=0.543, respectively). Prophylactic intraoperative use of 0.02% MMC can significantly reduce CXL-associated haze formation, especially in the early postoperative period, and no signs of weakening CXL efficacy were observed.

  13. The optical and chemical properties of discharge generated organic haze using in-situ real-time techniques

    Science.gov (United States)

    Ugelow, Melissa S.; Zarzana, Kyle J.; Day, Douglas A.; Jimenez, Jose L.; Tolbert, Margaret A.

    2017-09-01

    Organic hazes formed from methane are present in many planetary and satellite atmospheres and influence surface and atmospheric processes. Here we examine the compositional and optical properties of laboratory generated hazes, or tholins, formed with varying amounts of methane using spark discharge excitation. By studying the optical and chemical properties together as a function of methane precursor concentration, the radiative impact of haze can be better understood. To determine the complex refractive index of tholin, we combine two spectroscopic techniques: photoacoustic spectroscopy and cavity ring-down spectroscopy (PASCaRD). The refractive indices are retrieved at λ = 405 and 532 nm. Quadrupole aerosol mass spectrometry is used along with a technique that utilizes isotopically labeled and unlabeled methane gas to quantify elemental composition. Tholin optical and compositional measurements are performed within a flow system, eliminating the need for tholin collection on a substrate and possible post-collection changes. We observe n values within the range of n values from most previous studies. However, the observed k values, like most others from recent studies, are significantly lower than the values from Khare et al. (1984) (Khare, B.N., Sagan, C., Arakawa, E.T., Suits, F., Callcott, T.A., Williams, M.W. [1984]. Icarus 60, 127-137) that are commonly used in data retrieval programs and models. In addition, comparing the tholin k values to their approximate nitrogen and aromatic content suggests both chemical constituents are important factors for increased aerosol absorption.

  14. Characterization, mixing state, and evolution of urban single particles in Xi'an (China) during wintertime haze days.

    Science.gov (United States)

    Chen, Yang; Cao, Junji; Huang, Rujin; Yang, Fumo; Wang, Qiyuan; Wang, Yichen

    2016-12-15

    A Single Particle Aerosol Mass Spectrometer (SPAMS) was deployed in the urban area of Xi'an to investigate size-resolved chemical composition and mixing state of single particles during the heavy haze episode occurred from January 13 to January 27 in 2013. Nine major single particle types were resolved with ART-2a algorithm including biomass burning (BB), Potassium-Secondary (KSec), elemental and organic Carbon (ECOC), sodium-potassium-rich ECOC (NaKECOC), sodium-potassium-rich-secondary (NaKSec), EC, OC, and Dust. Daily PM2.5 mass concentration was 213±122μgm-3. ~96% of the ambient particles were carbonaceous and internally mixed with secondary species such as sulfate and nitrate. The major particle types were from combustion sources, including coal burning, biomass burning, and vehicle exhaust. Mixing state analysis suggests gas-to-particle conversion was an important mechanism forming organic species during the winter haze episode. The relative abundances of the aged particle types, such as KSec and NaKSec increased with the elevated RH when RH<80%. The fraction of aged particles in terms of number concentration was prominent during high levels of PM2.5 under stagnant air conditions. This study gained new knowledge on atmospheric aerosol formation and evolution in urban environment heavy winter haze condition. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Analysis of Venus Express optical extinction due to aerosols in the upper haze of Venus

    Science.gov (United States)

    Parkinson, Christopher; Bougher, Stephen; Mahieux, Arnaud; Tellmann, Silvia; Pätzold, Martin; Vandaele, Ann C.; Wilquet, Valérie; Schulte, Rick; Yung, Yuk; Gao, Peter; Bardeen, Charles

    Observations by the SPICAV/SOIR instruments aboard Venus Express (VEx) have revealed that the Upper Haze of Venus is populated by two particle modes, as reported by Wilquet et al. (J. Geophys. Res., 114, E00B42, 2009; Icarus 217, 2012). Gao et al. (In press, Icarus, 2013) posit that the large mode is made up of cloud particles that have diffused upwards from the cloud deck below, while the smaller mode is generated by the in situ nucleation of meteoric dust. They tested this hypothesis by using version 3.0 of the Community Aerosol and Radiation Model for Atmospheres, first developed by Turco et al. (J. Atmos. Sci., 36, 699-717, 1979) and upgraded to version 3.0 by Bardeen et al. (The CARMA 3.0 microphysics package in CESM, Whole Atmosphere Working Group Meeting, 2011). Using the meteoric dust production profile of Kalashnikova et al. (Geophys. Res. Lett., 27, 3293-3296, 2000), the sulfur/sulfate condensation nuclei production profile of Imamura and Hashimoto (J. Atmos. Sci., 58, 3597-3612, 2001), and sulfuric acid vapor production profile of Zhang et al. (Icarus, 217, 714-739, 2012), they numerically simulate a column of the Venus atmosphere from 40 to 100 km above the surface. Their aerosol number density results agree well with Pioneer Venus Orbiter (PVO) data from Knollenberg and Hunten (J. Geophys. Res., 85, 8039-8058, 1980), while their gas distribution results match that of Kolodner and Steffes below 55 km (Icarus, 132, 151-169, 1998). The resulting size distribution of cloud particles shows two distinct modes, qualitatively matching the observations of PVO. They also observe a third mode in their results with a size of a few microns at 48 km altitude, which appears to support the existence of the controversial third mode in the PVO data. This mode disappears if coagulation is not included in the simulation. The Upper Haze size distribution shows two lognormal-like distributions overlapping each other, possibly indicating the presence of the two distinct

  16. Bimodal distribution of sulfuric acid aerosols in the upper haze of Venus

    Science.gov (United States)

    Gao, Peter; Zhang, Xi; Crisp, David; Bardeen, Charles G.; Yung, Yuk L.

    2014-03-01

    Observations by the SPICAV/SOIR instruments aboard Venus Express have revealed that the upper haze (UH) of Venus, between 70 and 90 km, is variable on the order of days and that it is populated by two particle modes. We use a one-dimensional microphysics and vertical transport model based on the Community Aerosol and Radiation Model for Atmospheres to evaluate whether interaction of upwelled cloud particles and sulfuric acid particles nucleated in situ on meteoric dust are able to generate the two observed modes, and whether their observed variability are due in part to the action of vertical transient winds at the cloud tops. Nucleation of photochemically produced sulfuric acid onto polysulfur condensation nuclei generates mode 1 cloud droplets, which then diffuse upwards into the UH. Droplets generated in the UH from nucleation of sulfuric acid onto meteoric dust coagulate with the upwelled cloud particles and therefore cannot reproduce the observed bimodal size distribution. By comparison, the mass transport enabled by transient winds at the cloud tops, possibly caused by sustained subsolar cloud top convection, are able to generate a bimodal size distribution in a time scale consistent with Venus Express observations. Below the altitude where the cloud particles are generated, sedimentation and vigorous convection causes the formation of large mode 2 and mode 3 particles in the middle and lower clouds. Evaporation of the particles below the clouds causes a local sulfuric acid vapor maximum that results in upwelling of sulfuric acid back into the clouds. In the case where the polysulfur condensation nuclei are small and their production rate is high, coagulation of small droplets onto larger droplets in the middle cloud may set up an oscillation in the size modes of the particles such that precipitation of sulfuric acid "rain" may be possible immediately below the clouds once every few Earth months. Reduction of the polysulfur condensation nuclei production rate

  17. Laboratory investigations of Titan haze formation: In situ measurement of gas and particle composition

    Science.gov (United States)

    Hörst, Sarah M.; Yoon, Y. Heidi; Ugelow, Melissa S.; Parker, Alex H.; Li, Rui; de Gouw, Joost A.; Tolbert, Margaret A.

    2018-02-01

    Prior to the arrival of the Cassini-Huygens spacecraft, aerosol production in Titan's atmosphere was believed to begin in the stratosphere where chemical processes are predominantly initiated by far ultraviolet (FUV) radiation. However, measurements taken by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and Cassini Plasma Spectrometer (CAPS) indicate that haze formation initiates in the thermosphere where there is a greater flux of extreme ultraviolet (EUV) photons and energetic particles available to initiate chemical reactions, including the destruction of N2. The discovery of previously unpredicted nitrogen species in measurements of Titan's atmosphere by the Cassini Ion and Neutral Mass Spectrometer (INMS) indicates that nitrogen participates in the chemistry to a much greater extent than was appreciated before Cassini. The degree of nitrogen incorporation in the haze particles is important for understanding the diversity of molecules that may be present in Titan's atmosphere and on its surface. We have conducted a series of Titan atmosphere simulation experiments using either spark discharge (Tesla coil) or FUV photons (deuterium lamp) to initiate chemistry in CH4/N2 gas mixtures ranging from 0.01% CH4/99.99% N2 to 10% CH4/90% N2. We obtained in situ real-time measurements using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) to measure the particle composition as a function of particle size and a proton-transfer ion-trap mass spectrometer (PIT-MS) to measure the composition of gas phase products. These two techniques allow us to investigate the effect of energy source and initial CH4 concentration on the degree of nitrogen incorporation in both the gas and solid phase products. The results presented here confirm that FUV photons produce not only solid phase nitrogen bearing products but also gas phase nitrogen species. We find that in both the gas and solid phase, nitrogen is found in nitriles rather than amines and that both the

  18. Recommended metric for tracking visibility progress in the regional haze rule.

    Science.gov (United States)

    Gantt, Brett; Beaver, Melinda; Timin, Brian; Lorang, Phil

    2018-01-08

    For many Class I areas (national parks and wilderness areas with special air quality protections) in the western U.S., wildfire smoke and dust events can have a large impact on visibility. Currently, the Environmental Protection Agency's (EPA) 1999 Regional Haze Rule uses the 20% haziest days to track visibility changes over time even if they are dominated by smoke or dust. Visibility on the 20% haziest days has remained constant or degraded over the last 16 years at some Class I areas despite widespread emission reductions from anthropogenic sources. To better track visibility changes specifically associated with anthropogenic pollution sources rather than natural sources, the EPA as finalized a requirement to track visibility on the 20% most anthropogenically-impaired days rather than the haziest days. To support the implementation of this requirement, the EPA has also proposed (but not finalized) a specific recommended metric for characterizing the anthropogenic and natural portions of the daily extinction budget at each site. This metric selects the 20% most impaired days based on these portions using a "delta deciview" approach to quantify the deciview scale impact of anthropogenic light extinction. Using this metric, sulfate and nitrate make up the majority of the anthropogenic extinction in 2015 on these days, with natural extinction largely made up of organic carbon mass in the eastern U.S. and a combination of organic carbon mass, dust components, and sea-salt in the western U.S. For sites in the western U.S., the seasonality of days selected as the 20% most impaired is different than the seasonality of the 20% haziest days, with many more winter and spring days selected. Applying this new metric to the 2000-2015 period across sites representing Class I areas results in substantial changes in the calculated visibility trend for the Northern Rockies and southwest U.S. Implications Changing the approach for tracking visibility in Regional Haze Rule would

  19. Typical winter haze pollution in Zibo, an industrial city in China: Characteristics, secondary formation, and regional contribution.

    Science.gov (United States)

    Li, Hui; Ma, Yongliang; Duan, Fengkui; He, Kebin; Zhu, Lidan; Huang, Tao; Kimoto, Takashi; Ma, Xiaoxuan; Ma, Tao; Xu, Lili; Xu, Beiyao; Yang, Shuo; Ye, Siqi; Sun, Zhenli; An, Jiutao; Zhang, Zhaolu

    2017-10-01

    Heavy haze pollution occurs frequently in northern China, most critically in the Beijing-Tianjin-Hebei area (BTH). Zibo, an industrial city located in Shandong province, is often listed as one of the top ten most polluted cities in China, particularly in winter. However, no studies of haze in Zibo have been conducted, which limits the understanding of the source and formation of haze pollution in this area, as well as mutual effects with the BTH area. We carried out online and continuous integrated field observation of particulate matter in winter, from 11 to 25 January 2015. SO 4 2- , NO 3 - , and NH 4 + (SIA) and organics were the main constituents of PM 2.5 , contributing 59.4% and 33.6%, respectively. With the increasing severity of pollution, the contribution of SIA increased while that of organics decreased. Meteorological conditions play an important role in haze formation; high relative humidity (RH) and low wind speed increased both the accumulation of pollutants and the secondary transition from gas precursors (gas-particle phase partitioning). Since RH and the presence of O 3 can indicate heterogeneous and photochemistry processes, respectively, we carried out correlation analysis and linear regression to identify their relative importance to the three main secondary species (sulfate, nitrate, and secondary organic carbon (SOC)). We found that the impact of RH is in the order of SO 4 2-  > NO 3 -  > SOC, while the impact of O 3 is reversed, in the order of SOC > NO 3 -  > SO 4 2- , indicating different effect of these factors on the secondary formation of main species in winter. Cluster analysis of backward trajectories showed that, during the observation period, six directional sources of air masses were identified, and more than 90% came from highly industrialized areas, indicating that regional transport from industrialized areas aggravates the haze pollution in Zibo. Inter-regional joint prevention and control is necessary to prevent further

  20. Source tagging modeling study of heavy haze episodes under complex regional transport processes over Wuhan megacity, Central China.

    Science.gov (United States)

    Lu, Miaomiao; Tang, Xiao; Wang, Zifa; Gbaguidi, Alex; Liang, Shengwen; Hu, Ke; Wu, Lin; Wu, Huangjian; Huang, Zhen; Shen, Longjiao

    2017-12-01

    Wuhan as a megacity of Central China was suffering from severe particulate matter pollution according to previous observation studies, however, the mechanism behind the pollution formation especially the impact of regional chemical transport is still unclear. This study, carried out on the Nested Air Quality Prediction Modeling System (NAQPMS) coupled with an on-line source-tagging module, explores different roles regional transport had in two strong haze episodes over Wuhan in October 2014 and quantitatively assesses the contributions from local and regional sources to PM2.5 concentration. Validation of predictions based on observations shows modeling system good skills in reproducing key meteorological and chemical features. The first short-time haze episode occurred on 12 October under strong northerly winds, with a hourly PM2.5 peak of 180 μg m-3, and was found to be caused primarily by the long-range transport from the northern regions, which contributed 60.6% of the episode's PM2.5 concentration (versus a total of 32.7% from sources in and near Wuhan). The second episode lasted from the 15-20 October under stable regional large-scale synoptic conditions and weak winds, and had an hourly PM2.5 peak of 231.0 μg m-3. In this episode, both the long-distance transport from far regions and short-range transport from the Wuhan-cluster were the primary causes of the haze episode and account for 24.8% and 29.2% of the PM2.5 concentration respectively. Therefore, regional transport acts as a crucial driver of haze pollution over Wuhan through not only long-range transfer of pollutants, but also short-range aerosol movement under specific meteorological conditions. The present findings highlight the important role of regional transport in urban haze formation and indicate that the joint control of multi city-clusters are needed to reduce the particulate pollution level in Wuhan. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Unaccounted variability in NH3 agricultutral sources detected by IASI contributing to European spring haze episode

    Science.gov (United States)

    Fortems-Cheiney, Audrey; Dufour, Gaelle; Hamaoui-Laguel, Lynda; Foret, Gilles; SIour, Guillaume; Van Damme, Martin; Meleux, Frederik; Coheur, Pierre; Clerbaux, Cathy; Clarisse, Lieven; Wallasch, Markus; Beekmann, Matthias

    2017-04-01

    Ammonia (NH3), which main source is agriculture, is an important precursor gas for particulate matter concentrations. For the first time, we derived ammonia emissions from space, using NH3 total columns from the IASI instrument onboard Metop-A, at a high resolution (grid-cell of 0.5° x 0.5°, at a daily scale), for the European spring haze episode of March 2014, 8th to 15th. During this period, IASI reveals higher NH3 emissions than in the European reference EMEP inventory over Central Europe (especially over Germany, Czech Republic and eastern France), exhibiting in addition a large day-to-day variability. This suggests emissions due to punctual spreading practices, that are difficult to anticipate with an inventory-based approach. The increase or NH3 emissions, that could reach +300% locally, leads both to an increase of NH3 and PM25 surface concentrations and conducts to a better comparison with independent measurements (in terms of bias, root mean square error and correlation). The robustness of this preliminary study is promising for future quantification of NH3 emission estimates by atmospheric inversions.

  2. The Optimal Dispatch of a Power System Containing Virtual Power Plants under Fog and Haze Weather

    Directory of Open Access Journals (Sweden)

    Yajing Gao

    2016-01-01

    Full Text Available With the growing influence of fog and haze (F-H weather and the rapid development of distributed energy resources (DERs and smart grids, the concept of the virtual power plant (VPP employed in this study would help to solve the dispatch problem caused by multiple DERs connected to the power grid. The effects of F-H weather on photovoltaic output forecast, load forecast and power system dispatch are discussed according to real case data. The wavelet neural network (WNN model was employed to predict photovoltaic output and load, considering F-H weather, based on the idea of “similar days of F-H”. The multi-objective optimal dispatch model of a power system adopted in this paper contains several VPPs and conventional power plants, under F-H weather, and the mixed integer linear programming (MILP and the Yalmip toolbox of MATLAB were adopted to solve the dispatch model. The analysis of the results from a case study proves the validity and feasibility of the model and the algorithms.

  3. Source Contributions of PM2.5 in the Severe Haze Episode in Hebei Cities

    Directory of Open Access Journals (Sweden)

    Zhe Wei

    2015-01-01

    Full Text Available Beijing-Tianjin-Hebei area is one of the most polluted areas in China. This paper used the Fifth-Generation Penn State/NCAR Mesoscale Model (MM5 and Model-3/Community Multiscale Air Quality (CMAQ modeling system to quantify the source contribution to PM2.5 in Hebei cities in order to obtain an in-depth understanding haze process in January and February 2013, using the Multiresolution Emission Inventory for China (MEIC. The result showed that PM2.5 were mainly originated from the southern Hebei (SHB with the fractions of 70.8% and 66.4% to Shijiazhuang, 70.6% and 63.9% to Xingtai, and 68.5% and 63.0% to Handan in January and February 2013, respectively. The northern Hebei (NHB contributed 69.8% and 70.7% to Zhangjiakou, 68.7% and 66.2% to Chengde, and 57.7% and 59.6% to Qinhuangdao in January and February. In Cangzhou, Hengshui, and Langfang, regional joint policy making should be implemented due to the pollution of multiple sources. In Baoding and Tangshan, industrial emissions contributed 38.1% and 41.9% of PM2.5 to Baoding and 39.8% and 45.8% to Tangshan in January and February, respectively. Industrial and domestic emissions should be controlled in Tangshan and Baoding, especially for industrial emissions of NHB.

  4. Source Contributions of PM2.5 in the Severe Haze Episode in Hebei Cities.

    Science.gov (United States)

    Wei, Zhe; Wang, Litao; Ma, Simeng; Zhang, Fenfen; Yang, Jing

    2015-01-01

    Beijing-Tianjin-Hebei area is one of the most polluted areas in China. This paper used the Fifth-Generation Penn State/NCAR Mesoscale Model (MM5) and Model-3/Community Multiscale Air Quality (CMAQ) modeling system to quantify the source contribution to PM2.5 in Hebei cities in order to obtain an in-depth understanding haze process in January and February 2013, using the Multiresolution Emission Inventory for China (MEIC). The result showed that PM2.5 were mainly originated from the southern Hebei (SHB) with the fractions of 70.8% and 66.4% to Shijiazhuang, 70.6% and 63.9% to Xingtai, and 68.5% and 63.0% to Handan in January and February 2013, respectively. The northern Hebei (NHB) contributed 69.8% and 70.7% to Zhangjiakou, 68.7% and 66.2% to Chengde, and 57.7% and 59.6% to Qinhuangdao in January and February. In Cangzhou, Hengshui, and Langfang, regional joint policy making should be implemented due to the pollution of multiple sources. In Baoding and Tangshan, industrial emissions contributed 38.1% and 41.9% of PM2.5 to Baoding and 39.8% and 45.8% to Tangshan in January and February, respectively. Industrial and domestic emissions should be controlled in Tangshan and Baoding, especially for industrial emissions of NHB.

  5. Effects of haze particles and fog droplets on NLOS ultraviolet communication channels.

    Science.gov (United States)

    Xu, Changming; Zhang, Hongming; Cheng, Julian

    2015-09-07

    The performance of non-line-of-sight ultraviolet (UV) scattering communication depends largely on atmospheric parameters. In this paper, we consider haze, fog, two common types of aerosols, and introduce the density and size of aerosols as variables to study the channel path loss for the UV scattering communications. We modify a Monte-Carlo based multiple-scattering model and provide fitting functions to replace the complex calculations of Mie theory, which can be used to obtain the atmospheric coefficients and phase functions for the aerosols. Simulation results reveal that, given fixed elevation angles, the channel path loss is related to both communication range, the aerosol density, and size of aerosols. For a short communication range, an increase of aerosol density can reduce the path loss, which improves the performance of UV scattering communication. However, when the communication range is extended, the path loss will fall first and then rise with density of aerosols. This phenomenon also occurs for an increase of fog drop size. The density or size of aerosols that has the lowest path loss is inversely proportional to the communication range.

  6. The Hohenpeissenberg aerosol characterization experiment (HAZE2002): Aerosol composition derived from mass spectrometry

    Science.gov (United States)

    Hock, N.; Berresheim, H.; Borrmann, S.; Poeschl, U.; Roempp, A.; Schneider, J.

    2003-04-01

    The HAZE Experiment was conducted between 17.05.2002 and 31.05.2002, at the meteorological observatory of the Deutsche Wetterdienst (DWD) at Hohenpeissenberg (47^o48'N,11^o02'E, 985m). The objective was to make essential progress in understanding of the physical and chemical properties of the atmospheric aerosol, in particular relating to the Gas-To-Particle-Conversion and the interaction with meteorological processes. The measurements included online mass spectrometric analysis using the Aerosol Mass Spectrometer (AMS), filter samples with GC analyses of organic compounds, particle size distribution (Electrical Low Pressure Impactor (ELPI), SMPS, OPC), as well as the total particle concentration (CPC). Additionally, several gas-phase substances were measured (e.g. Benzene, Acetone). The measurements obtained with the AMS show a strong variability of the aerosol composition. The non-refractory aerosol composition was dominated by nitrate, sulphate, and organics, whereas ammonium was surprisingly low. High number concentration of up to 14000 particles/cm^3 were observed. These particles mostly had diameters between 200 nm and 400 nm and were mainly composed of ammonium sulphate and ammonium nitrate. Various meteorological conditions allowed to study their influence on the aerosol. For example, on rainy days the concentrations of ammonium sulphate particles decreased, whereas the concentrations of ammonium nitrate particles increased.

  7. Water

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-08-01

    Full Text Available , and of the remaining 2,5 percent, some 70 percent is frozen in the polar caps and around 30 percent is present as soil moisture or in underground aquifers. Less than 1 percent is thus accessible for direct use by humans, animals and plants. Consequently... be serviced with harvested water and/or grey water. Conserve and reuse cooling tower water by using efficient systems and strategies. Avoid ?once-through systems? commonly used for evaporation coolers, ice makers, hydraulic equipment, and air compressors...

  8. Water

    Directory of Open Access Journals (Sweden)

    E. Sanmuga Priya

    2017-05-01

    Full Text Available Phytoremediation through aquatic macrophytes treatment system (AMATS for the removal of pollutants and contaminants from various natural sources is a well established environmental protection technique. Water hyacinth (Eichhornia crassipes, a worst invasive aquatic weed has been utilised for various research activities over the last few decades. The biosorption capacity of the water hyacinth in minimising various contaminants present in the industrial wastewater is well studied. The present review quotes the literatures related to the biosorption capacity of the water hyacinth in reducing the concentration of dyestuffs, heavy metals and minimising certain other physiochemical parameters like TSS (total suspended solids, TDS (total dissolved solids, COD (chemical oxygen demand and BOD (biological oxygen demand in textile wastewater. Sorption kinetics through various models, factors influencing the biosorption capacity, and role of physical and chemical modifications in the water hyacinth are also discussed.

  9. Plasma rich in growth factors (PRGF-Endoret) stimulates corneal wound healing and reduces haze formation after PRK surgery.

    Science.gov (United States)

    Anitua, E; Muruzabal, F; Alcalde, I; Merayo-Lloves, J; Orive, G

    2013-10-01

    This study evaluated the efficacy of Plasma rich in growth factors (PRGF-Endoret) on the corneal wound healing process after Photorefractive keratectomy (PRK). To address this, blood from three healthy donors was collected, centrifuged and, the whole plasma column (WP) and the plasma fraction with the highest platelet concentration (F3) were collected. The effects of F3 and WP on the proliferation and migration of human corneal epithelial cells (HCE) were analyzed. PRK was performed on C57BL/6 mice. Animals were divided in three treatment groups: Control, F3, and WP. Corneal wound healing and haze formation were evaluated macroscopically. Eyes were collected at 1, 2, 3, and 7 days after surgery, and were processed for histological studies. Immunofluorescence was used to assess cellular proliferation, apoptosis and myofibroblast transformation in the mouse cornea. Results showed a significant increased on proliferation and wound healing after F3 and WP treatment when compared with control group. In vivo studies showed significant reduction on haze formation in mice treated with both PRGF-Endoret formulations (F3 and WP). Histological studies showed an increase of epithelial cell proliferation in corneas of control group, promoting an epithelial hyperplasia. The number of SMA-positive cells (corresponding to myofibroblast differentiation) was significantly lower in the PRGF-Endoret group than in the control group, correlating with the higher transparence results observed macroscopically in both PRGF-Endoret groups. According to this, it can be concluded that PRGF-Endoret accelerates corneal tissue regeneration after PRK, reducing haze formation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Study on the mechanism of amniotic extraction inhibiting haze formation after Epi-LASIK in rabbit cornea

    Directory of Open Access Journals (Sweden)

    Shi-Gang Xia

    2017-07-01

    Full Text Available AIM: To investigate the probably mechanism of amniotic extraction inhibiting haze formation after epipolis laser in situ keratomileusis(Epi-LASIKin rabbit cornea. METHODS: Thirty rabbit corneas were performed with Epi-LASIK. All eyes were randomly divided into three groups: eyes treated with amniotic extraction(AE group, eyes treated with 1g/L dexamethasone(hormone groupand eyes treated with solvent(solvent control group. Haze grade evaluation was performed under the slit lamp after Epi-LASIK for 1, 4 and 8wk. The repair of corneal epithelium was observed by using HE staining, and the expression of NF-kB protein P65 was detected by immunohistochemistry. The expression levels of inflammatory cytokines(TNF-α, TGF-β1 and IL-1and anti-inflammatory cytokines(IL-4, IL-10 and IL-13were determined by ELISA. RESULTS: HE staining showed that the basal cells of corneal epithelium were more uniform and arranged regularly in AE groups after Epi-LASIK for 1wk as compared with the hormone group and the solvent control group. After 4wk, there were a few of new collagen fibers in the superficial stroma of AE group, forming a small amount of scar. After 8wk, the corneal stroma of AE group showed a small amount of new collagen fibers, arranged regularly, and rarely formed scar. At the early stage(1 and 4wk, AE treatment has an obviously effect on inhibiting the secretion of inflammatory factors(TNF-α, TGF-β1 and IL-1and anti-inflammatory factors(IL-4, IL-10 and IL-13, and the difference was statistically significant(PCONCLUSION: Amniotic extraction may reduce the inflammatory response in corneal epithelial cells by inhibiting the NF-kB signaling pathway, thereby inhibiting the formation of collagen and scar and the occurrence of haze.

  11. Short-term aerosol radiative effects and their regional difference during heavy haze episodes in January 2013 in China

    Science.gov (United States)

    Cheng, Xinghong; Sun, Zhian; Li, Deping; Xu, Xiangde; Jia, Mengwei; Cheng, Siyang

    2017-09-01

    Short-term direct effects of aerosols on surface shortwave radiation and its regional difference during heavy haze episodes in January 2013 in China are investigated using the offline Weather Research and Forecasting (WRF) - the Community Multiscale Air Quality (CMAQ)- second Sun-Edward-Slingo radiative transfer (SES2) model system. The aerosol concentrations are first generated using the WRF-CMAQ model simulations and then corrected based on the observed concentrations of PM10 and PM2.5. The atmospheric profile data produced by the WRF model and the corrected aerosol concentrations are used as inputs to the SES2 model to calculate the global horizontal irradiance (GHI) and direct solar irradiance (DIR) at the surface for a period of heavy haze episodes in January 2013 in China. The effects of aerosol on the GHI and DIR at the surface are then analyzed. The modeled radiation is evaluated against the observations first and the results show some improvement due to the correction for the aerosol concentrations. The aerosol shortwave radiative effects are determined by the difference between the model calculations with and without the inclusion of aerosols. It is found that the short-term aerosol radiative impacts during heavy haze days are very large, range between 100 and 500 W m-2. The aerosol concentrations have a large spatial variation with the highest concentration occurring in the areas of Beijing-Tianjin-Hebei, which causes a large difference in the radiative effect nation wide. In addition to the total concentration, the aerosol vertical distributions s also vary from the north to south in China and this leads to a significant difference in radiative effect even when the PM10 concentration is similar at three regions.

  12. Characteristics of atmospheric non-methane hydrocarbons during haze episode in Beijing, China.

    Science.gov (United States)

    Guo, Songjun; Tan, Jihua; Duan, Jingchun; Ma, Yongliang; Yang, Fumo; He, Kebin; Hao, Jimin

    2012-12-01

    This study firstly focused on non-methane hydrocarbons (NMHCs) during three successive days with haze episode (16-18 August 2006) in Beijing. Concentrations of alkanes, alkenes, aromatic hydrocarbons, and ethyne all peaked at traffic rush hour, implying vehicular emission; and alkanes also peaked at non-traffic rush hour in the daytime, implying additional source. Especially, alkanes and aromatics clearly showed higher levels in the nighttime than that in the daytime, implying their active photochemical reactions in the daytime. Correlation coefficients (R (2)) showed that propane, n-butane, i-butane, ethene, propene, and benzene correlated with ethyne (R (2) = 0.61-0.66), suggesting that their main source is vehicular emission; 2-methylpentane and n-hexane correlated with i-pentane (R (2) = 0.61-0.64), suggesting that gasoline evaporation is their main source; and ethylbezene, m-/p-xylene, and o-xylene correlated with toluene (R (2) = 0.60-0.79), suggesting that their main source is similar to that of toluene (e.g., solvent usage). The R (2) of ethyne, i-pentane, and toluene with total NMHCs were 0.58, 0.76, and 0.60, respectively, indicating that ambient hydrocarbons are associated with vehicular emission, gasoline evaporation, and solvent usage. The sources of other hydrocarbons (e.g., ethane) might be natural gas leakage, biogenic emission, or long-range transport of air pollutants. Measured higher mean B/T ratio (0.78 ± 0.27) was caused by the more intensive photochemical activity of toluene than benzene, still indicating the dominant emission from vehicles.

  13. Aerosols optical properties in Titan's detached haze layer before the equinox

    Science.gov (United States)

    Seignovert, Benoît; Rannou, Pascal; Lavvas, Panayotis; Cours, Thibaud; West, Robert A.

    2017-08-01

    UV observations with Cassini ISS Narrow Angle Camera of Titan's detached haze is an excellent tool to probe its aerosols content without being affected by the gas or the multiple scattering. Unfortunately, its low extent in altitude requires a high resolution calibration and limits the number of images available in the Cassini dataset. However, we show that it is possible to extract on each profile the local maximum of intensity of this layer and confirm its stability at 500 ± 8 km during the 2005-2007 period for all latitudes lower than 45°N. Using the fractal aggregate scattering model of Tomasko et al. (2008) and a single scattering radiative transfer model, it is possible to derive the optical properties required to explain the observations made at different phase angles. Our results indicates that the aerosols have at least ten monomers of 60 nm radius, while the typical tangential column number density is about 2 · 1010 agg m-2. Moreover, we demonstrate that these properties are constant within the error bars in the southern hemisphere of Titan over the observed time period. In the northern hemisphere, the size of the aerosols tends to decrease relatively to the southern hemisphere and is associated with a higher tangential opacity. However, the lower number of observations available in this region due to the orbital constraints is a limiting factor in the accuracy of these results. Assuming a fixed homogeneous content we notice that the tangential opacity can fluctuate up to a factor 3 among the observations at the equator. These variations could be linked with short scale temporal and/or longitudinal events changing the local density of the layer.

  14. Contrasting aerosol optical and radiative properties between dust and urban haze episodes in megacities of Pakistan

    Science.gov (United States)

    Iftikhar, Muhammad; Alam, Khan; Sorooshian, Armin; Syed, Waqar Adil; Bibi, Samina; Bibi, Humera

    2018-01-01

    Satellite and ground based remote sensors provide vital information about aerosol optical and radiative properties. Analysis of aerosol optical and radiative properties during heavy aerosol loading events in Pakistan are limited and, therefore, require in-depth examination. This work examines aerosol properties and radiative forcing during Dust Episodes (DE) and Haze Episodes (HE) between 2010 and 2014 over mega cities of Pakistan (Karachi and Lahore). Episodes having the daily averaged values of Aerosol Optical Depth (AOD) exceeding 1 were selected. DE were associated with high AOD and low Ångström Exponent (AE) over Karachi and Lahore while high AOD and high AE values were associated with HE over Lahore. Aerosol volume size distributions (AVSD) exhibited a bimodal lognormal distribution with a noticeable coarse mode peak at a radius of 2.24 μm during DE, whereas a fine mode peak was prominent at a radius 0.25 μm during HE. The results reveal distinct differences between HE and DE for spectral profiles of several parameters including Single Scattering Albedo (SSA), ASYmmetry parameter (ASY), and the real and imaginary components of refractive index (RRI and IRI). The AOD-AE correlation revealed that dust was the dominant aerosol type during DE and that biomass burning and urban/industrial aerosol types were pronounced during HE. Aerosol radiative forcing (ARF) was estimated using the Santa Barbra DISORT Atmospheric Radiative Transfer (SBDART) model. Calculations revealed a negative ARF at the Top Of the Atmosphere (ARFTOA) and at the Bottom Of the Atmosphere (ARFBOA), with positive ARF within the Atmosphere (ARFATM) during both DE and HE over Karachi and Lahore. Furthermore, estimations of ARFATM by SBDART were shown to be in good agreement with values derived from AERONET data for DE and HE over Karachi and Lahore.

  15. The Influence of Asian Dust, Haze, Mist, and Fog on Hospital Visits for Airway Diseases.

    Science.gov (United States)

    Park, Jinkyeong; Lim, Myoung Nam; Hong, Yoonki; Kim, Woo Jin

    2015-10-01

    Asian dust is known to have harmful effects on the respiratory system. Respiratory conditions are also influenced by environmental conditions regardless of the presence of pollutants. The same pollutant can have different effects on the airway when the air is dry compared with when it is humid. We investigated hospital visits for chronic obstructive pulmonary disease (COPD) and asthma in relation to the environmental conditions. We conducted a retrospective study using the Korean National Health Insurance Service claims database of patients who visited hospitals in Chuncheon between January 2006 and April 2012. Asian dust, haze, mist, and fog days were determined using reports from the Korea Meteorological Administration. Hospital visits for asthma or COPD on the index days were compared with the comparison days. We used two-way case-crossover techniques with one to two matching. The mean hospital visits for asthma and COPD were 59.37 ± 34.01 and 10.04 ± 6.18 per day, respectively. Hospital visits for asthma significantly increased at lag0 and lag1 for Asian dust (relative risk [RR], 1.10; 95% confidence interval [CI], 1.01-1.19; pAsian dust (RR, 1.29; 95% CI, 1.05-1.59; pAsian dust showed an association with airway diseases and had effects for several days after the exposure. In contrast to Asian dust, mist and fog, which occur in humid air conditions, showed the opposite effects on airway diseases, after adjusting to the pollutants. It would require more research to investigate the effects of various air conditions on airway diseases.

  16. Light absorption enhancement of black carbon from urban haze in Northern China winter.

    Science.gov (United States)

    Chen, Bing; Bai, Zhe; Cui, Xinjuan; Chen, Jianmin; Andersson, August; Gustafsson, Örjan

    2017-02-01

    Atmospheric black carbon (BC) is an important pollutant for both air quality and Earth's energy balance. Estimates of BC climate forcing remain highly uncertain, e.g., due to the mixing with non-absorbing components. Non-absorbing aerosols create a coating on BC and may thereby act as a lens which may enhance the light absorption. However, this absorption enhancement is poorly constrained. To this end a two-step solvent dissolution protocol was employed to remove both organic and inorganic coatings, and then investigate their effects on BC light absorption. Samples were collected at a severely polluted urban area, Jinan, in the North China Plain (NCP) during February 2014. The BC mass absorption cross-section (MAC) was measured for the aerosol samples before and after the solvent-decoating treatment, and the enhancement of MAC (EMAC) from the coating effect was defined as the ratio. A distinct diurnal pattern for the enhancement was observed, with EMAC 1.3 ± 0.3 (1 S.D.) in the morning, increasing to 2.2 ± 1.0 in the afternoon, after that dropping to 1.5 ± 0.8 in the evening-night. The BC absorption enhancement primarily was associated with urban-scale photochemical production of nitrate and sulfate aerosols. In addition to that, regional-scale haze plume with increasing sulfate levels strengthened the absorption enhancement. These observations offer direct evidence for an increased absorption enhancement of BC due to severe air pollution in China. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Composition and sources of winter haze in the Bakken oil and gas extraction region

    Science.gov (United States)

    Evanoski-Cole, A. R.; Gebhart, K. A.; Sive, B. C.; Zhou, Y.; Capps, S. L.; Day, D. E.; Prenni, A. J.; Schurman, M. I.; Sullivan, A. P.; Li, Y.; Hand, J. L.; Schichtel, B. A.; Collett, J. L.

    2017-05-01

    In the past decade increased use of hydraulic fracturing and horizontal drilling has dramatically expanded oil and gas production in the Bakken formation region. Long term monitoring sites have indicated an increase in wintertime aerosol nitrate and sulfate in this region from particulate matter (PM2.5) measurements collected between 2000 and 2010. No previous intensive air quality field campaign has been conducted in this region to assess impacts from oil and gas development on regional fine particle concentrations. The research presented here investigates wintertime PM2.5 concentrations and composition as part of the Bakken Air Quality Study (BAQS). Measurements from BAQS took place over two wintertime sampling periods at multiple sites in the United States portion of the Bakken formation and show regionally elevated episodes of PM2.5 during both study periods. Ammonium nitrate was a major contributor to haze episodes. Periods of air stagnation or recirculation were associated with rapid increases in PM2.5 concentrations. Volatile organic compound (VOC) signatures suggest that air masses during these episodes were dominated by emissions from the Bakken region itself. Formation rates of alkyl nitrates from alkanes revealed an air mass aging timescale of typically less than a day for periods with elevated PM2.5. A thermodynamic inorganic aerosol model (ISORROPIA) was used to investigate gas-particle partitioning and to examine the sensitivity of PM2.5 concentrations to aerosol precursor concentrations. Formation of ammonium nitrate, the dominant component, was most sensitive to ammonia concentrations during winter and to nitric acid concentrations during early spring when ammonia availability increases. The availability of excess ammonia suggests capacity for further ammonium nitrate formation if nitrogen oxide emissions increase in the future and lead to additional secondary formation of nitric acid.

  18. Characterization of typical metal particles during haze episodes in Shanghai, China.

    Science.gov (United States)

    Li, Rui; Yang, Xin; Fu, Hongbo; Hu, Qingqing; Zhang, Liwu; Chen, Jianmin

    2017-08-01

    Aerosol particles were collected during three heavy haze episodes at Shanghai in the winter of 2013. Transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy was used to study the morphology and speciation of typical metal particles at a single-particle level. In addition, time-of-flight aerosol mass spectrometry (ATOFMS) was applied to identify the speciation of the Fe-containing particles. TEM analysis indicated that various metal-containing particles were hosted by sulfates, nitrates, and oxides. Fe-bearing particles mainly originated from vehicle emissions and/or steel production. Pb-, Zn-, and Sb-bearing particles were mainly contributed by anthropogenic sources. Fe-bearing particles were clustered into six groups by ATOFMS: Fe-Carbon, Fe-Inorganic, Fe-Trace metal, Fe-CN, Fe-PO3, and Fe-NO3. ATOFMS data suggested that Fe-containing particles corresponded to different origins, including industrial activities, resuspension of dusts, and vehicle emissions. Fe-Carbon and Fe-CN particles displayed significant diurnal variation, and high levels were observed during the morning rush hours. Fe-Inorganic and Fe-Trace metal particle levels peaked at night. Furthermore, Fe-Carbon and Fe-PO3 were mainly concentrated in the fine particles. Fe-CN, Fe-Inorganic, and Fe-Trace metal exhibited bimodal distribution. The mixing state of the particles revealed that all Fe-bearing particles tended to be mixed with sulfate and nitrate. The data presented herein is essential for elucidating the origin, evolution processes, and health effects of metal-bearing particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Development of textured ZnO-coated low-cost glass substrate with very high haze ratio for silicon-based thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hongsingthong, Aswin, E-mail: aswin.hongsingthong@nectec.or.th [Solar Energy Technology Laboratory, National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Road, Khlong 1, Khlong Luang, Pathumthani 12120 (Thailand); Krajangsang, Taweewat; Limmanee, Amornrat; Sriprapha, Kobsak; Sritharathikhun, Jaran [Solar Energy Technology Laboratory, National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Road, Khlong 1, Khlong Luang, Pathumthani 12120 (Thailand); Konagai, Makoto [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, NE-15, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2013-06-30

    Zinc oxide (ZnO) films with a very high haze ratio and low resistivity were developed on soda–lime glass substrate by using reactive ion etching (RIE) treatment with carbon tetrafluoride (CF{sub 4}) to modify the substrate surface morphology before the deposition of ZnO films. We found that the surface morphology of the ZnO films deposited by metal organic chemical vapor deposition (MOCVD) technique could be modified by varying the glass treatment conditions and the gas pressure was a key parameter. With increasing glass-etching pressure, the surface morphology of the ZnO films changed from conventional pyramid-like single texture to greater cauliflower-like double texture, leading to significant increases in root mean square roughness and haze ratio of the films. By employing the developed high-haze ZnO films as a front transparent conductive oxide (TCO) layer in microcrystalline silicon solar cells, an enhancement in the quantum efficiency in the long-wavelength region has been achieved. Experimental results have verified that our unique and original glass etching treatment is a simple and effective technique to improve the light-scattering properties of the ZnO films while preserving their good transparency and electrical properties. Thus, the ZnO films deposited on etched soda–lime glass have a high potential for the use as a front TCO layer in thin-film Si solar cells. - Highlights: • High-haze zinc oxide (ZnO) grown on low cost soda–lime glass has been developed. • Surface of the ZnO can be modified by varying glass-substrate etching conditions. • Glass-etching pressure is a key to increase haze ratio of the ZnO films. • Higher cell efficiency has been achieved from cell using etched glass. • High-haze ZnO coated glass is a promising transparent conductive oxide coated glass.

  20. Model elucidating the sources and formation mechanisms of severe haze pollution over Northeast mega-city cluster in China.

    Science.gov (United States)

    Yang, Ting; Gbaguidi, Alex; Yan, Pingzhong; Zhang, Wending; Zhu, Lili; Yao, Xuefeng; Wang, Zifa; Chen, Hui

    2017-11-01

    Recent studies on regional haze pollution over China come up in general with strong variability of main causes of heavy polluted episodes, in linkage with local specificities, sources and pollution characteristics. This paper therefore aims at elucidating the main specific sources and formation mechanisms of observed strong haze pollution episodes over 1-15 November 2015 in Northeast region considered as one of biggest megacity clusters in China. The Northeast China mega-city cluster, including Heilong Jiang, Jilin and Liaoning provinces, is adjacent to Russia in the north, Mongolian at the west, North Korea at east, and representing key geographical location in the regional and transnational air pollution issues in China due to the presence of heavy industries and intense economic activities. The present study, based on air quality monitoring, remote sensing satellite data and sensitivity experiments carried on the Nested Air Quality Prediction Modeling System (NAQPMS), quantitatively assesses the impact of meteorological conditions and potential contributions from regional chemical transport, intensive energy combustion, illegal emission and biomass burning emissions to PM2.5 concentration variation. The results indicate strong inversion occurrence at lower atmosphere with weak near-surface wind speed and high relative humidity, leading to PM2.5 concentration increase of about 30-50%. Intensive energy combustion (plausibly for heating activities) and illegal emission also significantly enhance the overall PM2.5 accumulation by 100-200 μg m-3 (60-70% increase), against 75-100 μg m-3 from the biomass burning under the northeast-southwest transport pathway, corresponding to a contribution of 10-20% to PM2.5 concentration increase. Obviously, stagnant meteorological conditions, energy combustion, illegal emission and biomass burning are main drivers of strong haze formation and spatial distribution over Northeast China megacity cluster. In clear, much effort on

  1. The observed day-to-day variability of Mars water vapor

    Science.gov (United States)

    Jakosky, Bruce M.; Lapointe, Michael R.; Zurek, Richard W.

    1987-01-01

    The diurnal variability of atmospheric water vapor as derived from the Viking MAWD data is discussed. The detection of day to day variability of atmospheric water would be a significant finding since it would place constraints on the nature of surface reservoirs. Unfortunately, the diurnal variability seen by the MAWD experiment is well correlated with the occurrence of dust and/or ice hazes, making it difficult to separate real variations from observational effects. Analysis of the day to day variability of water vapor in the Martian atmosphere suggests that the observations are, at certain locations and seasons, significantly affected by the presence of water-ice hazes. Because such effects are generally limited to specific locations, such as Tharsis, Lunae Planum, and the polar cap edge during the spring, the seasonal and latitudinal trends in water vapor that have been previously reported are not significantly affected.

  2. On the multiday haze in the Asian continental outflow: the important role of synoptic conditions combined with regional and local sources

    Directory of Open Access Journals (Sweden)

    J. Seo

    2017-08-01

    Full Text Available The air quality of the megacities in populated and industrialized regions like East Asia is affected by both local and regional emission sources. The combined effect of regional transport and local emissions on multiday haze was investigated through a synthetic analysis of PM2. 5 sampled at both an urban site in Seoul, South Korea and an upwind background site on Deokjeok Island over the Yellow Sea during a severe multiday haze episode in late February 2014. Inorganic components and carbonaceous species of daily PM2. 5 samples were measured, and gaseous pollutants, local meteorological factors, and synoptic meteorological conditions were also determined. A dominance of fine-mode particles (PM2. 5 ∕ PM10  ∼  0.8, a large secondary inorganic fraction (76 %, high OC ∕ EC (> 7, and highly oxidized aerosols (oxygen-to-carbon ratio of  ∼  0.6 and organic-mass-to-carbon ratio of  ∼  1.9 under relatively warm, humid, and stagnant conditions characterize the multiday haze episode in Seoul; however, the early and late stages of the episode show different chemical compositions of PM2. 5. High concentrations of sulfate in both Seoul and the upwind background in the early stage suggest a significant regional influence on the onset of the multiday haze. At the same time, high concentrations of nitrate and organic compounds in Seoul, which are local and highly correlated with meteorological factors, suggest the contribution of local emissions and secondary formation under stagnant meteorological conditions to the haze. A slow eastward-moving high-pressure system from southern China to the East China Sea induces the regional transport of aerosols and potential gaseous precursors for secondary aerosols from the North China Plain in the early stage but provides stagnant conditions conducive to the accumulation and the local formation of aerosols in the late stage. A blocking ridge over Alaska that developed during

  3. On the multiday haze in the Asian continental outflow: the important role of synoptic conditions combined with regional and local sources

    Science.gov (United States)

    Seo, Jihoon; Kim, Jin Young; Youn, Daeok; Lee, Ji Yi; Kim, Hwajin; Lim, Yong Bin; Kim, Yumi; Cher Jin, Hyoun

    2017-08-01

    The air quality of the megacities in populated and industrialized regions like East Asia is affected by both local and regional emission sources. The combined effect of regional transport and local emissions on multiday haze was investigated through a synthetic analysis of PM2. 5 sampled at both an urban site in Seoul, South Korea and an upwind background site on Deokjeok Island over the Yellow Sea during a severe multiday haze episode in late February 2014. Inorganic components and carbonaceous species of daily PM2. 5 samples were measured, and gaseous pollutants, local meteorological factors, and synoptic meteorological conditions were also determined. A dominance of fine-mode particles (PM2. 5 / PM10 ˜ 0.8), a large secondary inorganic fraction (76 %), high OC / EC (> 7), and highly oxidized aerosols (oxygen-to-carbon ratio of ˜ 0.6 and organic-mass-to-carbon ratio of ˜ 1.9) under relatively warm, humid, and stagnant conditions characterize the multiday haze episode in Seoul; however, the early and late stages of the episode show different chemical compositions of PM2. 5. High concentrations of sulfate in both Seoul and the upwind background in the early stage suggest a significant regional influence on the onset of the multiday haze. At the same time, high concentrations of nitrate and organic compounds in Seoul, which are local and highly correlated with meteorological factors, suggest the contribution of local emissions and secondary formation under stagnant meteorological conditions to the haze. A slow eastward-moving high-pressure system from southern China to the East China Sea induces the regional transport of aerosols and potential gaseous precursors for secondary aerosols from the North China Plain in the early stage but provides stagnant conditions conducive to the accumulation and the local formation of aerosols in the late stage. A blocking ridge over Alaska that developed during the episode hinders the zonal propagation of synoptic-scale systems

  4. Gas-particle phase partitioning and particle size distribution of chlorinated and brominated polycyclic aromatic hydrocarbons in haze.

    Science.gov (United States)

    Jin, Rong; Zheng, Minghui; Yang, Hongbo; Yang, Lili; Wu, Xiaolin; Xu, Yang; Liu, Guorui

    2017-12-01

    Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are emerging semi-volatile organic pollutants in haze-associated particulate matter (PM). Their gas-particle phase partitioning and distribution among PM fractions have not been clarified. Clarification would increase understanding of atmospheric behavior and health risks of Cl/Br-PAHs. In this study, samples of the gas phase and 4 PM phases (aerodynamic diameters (dae) > 10 μm, 2.5-10 μm, 1.0-2.5 μm, and distribution indicated that the Cl/Br-PAHs tended to adhere to fine particles. Over 80% of the Cl-PAHs and 70% of the Br-PAHs were associated with fine PM (dae particle phase partitioning and PM distribution of Cl/Br-PAHs when heating of buildings was required, which was associated with haze events, were obviously different from those when heating was not required. The relationship between the logarithmic geometric mean diameters of the Cl/Br-PAH congeners and reciprocal of the temperature (1/T) suggested that low air temperatures during the heating period could lead to high proportions of Cl/Br-PAHs in the fine particles. Increased coal burning during the heating period also contributed to high Cl/Br-PAH loads in the fine particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Long-term trend of haze pollution and impact of particulate matter in the Yangtze River Delta, China.

    Science.gov (United States)

    Cheng, Zhen; Wang, Shuxiao; Jiang, Jingkun; Fu, Qingyan; Chen, Changhong; Xu, Bingye; Yu, Jianqiao; Fu, Xiao; Hao, Jiming

    2013-11-01

    Haze pollution caused by heavy particulate matter (PM) loading brings significant damage in eastern China. Long-term monitoring from 1980 to 2011 and 1-year field measurement in 2011-2012 are used for investigating visibility variation and the impact of PM pollution for the Yangtze River Delta (YRD). It was found that visual range in the YRD endured a sharp reduction from 13.2 km to 10.5 km during 1980-2000. Average mass extinction efficiency (MEE) for inhalable PM (PM10) is 2.25 m(2)/g in 2001-2011, and extinction coefficient due to PM10 is 207 Mm(-1), accounting for 36.2% of total extinction coefficient. MEE of PM2.5 and PM2.5-10 are 4.08 m(2)/g and 0.58 m(2)/g, respectively. Extinction coefficient due to PM2.5 and PM2.5-10 is 198 Mm(-1) (39.6%) and 20 Mm(-1) (4.0%) in 2011-2012. Maximum daily concentration of PM10 and PM2.5 is estimated to be 63 μg/m(3) (RH: 73%) and 38 μg/m(3) (RH: 70%) to keep visual range above 10 km. Fine particulate matter is the key factor for haze pollution improvement in the YRD area. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. A field study of visual perception of complex natural targets through atmospheric haze by naïve observers

    Science.gov (United States)

    Henry, Ronald C.

    An air quality-visibility perception study was carried out in southern California in July and August of 2002. The study was designed to make simultaneous state-of-the-art measurements of human perception, physical light intensities from natural targets, and particle scattering coefficient of the atmosphere. The purpose of the study was to obtain data needed to estimate the probability of seeing a change in haze due to a decrease in extinction coefficient of the atmosphere. The basic results of the visibility perception study are given. The focus is on quantitative measurements of human perception of lightness, hue and chroma (or colorfulness) of natural and artificial targets determined by an advanced color matching instrument and training protocol that made it possible to use naïve observers. The lightness, chroma, and hue calculated from the CIE X, Y, and Z measured by a 16-bit industrial imaging photometer are compared to those actually reported by the observers under varying levels of haze. The results are consistent with the results of two previous visibility perception studies carried out in national parks in the USA.

  7. Metadata-assisted nonuniform atmospheric scattering model of image haze removal for medium-altitude unmanned aerial vehicle

    Science.gov (United States)

    Liu, Chunlei; Ding, Wenrui; Li, Hongguang; Li, Jiankun

    2017-09-01

    Haze removal is a nontrivial work for medium-altitude unmanned aerial vehicle (UAV) image processing because of the effects of light absorption and scattering. The challenges are attributed mainly to image distortion and detail blur during the long-distance and large-scale imaging process. In our work, a metadata-assisted nonuniform atmospheric scattering model is proposed to deal with the aforementioned problems of medium-altitude UAV. First, to better describe the real atmosphere, we propose a nonuniform atmospheric scattering model according to the aerosol distribution, which directly benefits the image distortion correction. Second, considering the characteristics of long-distance imaging, we calculate the depth map, which is an essential clue to modeling, on the basis of UAV metadata information. An accurate depth map reduces the color distortion compared with the depth of field obtained by other existing methods based on priors or assumptions. Furthermore, we use an adaptive median filter to address the problem of fuzzy details caused by the global airlight value. Experimental results on both real flight and synthetic images demonstrate that our proposed method outperforms four other existing haze removal methods.

  8. Possible influence of atmospheric circulations on winter haze pollution in the Beijing–Tianjin–Hebei region, northern China

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2016-01-01

    Full Text Available Using the daily records derived from the synoptic weather stations and the NCEP/NCAR and ERA-Interim reanalysis data, the variability of the winter haze pollution (indicated by the mean visibility and number of hazy days in the Beijing–Tianjin–Hebei (BTH region during the period 1981 to 2015 and its relationship with the atmospheric circulations at middle–high latitude were analyzed in this study. The winter haze pollution in BTH had distinct inter-annual and inter-decadal variabilities without a significant long-term trend. According to the spatial distribution of correlation coefficients, six atmospheric circulation indices (I1 to I6 were defined from the key areas in sea level pressure (SLP, zonal and meridional winds at 850 hPa (U850, V850, geopotential height field at 500 hPa (H500, zonal wind at 200 hPa (U200, and air temperature at 200 hPa (T200, respectively. All of the six indices have significant and stable correlations with the winter visibility and number of hazy days in BTH. In the raw (unfiltered correlations, the correlation coefficients between the six indices and the winter visibility (number of hazy days varied from 0.57 (0.47 to 0.76 (0.6 with an average of 0.65 (0.54; in the high-frequency ( < 10 years correlations, the coefficients varied from 0.62 (0.58 to 0.8 (0.69 with an average of 0.69 (0.64. The six circulation indices together can explain 77.7 % (78.7 % and 61.7 % (69.1 % variances of the winter visibility and the number of hazy days in the year-to-year (inter-annual variability, respectively. The increase in Ic (a comprehensive index derived from the six individual circulation indices can cause a shallowing of the East Asian trough at the middle troposphere and a weakening of the Siberian high-pressure field at sea level, and is then accompanied by a reduction (increase of horizontal advection and vertical convection (relative humidity in the lowest troposphere and a reduced boundary layer

  9. Evaluation and application of multi-decadal visibility data for trend analysis of atmospheric haze

    Directory of Open Access Journals (Sweden)

    C. Li

    2016-03-01

    Full Text Available There are few multi-decadal observations of atmospheric aerosols worldwide. This study applies global hourly visibility (Vis observations at more than 3000 stations to investigate historical trends in atmospheric haze over 1945–1996 for the US, and over 1973–2013 for Europe and eastern Asia. A comprehensive data screening and processing framework is developed and applied to minimize uncertainties and construct monthly statistics of inverse visibility (1/Vis. This data processing includes removal of relatively clean cases with high uncertainty, and change point detection to identify and separate methodological discontinuities such as the introduction of instrumentation. Although the relation between 1/Vis and atmospheric extinction coefficient (bext varies across different stations, spatially coherent trends of the screened 1/Vis data exhibit consistency with the temporal evolution of collocated aerosol measurements, including the bext trend of −2.4 % yr−1 (95 % CI: −3.7, −1.1 % yr−1 vs. 1/Vis trend of −1.6 % yr−1 (95 % CI: −2.4, −0.8 % yr−1 over the US for 1989–1996, and the fine aerosol mass (PM2.5 trend of −5.8 % yr−1 (95 % CI: −7.8, −4.2 % yr−1 vs. 1/Vis trend of −3.4 % yr−1 (95 % CI: −4.4, −2.4 % yr−1 over Europe for 2006–2013. Regional 1/Vis and Emissions Database for Global Atmospheric Research (EDGAR sulfur dioxide (SO2 emissions are significantly correlated over the eastern US for 1970–1995 (r = 0.73, over Europe for 1973–2008 (r ∼ 0.9 and over China for 1973–2008 (r ∼ 0.9. Consistent "reversal points" from increasing to decreasing in SO2 emission data are also captured by the regional 1/Vis time series (e.g., late 1970s for the eastern US, early 1980s for western Europe, late 1980s for eastern Europe, and mid 2000s for China. The consistency of 1/Vis trends with other in situ measurements and emission data demonstrates promise in applying these quality assured 1/Vis data

  10. The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model

    Science.gov (United States)

    Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid

    2017-10-01

    Here, we present the latest results on the gas- and solid phase analyses in the Titan Haze Simulation (THS) experiment, developed at the NASA Ames COSmIC simulation chamber. The THS is a unique experimental platform that allows us to simulate Titan’s complex atmospheric chemistry at Titan-like temperature (200 K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma. Because of the accelerated gas flow in the expansion, the residence time of the gas in the active plasma region is less than 3 µs. This results in a truncated chemistry that enables us to control how far in the chain of chemical reactions chemistry processes[1], by adding, in the initial gas mixture, heavier molecules that have been detected as trace elements on Titan.We discuss the results of recent Mid-infrared (MIR) spectroscopy[2] and X-ray Absorption Near Edge Structure spectroscopy studies of THS Titan tholins produced in different gas mixtures (with and without acetylene and benzene). Both studies have shown the presence of nitrogen chemistry, and differences in the level and nature of the nitrogen incorporation depending on the initial gas mixture. A comparison of THS MIR spectra to VIMS data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols.In addition, a new model has been developed to simulate the plasma chemistry in the THS. Electron impact and chemical kinetics equations for more than 120 species are followed. The calculated mass spectra[3] are in good agreement with the experimental THS mass spectra[1], confirming that the short residence time in the plasma cavity limits the growth of larger species and results in a truncated chemistry, a main feature of the THS.References:[1] Sciamma-O'Brien E. et al., Icarus, 243, 325 (2014)[2] Sciamma-O'Brien E. et al., Icarus

  11. Size distribution and source of black carbon aerosol in urban Beijing during winter haze episodes

    Science.gov (United States)

    Wu, Yunfei; Wang, Xiaojia; Tao, Jun; Huang, Rujin; Tian, Ping; Cao, Junji; Zhang, Leiming; Ho, Kin-Fai; Han, Zhiwei; Zhang, Renjian

    2017-06-01

    Black carbon (BC) has important impact on climate and environment due to its light absorption ability, which greatly depends on its physicochemical properties including morphology, size and mixing state. The size distribution of the refractory BC (rBC) was investigated in urban Beijing in the late winter of 2014, during which there were frequent haze events, through analysis of measurements obtained using a single-particle soot photometer (SP2). By assuming void-free rBC with a density of 1.8 g cm-3, the mass of the rBC showed an approximately lognormal distribution as a function of the volume-equivalent diameter (VED), with a peak diameter of 213 nm. Larger VED values of the rBC were observed during polluted periods than on clean days, implying an alteration in the rBC sources, as the size distribution of the rBC from a certain source was relative stable, and VED of an individual rBC varied little once it was emitted into the atmosphere. The potential source contribution function analysis showed that air masses from the south to east of the observation site brought higher rBC loadings with more thick coatings and larger core sizes. The mean VED of the rBC presented a significant linear correlation with the number fraction of thickly coated rBC, extrapolating to be ˜ 150 nm for the completely non-coated or thinly coated rBC. It was considered as the typical mean VED of the rBC from local traffic sources in this study. Local traffic was estimated to contribute 35 to 100 % of the hourly rBC mass concentration with a mean of 59 % during the campaign. Lower local traffic contributions were observed during polluted periods, suggesting increasing contributions from other sources (e.g., coal combustion and biomass burning) to the rBC. Thus, the heavy pollution in Beijing was greatly influenced by other sources in addition to the local traffic.

  12. On the influence of atmospheric super-saturation layer on China's heavy haze-fog events

    Science.gov (United States)

    Wang, Jizhi; Yang, Yuanqin; Zhang, Xiaoye; Liu, Hua; Che, Huizheng; Shen, Xiaojing; Wang, Yaqiang

    2017-12-01

    With the background of global change, the air quality in Earth's atmosphere has significantly decreased. The North China Plain (NCP), Yangtze River Delta (YRD), Pearl River Delta (PRD) and Si-Chuan Basin (SCB) are the major areas suffering the decreasing air quality and frequent pollution events in recent years. Studying the effect of meteorological conditions on the concentration of pollution aerosols in these pollution sensitive regions is a hot focus now. This paper analyses the characteristics of atmospheric super-saturation and the corresponding H_PMLs (height of supersaturated pollution mixing layer), investigating their contribution to the frequently-seen heavy haze-fog weather. The results suggest that: (1) in the above-mentioned pollution sensitive regions in China, super-saturated layers repeatedly appear in the low altitude and the peak value of supersaturation S can reach 6-10%, which makes pollution particles into the wet adiabatic uplift process in the stable-static atmosphere. After low-level atmosphere reaches the super-saturation state below the H_PMLs, meteorological condition contributes to humidification and condensation of pollution particles. (2) Caculation of condensation function Fc, one of PLAM sensetive parameter, indicates that super-saturation state helps promote condensation, beneficial to the formation of Condensational Kink (CK) in the pollution sensitive areas. This favors the formation of new aerosol particles and intensities the cumulative growth of aerosol concentration. (3) By calculating the convective inhibition energy on average │CIN│ > 1.0 × 104 J kg-1, we found the value is about 100 times higher than the stable critical value. The uplifting diffusion of the particles is inhibited by the ambient airflow. So, this is the important reason for the aggravation and persistence of aerosol pollutants in local areas. (4) H_PMLs is negatively correlated to the pollution meteorological condition index PLAM which can describe the

  13. Understanding the formation and composition of hazes in planetary atmospheres that contain carbon monoxide

    Science.gov (United States)

    Hörst, S. M.; Yoon, Y. H.; Hicks, R. K.; Tolbert, M. A.

    2012-09-01

    Measurements from the Cassini Plasma Spectrometer (CAPS) have revealed the presence of molecules in Titan's ionosphere with masses in excess of hundreds of amu. Negative ions with mass/charge (m/z) up to 10,000 amu/q [1] and positive ions with m/z up to 400 amu/q [2] have been detected. CAPS has also observed O+ flowing into Titan's upper atmosphere [3], which appears to originate from Enceladus and is likely the source of oxygen bearing molecules in Titan's atmosphere [4]. The observed O+ is deposited in the region now known to contain large organic molecules. A recent Titan atmosphere simulation experiment has shown that incorporation of oxygen into Titan aerosol analogues results in the formation of all five nucleotide bases and the two smallest amino acids, glycine and alanine [5]. Similar chemical processes may have occurred in the atmosphere of the early Earth, or in the atmospheres of extrasolar planets; atmospheric aerosols may be an important source of the building blocks of life. Atmospheric aerosols play an important role in determining the radiation budget of an atmosphere and can also provide a wealth of organic material to the surface. The presence of atmospheric aerosols has been invoked to explain the relatively featureless spectrum of HD 189773b, including the lack of predicted atmospheric Na and K spectral lines [9]. The majority of the O+ precipitating into Titan's atmosphere forms CO (O(3P)+CH3 -> CO+H2+H) [4]. CO has also been detected in the atmospheres of a number of exoplanets including HD 189733b, HD 209458b, and WASP-12b [6-8]. It is therefore important to understand the role CO plays in the formation and composition of hazes in planetary atmospheres. Using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) (see e.g. [10]) we have obtained in situ composition measurements of aerosol particles (so-called "tholins") produced in N2/CH4/CO gas mixtures subjected to either FUV radiation (deuterium lamp, 115-400 nm) or a

  14. Ground-based characterization of aerosol spectral optical properties of haze and Asian dust episodes under Asian continental outflow during winter 2014

    Science.gov (United States)

    Jung, Jinsang; Yu, JeongAh; Lyu, Youngsook; Lee, Minhee; Hwang, Taekyung; Lee, Sangil

    2017-04-01

    Long-range transported (LRT) haze can affect the regional radiation budget and the air quality in areas downwind of the Asian continental outflow. Because in situ observations of spectral aerosol optical properties of the LRT haze are rare, an intensive characterization of aerosol optical properties is needed. This study characterized the spectral optical properties of the LRT haze and Asian dust originating from the Asian continent. Integrated chemical and optical measurements of aerosol particles were carried out in a downwind area of the Asian continental outflow (Daejeon, South Korea) during winter 2014. High concentrations of PM10 (particulate matter with a diameter ≤ 10 µm) and light scattering coefficients at 550 nm, σs, 550, were observed during a long-range transport (LRT) haze episode (PM10 = 163.9 ± 25.0 µg m-3; σs, 550 = 503.4 ± 60.5 Mm-1) and Asian dust episode (PM10 = 211.3 ± 57.5 µg m-3; σs, 550 = 560.9 ± 151 Mm-1). During the LRT haze episode, no significant change in the relative contribution of PM2. 5 (particulate matter with a diameter ≤ 2.5 µm) chemical components was observed as particles accumulated under stagnant atmospheric conditions (13-17 January 2014), suggesting that the increase in PM2. 5 mass concentration was caused mainly by the accumulation of LRT pollutants. On the other hand, a gradual decrease in Ångström exponent (Å) and a gradual increase in single scattering albedo (ω) and mass scattering efficiency (MSE) were observed during the stagnant period, possibly due to an increase in particle size. These results imply that a change in particle size rather than chemical composition during the stagnant period is the dominant factor affecting the aerosol optical properties. During the Asian dust episode, a low PM2. 5 / PM10 ratio and Å(450/700) were observed with average values of 0.59 ± 0.06 and 1.08 ± 0.14, respectively, which were higher than those during the LRT haze episode (0.75 ± 0.06 and 1.39 ± 0

  15. Study on an Air Quality Evaluation Model for Beijing City Under Haze-Fog Pollution Based on New Ambient Air Quality Standards

    Directory of Open Access Journals (Sweden)

    Li Li

    2014-08-01

    Full Text Available Since 2012, China has been facing haze-fog weather conditions, and haze-fog pollution and PM2.5 have become hot topics. It is very necessary to evaluate and analyze the ecological status of the air environment of China, which is of great significance for environmental protection measures. In this study the current situation of haze-fog pollution in China was analyzed first, and the new Ambient Air Quality Standards were introduced. For the issue of air quality evaluation, a comprehensive evaluation model based on an entropy weighting method and nearest neighbor method was developed. The entropy weighting method was used to determine the weights of indicators, and the nearest neighbor method was utilized to evaluate the air quality levels. Then the comprehensive evaluation model was applied into the practical evaluation problems of air quality in Beijing to analyze the haze-fog pollution. Two simulation experiments were implemented in this study. One experiment included the indicator of PM2.5 and was carried out based on the new Ambient Air Quality Standards (GB 3095-2012; the other experiment excluded PM2.5 and was carried out based on the old Ambient Air Quality Standards (GB 3095-1996. Their results were compared, and the simulation results showed that PM2.5 was an important indicator for air quality and the evaluation results of the new Air Quality Standards were more scientific than the old ones. The haze-fog pollution situation in Beijing City was also analyzed based on these results, and the corresponding management measures were suggested.

  16. Study on an air quality evaluation model for Beijing City under haze-fog pollution based on new ambient air quality standards.

    Science.gov (United States)

    Li, Li; Liu, Dong-Jun

    2014-08-28

    Since 2012, China has been facing haze-fog weather conditions, and haze-fog pollution and PM2.5 have become hot topics. It is very necessary to evaluate and analyze the ecological status of the air environment of China, which is of great significance for environmental protection measures. In this study the current situation of haze-fog pollution in China was analyzed first, and the new Ambient Air Quality Standards were introduced. For the issue of air quality evaluation, a comprehensive evaluation model based on an entropy weighting method and nearest neighbor method was developed. The entropy weighting method was used to determine the weights of indicators, and the nearest neighbor method was utilized to evaluate the air quality levels. Then the comprehensive evaluation model was applied into the practical evaluation problems of air quality in Beijing to analyze the haze-fog pollution. Two simulation experiments were implemented in this study. One experiment included the indicator of PM2.5 and was carried out based on the new Ambient Air Quality Standards (GB 3095-2012); the other experiment excluded PM2.5 and was carried out based on the old Ambient Air Quality Standards (GB 3095-1996). Their results were compared, and the simulation results showed that PM2.5 was an important indicator for air quality and the evaluation results of the new Air Quality Standards were more scientific than the old ones. The haze-fog pollution situation in Beijing City was also analyzed based on these results, and the corresponding management measures were suggested.

  17. Sources and health risks of polycyclic aromatic hydrocarbons during haze days in eastern China: A 1-year case study in Nanjing City.

    Science.gov (United States)

    Kang, Fuxing; Mao, Xuewei; Wang, Xiyu; Wang, Jian; Yang, Bing; Gao, Yanzheng

    2017-06-01

    The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in ambient air were investigated for a 1-year period to assess their sources and health risks during haze days in Nanjing City, eastern China. The highest level of total PAHs (∑16 PAHs) in the gaseous phase during the haze days was 18.0±13.3µg/m(3). Their sources may be attributable to pyrogenic products (55.2%), petrochemical refining industry (8.7%), and petrol volatilization (36.1%). The incremental lifetime cancer risk during the haze days exceeded or was close to the priority level of risk (10(-4)), indicating that PAH pollution during the haze days has caused public health problems associated with the respiratory system. The priority PAHs in the particle phase are mainly composed of low-ring components (<4 rings), accounting for 65.2-96.8% of the ∑16 PAHs during haze days. These particles are derived from petroleum hydrocarbons (16.5%), incomplete combustion of gasoline (62.2%), and burning of coal and biomass (21.4%). The priority level of risk fell within an acceptable range (10(-7)-10(-6)). The PAHs in suspended particles can be transported to the surfaces of vegetables by gravitational deposition, causing an increase in PAH concentrations in vegetable leaves. The increased carcinogenic risk associated with human dietary intake was 6.9×10(-5) for S. oleracea, 1.7×10(-5) for B. pekinensis, and 6.2×10(-6) for B. chinensis. These levels were close to the critical value (10(-4)), and the potential health risks from dietary intake of PAHs should be prioritized. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Indoor human exposure to size-fractionated aerosols during the 2015 Southeast Asian smoke haze and assessment of exposure mitigation strategies

    Science.gov (United States)

    Sharma, Ruchi; Balasubramanian, Rajasekhar

    2017-11-01

    The 2015 smoke haze episode was one of the most severe and prolonged transboundary air pollution events ever seen in Southeast Asia (SEA), affecting the air quality of several countries within the region including Indonesia, Malaysia and Singapore. The 24 h mean outdoor PM2.5 (particulate matter (PM) with aerodynamic diameter ≤ 2.5 μm) concentrations ranged from 72–157 μg m‑3 in Singapore during this episode, exceeding the WHO 24 h mean PM2.5 guidelines (25 μg m‑3) several times over. The smoke haze episode not only affected ambient air quality, but also indoor air quality due to the migration of PM of different sizes from the outdoor to the indoor environment. Despite the frequent occurrence of smoke haze episodes over the years, their potential health impacts on indoor building occupants remain largely unknown in SEA due to the lack of systematic investigations and observational data. The current work was carried out in Singapore to assess human exposure to size-resolved PM during the 2015 smoke haze episode, and to evaluate the effectiveness of exposure mitigation measures in smoke-haze-impacted naturally ventilated indoor environments. The potential health risks associated with exposure to PM2.5 were assessed based on the concentrations of redox active particulate-bound trace elements, which are known to be harmful to human health, with and without exposure mitigation. Overall, it was observed that human health exposure to PM2.5 and its carcinogenic chemical components was reduced substantially by 62% (p < 0.05) while using an air cleaner. However, extremely small hazardous particles were only partially removed by the air cleaner and remain a matter of concern for public health.

  19. Evaluation of the prophylactic use of mitomycin-C to inhibit haze formation after photorefractive keratectomy in high myopia: a prospective clinical study

    Directory of Open Access Journals (Sweden)

    Fotouhi Akbar

    2004-09-01

    Full Text Available Abstract Background To study the effect of prophylactic application of mitomycin-C on haze formation in photorefractive keratectomy (PRK for high myopia. Methods Fifty-four eyes of 28 myopic patients were enrolled in this prospective study. All eyes were operated by PRK followed by 0.02% mitomycin-C application for two minutes and washed with 20 ml normal saline afterwards. All eyes were examined thoroughly on the first 7 days and one month after surgery; 48 eyes (88.9% at 3 and 6 months postoperatively. Hanna grading (in the scale of 0 to 4+ was used for assessment of corneal haze. Results The mean spherical equivalent refraction (SE was -7.08 diopters (D ± 1.11 (SD preoperatively. Six months after surgery, 37 eyes (77.1% achieved an uncorrected visual acuity (UCVA of 20/20 or better, all eyes had a UCVA of 20/40 or better and 45 (93.7% eyes had an SE within ± 1.00D. One month postoperatively, 2 eyes (3.7% had grade 0.5+ of haze, while at 3 and 6 months after surgery no visited eye had haze at all. All eyes had a best corrected visual acuity (BCVA of 20/40 or better and there were no lost lines in BCVA by 6 months after surgery. In spatial frequencies of 6 and 12 cycles per degree contrast sensitivity had decreased immediately after PRK and it had increased 1.5 lines by the 6th postoperative month compared to the preoperative data. Conclusions The results show the efficacy of mitomycin-C in preventing corneal haze after treatment of high myopia with PRK. This method- PRK + mitomycin-C – can be considered an alternative treatment for myopic patients whose corneal thicknesses are inadequate for laser in situ keratomileusis (LASIK. However, the results should be confirmed in longer follow-ups.

  20. Study on an Air Quality Evaluation Model for Beijing City Under Haze-Fog Pollution Based on New Ambient Air Quality Standards

    Science.gov (United States)

    Li, Li; Liu, Dong-Jun

    2014-01-01

    Since 2012, China has been facing haze-fog weather conditions, and haze-fog pollution and PM2.5 have become hot topics. It is very necessary to evaluate and analyze the ecological status of the air environment of China, which is of great significance for environmental protection measures. In this study the current situation of haze-fog pollution in China was analyzed first, and the new Ambient Air Quality Standards were introduced. For the issue of air quality evaluation, a comprehensive evaluation model based on an entropy weighting method and nearest neighbor method was developed. The entropy weighting method was used to determine the weights of indicators, and the nearest neighbor method was utilized to evaluate the air quality levels. Then the comprehensive evaluation model was applied into the practical evaluation problems of air quality in Beijing to analyze the haze-fog pollution. Two simulation experiments were implemented in this study. One experiment included the indicator of PM2.5 and was carried out based on the new Ambient Air Quality Standards (GB 3095-2012); the other experiment excluded PM2.5 and was carried out based on the old Ambient Air Quality Standards (GB 3095-1996). Their results were compared, and the simulation results showed that PM2.5 was an important indicator for air quality and the evaluation results of the new Air Quality Standards were more scientific than the old ones. The haze-fog pollution situation in Beijing City was also analyzed based on these results, and the corresponding management measures were suggested. PMID:25170682

  1. The structure of the haze plume over the Indian Ocean during INDOEX: tracer simulations and LIDAR observations

    Directory of Open Access Journals (Sweden)

    G. Forêt

    2006-01-01

    Full Text Available Three-dimensional, nested tracer simulations of a pollution plume originating from the Indian sub-continent over the Indian Ocean, in the framework of the Indian Ocean Experiment (INDOEX, between 5 and 9 March 1999, were performed with the Regional Atmospheric Modeling System (RAMS, to provide insight into the transport patterns of the pollutants, as well as to investigate the dynamical mechanisms controlling the vertical structure of the plume and its evolution in the vicinity of the Maldives Islands. Airborne and ground-based LIDAR observations of the structure of the haze plume made on 7 March 1999 were used to assess the quality of the simulations, as well as the impact of grid resolution on the vertical structure of the simulated plume. It is shown that, over the Arabian Sea, in the vicinity of the Maldives Islands, the pollutants composing the plume observed by the airborne LIDAR essentially originated from the city of Madras and that the vertical structure of the plume was controlled by the diurnal cycle of the continental boundary layer depth. A combination of tracer simulations and remote sensing observations (airborne LIDAR, ship-borne photometer, ground-based LIDAR in Goa was used to analyse the diurnal evolution of the haze plume over the sea. We find evidence that the sea breeze circulation and orographic lifting taking place in the southern part of the Indian sub-continent during the daytime play a crucial role in the modulation of the continental boundary layer depth, and in turn, the haze plume depth. The eastward shift of the subtropical high from central India to the Bay of Bengal after 6 March lead to an increase in the tracer concentrations simulated over the Arabian Sea, in the region of intensive observations north of the Maldives, as transport pathways form Hyderabad and Madras were modified significantly. The nesting of a high horizontal resolution domain (5 km, with 39 vertical levels below 4000 m above mean seal level

  2. Particle size distribution and respiratory deposition estimates of airborne perfluoroalkyl acids during the haze period in the megacity of Shanghai.

    Science.gov (United States)

    Guo, Mengjie; Lyu, Yan; Xu, Tingting; Yao, Bo; Song, Weihua; Li, Mei; Yang, Xin; Cheng, Tiantao; Li, Xiang

    2017-11-16

    This study presents the particle size distribution and respiratory deposition estimates of airborne perfluoroalkyl acids (PFAAs) during the haze period. Size-segregated haze aerosols were collected from an urban location in Shanghai using an eight-stage air sampler. The samples were analyzed for eight PFAAs using ultra-high-performance liquid chromatography tandem triple quadrupole mass spectrometry. The quantification results showed that the concentrations of particle-bound Σ 8PFAAs ranged from 0.26 to 1.90 ng m-3 (mean: 1.44 ng m-3). All of the measured PFAAs particle size distributions had a bimodal mode that peaked respectively in accumulation size range (0.4 size ranges (Dp > 2.1 μm), but the width of each distribution somewhat varied by compound. The emission source, molecular weight, and volatility of the PFAAs were important factors influencing the size distribution of particle-bound PFAAs. Of these compounds, PFUnDA presented a strong accumulation in the fine size range (average 75% associated with particles size distribution, with a 2-fold higher risk for the fine particle fraction compared to the coarse particle fraction at urban sites. Approximately 30.3-82.0% of PFAA deposition (∑PFAA: 72.5%) in the alveolar region was associated with particles particles to the total PFAAs concentration in urban air was only 28-57% (∑8PFAAs: 48%). These results suggested that fine particles are significant contributors to the deposition of PFAAs in the alveolar region of the lung. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Composition and mixing states of brown haze particle over the Himalayas along two transboundary south-north transects

    Science.gov (United States)

    Dong, Zhiwen; Kang, Shichang; Guo, Junming; Zhang, Qianggong; Wang, Xuejia; Qin, Dahe

    2017-05-01

    Pollutants that are usually transported from southern Asia to the Tibetan Plateau deposit on the Plateau surface, change snow albedo and thereby surface radiative flux. This results numerous climatic implications like as erratic monsoon, perturbation in hydrological cycle, etc. However, the accurate estimation of these climatic implications is not well understood, because the atmospheric pollution is a heterogeneous mixture of various particle types. Therefore, this part of climate research requires a detailed investigation of physical and chemical properties of atmospheric pollutants. This study aimed to examine the physical and chemical properties of atmospheric pollutants across the Himalayan regions along two transboundary south-north transects. The information of individual-particles was obtained using microscopy-based techniques that comprises transmission electron microscope (TEM) and Energy-dispersive X-ray spectrometer (EDX). Study capture the signatures of various types of atmospheric species such as black carbon (BC), mineral dust, fly ash, organic matter, sulfate, nitrite, ammonium, and NaCl. Microscopy-based techniques confirm that these particles were generally in mixing state, for example salt-coated particles accounting for 25-56% of the total particles in sampled locations. Our analysis shows that urban and rural locations are characterized with atmospheric particles which sourced from anthropogenic activities, whereas remote locations with those released from natural crustal. However, the relative contributions of anthropogenic particles were higher than that of particles released from natural crustal. The presence of such particles over remote locations of Himalayan region provides an evidence of prevailing atmospheric transport processes, which further need to be well understood. It is expected that this work would be helpful in understanding the regional atmospheric conditions and the transboundary transport process of haze particles. As these

  4. Simulations of sulfate-nitrate-ammonium (SNA) aerosols during the extreme haze events over northern China in October 2014

    Science.gov (United States)

    Chen, Dan; Liu, Zhiquan; Fast, Jerome; Ban, Junmei

    2016-08-01

    Extreme haze events have occurred frequently over China in recent years. Although many studies have investigated the formation mechanisms associated with PM2.5 for heavily polluted regions in China based on observational data, adequately predicting peak PM2.5 concentrations is still challenging for regional air quality models. In this study, we evaluate the performance of one configuration of the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and use the model to investigate the sensitivity of heterogeneous reactions on simulated peak sulfate, nitrate, and ammonium concentrations in the vicinity of Beijing during four extreme haze episodes in October 2014 over the North China Plain. The highest observed PM2.5 concentration of 469 µg m-3 occurred in Beijing. Comparisons with observations show that the model reproduced the temporal variability in PM2.5 with the highest PM2.5 values on polluted days (defined as days in which observed PM2.5 is greater than 75 µg m-3), but predictions of sulfate, nitrate, and ammonium were too low on days with the highest observed concentrations. Observational data indicate that the sulfur/nitric oxidation rates are strongly correlated with relative humidity during periods of peak PM2.5; however, the model failed to reproduce the highest PM2.5 concentrations due to missing heterogeneous/aqueous reactions. As the parameterizations of those heterogeneous reactions are not well established yet, estimates of SO2-to-H2SO4 and NO2/NO3-to-HNO3 reaction rates that depend on relative humidity were applied, which improved the simulation of sulfate, nitrate, and ammonium enhancement on polluted days in terms of both concentrations and partitioning among those species. Sensitivity simulations showed that the extremely high heterogeneous reaction rates and also higher emission rates than those reported in the emission inventory were likely important factors contributing to those peak PM2.5 concentrations.

  5. Wintertime aerosol chemistry and haze evolution in an extremely polluted city of the North China Plain: significant contribution from coal and biomass combustion

    Science.gov (United States)

    Li, Haiyan; Zhang, Qi; Zhang, Qiang; Chen, Chunrong; Wang, Litao; Wei, Zhe; Zhou, Shan; Parworth, Caroline; Zheng, Bo; Canonaco, Francesco; Prévôt, André S. H.; Chen, Ping; Zhang, Hongliang; Wallington, Timothy J.; He, Kebin

    2017-04-01

    The North China Plain (NCP) frequently experiences heavy haze pollution, particularly during wintertime. In winter 2015-2016, the NCP region suffered several extremely severe haze episodes with air pollution red alerts issued in many cities. We have investigated the sources and aerosol evolution processes of the severe pollution episodes in Handan, a typical industrialized city in the NCP region, using real-time measurements from an intensive field campaign during the winter of 2015-2016. The average (±1σ) concentration of submicron aerosol (PM1) during 3 December 2015-5 February 2016 was 187.6 (±137.5) µg m-3, with the hourly maximum reaching 700.8 µg m-3. Organic was the most abundant component, on average accounting for 45 % of total PM1 mass, followed by sulfate (15 %), nitrate (14 %), ammonium (12 %), chloride (9 %) and black carbon (BC, 5 %). Positive matrix factorization (PMF) with the multilinear engine (ME-2) algorithm identified four major organic aerosol (OA) sources, including traffic emissions represented by a hydrocarbon-like OA (HOA, 7 % of total OA), industrial and residential burning of coal represented by a coal combustion OA (CCOA, 29 % of total OA), open and domestic combustion of wood and crop residuals represented by a biomass burning OA (BBOA, 25 % of total OA), and formation of secondary OA (SOA) in the atmosphere represented by an oxygenated OA (OOA, 39 % of total OA). Emissions of primary OA (POA), which together accounted for 61 % of total OA and 27 % of PM1, are a major cause of air pollution during the winter. Our analysis further uncovered that primary emissions from coal combustion and biomass burning together with secondary formation of sulfate (mainly from SO2 emitted by coal combustion) are important driving factors for haze evolution. However, the bulk composition of PM1 showed comparatively small variations between less polluted periods (daily PM2. 5 ≤ 75 µg m-3) and severely polluted periods (daily PM2. 5 > 75 µg m-3

  6. The Effects of Anthropogenic Heat Release on Urban Meteorology and Implication for Haze Pollution in the Beijing-Tianjin-Hebei Region

    Directory of Open Access Journals (Sweden)

    Ruiting Liu

    2016-01-01

    Full Text Available In this study, the effect of anthropogenic heat release (AHR on meteorological variables and atmospheric diffusion capability and implication for haze pollution in the Beijing-Tianjin-Hebei region in January 2013 were investigated by using Weather Research and Forecasting (WRF model with an urban canopy model (UCM and an AHR scheme. The comparison with observation demonstrated the WRF/UCM model taking AHR into account apparently improved meteorological prediction, especially for surface air temperature at 2 m (T2. The model also exhibited a better performance for planetary boundary layer (PBL height. This study revealed that AHR from cities exerted a significant impact on meteorology by generally increasing surface air temperature and wind speed, decreasing relative humidity, and elevating PBL height and near surface turbulent kinetic energy (TKE, which could consequently reduce surface pollutant concentration and mitigate haze pollution by enhancing atmospheric instability and turbulent mixing and reducing aerosol hygroscopic growth.

  7. The Effects of Anthropogenic Heat Release on Urban Meteorology and Implication for Haze Pollution in the Beijing-Tianjin-Hebei Region

    OpenAIRE

    Ruiting Liu; Zhiwei Han

    2016-01-01

    In this study, the effect of anthropogenic heat release (AHR) on meteorological variables and atmospheric diffusion capability and implication for haze pollution in the Beijing-Tianjin-Hebei region in January 2013 were investigated by using Weather Research and Forecasting (WRF) model with an urban canopy model (UCM) and an AHR scheme. The comparison with observation demonstrated the WRF/UCM model taking AHR into account apparently improved meteorological prediction, especially for surface ai...

  8. Climatology of the meteorological factors associated with haze events over northern China and their potential response to the Quasi-Biannual Oscillation

    Science.gov (United States)

    Liang, Ju; Tang, Yaoguo

    2017-10-01

    An upswing in haze weather during autumn and winter has been observed over North and Northeast China in recent years, imposing adverse impacts upon local socioeconomic development and human health. However, such an increase in the occurrence of haze events and its association with natural climate variability and climate change are not well understood. To investigate the climatology of the meteorological factors associated with haze events and their natural variability, this study uses a meteorological pollution index called PLAM (Parameter Linking Air-quality to Meteorological conditions) and ERA-Interim reanalysis data. The results suggest that high PLAM values tend to occur over southern parts of northern China, implying the weather conditions over this area are favorable for the occurrence of haze weather. For the period 1979-2014, the regional mean PLAM shows an overall increase across Beijing, Tianjin, and Hebei Province, and parts of Shanxi Province. Also, a periodicity of 28-34 months is found in the temporal variation of PLAM, which implies a potential association of PLAM with the stratospheric Quasi-Biannual Oscillation (QBO). By using the QBO index during the autumn and winter seasons in the preceding year, an increase in PLAM is found for the westerly phases of the QBO, relative to the easterly phases. An upper-tropospheric warming is also found in the westerly phases, which can induce a stable stratification that favors the increase in PLAM across the midlatitudes. The modulations of large-scale environmental factors, including moist static stability, vertical velocity, and temperature advection, also act to enhance PLAM in the westerly phases. However, the baroclinic term of moist potential vorticity at 700 hPa tends to decrease over the south, and an increase in low-level ascent is found over the north. These factors can reduce PLAM and possibly limit the statistical significance of the increased PLAM in the westerly phases of the QBO.

  9. 77 FR 30248 - Approval and Promulgation of Implementation Plans; State of Idaho; Regional Haze State...

    Science.gov (United States)

    2012-05-22

    ... generate steam or hot water in manufacturing, material processing, mining, refining, and/or electricity... efficiency to New Source Performance Standards and tail gas treatment. See SIP submittal section 11.4.3 for...

  10. Risk factors for early-onset corneal haze after photorefractive keratectomy in an Asian population: Outcomes from the Singapore Armed Forces Corneal Refractive Surgery Programme 2006 to 2013.

    Science.gov (United States)

    Ang, Bryan Chin Hou; Foo, Reuben Chao Ming; Lim, Edmund Wei Long; Tan, Mellisa Mei Hui; Nah, Gerard Kwang Ming; Thean, Lennard See Yin; Tan, Clement Woon Teck; Zhao, Paul Song Bo

    2016-05-01

    To assess the incidence and risk factors for early corneal haze after myopic photorefractive keratectomy (PRK). Tertiary eye center, Singapore. Retrospective case series. The refractive results and corneal haze severity 3 months after PRK were analyzed. Eyes were categorized into 4 groups based on haze severity. Multivariate ordinal logistic regression analysis adjusting for age, ethnicity, sex, use of intraoperative mitomycin-C (MMC), preoperative sphere, and preoperative cylinder was performed. The study reviewed data from 177 patients (347 eyes) with a mean age of 22.6 years ± 4.1 (SD). The majority of the patients were Chinese (98.3%) and men (98.3%). The mean preoperative spherical equivalent (SE) was -3.34 ± 1.19 diopters (D). One hundred thirty-five eyes (38.9%) had PRK with MMC. Ten eyes (2.9%) had enhancement surgery. The overall efficacy index was 0.88 and the safety index was 1.07. At 3 months, 187 eyes (53.9%) had no haze, 76 eyes (21.9%) had a haze grade of more than 0 and less than 1, 76 eyes (21.9%) had a haze grade of 1 or more and less than 2, and 8 eyes (2.3%) had grade 2 haze. Higher degrees of myopia (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.13-1.63; P = .001) and astigmatism (OR, 1.56; 95% CI, 1.09-2.24; P = .014) were associated with increased severity of corneal haze, whereas older age (OR, 0.94; 95% CI, 0.88-0.99; P = .023) had a protective effect. Myopia and astigmatism were associated with increased severity of haze, and older age was protective against early corneal haze development after PRK in an Asian population. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  11. Broadband polarimetry of exoplanets: modelling signals of surfaces, hazes and clouds

    OpenAIRE

    Karalidi, Theodora

    2013-01-01

    It is less than 20 years since astronomers discovered the first exoplanet orbiting a Sun-like star. In this short period more than 770 confirmed exoplanets have been detected. With so many exoplanets the next step is their characterization. What is their atmosphere made of? Does it contain water clouds? Is there water on the planetary surface? Could there be life on these planets? To answer all these questions good and reliable models are necessary for interpreting the signal we observe from ...

  12. McDonald Observatory data on the comet Shoemaker-Levy 9 impacts on Jupiter and the resulting haze particles

    Science.gov (United States)

    Pryor, W. R.; Na, C. Y.; Cochran, A. L.; Cochran, W. D.; Barker, E. S.; Armosky, B. J.; Pulliam, C. E.

    1997-10-01

    Simultaneous light curves of the Comet Shoemaker-Levy 9 fragment R and V impacts were measured with the McDonald Observatory 2.7 m and 0.8 m telescopes, at wavelengths of 2.12 μm and 0.893 μm, respectively. The R impact was clearly detected at 2.12 μm, but not at 0.893 μm, leading to an upper limit on the "main event" temperature of 1300 K. The V impact was not detected. A possible detection of the U impact at 2.12 μm was recorded. CCD spectrophotometry of Jupiter was obtained with the McDonald 2.1 m telescope during the Shoemaker-Levy 9 impact period (17 July-23 July 1994 UT; Barker et al. (1994) Bull. Am. Astron. Soc.26, 1569). Spectra of Jupiter from 0.55 to 1.08 μm (10 Å resolution) were obtained using a long-slit CCD spectrograph (ES2), with a seeing-limited spatial resolution of about 1-2″. Impact regions were darker than neighboring non-impact regions by some 5-10% at all wavelengths except in the strong methane absorption bands (0.727, 0.864, and 0.890 μm) where the impact sites are brighter. Aerosol models of this spectral change are examined. The grey absorption observed is not typical of a population of particles much smaller than the wavelength. Neither is the similar haze brightening seen in two methane bands of similar strength at 0.727 and 0.864 μm. Our radiative transfer models of the H and E impact aites favor broad particle size distributions, with a mean particle radius = 0.25 μm and a log-normal size distribution of width b ≈ 0.6. A constant imaginary refractive index of 0.006 in this wavelength range provides an adequate spectral fit to the H data, while an index of 0.012 better fits the E data. Additional ES2 Jupiter spectra from June 1995 with both "blue" (0.31-0.58 μm) and "red" (0.55-1.08 μm) gratings were obtained. Blue spectra and images still show some evidence for residual impact haze opacity near the impact latitudes; red spectra and images do not. Apparently sedimentation of the larger particles in a broad initial size

  13. Stromal wound healing explains refractive instability and haze development after photorefractive keratectomy: a 1-year confocal microscopic study.

    Science.gov (United States)

    Moller-Pedersen, T; Cavanagh, H D; Petroll, W M; Jester, J V

    2000-07-01

    To evaluate the mechanism(s) producing refractive instability and corneal haze development after photorefractive keratectomy (PRK). Prospective, nonrandomized, comparative case series, self-controlled. Seventeen eyes of 17 patients with low- to moderate-grade myopia (-2.88 to -9.13 diopters [D]) were included. Surgical intervention was a standardized, 6-mm diameter PRK procedure using the Meditec MEL 60 excimer laser (Aesculap-Meditec, Heroldsberg, Germany). The photoablation center was evaluated before surgery and at 1, 3, 6, 9, and 12 months after PRK using rapid, continuous z-scans of confocal images, termed confocal microscopy through focusing (CMTF). Simultaneous epithelial and stromal thickness analysis and objective assessment of corneal light backscattering were obtained from digital image analysis of the CMTF scans. Corneal reinnervation and anterior stromal keratocyte density and wound healing morphologic features were evaluated on high resolution, in vivo confocal images. Manifest refraction was measured and corneal clarity was graded by slit-lamp biomicroscopy. Epithelial thickness averaged 45+/-10 microm at 1 month, 50+/-8 microm at 3 months, and 52+/-6 microm at 12 months after PRK, as compared with 51+/-4 microm before surgery, demonstrating complete restoration of the preoperative thickness without compensatory hyperplasia. Interestingly, epithelial rethickening had no significant correlation with refractive regression. By contrast, stromal regrowth (from 1-12 months) averaged 6+/-12 microm (range, 27 microm thinning-22 microm rethickening) and correlated closely (r = 0.84, Pwound healing mechanisms. In agreement with these findings, all "hazy" corneas showed increased numbers of anterior stromal wound healing keratocytes with increased reflectivity of both nuclei and cell bodies, suggesting that cellular-based reflections, as opposed to extracellular matrix deposition, are the major origin of increased corneal light scattering after PRK. Taken

  14. Broadband polarimetry of exoplanets : modelling signals of surfaces, hazes and clouds

    NARCIS (Netherlands)

    Karalidi, Theodora

    2013-01-01

    It is less than 20 years since astronomers discovered the first exoplanet orbiting a Sun-like star. In this short period more than 770 confirmed exoplanets have been detected. With so many exoplanets the next step is their characterization. What is their atmosphere made of? Does it contain water

  15. A robust haze-removal scheme in polarimetric dehazing imaging based on automatic identification of sky region

    Science.gov (United States)

    Zhang, Wenfei; Liang, Jian; Ju, Haijuan; Ren, Liyong; Qu, Enshi; Wu, Zhaoxin

    2016-12-01

    Quality enhancement of images acquired in hazy conditions is a significant research area in civil and military applications. The polarimetric dehazing methods have been exploited to dehaze hazy images and have proven to be effective in enhancing their quality. In this paper, by combining the polarimetric imaging technique and the dark channel prior technique, a robust haze-removal scheme is presented for the first time. On the one hand, the polarimetric imaging technique has advantages in recovering detailed information well, especially in dense hazy conditions; on the other hand, the dark channel prior technique provides a much more precise and convenient way to estimate the airlight radiance through extracting the sky region automatically. The experiments verify the practicability and effectiveness of the proposed dehazing scheme in quality enhancement of hazy images. Furthermore, comparison study demonstrates that the proposed scheme is superior to some sophisticated methods in terms of the visibility and contrast. We believe this scheme is beneficial in the image dehazing applications, especially for real-time applications.

  16. Real-Time Characterization of Fluorescent Biological Aerosol Particles for Clear and Haze Episodes in Winter Beijing

    Science.gov (United States)

    Yue, S.; Fu, P.; Ren, H.; Fan, S.; Wei, L.; Hou, S.; Sun, Y.; Wang, Z.

    2016-12-01

    Primary biological aerosol particles (PBAP) such as pollen, fungal spore, bacteria and virus represent a major subset of particulate compositions for both coarse and fine aerosols. This category of aerosols affects weather, climate and human and plant health. We report the first multi-band quantification of fluorescent biological aerosol particles in Beijing, China in winter. The number concentrations and size distributions of FBAP were acquired by a Wideband Integrated Bioaerosol Sensor (WIBS-4A). Three-hour samples of total suspended particles (TSP) were concurrently collected during a transition of a haze event to a clear period. It was found that the fraction of FBAP in all particles (> 0.8 µm) in pollution episodes (average value: 17%) was slightly higher than that during clear periods (13%). Besides, size-segregated FBAP in different fluorescent channels were less correlated (Pearson correlation coefficient) and existed diverse diurnal trends, indicating various sources of FBAP. Our results provide a better understanding of the roles of biological aerosols in an urban environment that is frequently suffered from severe air pollution.

  17. Development of Historical Coefficient-of-Haze Datasets as a Surrogate for Fine Particle Air Quality Data

    Science.gov (United States)

    Miller, W. C.

    2002-05-01

    Recent developments in the instrumentation methods for measuring airborne fine particles have permitted the comparison of the Coefficient-of-Haze (COH) parameter with Black Carbon (BC) and Elemental Carbon (EC) continuous measurements via Aethalometer. The Harvard School of Public Health (HSPH) performed a field study in Philadelphia, Pennsylvania during 1992 which revealed a strong linear relationship between COH and BC (R=0.994, p-valuemethods were limited to a 24-hour composite sample. In 1998 the authors of the HSPH study proposed that the analysis of historical COH datasets in urban areas in the post-WWII era would be useful in retrospective epidemiological studies concerning the health effects of fine particles. The City of Philadelphia operated six COH monitoring sites during the period 1956 through 1975. All of the datasets were in paper format. The Philadelphia Department of Public Health in cooperation with the Hahnemann University Medical School (now managed by Drexel University) converted the paper datasets into computer files for use by the research community. This paper presents a statistical analysis of those data sets including the application of contemporary spatial and temporal data analysis tools for data presentation, mapping, and integration with other statistical datasets.

  18. Simulation of the Upper Clouds and Hazes of Venus Using a Microphysical Cloud Model

    Science.gov (United States)

    McGouldrick, K.

    2012-12-01

    Several different microphysical and chemical models of the clouds of Venus have been developed in attempts to reproduce the in situ observations of the Venus clouds made by Pioneer Venus, Venera, and Vega descent probes (Turco et al., 1983 (Icarus 53:18-25), James et al, 1997 (Icarus 129:147-171), Imamura and Hashimoto, 2001 (J. Atm. Sci. 58:3597-3612), and McGouldrick and Toon, 2007 (Icarus 191:1-24)). The model of McGouldrick and Toon has successfully reproduced observations within the condensational middle and lower cloud decks of Venus (between about 48 and 57 km altitude, experiencing conditions similar to Earth's troposphere) and it now being extended to also simulate the microphysics occurring in the upper cloud deck (between altitudes of about 57 km and 70 km, experiencing conditions similar to Earth's stratosphere). In the upper clouds, aerosols composed of a solution of sulfuric acid in water are generated from the reservoir of available water vapor and sulfuric acid vapor that is photochemically produced. The manner of particle creation (e.g., activation of cloud condensation nuclei, or homogeneous or heterogeneous nucleation) is still incompletely understood, and the atmospheric environment has been measured to be not inconsistent with frozen aerosol particles (either sulfuric acid monohydrate or water ice). The material phase, viscosity, and surface tension of the aerosols (which are strongly dependent up on the local temperature and water vapor concentration) can affect the coagulation efficiencies of the aerosol, leading to variations in the size distributions, and other microphysical and radiative properties. Here, I present recent work exploring the effects of nucleation rates and coalescence efficiencies on the simulated Venus upper clouds.

  19. REMOTE SENSING MEASUREMENTS OF AEROSOL OPTICAL THICKNESS AND CORRELATION WITH IN-SITU AIR QUALITY PARAMETERS DURING A SMOKE HAZE EPISODE IN SOUTHEAST ASIA

    Science.gov (United States)

    Chew, B.; Salinas Cortijo, S. V.; Liew, S.

    2009-12-01

    Transboundary smoke haze due to biomass burning is a major environmental problem in Southeast Asia which has not only affected air quality in the source region, but also in the surrounding countries. Air quality monitoring stations and meteorological stations can provide valuable information on the concentrations of criteria pollutants such as sulphur dioxide, nitrogen oxide, carbon monoxide, ozone and particulate mass (PM10) as well as health advisory to the general public during the haze episodes. Characteristics of aerosol particles in the smoke haze such as the aerosol optical thickness (AOT), aerosol size distribution and Angstrom exponent are also measured or retrieved by sun-tracking photometers, such as those deployed in the world-wide AErosol RObotic NETwork (AERONET). However, due to the limited spatial coverage by the air quality monitoring stations and AERONET sites, it is difficult to study and monitor the spatial and temporal variability of the smoke haze during a biomass burning episode, especially in areas without ground-based instrumentation. As such, we combine the standard in-situ measurements of PM10 by air quality monitoring stations with the remote sensing imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA's Terra and Aqua satellites. The columnar AOT is first derived from the MODIS images for regions where PM10 measurements are available. Empirical correlations between AOT and PM10 measurements are then established for 50 sites in both Malaysia and Singapore during the smoke haze episode in 2006. When available, vertical feature information from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) is used to examine the validity of the correlations. Aloft transport of aerosols, which can weaken the correlations between AOT and PM10 measurements, is also identified by CALIPSO and taken into consideration for the analysis. With this integrated approach, we hope to enhance and

  20. Wintertime aerosol chemistry and haze evolution in an extremely polluted city of North China Plain: significant contribution from coal and biomass combustions

    Science.gov (United States)

    Li, Haiyan; Zhang, Qi; Zhang, Qiang; Chen, Chunrong; Wang, Litao; Wei, Zhe; Zhou, Shan; Parworth, Caroline; Zheng, Bo; Canonaco, Francesco; Prévôt, André; Chen, Ping; Zhang, Hongliang; He, Kebin

    2017-04-01

    The North China Plain (NCP) frequently encountered heavy haze pollution in recent years, particularly during wintertime. In 2015-2016 winter, the NCP region suffered several extremely severe haze episodes with air pollution red alerts issued in many cities. In this work, we investigated the sources and aerosol evolution processes of the severe pollution episodes in Handan, a typical industrialized city in the NCP region, using real-time measurements from an intensive field campaign during the winter of 2015-2016. The average (± 1σ) concentration of submicron aerosol (PM1) during December 3, 2015 - February 5, 2016 was 187.6 (± 137.5) μg m-3, with the hourly maximum reaching 700.8 μg m-3. Organic was the most abundant component, on average accounting for 45% of total PM1 mass, followed by sulfate (15%), nitrate (14%), ammonium (12%), chloride (9%) and BC (5%). Positive matrix factorization (PMF) with multi-linear engine (ME-2) identified four major organic aerosol (OA) sources, including traffic emissions represented by a hydrocarbon-like OA (HOA, 7% of total OA), industrial and residential burning of coal represented by a coal combustion OA (CCOA, 29% of total OA), open and domestic combustion of wood and crop residuals represented by a biomass burning OA (BBOA, 25% of total OA), and formation of secondary OA (SOA) in the atmosphere represented by an oxygenated OA (OOA, 39% of total OA). Emissions of primary OA (POA), which together accounted for 61% of total OA and 27% of PM1, are a major cause of air pollution in this region during the winter. Our analysis further uncovered that, primary emissions from coal combustion and biomass burning together with secondary formation of sulfate (mainly from SO2 emitted by coal combustion) are important driving factors for haze evolution. However, the bulk composition of PM1 showed comparatively small variations between less polluted periods (daily PM2.5 ≤ 75 μg m-3) and severely polluted periods (daily PM2.5 > 75

  1. [Health damage assessment due to PM2.5 exposure during haze pollution events in Beijing-Tianjin-Hebei region in January 2013].

    Science.gov (United States)

    Zhang, Yan-shen; Ma, Guo-xia; Yu, Fang; Cao, Dong

    2013-09-10

    To assess the human health damage due to particulate matter ≤ 2.5 µm (PM2.5) exposure during the haze pollution events in 12 cities of Beijing-Tianjin-Hebei region in January 2013. The data were collected for urban population, ambient air quality, baseline mortality rate and emergency visits in Beijing, Tianjin, Shijiazhuang, Baoding, Chengde, Handan, Langfang, Hengshui, Qinhuangdao, Tangshan, Xingtai and Zhangjiakou. Then the exposure-response relationship was constructed between short-term PM2.5 exposure and mortality and emergency room visits with meta-analysis. Thus the excess deaths and emergency room visits due to PM2.5 exposure were estimated during the haze pollution events using city-specific exposure population, PM2.5 daily concentration and exposure-response coefficients. Three serious PM2.5 pollution events occurred on January 12, January 19 and January 27 in Beijing-Tianjin-Hebei region respectively. From January 10 to January 31, the 24 h mean concentrations of PM2.5 in Beijing, Tianjin, Shijiazhuang, Tangshan, Qinhuangdao, Handan, Xingtai, Baoding, Zhangjiakou, Chengde, Langfang, Hengshui were 705, 411, 675, 506, 255, 598, 698, 667, 231, 178, 718 and 405 µg/m(3). Xingtai, Shijiazhuang, Handan, Baoding, Langfang and Beijing were the more polluted areas. And there were 17 days (77.3%), 13 days (59.1%), 12 days (54.5%), 11 days (50.0%), 10 days (45.5%) and 8 days (36.4%) of Air Quality Index reaching the serious level respectively. The short-term PM2.5 exposure caused 2725 excess death including 846 excess deaths duo to respiratory disease and 1878 excess deaths due to circulatory disease in Beijing-Tianjin-Hebei region from January 10 to January 31. The haze pollution events led to serious public health damage. And it is imperative to take actions of controlling PM2.5 pollution.

  2. Role of climate anomalies on decadal variation in the occurrence of wintertime haze in the Yangtze River Delta, China.

    Science.gov (United States)

    Xu, Jianming; Chang, Luyu; Yan, Fengxia; He, JinHai

    2017-12-01

    The wintertime haze day (HD) in the Yangtze River Delta (YRD) region of China shows a significant upward trend during the past decades due to the rapid industrialization and urbanization. Besides the enhanced anthropogenic emission, climate change also plays the important role in the long term HD variations. In this study, the significant decadal variation of wintertime HD during the period 1960-2012 in YRD is examined by the empirical orthogonal function (EOF) analysis, featured as less HD occurrence before 1980 and more occurrence after 2000. The numerical simulations by the global transport and chemical model (Model for Ozone and Related chemical Tracers, MOZART) with the same emission inventory suggest 8.4% enhancement of wintertime PM2.5 (particulate matter with the equivalent diameter of air dynamics less than or equal to 2.5μm) mass concentration in YRD during 2001-2009 compared with that during 1971-1979 attributed to meteorological changes, indicating the significant effect of climate anomaly on the decadal variations of wintertime HD. Through the composite analysis on the atmospheric dynamical and thermal conditions based on the reanalysis data, the faster warming in the lower and middle troposphere over the continent in the recent decade is suggested to be important for the out-of-phase decadal HD variation in YRD. The thermal anomaly not only reverses the zonal thermal difference of land-sea to stimulate the anomalous southerlies over YRD leading to reduced prevailing north wind in winter, but also develops the deep inversion below the mid-troposphere to enhance the atmospheric stability. As a result, more frequent and persistent air stagnations in recent decade are expected for the reduction of atmospheric horizontal dispersion and vertical diffusion capacity leading to more occurrence of wintertime HD in YRD. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Sources of organic matter (PAHs and n-alkanes) in PM2.5 of Beijing in haze weather analyzed by combining the C-N isotopic and PCA-MLR analyses.

    Science.gov (United States)

    Guo, Xinyue; Li, Cai; Gao, Yang; Tang, Lei; Briki, Meryem; Ding, Huaijian; Ji, Hongbing

    2016-03-01

    Organic molecular composition and carbon and nitrogen isotope ratios of PM2.5 samples collected in November 2013 were analyzed using gas chromatography/mass spectrometry and isotope ratio mass spectrometry. The samples represented six potential sources and seven sampling sites situated in concentric zones around Beijing under both haze and non-haze conditions. Our results showed that the average concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes were 258.2 ± 208.8 ng m(-3) and 499.5 ± 347.8 ng m(-3), while the δ(13)C and δ(15)N values for PM2.5 varied from -26.29 to -25.26‰ and from 8.68 to 14.50‰ with an average of -25.70 ± 0.3‰ and 11.97 ± 1.79‰, respectively. The highest concentrations of PAHs and n-alkanes were recorded in the sixth ring road, with the lowest ones in the third ring road. Concentrations of PAHs during haze were higher than during non-haze conditions, while concentrations of n-alkanes were not markedly different. Principal component analysis/multiple linear regression analyses indicated that the main sources of PAHs were vehicle and coal combustion emissions, while n-alkanes had high contributions from petroleum emissions. These sources were supported by isotopic analyses. Thus, the main sources of organic matter contributing to haze in Beijing were coal combustion and vehicle emissions. Such results provide guidance towards managing haze in Beijing.

  4. Chemical characteristics and source of size-fractionated atmospheric particle in haze episode in Beijing

    Science.gov (United States)

    Tan, Jihua; Duan, Jingchun; Zhen, Naijia; He, Kebin; Hao, Jiming

    2016-01-01

    The abundance, behavior, and source of chemical species in size-fractionated atmospheric particle were studied with a 13-stage low pressure impactor (ELPI) during high polluted winter episode in Beijing. Thirty three elements (Al, Ca, Fe, K, Mg, Na, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, and Pb) and eight water soluble ions (Cl-, NO3-, SO42 -, NH4+, Na+, K+, Ca2 +, and Mg2 +) were determined by ICP/MS and IC, respectively. The size distribution of TC (OC + EC) was reconstructed. Averagely, 51.5 ± 5.3% and 74.1 ± 3.7% of the total aerosol mass was distributed in the sub-micron (PM1) and fine particle (PM2.5), respectively. A significant shift to larger fractions during heavy pollution episode was observed for aerosol mass, NH4+, SO42 -, NO3-, K, Fe, Cu, Zn, Cd, and Pb. The mass size distributions of NH4+, SO42 -, NO3-, and K were dominated by accumulation mode. Size distributions of elements were classified into four main types: (I) elements were enriched within the accumulation mode (< 1 μm, Ge, Se, Ag, Sn, Sb, Cs, Hg, Ti, and Pb); (II) those mass (K, Cr, Mn, Cu, Zn, As, Mo, and Cd) was resided mainly within the accumulation mode, ranged from 1 to 2 μm; (III) Na, V, Co, Ni, and Ga were distributed among fine, intermediate, and coarse modes; and (IV) those which were mainly found within particles larger than 2.7 μm (Al, Mg, Si, Ca, Sc, Tl, Fe, Sr, Zr, and Ba). [H+]cor showed an accumulation mode at 600-700 nm and the role of Ca2 + should be fully considered in the estimation of acidity. The acidity in accumulation mode particles suggested that generally gaseous NH3 was not enough to neutralize sulfate completely. PMF method was applied for source apportionment of elements combined with water soluble ions. Dust, vehicle, aged coal combustion, and sea salt were identified, and the size resolved source apportionments were discussed. Aged coal combustion was the important source of fine particles and

  5. A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion.

    Science.gov (United States)

    Sing, David K; Fortney, Jonathan J; Nikolov, Nikolay; Wakeford, Hannah R; Kataria, Tiffany; Evans, Thomas M; Aigrain, Suzanne; Ballester, Gilda E; Burrows, Adam S; Deming, Drake; Désert, Jean-Michel; Gibson, Neale P; Henry, Gregory W; Huitson, Catherine M; Knutson, Heather A; des Etangs, Alain Lecavelier; Pont, Frederic; Showman, Adam P; Vidal-Madjar, Alfred; Williamson, Michael H; Wilson, Paul A

    2016-01-07

    Thousands of transiting exoplanets have been discovered, but spectral analysis of their atmospheres has so far been dominated by a small number of exoplanets and data spanning relatively narrow wavelength ranges (such as 1.1-1.7 micrometres). Recent studies show that some hot-Jupiter exoplanets have much weaker water absorption features in their near-infrared spectra than predicted. The low amplitude of water signatures could be explained by very low water abundances, which may be a sign that water was depleted in the protoplanetary disk at the planet's formation location, but it is unclear whether this level of depletion can actually occur. Alternatively, these weak signals could be the result of obscuration by clouds or hazes, as found in some optical spectra. Here we report results from a comparative study of ten hot Jupiters covering the wavelength range 0.3-5 micrometres, which allows us to resolve both the optical scattering and infrared molecular absorption spectroscopically. Our results reveal a diverse group of hot Jupiters that exhibit a continuum from clear to cloudy atmospheres. We find that the difference between the planetary radius measured at optical and infrared wavelengths is an effective metric for distinguishing different atmosphere types. The difference correlates with the spectral strength of water, so that strong water absorption lines are seen in clear-atmosphere planets and the weakest features are associated with clouds and hazes. This result strongly suggests that primordial water depletion during formation is unlikely and that clouds and hazes are the cause of weaker spectral signatures.

  6. SVOC emissions from diesel trucks operating of biodiesel fuels

    Science.gov (United States)

    The U.S. currently produces roughly 5 billion liters of biodiesel per year. Use of biodiesel is projected to increase based on its potential economic, energy, and environmental benefits. Despite these benefits, there is public health concern about the possible direct and indirect...

  7. Ion balance and acidity of size-segregated particles during haze episodes in urban Beijing

    Science.gov (United States)

    Tian, Shili; Pan, Yuepeng; Wang, Yuesi

    2018-03-01

    In this study, we investigated how the ion balance causes variations in size segregated aerosol acidity and atmospheric processing on clean versus hazy days using a 9-stage sampler. We calculated the ratios (in charge equivalents, RC/A) between measured cations (Na+, NH4+, K+, Mg2 +, and Ca2 +) and anions (SO42 -, NO3- and Cl-) for different aerosol size fractions. The ratios were typically close to unity in the accumulation mode (0.65-2.1 μm), and increased significantly when the particle size increased or decreased. In the coarse size range (aerodynamic diameter > 2.1 μm), high RC/A values were most likely caused by the undetermined CO32- and HCO3- content of the mineral dust. In contrast, the high RC/A values for submicron aerosols (< 1.1 μm) were likely caused by the presence of water-soluble organic anions. The RC/A values for all size fractions were lower on hazy days than clean days, indicating that aerosol acidity was enhanced on polluted days. Simiar temporal trend between RC/A and in-situ pH indicated that RC/A was a good indicator of aerosol acidity in fine mode aerosol. The SO42 - and NO3- contents in fine particles were completely neutralized as the RC/A values for PM2.1 approached unity, and mean values of RC/A were 1.34 and 1.16 during the transition and polluted periods, respectively. The lowest RC/A values were observed in the size fraction with the highest concentrations of SO42 -, NO3- and NH4+ (SNA) and concentrations of SNA increased with the increasing aerosol acidity. Significant correlations between [NO3-]/[SO42 -] and [NH4+]/[SO42 -] during NH4+-rich conditions in fine size fractions indicated fine mode NO3- in Beijing was mainly formed by gas-phase homogeneous reaction between the ambient NH3 and HNO3.

  8. Highly transparent conductive electrode with ultra-low HAZE by grain boundary modification of aqueous solution fabricated alumina-doped zinc oxide nanocrystals

    Directory of Open Access Journals (Sweden)

    Qiong Nian

    2015-06-01

    Full Text Available Commercial production of transparent conducting oxide (TCO polycrystalline films requires high electrical conductivity with minimal degradation in optical transparency. Aqueous solution deposited TCO films would reduce production costs of TCO films but suffer from low electrical mobility, which severely degrades both electrical conductivity and optical transparency in the visible spectrum. Here, we demonstrated that grain boundary modification by ultra-violet laser crystallization (UVLC of solution deposited aluminium-doped zinc oxide (AZO nanocrystals results in high Hall mobility, with a corresponding dramatic improvement in AZO electrical conductance. The AZO films after laser irradiation exhibit electrical mobility up to 18.1 cm2 V−1 s−1 with corresponding electrical resistivity and sheet resistances as low as 1 × 10−3 Ω cm and 75 Ω/sq, respectively. The high mobility also enabled a high transmittance (T of 88%-96% at 550 nm for the UVLC films. In addition, HAZE measurement shows AZO film scattering transmittance as low as 1.8%, which is superior over most other solution deposited transparent electrode alternatives such as silver nanowires. Thus, AZO films produced by the UVLC technique have a combined figure of merit for electrical conductivity, optical transparency, and optical HAZE higher than other solution based deposition techniques and comparable to vacuumed based deposition methods.

  9. The Impacts of Different PBL Schemes on the Simulation of PM2.5 during Severe Haze Episodes in the Jing-Jin-Ji Region and Its Surroundings in China

    Directory of Open Access Journals (Sweden)

    Tian Li

    2016-01-01

    Full Text Available In this study, three schemes [Yonsei University (YSU, Mellor-Yamada-Janjic (MYJ, and Bougeault-Lacarrère (Boulac] were employed in the Weather Research and Forecasting/Chemistry (WRF-Chem model to simulate the severe haze that occurred in February 2014 in the Jing-Jin-Ji region and its surroundings. The PM2.5 concentration simulated using the three schemes, together with the meteorological factors closely related to PM2.5 (wind speed, local vertical diffusivity, and PBL height, was evaluated through comparison with observations. The results indicated that the eastern plain cities produced better simulation results than the western cities, and the cities under the eastern root of Taihang Mountain produced the worst results in simulating high PM2.5 concentration in haze. All three schemes simulated very similar variation trends of the surface PM2.5 concentration compared with observations. The diurnal variations of simulated surface PM2.5 were not as reasonable as their reflection of daily averaged variation. The simulated concentrations of surface PM2.5 using the YSU, MYJ, and Boulac schemes all showed large negative errors during daytime in polluted days due to their inefficient descriptions of local atmospheric stability or diffusion processes in haze. The lower ability of PBL schemes in distinguishing the diffusion between haze and clean days in the complex topography areas in China is an important problem for PM2.5 forecasting, which is worthy of being studied in detail.

  10. Significant concentration changes of chemical components of PM1 in the Yangtze River Delta area of China and the implications for the formation mechanism of heavy haze-fog pollution.

    Science.gov (United States)

    Zhang, Y W; Zhang, X Y; Zhang, Y M; Shen, X J; Sun, J Y; Ma, Q L; Yu, X M; Zhu, J L; Zhang, L; Che, H C

    2015-12-15

    Since the winter season of 2013, a number of persistent haze-fog events have occurred in central-eastern China. Continuous measurements of the chemical and physical properties of PM1 at a regional background station in the Yangtze River Delta area of China from 16 Nov. to 18 Dec., 2013 revealed several haze-fog events, among which a heavy haze-fog event occurred between 6 Dec. and 8 Dec. The mean concentration of PM1 was 212μgm(-3) in the heavy haze-fog period, which was about 10 times higher than on clean days and featured a peak mass concentration that reached 298μgm(-3). Organics were the largest contributor to the dramatic rise of PM1 on heavy haze-fog days (average mass concentration of 86μgm(-3)), followed by nitrate (58μgm(-3)), sulfate (35μgm(-3)), ammonium (29μgm(-3)), and chloride (4.0μgm(-3)). Nitrate exhibited the largest increase (~20 factors), associated with a significant increase in NOx. This was mainly attributable to increased coal combustion emissions, relative to motor vehicle emissions, and was caused by short-distance pollutant transport within surrounding areas. Low-volatility oxidized organic aerosols (OA) (LV-OOA) and biomass-burning OA (BBOA) also increased sharply on heavy haze-fog days, exhibiting an enhanced oxidation capacity of the atmosphere and increased emissions from biomass burning. The strengthening of the oxidation capacity during the heavy pollution episode, along with lower solar radiation, was probably due to increased biomass burning, which were important precursors of O3. The prevailing meteorological conditions, including low wind and high relative humidity, and short distance transported gaseous and particulate matter surrounding of the sampling site, coincided with the increased pollutant concentrations mainly from biomass-burning mentioned above to cause the persistent haze-fog event in the YRD area. Copyright © 2015. Published by Elsevier B.V.

  11. Water mobility in the endosperm of high beta-glucan barley mutants as studied by nuclear magnetic resonance imaging

    DEFF Research Database (Denmark)

    Seefeldt, Helene Fast; van den Berg, Frans W.J.; Köckenberger, Walter

    2007-01-01

    where it leads to clotting of filters and hazing of beer as well as in animal feed where it hinders the rapid uptake of energy. However, a high content of BG has a positive nutritional effect, as it lowers the cholesterol and the glycaemic index. It was studied whether water distribution and mobility...... the seeds. A principal component analysis (PCA) discriminated control seeds from the high-BG mutant seeds. MRI proved efficient in tracing the differences in water-holding capacity of contrasting barley seeds. All accessions showed nonuniform distribution of water at full hydration as well as during...

  12. Real-time aerosol optical properties, morphology and mixing states under clear, haze and fog episodes in the summer of urban Beijing

    Science.gov (United States)

    Li, Rui; Hu, Yunjie; Li, Ling; Fu, Hongbo; Chen, Jianmin

    2017-04-01

    Elucidating the relationship between characteristics of aerosol particles and optical absorption is important to deepen the understanding of atmospheric chemistry. Aerosol particles play significant roles in climate forcing via their optical absorption properties. However, the relationship between characteristics of aerosol particles and optical absorption remains poorly understood. Aerosol optical properties and morphologies were measured by a transmission electron microscope (TEM), cavity ring-down spectrometer (CRDS), a nephelometer and an Aethalometer in a urban site of Beijing from 24 May to 22 June. Five episodes were categorized according to the meteorological conditions and composition. The results showed that the clear episode (EP-2 and EP-4) featured as the low aerosol optical depth (AOD = 0.72) and fewer pollutants compared with haze (1.14) and fog (2.92) episodes and the particles are mostly externally mixed. The high Ångström exponent (> 2.0) suggests that coarse particles were scarcely observed in EP-2 due to the washout of a previous heavy rain, whereas they were widespread in EP-4 (Ångström exponent = 0.04), which had some mineral particles introduced from the north. In contrast, industry-induced haze (EP-1) and biomass-burning-induced haze (EP-5) were both affected by the south air mass. Compared with the EP-2 and EP-4, the AOD values and the size distribution of particles during EP-1 and EP-5 were much greater because of relatively high particle concentrations. All of the particles were classified into nine categories, i.e. S-rich, N-rich, mineral, K-rich, soot, tar ball, organic, metal and fly ash, on the basis of TEM analysis. In contrast to the EP-1, a large fraction of soot, which sticks to KCl, sulfate or nitrate particles, was detected during EP-5. Additionally, evident enhancement of light absorption was observed during the EP-5, which was mainly ascribed to both black carbon (BC) acceleration and other absorbing substances. However

  13. [Application of ICP-MS and ICP-AES for Studying on Source Apportionment of PM2.5 during Haze Weather in Urban Beijing].

    Science.gov (United States)

    Chen, Xi; Du, Peng; Guan, Qing; Feng, Xu; Xu, Dong-qun; Lin, Shao-bin

    2015-06-01

    To investigate the characteristics of chemical constitute and pollution sources of aerosol fine particulate matter during haze-fog day in Beijing in winter 2013. The samples of PM2.5 were collected in Beijing from January to February, 2013. The technique of ICP-MS and ICP-AES coupled with procedure of bathing-ultrasonic extraction was applied to determine the concentration of 40 elements in the aerosol samples to analyze the characteristics of elements distribution statistically. The absolute principal factor method was used to apportion the pollution sources of PM2.5 during the haze weather in Beijing city in winter 2013. The results showed that during the period of sampling, the volume concentration of Li, Mn, Pb, S etc. obeyed normal distribution approximately, and according to National Ambient Air Quality Standard issued by Ministry of Environmental Protection of the People's Republic of China, the geometric mean concentration of As was twice the annual limit of standard reference, while Pb of some aerosol samples beyond the annual limit of standard reference respectively. The mass fraction of Fe, Zn, Pb, Ti accounted for over 0.1%, while that of Mn, Cu, As, Se etc. 0.01%. These elements were primary inorganic pollutants, and especially the hazards and sources of As and Pb should be concerned. There were 6 main pollution sources were chosen by the factor analysis method, including industrial dust and human beings activities, biomass combustion and building dust, soil and sand dusts, fossil fuel, electronic waste and metal smelting, with the variance contribution rate of 40.3%, 27.0%, 9.1%, 4.9%, 4.8% and 4.6% respectively. ICP-MS and ICP-AES can be applied to analyzing multi-elements in PM2.5 accurately and quickly to facilitate source apportionment, and it indicated that the relevant pollution sources should be considered and the effect of regional transferring of haze pollution sources should be taken into account, and specific measures should be taken for

  14. Indonesia's Fires and Haze

    International Development Research Centre (IDRC) Digital Library (Canada)

    The fires were exacerbated by the droughts induced in many parts of the world by the most severe El Niño event ever recorded. (The increasing severity and frequency of the El Niño is thought by some climate experts to be a consequence of global warming, itself the cumulative result of human activities that release carbon ...

  15. Seeing through the haze

    Science.gov (United States)

    Bowman, D.; Lambert, A.; Fraser, D.; Swierkowski, L.

    2008-11-01

    Methods to correct for atmospheric degradation of imagery and improve the "seeing" of a telescope are well known in astronomy but, to date, have rarely been applied to more earthly matters such as surveillance. The intrinsically more complicated visual fields, the dominance of low-altitude distortion effects, the requirement to process large volumes of data in near real-time, the inability to pre-select ideal sites and the desirability of ruggedness and portability all combine to pose a significant challenge. Field Programmable Gate Array (FPGA) technology has advanced to the point where modern devices contain hundreds of thousands of logic gates, multiple "hard" processors and multi-gigabit serial communication links. Such devices present an ideal platform to tackle the demands of surveillance image processing. We report a rugged, lightweight system which allows multiple FPGA "modules" to be added together in order to quickly and easily reallocate computing resources. The devices communicate via 2.5Gbps serial links and process image data in a streaming fashion, reducing as much data as possible on-the-fly in order to present a minimised load to storage and/or communication devices. To maximise the benefit of such a system we have devised an open protocol for FPGA-based image processing called "OpenStream". This allows image processing cores to be quickly and easily added into or removed from the data stream and harnesses the benefits of code-reuse and standardisation. It further allows image processing tasks to be easily partitioned across multiple, heterogeneous FPGA domains and permits a designer the flexibility to allocate cores to the most appropriate FPGA. OpenStream is the infrastructure to facilitate rapid, graphical, development of FPGA based image processing algorithms especially when they must be partitioned across multiple FPGAs. Ultimately it will provide a means to automatically allocate and connect resources across FPGA domains in a manner analogous to the way logic synthesis tools allocate and connect resources within an FPGA.

  16. Transmission spectroscopy of HAT-P-32b with the LBT: confirmation of clouds/hazes in the planetary atmosphere

    Science.gov (United States)

    Mallonn, M.; Strassmeier, K. G.

    2016-05-01

    Aims: Spectroscopic observations of a transit event of an extrasolar planet offer the opportunity to study the composition of the planetary atmosphere. This can be done with comparably little telescope time using a low-resolution multi-object spectrograph at a large aperture telescope. We observed a transit of the inflated hot Jupiter HAT-P-32b with the Multi-Object Double Spectrograph at the Large Binocular Telescope to characterize its atmosphere from 3300 to 10 000 Å. Methods: A time series of target and reference star spectra was binned in two broad-band wavelength channels, from which differential transit light curves were constructed. These broad-band light curves were used to confirm previous transit parameter determinations. To derive the planetary transmission spectrum with a resolution of R ~ 60, we created a chromatic set of 62 narrow-band light curves. The spectrum was corrected for the third light of a nearby M star. Additionally, we undertook a photometric monitoring campaign of the host star to correct for the influence of starspots. Results: The transmission spectrum of HAT-P-32b shows no pressure-broadened absorption features from Na and K, which is interpreted by the presence of clouds or hazes in the planetary atmosphere. This result is in agreement with previous studies on the same planet. The presence of TiO in gas phase could be ruled out. We find a 2.8σ indication of increased absorption in the line core of potassium (K I 7699 Å). No narrow absorption features of Na and Hα were detected. Furthermore, tentative indications were found for a slope of increasing opacity toward blue wavelengths from the near-IR to the near-UV with an amplitude of two scale heights. If confirmed by follow-up observations, it can be explained by aerosols either causing Mie scattering or causing Rayleigh scattering with an aerosol - gas scale height ratio below unity. The host star was found to be photometrically stable within the measurement precision. Based on

  17. Statistical Estimation of Dose-response Functions of Respiratory Diseases and Societal Costs of Haze-related Air Pollution in Brunei Darussalam

    Science.gov (United States)

    Anaman, K. A.; Ibrahim, N.

    - The effects on human health resulting from the January to April 1998 haze-related air pollution episode in Brunei Darussalam were analysed for five groups of diseases of the respiratory system. The analysis concentrated on the statistical estimation of dose-response functions which related the number of cases of respiratory diseases to the level of quality of ambient environment as measured by the pollutants standards index (PSI) and other environmental variables. The total number of cases of the five groups of diseases was shown to be significantly related to PSI and temperature. Societal costs were also estimated. The results showed that societal costs were significantly related to PSI, temperature and relative humidity. Societal costs increased with higher PSI and relative humidity but decreased with increasing temperature.

  18. Morphology and chemical characteristics of micro- and Nano-particles in the haze in Beijing studied by XPS and TEM/EDX

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Peng [Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, and Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190 (China); Xu, Jianxun; He, Meng [CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190 (China); Song, Lexin [Department of Chemistry, University of Science and Technology of China, Hefei, 230026 (China); Chen, Dongliang, E-mail: chendl@mail.buct.edu.cn [College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Guo, Guangsheng, E-mail: guogs@bjut.edu.cn [Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, and Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Dai, Hongxing, E-mail: hxdai@bjut.edu.cn [Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, and Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

    2016-09-15

    X-ray Photoelectron Spectroscopy (XPS) is a useful surface sensitive tool to explore the particulate matter with different particle sizes. In this work, we report the analysis of elemental species in particulate matter with size ranging from 100 nm to 10 μm during the autumn haze of 2014 in Beijing. The size dependence of element composition and chemical state distribution on the particle surface was investigated. It was found that the number of investigated element species decreased from 8 (at stage 2) to 4 (at stage 10) with the decrease of particle sizes down to 100 nm, which is in accordance with the result from Transmission electron microscopy (TEM/EDX) observations. Three chemical states of nitrogen, the amide group (399.9 eV), the ammonium group (401.6 eV), and the nitrate group (407.2 eV), were confirmed according to the different binding energies. Nitrate was the main composition on the coarse particles, while the percentage of amide and ammonium at stage 3 (13.9% and 10.8% respectively) increased on the fine particles at stage 9 (46.8% and 38.8% respectively). The relative ratio of sulfate and ammonium (calculated 1:1) in the fine particles suggests that there is no enough NH{sub 4}{sup +} to neutralize the sulfuric acid and the surface of the PM is acidic. The result is useful to investigate the generation processes and the sources of collected particles. - Highlights: • The element composition of particles from 100 nm to 10 μm in haze was discussed • The chemical state was dominated by the particle size • The surface of PM was acidity • XPS was shown a useful tool in the aerosol research.

  19. Characterization of Soluble Organics in Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, D.T.

    2002-01-16

    Soluble organics in produced water and refinery effluents represent treatment problems for the petroleum industry. Neither the chemistry involved in the production of soluble organics nor the impact of these chemicals on total effluent toxicity is well understood. The U.S. Department of Energy provides funding for Oak Ridge National Laboratory (ORNL) to support a collaborative project with Shell, Chevron, Phillips, and Statoil entitled ''Petroleum and Environmental Research Forum project (PERF 9844: Manage Water-Soluble Organics in Produced Water''). The goal of this project, which involves characterization and evaluation of these water-soluble compounds, is aimed at reducing the future production of such contaminants. To determine the effect that various drilling conditions might have on water-soluble organics (WSO) content in produced water, a simulated brine water containing the principal inorganic components normally found in Gulf of Mexico (GOM) brine sources was prepared. The GOM simulant was then contacted with as-received crude oil from a deep well site to study the effects of water cut, produced-water pH, salinity, pressure, temperature, and crude oil sources on the type and content of the WSO in produced water. The identities of individual semivolatile organic compounds (SVOCs) were determined in all as-received crude and actual produced water samples using standard USEPA Method (8270C) protocol. These analyses were supplemented with the more general measurements of total petroleum hydrocarbon (TPH) content in the gas (C{sub 6}-C{sub 10}), diesel (C{sub 10}-C{sub 20}), and oil (C{sub 20}-C{sub 28}) carbon ranges as determined by both gas chromatographic (GC) and infrared (IR) analyses. An open liquid chromatographic procedure was also used to differentiate the saturated hydrocarbon, aromatic hydrocarbon, and polar components within the extractable TPH. Inorganic constituents in the produced water were analyzed by ion

  20. Sulfate Formation Enhanced by a Cocktail of High NOx, SO2, Particulate Matter, and Droplet pH during Haze-Fog Events in Megacities in China: An Observation-Based Modeling Investigation.

    Science.gov (United States)

    Xue, Jian; Yuan, Zibing; Griffith, Stephen M; Yu, Xin; Lau, Alexis K H; Yu, Jian Zhen

    2016-07-19

    In recent years in a few Chinese megacities, fog events lasting one to a few days have been frequently associated with high levels of aerosol loading characterized by high sulfate (as high as 30 μg m(-3)), therefore termed as haze-fog events. The concomitant pollution characteristics include high gas-phase mixing ratios of SO2 (up to 71 ppbv) and NO2 (up to 69 ppbv), high aqueous phase pH (5-6), and smaller fog droplets (as low as 2 μm), resulting from intense emissions from fossil fuel combustion and construction activities supplying abundant Ca(2+). In this work, we use an observation-based model for secondary inorganic aerosols (OBM-SIA) to simulate sulfate formation pathways under conditions of haze-fog events encountered in Chinese megacities. The OBM analysis has identified, at a typical haze-fogwater pH of 5.6, the most important pathway to be oxidation of S(IV) by dissolved NO2, followed by the heterogeneous reaction of SO2 on the aerosol surface. The aqueous phase oxidation of S(IV) by H2O2 is a very minor formation pathway as a result of the high NOx conditions suppressing H2O2 formation. The model results indicate that the unique cocktail of high fogwater pH, high concentrations of NO2, SO2, and PM, and small fog droplets are capable of greatly enhancing sulfate formation. Such haze-fog conditions could lead to rapid sulfate production at night and subsequently high PM2.5 in the morning when the fog evaporates. Sulfate formation is simulated to be highly sensitive to fogwater pH, PM, and precursor gases NO2 and SO2. Such insights on major contributing factors imply that reduction of road dust and NOx emissions could lessen PM2.5 loadings in Chinese megacities during fog events.

  1. A CRITICAL REVIEW AND EVALUATION OF APPLYING SEMI-VOLATILE ORGANIC COMPOUNDS (SVOCS AS A GEOCHEMICAL TRACER TO INDICATE TSUNAMI BACKWASH: The Bilateral, Deutsche Forschungsgemeinschaft (DFG and National Research Council of Thailand (NRCT Funded Project “Tsunami Deposits in Near-Shore- and Coastal Waters of Thailand (TUNWAT”

    Directory of Open Access Journals (Sweden)

    Siwatt Pongpiachan

    2013-10-01

    Full Text Available Tsunamis symbolize one of the most harmful natural disasters for low-lying coastal zones and their residents, due to both its destructive power and irregularity. The 2004 Boxing Day tsunami, which attack the Andaman Sea coast of Thailand, resulted 5,395 of deaths and inestimable casualties, interrupted economies and social well-being in numerous coastal villages and caused in extreme alterations of both onshore and offshore coastal morphology. The Great Indian Ocean tsunami also highlighted that there are many missing jigsaw puzzle pieces in scientific knowledge, starting from the generating of tsunamis offshore to the countless influences to the marine ecosystems on the continental shelf, coastal areas and on land and to the economic and social systems consequences. As with all deposits that do not have a direct physical link to their causative sources, marine tsunami deposits must be distinguished from other deposits through regional correlation, dating and criteria for recognition within the deposits themselves. This study aims to provide comprehensive reviews on using Polycyclic Aromatic Hydrocarbons (PAHs as a chemical proxy to discriminate tsunami relateddeposits from typical marine sediments. The advantages and disadvantages of this chemical tracer will be critically reviewed and further discussed.

  2. The association of weather patterns with haze episodes: Recognition by PM2.5 oriented circulation classification applied in Xiamen, Southeastern China

    Science.gov (United States)

    Chang, Wenyuan; Zhan, Jianqiong

    2017-11-01

    Investigating the association between weather circulation patterns and high PM2.5 episodes is useful for interpreting the connection between physical weather and chemical weather. Principal component analysis (PCA) is often applied to decompose circulation modes but has limitations for studying high PM2.5 events related circulation patterns. This study describes an improved circulation classification integrated with PCA and k-means algorithm oriented to high local PM2.5. The classification scheme was applied in Xiamen, southeastern China, when local PM2.5 exceeded 75 μg m- 3 (the 24-hour limit Chinese Ambient Air Quality Grade II standard) during the winter 2013. Nine typical circulation patterns were classified. Circulation patterns related to the highest PM2.5 concentrations were associated with a negative pressure anomaly at 850 hPa over the Sea of Japan which yielded a strong transport of PM2.5 from northern China during windy days. The improved classification methodology links large-scale circulation to local PM2.5 in target city and is able to distinguish possibly different circulation patterns over continual haze episodes. This clustering method can be applied in any cities and would be useful for predicting chemical weather and serving local environmental policymakers.

  3. Fossil Fuel Combustion-Related Emissions Dominate Atmospheric Ammonia Sources during Severe Haze Episodes: Evidence from 15N-Stable Isotope in Size-Resolved Aerosol Ammonium

    Science.gov (United States)

    Pan, Y.; Tian, S.; Liu, D.; Fang, Y.; Zhu, X.; Zhang, Q.; Zheng, B.; Michalski, G. M.; Wang, Y.

    2016-12-01

    The reduction of ammonia (NH3) emissions is urgently needed due to its major contributions to nitrogen deposition and particle pollution. However, the relative contributions of individual NH3 sources are unclear, and debate remains over whether agricultural emissions dominate atmospheric NH3 in urban areas. Based on the chemical and isotopic measurements of size-resolved aerosols in urban Beijing, China, we find that the natural abundance of 15N (expressed using δ15N values) of ammonium (NH4+) in fine particles varies with the development of haze episodes, ranging from -37.1‰ to -21.7‰ during clean/dusty days (relative humidity: ˜ 40%), to -13.1‰ to +5.8‰ during hazy days (relative humidity: 70-90%). After factoring the isotope exchange between NH3 gas and aerosol NH4+, the δ15N value of the initial NH3 during hazy days is found to be -14.5‰ to -1.6‰, which indicates fossil fuel-based emissions. These emissions contribute 90% of the total NH3 during hazy days in urban Beijing. This work demonstrates the analysis of δ15N values of aerosol NH4+ to be a promising new tool for partitioning atmospheric NH3 sources, providing policy makers with insights into NH3 emissions and secondary aerosols for regulation in urban environments. This work also shed lights on the sources of nitrogen deposition in downwind ecosystems.

  4. Anthocyanin composition of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) cultivars Antonina, Beta Sweet, Deep Purple, and Purple Haze.

    Science.gov (United States)

    Montilla, Elyana Cuevas; Arzaba, Miriam Rodriguez; Hillebrand, Silke; Winterhalter, Peter

    2011-04-13

    This study aimed to identify the pigment composition of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) cultivars Antonina, Beta Sweet, Deep Purple, and Purple Haze. Cyanidin 3-xylosyl(glucosyl)galactosides acylated with sinapic acid, ferulic acid, and coumaric acid were detected as major anthocyanins by high-performance liquid chromatography with diode array detection (HPLC-DAD) and with electrospray ionization multiple mass spectrometry (HPLC-ESI-MS(n)) analyses. The preparative isolation of these pigments was carried out by means of high-speed countercurrent chromatography (HSCCC). The color activity concept was applied to the isolated anthocyanins at three pH values. Cyanidin 3-xylosyl(sinapoylglucosyl)galactoside was found to exhibit a lower visual detection threshold and a higher pH stability than cyanidin 3-xylosyl(feruloylglucosyl)galactoside and cyanidin 3-xylosyl(coumaroylglucosyl)galactoside. The color parameters of the fresh roots of the four cultivars were described by the CIELab coordinates L* (lightness), C* (chroma), and h(ab) (hue angles). Total phenolics varied among the cultivars and ranged from 17.9 to 97.9 mg gallic acid equivalents (GAE)/100 g fresh weight (fw). For the content of monomeric anthocyanins, values between 1.5 and 17.7 mg/100 g fw were determined.

  5. Attributions of meteorological and emission factors to the 2015 winter severe haze pollution episodes in China's Jing-Jin-Ji area

    Science.gov (United States)

    Liu, Tingting; Gong, Sunling; He, Jianjun; Yu, Meng; Wang, Qifeng; Li, Huairui; Liu, Wei; Zhang, Jie; Li, Lei; Wang, Xuguan; Li, Shuli; Lu, Yanli; Du, Haitao; Wang, Yaqiang; Zhou, Chunhong; Liu, Hongli; Zhao, Qichao

    2017-02-01

    In the 2015 winter month of December, northern China witnessed the most severe air pollution phenomena since the 2013 winter haze events occurred. This triggered the first-ever red alert in the air pollution control history of Beijing, with an instantaneous fine particulate matter (PM2. 5) concentration over 1 mg m-3. Air quality observations reveal large temporal-spatial variations in PM2. 5 concentrations over the Beijing-Tianjin-Hebei (Jing-Jin-Ji) area between 2014 and 2015. Compared to 2014, the PM2. 5 concentrations over the area decreased significantly in all months except November and December of 2015, with an increase of 36 % in December. Analysis shows that the PM2. 5 concentrations are significantly correlated with the local meteorological parameters in the Jing-Jin-Ji area such as the stable conditions, relative humidity (RH), and wind field. A comparison of two month simulations (December 2014 and 2015) with the same emission data was performed to explore and quantify the meteorological impacts on the PM2. 5 over the Jing-Jin-Ji area. Observation and modeling results show that the worsening meteorological conditions are the main reasons behind this unusual increase of air pollutant concentrations and that the emission control measures taken during this period of time have contributed to mitigate the air pollution ( ˜ 9 %) in the region. This work provides a scientific insight into the emission control measures vs. the meteorology impacts for the period.

  6. JUPITER AS AN EXOPLANET: UV TO NIR TRANSMISSION SPECTRUM REVEALS HAZES, A Na LAYER, AND POSSIBLY STRATOSPHERIC H{sub 2}O-ICE CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Montañés-Rodríguez, Pilar; González-Merino, B.; Pallé, E. [Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, E-38200 La Laguna (Spain); López-Puertas, Manuel [Departamento de Astrofísica, Universidad de La Laguna, Av., Astrofísico Francisco Sánchez, s/n, E-38206 La Laguna (Spain); García-Melendo, E., E-mail: pmr@iac.es [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, E-18080 Granada (Spain)

    2015-03-01

    Currently, the analysis of transmission spectra is the most successful technique to probe the chemical composition of exoplanet atmospheres. However, the accuracy of these measurements is constrained by observational limitations and the diversity of possible atmospheric compositions. Here, we show the UV–VIS–IR transmission spectrum of Jupiter as if it were a transiting exoplanet, obtained by observing one of its satellites, Ganymede, while passing through Jupiter’s shadow, i.e., during a solar eclipse from Ganymede. The spectrum shows strong extinction due to the presence of clouds (aerosols) and haze in the atmosphere and strong absorption features from CH{sub 4}. More interestingly, the comparison with radiative transfer models reveals a spectral signature, which we attribute here to a Jupiter stratospheric layer of crystalline H{sub 2}O ice. The atomic transitions of Na are also present. These results are relevant for the modeling and interpretation of giant transiting exoplanets. They also open a new technique to explore the atmospheric composition of the upper layers of Jupiter’s atmosphere.

  7. Water, Water Everywhere

    Science.gov (United States)

    Keeler, Rusty

    2009-01-01

    Everybody knows that children love water and how great water play is for children. The author discusses ways to add water to one's playscape that fully comply with health and safety regulations and are still fun for children. He stresses the importance of creating water play that provides children with the opportunity to interact with water.

  8. Public health impacts of the severe haze in Equatorial Asia in September-October 2015: demonstration of a new framework for informing fire management strategies to reduce downwind smoke exposure

    Science.gov (United States)

    Koplitz, Shannon N.; Mickley, Loretta J.; Marlier, Miriam E.; Buonocore, Jonathan J.; Kim, Patrick S.; Liu, Tianjia; Sulprizio, Melissa P.; DeFries, Ruth S.; Jacob, Daniel J.; Schwartz, Joel; Pongsiri, Montira; Myers, Samuel S.

    2016-09-01

    In September-October 2015, El Niño and positive Indian Ocean Dipole conditions set the stage for massive fires in Sumatra and Kalimantan (Indonesian Borneo), leading to persistently hazardous levels of smoke pollution across much of Equatorial Asia. Here we quantify the emission sources and health impacts of this haze episode and compare the sources and impacts to an event of similar magnitude occurring under similar meteorological conditions in September-October 2006. Using the adjoint of the GEOS-Chem chemical transport model, we first calculate the influence of potential fire emissions across the domain on smoke concentrations in three receptor areas downwind—Indonesia, Malaysia, and Singapore—during the 2006 event. This step maps the sensitivity of each receptor to fire emissions in each grid cell upwind. We then combine these sensitivities with 2006 and 2015 fire emission inventories from the Global Fire Assimilation System (GFAS) to estimate the resulting population-weighted smoke exposure. This method, which assumes similar smoke transport pathways in 2006 and 2015, allows near real-time assessment of smoke pollution exposure, and therefore the consequent morbidity and premature mortality, due to severe haze. Our approach also provides rapid assessment of the relative contribution of fire emissions generated in a specific province to smoke-related health impacts in the receptor areas. We estimate that haze in 2015 resulted in 100 300 excess deaths across Indonesia, Malaysia and Singapore, more than double those of the 2006 event, with much of the increase due to fires in Indonesia’s South Sumatra Province. The model framework we introduce in this study can rapidly identify those areas where land use management to reduce and/or avoid fires would yield the greatest benefit to human health, both nationally and regionally.

  9. Modeling study of source contributions and emergency control effects during a severe haze episode over the Beijing-Tianjin-Hebei area of China

    Science.gov (United States)

    Chen, Huansheng; Li, Jie; Ge, Baozhu; Yang, Wenyi; Wang, Zifa

    2017-04-01

    In February 2014, the Beijing-Tianjin-Hebei (BTH) area of China experienced a weeklong episode of heavy haze pollution. Cities such as Beijing (BJ) and Shijiazhuang (SJZ) issued heavy pollution alerts for the first time in the history and took emergency control measures. This study employed the Nested Air Quality Prediction Modeling System (NAQPMS) to simulate and analyze the three dimensional structure of the source contributions of PM2.5 in the BTH area during this pollution episode and quantitatively assess the effects of the emergency control measures. The results showed that during the polluted period (19-26th), surface PM2.5 mainly came from local sources (48-72%). In the whole BTH area, southern Hebei (SHB) represented the largest internal contribution (33%), while the main external contributions came from Shandong (SD) (10%) and Henan (HN) (4%). Vertically, the local contribution was constrained below near-ground layer, and rapidly decreased with altitude. The regional transport path from SHB and Shanxi (SX) to BJ appeared in 0.5-1.5 km and 1.5-2.5 km, with contribution of 32-42% and 13-27%, respectively. The non-local source regions for the BTH area were SD below 1 km and mainly SX and HN above 1 km. Compared to the non-polluted period (27-28th), the contribution from regional transport increased during the polluted period, which indicated the key role of regional transport in the pollution formation. The emergency control measures had a relatively large effect on NOx and SO2 concentrations, but a limited effect on PM2.5. The stronger regional transport during the polluted period may have weakened the effects of local emergency control measures. These results indicated that coordinated emission control should be implemented not only over the BTH area but also its surrounding provinces (e.g. SD, HN).

  10. Heavy haze episodes in Beijing during January 2013: Inorganic ion chemistry and source analysis using highly time-resolved measurements from an urban site.

    Science.gov (United States)

    Han, Bin; Zhang, Rui; Yang, Wen; Bai, Zhipeng; Ma, Zhiqiang; Zhang, Wenjie

    2016-02-15

    The heavy air pollution that occurred in Beijing in January of 2013 attracted intense attention around the world. During this period, we conducted highly time-resolved measurements of inorganic ions associated with PM2.5 at an urban site of Beijing, and investigated ion chemistry and potential sources. Hourly concentrations of Cl(-), NO3(-), SO4(2-), Na(+), NH4(+), K(+), Mg(2+), and Ca(2+) were measured. Peak concentrations of SO4(2-) and NO3(-) were observed on the 10th-15th, 21st-24th, and the 26th-30th during this monitoring campaign. The percentages of SO4(2-) and NH4(+) in total ion concentration increased with the enhancement of PM2.5 concentrations, indicating that high concentrations of SO4(2-) and NH4(+) may play important roles in the formation of haze episodes. The ratio of [NO3(-)]/[SO4(2-)] was calculated, revealing that the sources of SO4(2-) would contribute more to the formation of PM2.5 than mobile sources. Diurnal variations of SO4(2-), NO3(-), NH4(+) (SNA) exhibited a similar pattern, with high concentrations at night and low levels during the day, revealing that meteorological conditions, such as mixing layer height, relative humidity, were likely to be responsible for high levels of SNA at night. The roles of meteorological conditions were further discussed in the formation of secondary inorganic ions. Relative humidity and temperature played key roles and exhibited positive correlations with secondary inorganic ions. An aerosol inorganics simulation model showed that SNA existed mainly in the aqueous phase during the sampling period. Furthermore, potential sources were identified by applying positive matrix factorization model. Secondary nitrate, secondary sulfate, coal combustion and biomass burning, as well as fugitive dust, were considered to be major contributors to total ions. Copyright © 2015. Published by Elsevier B.V.

  11. Application of VUV-PIMS coupled with GC-MS in chemical characterization, identification and comparative analysis of organic components in both vehicular-derived SOA and haze particles

    Science.gov (United States)

    Zhang, Peng; Ma, Pengkun; Zhang, Haixu; Shu, Jinian; Yang, Bo; Li, Zhen

    2017-09-01

    Gasoline vehicle exhaust is a significant source of volatile organic compounds (VOCs) in megacities. In this study, chemical characterization of secondary aerosol particles from the oxidation of gasoline vehicular exhaust by O3, OH, and NO3 radicals and the airborne aerosol particles collected during a heavy haze episode (23-25 December 2015) in Beijing were elaborately investigated. The secondary organic aerosols (SOAs) collected from the exhaust and airborne aerosol particles were characterized with a newly built vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS) after thermal desorption, and identified by gas chromatography mass spectrometry (GC-MS). The obtained photoionization mass spectra revealed that the SOAs from the oxidation of gasoline vehicular exhaust and airborne aerosol particles possess a series of common characteristic mass peaks at m/z 98, 112, 126, and 140. The components at m/z 98, 112, 126, 140 were further identified to be carbonyl species after PFBHA derivatization followed by GC-MS analyses. The carbonyl species from exhaust SOAs were found to be responsible for 51.7%, 57.5%, 36.3%, and 27.9% of the chemical components in haze particles at m/z 98, 112, 126, and 140, respectively, which indicates that these SOA components from the oxidation of gasoline vehicular exhaust are a major factor that affects the air quality in Beijing. Among the exhaust SOAs, the carbonyl species detected simultaneously in two (P(O3/OH)) or three kinds of exhaust oxidation reactions (P(O3/NO3/OH)) make a significant contributions to these carbonyl species in haze particles (10.6% for m/z 98, 18.3% for m/z 112, 23.4% for m/z 126, and 20.5% for m/z 140). These results implies that the unsaturated VOCs (i.e. alkenes) from exhaust may be one kind of important SOA precursor and that their chemical degradation in the atmosphere may have an important impact on urban air quality in heavy polluted cities such as Beijing, especially during severe winter haze

  12. Column Aerosol Optical Properties and Aerosol Radiative Forcing During a Serious Haze-Fog Month over North China Plain in 2013 Based on Ground-Based Sunphotometer Measurements

    Science.gov (United States)

    Che, H.; Xia, X.; Zhu, J.; Li, Z.; Dubovik, O.; Holben, Brent N.; Goloub, P.; Chen, H.; Estelles, V.; Cuevas-Agullo, E.

    2014-01-01

    In January 2013, North China Plain experienced several serious haze events. Cimel sunphotometer measurements at seven sites over rural, suburban and urban regions of North China Plain from 1 to 30 January 2013 were used to further our understanding of spatial-temporal variation of aerosol optical parameters and aerosol radiative forcing (ARF). It was found that Aerosol Optical Depth at 500 nm (AOD500nm) during non-pollution periods at all stations was lower than 0.30 and increased significantly to greater than 1.00 as pollution events developed. The Angstrom exponent (Alpha) was larger than 0.80 for all stations most of the time. AOD500nm averages increased from north to south during both polluted and non-polluted periods on the three urban sites in Beijing. The fine mode AOD during pollution periods is about a factor of 2.5 times larger than that during the non-pollution period at urban sites but a factor of 5.0 at suburban and rural sites. The fine mode fraction of AOD675nm was higher than 80% for all sites during January 2013. The absorption AOD675nm at rural sites was only about 0.01 during pollution periods, while 0.03-0.07 and 0.01-0.03 during pollution and non-pollution periods at other sites, respectively. Single scattering albedo varied between 0.87 and 0.95 during January 2013 over North China Plain. The size distribution showed an obvious tri-peak pattern during the most serious period. The fine mode effective radius in the pollution period was about 0.01-0.08 microns larger than during nonpollution periods, while the coarse mode radius in pollution periods was about 0.06-0.38 microns less than that during nonpollution periods. The total, fine and coarse mode particle volumes varied by about 0.06-0.34 cu microns, 0.03-0.23 cu microns, and 0.03-0.10 cu microns, respectively, throughout January 2013. During the most intense period (1-16 January), ARF at the surface exceeded -50W/sq m, -180W/sq m, and -200W/sq m at rural, suburban, and urban sites

  13. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    Science.gov (United States)

    Knote, C.; Hodzic, A.; Jimenez, J. L.

    2015-01-01

    The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs) in the gas phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (-40 vs. -8% for anthropogenics, and -52 vs. -11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics). Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm-1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility of SVOCs made in

  14. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    Directory of Open Access Journals (Sweden)

    C. Knote

    2015-01-01

    Full Text Available The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs in the gas phase on the concentrations of secondary organic aerosol (SOA is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (−40 vs. −8% for anthropogenics, and −52 vs. −11% for biogenics. Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics. Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm−1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water

  15. Drinking Water

    Science.gov (United States)

    ... the safest water supplies in the world, but drinking water quality can vary from place to place. It ... water supplier must give you annual reports on drinking water. The reports include where your water came from ...

  16. Water Contamination

    Science.gov (United States)

    ... Statistics Training & Education Policy & Recommendations Fast Facts Healthy Water Sites Healthy Water Drinking Water Healthy Swimming Global ... type=”submit” value=”Submit” /> Healthy Water Home Water Contamination Recommend on Facebook Tweet Share Compartir On ...

  17. Harmattan Haze and Environmental Health

    African Journals Online (AJOL)

    Administrator

    It is the season to cover up. Beginning in November of every year and ending around March, fine particulate matter. (typically 0.5 – 10 micrometers) emanating from the Sahara desert blow south, obscuring vision and laboring breathing for everyone (Figure 1). In addition, the dry dusty winds cause a variety of domestic ...

  18. Arctic Haze: Natural or Pollution?

    Science.gov (United States)

    1980-08-01

    occur in specific minerals which strongly resist weathering. An example would be zircons , which contain zirconium and hafnium . If this is correct, and if...the YMEF in August and September 1980. A summary of Mr. Borys’ field work to date is shown in Table 1. Samples were collected during approximately 10...XRF microprobe. -1.1- Table 1. Summary of field studies of cloud-active aerosol in the Arctic and environs. Site Dates , Number of 24-h samples Barrow

  19. Arctic Haze: Natural or Pollution

    Science.gov (United States)

    1977-09-01

    l’Atlantique. Sur la base de mesures d’opacite’ et du modele de transport propose une estimation de 1’emmxission totale du Sahara est presentee . Finalement...institute. This work took more than 6 months, and represented a considerable cost -free contribution to our project. Methods used were dry sieving and...communications associated with the proposed Arctic Network. The filter samples will cost this project nothing; the aerosol vertical profiles will be

  20. Airborne Multiwavelength High-Spectral-Resolution Lidar (HSRL-2) Observations During TCAP 2012: Vertical Proles of Optical and Microphysical Properties of a Smoke/Urban Haze Plume Over the Northeastern Coast of the US

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Detlef; Hostetler, Chris A.; Ferrare, R. A.; Burton, S. P.; Chemyakin, Eduard; Kolgotin, A.; Hair, John; Cook, A. L.; Harper, David; Rogers, R. R.; Hare, Rich; Cleckner, Craig; Obland, Michael; Tomlinson, Jason M.; Berg, Larry K.; Schmid, Beat

    2014-10-10

    We present rst measurements with the rst airborne multiwavelength High-Spectral Resolution Lidar (HSRL-2), developed by NASA Langley Research Center. The instrument was operated during the Department of Energy (DOE) Two-Column Aerosol Project (TCAP) in July 2012. We observed out ow of urban haze and fresh biomass burning smoke from the East Coast of the US out over the West Atlantic Ocean. Lidar ratios at 355 and 532 nm were ... sr indicating moderately absorbing aerosols. Extinctionrelated Angstrom exponents were 1.5{2 pointing at comparably small particles. Our novel automated, unsupervised data inversion algorithm retrieves particle e*ective radii of approximately 0.2 *m, which is in agreement with the large Angstrom exponents. We nd reasonable agreement to particle size parameters obtained from situ measurements carried out with the DOE G-1 aircraft that ew during the lidar observations.

  1. Healthy Water

    Science.gov (United States)

    ... recreational water activities like swimming, also helps promote healthy living. Often, water’s vital role is most apparent during an emergency or disaster. We launched the Healthy Water website to provide answers to your water- ...

  2. Remote sensing evidence for regolith water vapor sources on Mars

    Science.gov (United States)

    Huguenin, R. L.; Clifford, S. M.

    1982-01-01

    McCord et al. (1977) have presented earth-based photometric imaging data of an event associated with the 1973 dust storm on Mars. The initial dust cloud in Solis Lacus and two regions to the north and south appeared anomalously bright at blue wavelengths. Water frosts, hazes, and/or clouds were identified, and it was suggested that the water responsible for these findings may have originated from Solis Lacus. More recently, a more intensive review of the observational record of Mars was undertaken. Earth-based telescope observations and data from the Mariner and Viking missions have revealed that Solis Lacus has been a center of repeated activity. Persistent activity in the vicinity of Noachis-Hellespontus and in the border regions of Syrtis Major was also discovered. A review of the observations is provided and possible interpretations are discussed. The obtained results appear to support the original proposal that Solis Lacus may be a source of water vapor. Noachis-Hellespontus seems to be a similar vapor source

  3. Water Ice Clouds in the Martian Atmosphere: A Comparison of Two Methods and Eras

    Science.gov (United States)

    Hale, A. S.; Tamppari, L. K.; Christensen, P. R.; Smith, M. D.; Bass, Deborah; Pearl, J. C.

    2003-01-01

    Similar cloud features are seen in maps generated with each method with no obvious outliers. The temperature differencing method appears to possibly be somewhat more sensitive to weaker water ice signatures. We have also generated correlation plots comparing the two methods. At strong delta-T signals, the correlation between the two methods is quite good, and therefore extraction of opacities from earlier Viking data may be possible for these stronger detection levels. Weaker detections do not, however, show such a good correlation. We are currently analyzing why the correlation becomes poor at weak signal levels, though it may be due to the fact that the differencing method may be more sensitive to thin cloud hazes. Results of this ongoing analysis will be presented. A comparison of the Viking and Mars Global Surveyor (MGS) eras are also presented.

  4. Water citizenship

    DEFF Research Database (Denmark)

    Paerregaard, Karsten; Stensrud, Astrid Bredholt; Andersen, Astrid Oberborbeck

    2016-01-01

    This article examines the implementation of Peru’s new water law and discusses how it produces new forms of water citizenship. Inspired by the global paradigm of “integrated water resources management,” the law aims to include all citizens in the management of the country’s water resources...... by embracing a “new water culture.” We ask what forms of water citizenship emerge from the new water law and how they engage with local water practices and affect existing relations of inequality. We answer these questions ethnographically by comparing previous water legislation and how the new law currently...... is negotiated and contested in three localities in Peru’s southern highlands. We argue that the law creates a new water culture that views water as a substance that is measurable, quantifiable, and taxable, but that it neglects other ways of valuing water. We conclude that water citizenship emerges from...

  5. Water Safety

    Science.gov (United States)

    ... School Counselors Kidney Stones Brain and Nervous System Water Safety KidsHealth > For Teens > Water Safety Print A ... tied to alcohol use. previous continue At the Water Park OK, so you do more splashing than ...

  6. Water pollution

    OpenAIRE

    Institute, Marine

    2013-01-01

    Students will learn about what causes water pollution and how to be environmentally aware. *Note: Students should understand the concept of the water cycle before moving onto water pollution (see Lesson Plan “Oceans all Around Us”).

  7. Water Safety

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Water Safety KidsHealth / For Parents / Water Safety What's in ... remains your best measure of protection. Making Kids Water Wise It's important to teach your kids proper ...

  8. Fluoridated Water

    Science.gov (United States)

    ... Genetics Services Directory Cancer Prevention Overview Research Fluoridated Water On This Page What is fluoride, and where is it found? What is water fluoridation? When did water fluoridation begin in the ...

  9. Parasites: Water

    Science.gov (United States)

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Water Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir Parasites can live in natural water sources. When outdoors, treat your water before drinking ...

  10. Air-sea interactions of semi-volatile organic compounds in the tropical environment of Southeast Asia

    Directory of Open Access Journals (Sweden)

    Balasubramanian R.

    2010-12-01

    Full Text Available Major urban and industrial centers increase loadings of semi-volatile organic compounds (SVOCs to proximate sea waters through riverine transport, atmospheric deposition via dry particle deposition, wet deposition, and air-sea gas exchange. In addition to acting as sinks for SVOCs, oceans can act as sources of SVOCs to coastal atmospheres and play important roles in the global biogeochemistry of SVOCs. Particle-sorbed SVOCs can settle to the ocean surface by dry particle deposition, a uni-directional advective transport process from the atmosphere to the water, the removal rate by which is a function of the physical and chemical properties of the aerosols and bound pollutants, meteorological conditions and surface characteristics. In addition, SVOCs are removed from the atmosphere and transported to the waters by precipitation scavenging of atmospheric vapors and particles, which are incorporated into the rain within or below the clouds. After SVOCs are deposited into the bulk seawater, water-column partitioning can affect the distribution of pollutants between the dissolved aqueous and the solid phases and eventually impact the fate of these compounds in oceans. Other than the abovementioned processes, air-sea exchange can make SVOCs diffuse across the air-sea interface; however, the sea surface microlayer (SML, a unique compartment at the air-sea boundary defined operationally as the upper millimeter (1 ∼ 1000 μm of the sea surface, has large storage capacity to delay the transport of SVOCs across the interface. This article reports the dry particle deposition and wet deposition of selected SVOCs based on an extensive set of yearly data collected in Singapore. Singapore, a representative country of Southeast Asia (SEA, is a small but highly developed island with dense industrial parks in the Southwestern part, where the terrestrial sources affect the surrounding coasts. In this study, Singapore’s Southern coastline was chosen during

  11. Fire water

    Energy Technology Data Exchange (ETDEWEB)

    Thorpe, K. [Lawrence Webster Forrest Ltd. (United Kingdom)

    2001-01-01

    The article focuses on the value of water in fighting fires and discusses why refineries should identify water supply and distribution in contingency planning against fire. In the event of a fire, water will be required for (i) extinguishing the fire; (ii) protection of equipment and (iii) confinement of the fire. The thought process for identifying the water demand in the event of a fire is outlined. Tables give data on (a) water rates for cooling storage tanks; (b) water rates for cooling process units (c) guide to water requirements for various sizes of process units and (d) pumping requirements.

  12. [Health risk analysis of VOC/SVOC contaminated soil in an abandoned chemical plant].

    Science.gov (United States)

    Guo, Guan-lin; Wang, Shi-jie; Shi, Lie-yan; Li, Hui-ying; Han, Chun-mei; Gu, Qing-bao; Cao, Yun-zhe; Li, Fa-sheng

    2010-02-01

    Environmental health risk of contaminated soil in a typical abandoned industry was analyzed based on the full field investigation according to the site assessment procedure of American Society for Testing and Material (ASTM). Parameters were modified with the combination of Chinese crowd character and site specifics. Results indicated that the site was mainly contaminated with volatile and semi-volatile organic compounds in soil profiles. And the contents of carbon tetrachloride, tetrachloroethylene, pentachloroethane, hexachlorobutadiene, hexachloroethane and hexachlorobenzene in soil samples were exceeded the national environmental standard. These contaminants ranked the carcinogenic risks and hazard quotients more than 10(-2) and 1 in some locations with the exposure by oral ingestion, dermal contact and inhalation. Contaminants in this site had resulted in the high health risks to the residents and surrounding communities. The risk should be reduced to the health acceptable level by the treatment and remediation before further development for residential and commercial utilization.

  13. Water Reuse: Using Reclaimed Water For Irrigation

    OpenAIRE

    Haering, Kathryn; Evanylo, Gregory K.; Benham, Brian Leslie, 1960-; Goatley, Michael

    2009-01-01

    Describes water reuse and reclaimed water, explains how reclaimed water is produced, options for water reuse, water reuse regulations, and agronomic concerns with water reuse, and provides several case studies of water reuse.

  14. Water tight.

    Science.gov (United States)

    Postel, S

    1993-01-01

    Many cities worldwide have gone beyond the limits of their water supply. Growing urban populations increase their demand for water, thereby straining local water supplies and requiring engineers to seek our even more distant water sources. It is costly to build and maintain reservoirs, canals, pumping stations, pipes, sewers, and treatment plants. Water supply activities require much energy and chemicals, thereby contributing to environmental pollution. Many cities are beginning to manage the water supply rather than trying to keep up with demand. Pumping ground water for Mexico City's 18 million residents (500,000 people added/year) surpasses natural replenishment by 50% to 80%, resulting in falling water tables and compressed aquifers. Mexico City now ambitiously promotes replacement of conventional toilets with 1.6 gallon toilets (by late 1991, this had saved almost 7.4 billion gallons of water/year). Continued high rural-urban migration and high birth rates could negate any savings, however. Waterloo, Ontario, has also used conservation efforts to manage water demand. These efforts include retrofit kits to make plumbing fixtures more efficient, efficiency standards for plumbing fixtures, and reduction of water use outdoors. San Jose, California, has distributed water savings devices to about 220,000 households with a 90% cooperation rate. Boston, Massachusetts, not only promoted water saving devices but also repaired leaks and had an information campaign. Increasing water rates to actually reflect true costs also leads to water conservation, but not all cities in developing countries use water meters. All households in Edmonton, Alberta, are metered and its water use is 1/2 of that of Calgary, where only some households are metered. Tucson, Arizona, reduced per capita water use 16% by raising water rates and curbing water use on hot days. Bogor, Indonesia, reduced water use almost 30% by increasing water rates. In the US, more and more states are mandating use

  15. Branding water.

    Science.gov (United States)

    Dolnicar, Sara; Hurlimann, Anna; Grün, Bettina

    2014-06-15

    Branding is a key strategy widely used in commercial marketing to make products more attractive to consumers. With the exception of bottled water, branding has largely not been adopted in the water context although public acceptance is critical to the implementation of water augmentation projects. Based on responses from 6247 study participants collected between 2009 and 2012, this study shows that (1) different kinds of water - specifically recycled water, desalinated water, tap water and rainwater from personal rainwater tanks - are each perceived very differently by the public, (2) external events out of the control of water managers, such as serious droughts or floods, had a minimal effect on people's perceptions of water, (3) perceptions of water were stable over time, and (4) certain water attributes are anticipated to be more effective to use in public communication campaigns aiming at increasing public acceptance for drinking purposes. The results from this study can be used by a diverse range of water stakeholders to increase public acceptance and adoption of water from alternative sources. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Water SA

    African Journals Online (AJOL)

    This journal publishes refereed, original work in all branches of water science, technology, engineering and policy. This includes: water resource development; the hydrological cycle; surface hydrology; geohydrology, hydropedology and hydrometeorology; limnology; freshwater and estuarine ecology; salinisation; treatment ...

  17. Water Pollution

    Science.gov (United States)

    Bowen, H. J. M.

    1975-01-01

    Deals with water pollution in the following categories: a global view, self purification, local pollution, difficulties in chemical analysis, and remedies for water pollution. Emphasizes the extent to which man's activities have modified the cycles of certain elements. (GS)

  18. Water Pollution

    Science.gov (United States)

    ... NIEHS Doing? Further Reading For Educators Introduction Water pollution is any contamination of water with chemicals or other foreign substances that are detrimental to human, plant, or animal health. These pollutants include fertilizers and pesticides from agricultural ...

  19. Water Resilience

    Science.gov (United States)

    The Drinking Water and Wastewater Resiliency site provides tools and resources for drinking water and wastewater utilities in the full spectrum of emergency management which includes prevention, mitigation, preparedness, response and recovery.

  20. Water quality

    Science.gov (United States)

    Aquatic animals are healthiest and grow best when environmental conditions are within certain ranges that define, for a particular species, “good” water quality. From the outset, successful aquaculture requires a high-quality water supply. Water quality in aquaculture systems also deteriorates as an...

  1. Water-Quality Data

    Science.gov (United States)

    ... Water Quality? [1.7MB PDF] Past featured science... Water Quality Data Today's Water Conditions Get continuous real- ... list of USGS water-quality data resources . USGS Water Science Areas Water Resources Groundwater Surface Water Water ...

  2. [Pollution Characteristics and Light Extinction Effects of Water-soluble Ions in PM2.5 During Winter Hazy Days at North Suburban Nanjing].

    Science.gov (United States)

    Zhou, Yao-yao; Ma, Yan; Zheng, Jun; Cui, Fen-ping; Wang, Li

    2015-06-01

    To investigate the characteristics of water-soluble ions in PM2.5 and their contribution to light extinction in haze days, on-line monitoring of PM2.5. was conducted at North Suburban Nanjing from 25 January through 3 February, 2013. Water-soluble components were collected with a particle-into-liquid sampler (PILS), and analyzed by ion chromatography (IC) for the contents of SO4(2-), NO3-, NH4+, Cl-, Na+, K+, Mg2+ and Ca2+ Simultaneously particle size distributions were measured using scanning mobility particle sizer (SMPS) and Aerodynamic Particle Sizer (APS). The absorption and scattering coefficients were measured by three-wavelength photoacoustic soot spectrometer (PASS-3). Trace gases (SO2, NO2 etc.) were also monitored. The results showed that the average concentrations of total water-soluble ions were 70.3 and 22.9 microg x m(-3) in haze and normal days, respectively. Secondary hygroscopic components including SO4(2-), NO3- and NH4+ were the major ionic pollutants. Hazy days favored the conversion of SO2 and NOx, to SO4(2-) and NO3-, respectively, and in particular the oxidation of NOx. Using multiple linear regression statistical method, the empirical relationship between the dry aerosol extinction coefficient and the chemical composition was established. NH4NO3 was found to be the largest contributor to aerosol extinction in winter in Nanjing, followed by (NH4)2SO4, OC and EC. In two heavy pollution events, the increase of ion concentrations was influenced by the increase of primary emissions and secondary transformation.

  3. Analysis of the build-up of semi and non volatile organic compounds on urban roads.

    Science.gov (United States)

    Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna

    2011-04-01

    Vehicular traffic in urban areas may adversely affect urban water quality through the build-up of traffic generated semi and non volatile organic compounds (SVOCs and NVOCs) on road surfaces. The characterisation of the build-up processes is the key to developing mitigation measures for the removal of such pollutants from urban stormwater. An in-depth analysis of the build-up of SVOCs and NVOCs was undertaken in the Gold Coast region in Australia. Principal Component Analysis (PCA) and Multicriteria Decision tools such as PROMETHEE and GAIA were employed to understand the SVOC and NVOC build-up under combined traffic scenarios of low, moderate, and high traffic in different land uses. It was found that congestion in the commercial areas and use of lubricants and motor oils in the industrial areas were the main sources of SVOCs and NVOCs on urban roads, respectively. The contribution from residential areas to the build-up of such pollutants was hardly noticeable. It was also revealed through this investigation that the target SVOCs and NVOCs were mainly attached to particulate fractions of 75-300 μm whilst the redistribution of coarse fractions due to vehicle activity mainly occurred in the >300 μm size range. Lastly, under combined traffic scenario, moderate traffic with average daily traffic ranging from 2300 to 5900 and average congestion of 0.47 were found to dominate SVOC and NVOC build-up on roads. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Water Filter

    Science.gov (United States)

    1982-01-01

    A compact, lightweight electrolytic water sterilizer available through Ambassador Marketing, generates silver ions in concentrations of 50 to 100 parts per billion in water flow system. The silver ions serve as an effective bactericide/deodorizer. Tap water passes through filtering element of silver that has been chemically plated onto activated carbon. The silver inhibits bacterial growth and the activated carbon removes objectionable tastes and odors caused by addition of chlorine and other chemicals in municipal water supply. The three models available are a kitchen unit, a "Tourister" unit for portable use while traveling and a refrigerator unit that attaches to the ice cube water line. A filter will treat 5,000 to 10,000 gallons of water.

  5. Water decontamination

    Science.gov (United States)

    Roger Rowell

    2004-01-01

    For 1.5 to 2.5 billion people in the world, lack of clean water is a critical issue. It is estimated that by the year 2025 there will be an additional 2.5 billion people who will live in regions already lacking sufficient clean water. In the United States today, it is estimated that 90% of citizens live within 10 mi of a body of contaminated water. Large numbers of...

  6. Water underground

    Science.gov (United States)

    de Graaf, Inge

    2015-04-01

    The world's largest assessable source of freshwater is hidden underground, but we do not know what is happening to it yet. In many places of the world groundwater is abstracted at unsustainable rates: more water is used than being recharged, leading to decreasing river discharges and declining groundwater levels. It is predicted that for many regions of the world unsustainable water use will increase, due to increasing human water use under changing climate. It would not be long before shortage causes widespread droughts and the first water war begins. Improving our knowledge about our hidden water is the first step to stop this. The world largest aquifers are mapped, but these maps do not mention how much water they contain or how fast water levels decline. If we can add a third dimension to the aquifer maps, so a thickness, and add geohydrological information we can estimate how much water is stored. Also data on groundwater age and how fast it is refilled is needed to predict the impact of human water use and climate change on the groundwater resource.

  7. Water Filters

    Science.gov (United States)

    1993-01-01

    The Aquaspace H2OME Guardian Water Filter, available through Western Water International, Inc., reduces lead in water supplies. The filter is mounted on the faucet and the filter cartridge is placed in the "dead space" between sink and wall. This filter is one of several new filtration devices using the Aquaspace compound filter media, which combines company developed and NASA technology. Aquaspace filters are used in industrial, commercial, residential, and recreational environments as well as by developing nations where water is highly contaminated.

  8. 4SM: A Novel Self-Calibrated Algebraic Ratio Method for Satellite-Derived Bathymetry and Water Column Correction.

    Science.gov (United States)

    Morel, Yann G; Favoretto, Fabio

    2017-07-21

    All empirical water column correction methods have consistently been reported to require existing depth sounding data for the purpose of calibrating a simple depth retrieval model; they yield poor results over very bright or very dark bottoms. In contrast, we set out to (i) use only the relative radiance data in the image along with published data, and several new assumptions; (ii) in order to specify and operate the simplified radiative transfer equation (RTE); (iii) for the purpose of retrieving both the satellite derived bathymetry (SDB) and the water column corrected spectral reflectance over shallow seabeds. Sea truth regressions show that SDB depths retrieved by the method only need tide correction. Therefore it shall be demonstrated that, under such new assumptions, there is no need for (i) formal atmospheric correction; (ii) conversion of relative radiance into calibrated reflectance; or (iii) existing depth sounding data, to specify the simplified RTE and produce both SDB and spectral water column corrected radiance ready for bottom typing. Moreover, the use of the panchromatic band for that purpose is introduced. Altogether, we named this process the Self-Calibrated Supervised Spectral Shallow-sea Modeler (4SM). This approach requires a trained practitioner, though, to produce its results within hours of downloading the raw image. The ideal raw image should be a "near-nadir" view, exhibit homogeneous atmosphere and water column, include some coverage of optically deep waters and bare land, and lend itself to quality removal of haze, atmospheric adjacency effect, and sun/sky glint.

  9. Source Water Protection Basics

    Science.gov (United States)

    Defines drinking water sources (source water), identifies drinking water sources, and describes source water assessments and protection, roles of government and organizations in drinking water source protection

  10. WATER TREATMENT

    Science.gov (United States)

    Pitman, R.W.; Conley, W.R. Jr.

    1962-12-01

    An automated system for adding clarifying chemicals to water in a water treatment plant is described. To a sample of the floc suspension polyacrylamide or similar filter aid chemicals are added, and the sample is then put through a fast filter. The resulting filtrate has the requisite properties for monitoring in an optical turbidimeter to control the automated system. (AEC)

  11. Water conservation

    CSIR Research Space (South Africa)

    Gibberd, Jeremy T

    2009-02-01

    Full Text Available This chapter describes water systems used in green buildings and sets out some objectives that could be aimed for. It also outlines some calculations that can be used to design water systems in green buildings. Finally, aspects of green building...

  12. Water Filters

    Science.gov (United States)

    1987-01-01

    A compact, lightweight electrolytic water filter generates silver ions in concentrations of 50 to 100 parts per billion in the water flow system. Silver ions serve as effective bactericide/deodorizers. Ray Ward requested and received from NASA a technical information package on the Shuttle filter, and used it as basis for his own initial development, a home use filter.

  13. Water Pollution

    Science.gov (United States)

    We all need clean water. People need it to grow crops and to operate factories, and for drinking and recreation. Fish and wildlife depend on ... and phosphorus make algae grow and can turn water green. Bacteria, often from sewage spills, can pollute ...

  14. Water tower

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    The water tower, being built on the highest point of the site, 460.5 m above the sea level. The tank will hold 750 m3 of water, and the tower will be topped by a knob which can serve as a geological survey reference mark.

  15. Water futures

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2016-01-01

    This article explores the potential construction of a water reservoir in Peru’s Cordillera Blanca. Proposed by a peasant group, it would have served important productive purposes but have its intake within the perimeter of a national park. Thus, different notions about water and landscape emerge...... in the encounters between place-based practices and state-sponsored conservation efforts. Empirically tracing the efforts to construct the reservoir, the analytical focus of the article is on how different ways of knowing water within a particular landscape conjure and collide in the process. It is argued...... that the movement of water extends itself beyond the physical properties of the reservoir and irrigation channels as these are produced in encounters between different notions of the role of water in the landscape....

  16. The Ice Cracks for Frozen Flow: Comprehending the Irony of Development through Metaphor of Water

    Directory of Open Access Journals (Sweden)

    Bhumika Sharma

    2014-01-01

    Full Text Available Water, one of the five elements, runs through the course of evolution as life line. Conceived as the source of origin, sustenance and annihilation, it is believed to be the crux of existence. Whether scientific or mythical, it serves as the foundation of cyclical nature of life that begins with Ice Age and ends in great Deluge. Water, being chiefly conceived as the life giving fluid, is mainly associated with the flow that designates existence. But interestingly, the flow of water does not remain restricted to single form or shape. Through its adaptability, malleability and transforming flamboyance, it narrates the beauty, splendour, exoticism, functionality, and dynamism inherent in nature. In literary and cultural discourses water emerges as a chief motif to communicate concrete as well as abstract realities of life. Envisaged in myriad forms such as haze, mist, fog, frost, ice, vapour, and so on it appears in various semblances and disguise to whisper some message in human ears. Its dripping sound echoes the essence of being. Creating a wondrous spectrum of variability, it extends from tiny dew drops to vast oceans. In fact, the metaphor of water serves one of the foundational artistic imagery of visualising life. Present paper studies how water is projected in our literary and cultural discourses to comprehend various experiential truths of human civilisation. It probes into the mystery of incredulous development of humankind that amazes with its incredible achievements. Human civilisation may boast of its consistent progress over the years, but literary delineations in the metaphorical renderings of water question how far do we agree with the progressive march of humankind. What are the ironies that constitute the dilemma of human rationality and the development of a civilisation across cultures?

  17. Visualizing water

    Science.gov (United States)

    Baart, F.; van Gils, A.; Hagenaars, G.; Donchyts, G.; Eisemann, E.; van Velzen, J. W.

    2016-12-01

    A compelling visualization is captivating, beautiful and narrative. Here we show how melding the skills of computer graphics, art, statistics, and environmental modeling can be used to generate innovative, attractive and very informative visualizations. We focus on the topic of visualizing forecasts and measurements of water (water level, waves, currents, density, and salinity). For the field of computer graphics and arts, water is an important topic because it occurs in many natural scenes. For environmental modeling and statistics, water is an important topic because the water is essential for transport, a healthy environment, fruitful agriculture, and a safe environment.The different disciplines take different approaches to visualizing water. In computer graphics, one focusses on creating water as realistic looking as possible. The focus on realistic perception (versus the focus on the physical balance pursued by environmental scientists) resulted in fascinating renderings, as seen in recent games and movies. Visualization techniques for statistical results have benefited from the advancement in design and journalism, resulting in enthralling infographics. The field of environmental modeling has absorbed advances in contemporary cartography as seen in the latest interactive data-driven maps. We systematically review the design emerging types of water visualizations. The examples that we analyze range from dynamically animated forecasts, interactive paintings, infographics, modern cartography to web-based photorealistic rendering. By characterizing the intended audience, the design choices, the scales (e.g. time, space), and the explorability we provide a set of guidelines and genres. The unique contributions of the different fields show how the innovations in the current state of the art of water visualization have benefited from inter-disciplinary collaborations.

  18. Water Filters

    Science.gov (United States)

    1988-01-01

    Seeking to find a more effective method of filtering potable water that was highly contaminated, Mike Pedersen, founder of Western Water International, learned that NASA had conducted extensive research in methods of purifying water on board manned spacecraft. The key is Aquaspace Compound, a proprietary WWI formula that scientifically blends various types of glandular activated charcoal with other active and inert ingredients. Aquaspace systems remove some substances; chlorine, by atomic adsorption, other types of organic chemicals by mechanical filtration and still others by catalytic reaction. Aquaspace filters are finding wide acceptance in industrial, commercial, residential and recreational applications in the U.S. and abroad.

  19. Water Purification

    Science.gov (United States)

    1994-01-01

    The Vision Catalyst Purifier employs the basic technology developed by NASA to purify water aboard the Apollo spacecraft. However, it also uses an "erosion" technique. The purifier kills bacteria, viruses, and algae by "catalytic corrosion." A cartridge contains a silver-impregnated alumina bed with a large surface area. The catalyst bed converts oxygen in a pool of water to its most oxidative state, killing over 99 percent of the bacteria within five seconds. The cartridge also releases into the pool low levels of ionic silver and copper through a controlled process of erosion. Because the water becomes electrochemically active, no electricity is required.

  20. Water Fibers

    CERN Document Server

    Douvidzon, Mark L; Martin, Leopoldo L; Carmon, Tal

    2016-01-01

    Fibers constitute the backbone of modern communication and are used in laser surgeries; fibers also genarate coherent X-ray, guided-sound and supercontinuum. In contrast, fibers for capillary oscillations, which are unique to liquids, were rarely considered in optofluidics. Here we fabricate fibers by water bridging an optical tapered-coupler to a microlensed coupler. Our water fibers are held in air and their length can be longer than a millimeter. These hybrid fibers co-confine two important oscillations in nature: capillary- and electromagnetic-. We optically record vibrations in the water fiber, including an audio-rate fundamental and its 3 overtones in a harmonic series, that one can hear in soundtracks attached. Transforming Micro-Electro-Mechanical-Systems [MEMS] to Micro-Electro-Capillary-Systems [MECS], boosts the device softness by a million to accordingly improve its response to minute forces. Furthermore, MECS are compatible with water, which is a most important liquid in our world.

  1. Extraterrestrial Water

    Science.gov (United States)

    Kasting, J. F.

    2002-12-01

    Life as we know it, i.e., carbon-based organisms that rely on RNA and DNA for information storage and transfer, requires liquid water. Thus, the search for life elsewhere in the universe generally begins with a search for liquid water. In our own Solar System, Earth is the only planet (or moon) that has liquid water at its surface. Mars and Europa both probably have subsurface water. Researchers from NASA and elsewhere are hoping to eventually probe these subsurface reservoirs and determine whether life exists there. A more promising venue for finding extraterrestrial life is on Earth-like planets around other stars. Such planets can in principle be located and analyzed spectroscopically using large space-based telescopes like NASA's proposed Terrestrial Planet Finder (TPF) Mission (1). The chances of success for this mission depend critically on the abundance of Earth-like planets with liquid water at their surfaces because only there could a biota exist that would be widespread enough to modify the planet's atmosphere in a way that would be detectable. Models of planetary accretion suggest that most terrestrial planets should be endowed with substantial amounts of water (2). Climate models suggest that the "habitable zone" around solar-type stars is relatively wide so that water can remain liquid on a planet's surface for long times (3). Thus, the chances of finding water, and maybe life, elsewhere appear to be good. References: (1) Beichman, C. A., Woolf, N. J. and Lindensmith, C. A. The Terrestrial Planet Finder (TPF): A NASA Origins Program to Search for Habitable Planets (JPL Publication 99-3) (NASA Jet Propulsion Laboratory, Pasadena, CA, 1999). (2) Morbidelli, A., Chambers, J., Lunine, J. I., Petit, J. M., Robert, F., Valsecchi, G. B. and Cyr, K. E. Meteoritics and Planet. Sci. 35, 1309-1320 (2000). (3) Kasting, J. F., Whitmire, D. P. and Reynolds, R. T. Icarus 101, 108-128 (1993).

  2. Water vapour absorption in the clear atmosphere of a Neptune-sized exoplanet.

    Science.gov (United States)

    Fraine, Jonathan; Deming, Drake; Benneke, Bjorn; Knutson, Heather; Jordán, Andrés; Espinoza, Néstor; Madhusudhan, Nikku; Wilkins, Ashlee; Todorov, Kamen

    2014-09-25

    Transmission spectroscopy has so far detected atomic and molecular absorption in Jupiter-sized exoplanets, but intense efforts to measure molecular absorption in the atmospheres of smaller (Neptune-sized) planets during transits have revealed only featureless spectra. From this it was concluded that the majority of small, warm planets evolve to sustain atmospheres with high mean molecular weights (little hydrogen), opaque clouds or scattering hazes, reducing our ability to observe the composition of these atmospheres. Here we report observations of the transmission spectrum of the exoplanet HAT-P-11b (which has a radius about four times that of Earth) from the optical wavelength range to the infrared. We detected water vapour absorption at a wavelength of 1.4 micrometres. The amplitude of the water absorption (approximately 250 parts per million) indicates that the planetary atmosphere is predominantly clear down to an altitude corresponding to about 1 millibar, and sufficiently rich in hydrogen to have a large scale height (over which the atmospheric pressure varies by a factor of e). The spectrum is indicative of a planetary atmosphere in which the abundance of heavy elements is no greater than about 700 times the solar value. This is in good agreement with the core-accretion theory of planet formation, in which a gas giant planet acquires its atmosphere by accreting hydrogen-rich gas directly from the protoplanetary nebula onto a large rocky or icy core.

  3. Water Conservation and Water Storage

    Science.gov (United States)

    Narayanan, M.

    2014-12-01

    Water storage can be a viable part of the solution to water conservation. This means that we should include reservoirs. Regardless, one should evaluate all aspects of water conservation principles. Recent drought in California indicates that there is an urgent need to re-visit the techniques used to maintain the water supply-chain mechanism in the entire state. We all recognize the fact that fish and wildlife depend on the streams, rivers and wetlands for survival. It is a well-known fact that there is an immediate need to provide solid protection to all these resources. Laws and regulations should help meet the needs of natural systems. Farmers may be forced to drilling wells deeper than ever. But, they will be eventually depleting groundwater reserves. Needless to say that birds, fish and wildlife cannot access these groundwater table. California is talking a lot about conservation. Unfortunately, the conservation efforts have not established a strong visible hold. The Environmental Protection Agency has a plan called E2PLAN (Narayanan, 2012). It is EPA's plan for achieving energy and environmental performance, leadership, accountability, and carbon neutrality. In June 2011, the EPA published a comprehensive, multi-year planning document called Strategic Sustainability Performance Plan. The author has previously reported these in detail at the 2012 AGU fall meeting. References: Ziegler, Jay (15 JUNE 2014). The Conversation: Water conservation efforts aren't taking hold, but there are encouraging signs. THE SACRAMENTO BEE. California. Narayanan, Mysore. (2012). The Importance of Water Conservation in the 21st Century. 72nd AGU International Conference. Eos Transactions: American Geophysical Union, Vol. 92, No. 56, Fall Meeting Supplement, 2012. H31I - 1255.http://www.sacbee.com/2014/06/15/6479862/jay-ziegler-water-conservation.html#storylink=cpy

  4. Ultrahydrophobic water

    Science.gov (United States)

    Landgraf, J.; Kanitz, C.

    2017-05-01

    When a water drop falls on an oscillating soapy water surface it is observed that coalescence of the drop is inhibited because the drops are bouncing on the surface like on a trampoline. In our research we made experimental and theoretical investigations to an undeformable drop on a deformable bath. We described the vertical movement, predicted the critical bouncing threshold and also made experiments to the effects of an increased Weber number and the horizontal movement of the drop caused by a vertical movement.

  5. Water Condensation

    DEFF Research Database (Denmark)

    Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund

    2014-01-01

    The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics......, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address...

  6. Water Hyacinth

    Science.gov (United States)

    An important new reference book entitled the “Encyclopedia of Invasive Introduced Species” is being published by the University of California Press. We were invited to provide a chapter on water hyacinth, which is the world’s worst aquatic weed. In this chapter, we provide information on the origi...

  7. Water Spout

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2013-01-01

    During the AAPT summer meeting at Creighton University in 2011, Vacek Miglus and I took pictures of early apparatus at the Creighton physics department. The apparatus in the left-hand picture, shown with the spigot closed, appeared to be a liquid-level device: the water level was the same in both the narrow tube and the flaring glass vase.…

  8. Water Play

    Science.gov (United States)

    Cline, Jane E.; Smith, Brandy A.

    2016-01-01

    The inclusion of activities to develop sensory awareness, spatial thinking, and physical dexterity, operationalized through hands-on science lessons such as water play, have long been part of early childhood education. This practical article addresses Next Generation Science Standards K-2 ETS1-3 and K-2 ETS1-2 by having four-year-old…

  9. Drinking water

    OpenAIRE

    Kostik, Vesna

    2012-01-01

    Centre of reference laboratories as a part of Institute of Public Health- Skopje is consisted of following laboratories: - Laboratory of Sanitary Microbiology - Laboratory for Food Quality Control - Laboratory for Water Quality Control - Laboratory for Contaminants and Eco - toxicology - Laboratory for Testing of Metals - Laboratory for Radioecology - Laboratory for Ionizing Radiation - Laboratory for Testing common use items Lab...

  10. A SEARCH FOR WATER IN THE ATMOSPHERE OF HAT-P-26b USING LDSS-3C

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, Kevin B.; Bean, Jacob L.; Seifahrt, Andreas; Gilbert, Gregory J. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S Ellis Avenue, Chicago, IL 60637 (United States); Line, Michael R. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Désert, Jean-Michel [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam (Netherlands); Fortney, Jonathan J., E-mail: kbs@uchicago.edu [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2016-02-01

    The characterization of a physically diverse set of transiting exoplanets is an important and necessary step toward establishing the physical properties linked to the production of obscuring clouds or hazes. It is those planets with identifiable spectroscopic features that can most effectively enhance our understanding of atmospheric chemistry and metallicity. The newly commissioned LDSS-3C instrument on Magellan provides enhanced sensitivity and suppressed fringing in the red optical, thus advancing the search for the spectroscopic signature of water in exoplanetary atmospheres from the ground. Using data acquired by LDSS-3C and the Spitzer Space Telescope, we search for evidence of water vapor in the transmission spectrum of the Neptune-mass planet HAT-P-26b. Our measured spectrum is best explained by the presence of water vapor, a lack of potassium, and either a high-metallicity, cloud-free atmosphere or a solar-metallicity atmosphere with a cloud deck at ∼10 mbar. The emergence of multi-scale-height spectral features in our data suggests that future observations at higher precision could break this degeneracy and reveal the planet’s atmospheric chemical abundances. We also update HAT-P-26b’s transit ephemeris, t{sub 0} = 2455304.65218(25) BJD{sub TDB}, and orbital period, p = 4.2345023(7) days.

  11. Water from (waste)water--the dependable water resource.

    Science.gov (United States)

    Asano, Takashi

    2002-01-01

    Water reclamation and reuse provides a unique and viable opportunity to augment traditional water supplies. As a multi-disciplined and important element of water resources development and management, water reuse can help to close the loop between water supply and wastewater disposal. Effective water reuse requires integration of water and reclaimed water supply functions. The successful development of this dependable water resource depends upon close examination and synthesis of elements from infrastructure and facilities planning, wastewater treatment plant siting, treatment process reliability, economic and financial analyses, and water utility management. In this paper, fundamental concepts of water reuse are discussed including definitions, historical developments, the role of water recycling in the hydrologic cycle, categories of water reuse, water quality criteria and regulatory requirements, and technological innovations for the safe use of reclaimed water. The paper emphasizes the integration of this alternative water supply into water resources planning, and the emergence of modern water reclamation and reuse practices from wastewater to reclaimed water to repurified water.

  12. Editorial: Harmattan Haze and Environmental Health | Ogunseitan ...

    African Journals Online (AJOL)

    African Journal of Environmental Science and Technology. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 1, No 4 (2007) >. Log in or Register to get access to full text downloads.

  13. HAZE POLLUTION IN INDONESIA MELDA KAMIL ARIADNO*

    African Journals Online (AJOL)

    Chikara Onda

    international law arena such as sustainable development, precautionary principle, foreseeability, due diligence and good ... Melda Kamil Ariadno is a Senior Lecturer (Associate Professor) of International Law at the. Faculty of Law, University of Indonesia, ..... countries and international organizations. We noted the ASEAN ...

  14. Water Pressure. Water in Africa.

    Science.gov (United States)

    Garrett, Carly Sporer

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning units were created for K-12 students. This unit, "Water…

  15. Groundwater Waters

    OpenAIRE

    Ramón Llamas; Emilio Custodio

    1999-01-01

    The groundwaters released through springs constituted a basic element for the survival and progressive development of human beings. Man came to learn how to take better advantage of these waters by digging wells, irrigation channels, and galleries. Nevertheless, these activities do not require cooperation nor the collective agreement of relatively large groups of people, as in the case of creating the necessary structures to take advantage of the resources of surfacewaters. The construction a...

  16. How to distinguish between cloudy mini-Neptunes and water/volatile-dominated super-Earths

    Energy Technology Data Exchange (ETDEWEB)

    Benneke, Björn; Seager, Sara, E-mail: bbenneke@mit.edu [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-12-01

    One of the most profound questions about the newly discovered class of low-density super-Earths is whether these exoplanets are predominately H{sub 2}-dominated mini-Neptunes or volatile-rich worlds with gas envelopes dominated by H{sub 2}O, CO{sub 2}, CO, CH{sub 4}, or N{sub 2}. Transit observations of the super-Earth GJ 1214b rule out cloud-free H{sub 2}-dominated scenarios, but are not able to determine whether the lack of deep spectral features is due to high-altitude clouds or the presence of a high mean molecular mass atmosphere. Here, we demonstrate that one can unambiguously distinguish between cloudy mini-Neptunes and volatile-dominated worlds based on wing steepness and relative depths of absorption features in moderate-resolution near-infrared transmission spectra (R ∼ 100). In a numerical retrieval study, we show for GJ 1214b that an unambiguous distinction between a cloudy H{sub 2}-dominated atmosphere and cloud-free H{sub 2}O atmosphere will be possible if the uncertainties in the spectral transit depth measurements can be reduced by a factor of ∼3 compared to the published Hubble Space Telescope Wide-Field Camera 3 and Very Large Telescope transit observations by Berta et al. and Bean et al. We argue that the required precision for the distinction may be achievable with currently available instrumentation by stacking 10-15 repeated transit observations. We provide a scaling law that scales our quantitative results to other transiting super-Earths and Neptunes such as HD 97658b, 55 Cnc e, GJ 3470b and GJ 436b. The analysis in this work is performed using an improved version of our Bayesian atmospheric retrieval framework. The new framework not only constrains the gas composition and cloud/haze parameters, but also determines our confidence in having detected molecules and cloud/haze species through Bayesian model comparison. Using the Bayesian tool, we demonstrate quantitatively that the subtle transit depth variation in the Berta et al. data is

  17. Water markets between Mexican water user associations

    NARCIS (Netherlands)

    Kloezen, W.H.

    1998-01-01

    Internationally, introducing water markets is regarded as a strong alternative institutional arrangement for managing irrigation water more effectively. Also in Mexico, the National Water Law of 1992 allows individual farmers as well as water user associations (WUA) to trade water. Although farmer

  18. The Gulf of Aden Intermediate Water Intrusion Regulates the Southern Red Sea Summer Phytoplankton Blooms

    KAUST Repository

    Dreano, Denis

    2017-01-09

    Knowledge on large-scale biological processes in the southern Red Sea is relatively limited, primarily due to the scarce in situ, and satellite-derived chlorophyll-a (Chl-a) datasets. During summer, adverse atmospheric conditions in the southern Red Sea (haze and clouds) have long severely limited the retrieval of satellite ocean colour observations. Recently, a new merged ocean colour product developed by the European Space Agency (ESA)-the Ocean Color Climate Change Initiative (OC-CCI)-has substantially improved the southern Red Sea coverage of Chl-a, allowing the discovery of unexpected intense summer blooms. Here we provide the first detailed description of their spatiotemporal distribution and report the mechanisms regulating them. During summer, the monsoon-driven wind reversal modifies the circulation dynamics at the Bab-el-Mandeb strait, leading to a subsurface influx of colder, fresher, nutrient-rich water from the Indian Ocean. Using satellite observations, model simulation outputs, and in situ datasets, we track the pathway of this intrusion into the extensive shallow areas and coral reef complexes along the basin\\'s shores. We also provide statistical evidence that the subsurface intrusion plays a key role in the development of the southern Red Sea phytoplankton blooms.

  19. Water vapor in the spectrum of the extrasolar planet HD 189733b. II. The eclipse

    Energy Technology Data Exchange (ETDEWEB)

    Crouzet, Nicolas [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); McCullough, Peter R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, Nikku, E-mail: crouzet@dunlap.utoronto.ca [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2014-11-10

    Spectroscopic observations of exoplanets are crucial to infer the composition and properties of their atmospheres. HD 189733b is one of the most extensively studied exoplanets and is a cornerstone for hot Jupiter models. In this paper, we report the dayside emission spectrum of HD 189733b in the wavelength range 1.1-1.7 μm obtained with the Hubble Space Telescope Wide Field Camera 3 (WFC3) in spatial scan mode. The quality of the data is such that even a straightforward analysis yields a high-precision Poisson noise-limited spectrum: the median 1σ uncertainty is 57 ppm per 0.02 μm bin. We also build a white-light curve correcting for systematic effects and derive an absolute eclipse depth of 96 ± 39 ppm. The resulting spectrum shows marginal evidence for water vapor absorption, but can also be well explained by a blackbody spectrum. However, the combination of these WFC3 data with previous Spitzer photometric observations is best explained by a dayside atmosphere of HD 189733b with no thermal inversion and a nearly solar or subsolar H{sub 2}O abundance in a cloud-free atmosphere. Alternatively, this apparent subsolar abundance may be the result of clouds or hazes that future studies need to investigate.

  20. Improved water does not mean safe water

    Science.gov (United States)

    MacDonald, L. H.; Guo, Y.; Schwab, K. J.

    2012-12-01

    This work presents a model for estimating global access to drinking water that meets World Health Organization (WHO) water quality guidelines. The currently accepted international estimate of global access to safe water, the WHO and United Nations Children's Fund's (UNICEF) Joint Monitoring Program (JMP) report, estimates the population with access to water service infrastructure that is classified as improved and unimproved. The JMP report uses access to improved water sources as a proxy for access to safe water, but improved water sources do not always meet drinking water quality guidelines. Therefore, this report likely overestimates the number of people with access to safe water. Based on the JMP estimate, the United Nations has recently announced that the world has reached the Millennium Development Goal (MDG) target for access to safe water. Our new framework employs a statistical model that incorporates source water quality, water supply interruptions, water storage practices, and point of use water treatment to estimate access to safe water, resulting in a figure that is lower than the JMP estimate of global access to safe water. We estimate that at least 28% of the world does not have access to safe water today, as compared to the JMP estimate of 12%. These findings indicate that much more work is needed on the international scale to meet the MDG target for access to safe water.

  1. Healing Waters

    Directory of Open Access Journals (Sweden)

    Cátedra Tomás, María

    2009-06-01

    Full Text Available Based on fieldwork in four different spas —two in Spain and two in Portugal— this paper shows the mutiple social mediations operating in water therapies in different contexts: from the local use inscribed in popular knowledge, including playful elements inserted in therapeutic practices under the illusion of a return to nature when nature itself has stopped being «natural», to others in which leisure time is an expression of an exclusive life style including a reevaluation of landscape as part of a time-bound aesthetics and as a refuge from urban stress. These different uses of water allow us to understand spas both as nature sanatoriums as well as a form of business where medical power bends to the interests of turistic enterpreneurs transformed into health advisors, linked to different conceptions not only of water but also of society itself.

    Focalizando la reflexión en cuatro balnearios diferentes —dos en España y dos en Portugal—, el artículo muestra las múltiples mediaciones sociales que operan en la terapéutica del agua en diferentes contextos: desde el uso local inserto en saberes populares, incluyendo lo lúdico en lo terapéutico que puede conectarse con la ilusión de un regreso a la naturaleza cuando ésta ya ha dejado de ser “natural”, a otros en los que el ocio es expresión de un estilo de vida exclusivo que incluye un acercamiento al paisaje como parte de la estética de una época y como refugio ante el stress urbano. Se observa así cómo estos usos del agua, que permiten concebir los balnearios bien como sanatorios de la naturaleza bien como negocios en los que el poder médico se pliega al de promotores turísticos convertidos en asesores de salud, se vinculan a concepciones diferentes no sólo del agua, sino de la sociedad misma y sus diferentes grupos.

  2. About Body Water

    Science.gov (United States)

    ... Video) Diabetic Retinopathy Additional Content Medical News About Body Water By James L. Lewis, III, MD, Attending ... here for the Professional Version Water Balance About Body Water Dehydration Dehydration Overhydration Water accounts for about ...

  3. Landscape Water Budget Tool

    Science.gov (United States)

    WaterSense created the Water Budget Tool as one option to help builders, landscape professionals, and irrigation professionals certified by a WaterSense labeled program meet the criteria specified in the WaterSense New Home Specification.

  4. Why Do Eyes Water?

    Science.gov (United States)

    ... for Educators Search English Español Why Do Eyes Water? KidsHealth / For Kids / Why Do Eyes Water? What's ... coming out of your nose. Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  5. Lead and tap water

    Science.gov (United States)

    Water contaminated with lead ... The Environmental Protection Agency (EPA) monitors drinking water in the United States. It requires water suppliers to produce annual water quality reports. These reports include information about lead amounts, and they ...

  6. Bottled Water and Fluoride

    Science.gov (United States)

    ... What's this? Submit What's this? Submit Button Bottled Water Recommend on Facebook Tweet Share Compartir Consumers drink ... questions about bottled water and fluoride. Does bottled water contain fluoride? Bottled water products may contain fluoride, ...

  7. 76 FR 76314 - National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List...

    Science.gov (United States)

    2011-12-07

    ... stored on-site. Removal activities included waste removal, water treatment, oil/water separation, and... investigations of the Site included the wastewater aboveground storage tank (AST), boiler house ASTs, open top...), and pesticides. Several samples containing above background concentrations of metals and SVOCs were...

  8. 4SM: A Novel Self-Calibrated Algebraic Ratio Method for Satellite-Derived Bathymetry and Water Column Correction

    Directory of Open Access Journals (Sweden)

    Yann G. Morel

    2017-07-01

    Full Text Available All empirical water column correction methods have consistently been reported to require existing depth sounding data for the purpose of calibrating a simple depth retrieval model; they yield poor results over very bright or very dark bottoms. In contrast, we set out to (i use only the relative radiance data in the image along with published data, and several new assumptions; (ii in order to specify and operate the simplified radiative transfer equation (RTE; (iii for the purpose of retrieving both the satellite derived bathymetry (SDB and the water column corrected spectral reflectance over shallow seabeds. Sea truth regressions show that SDB depths retrieved by the method only need tide correction. Therefore it shall be demonstrated that, under such new assumptions, there is no need for (i formal atmospheric correction; (ii conversion of relative radiance into calibrated reflectance; or (iii existing depth sounding data, to specify the simplified RTE and produce both SDB and spectral water column corrected radiance ready for bottom typing. Moreover, the use of the panchromatic band for that purpose is introduced. Altogether, we named this process the Self-Calibrated Supervised Spectral Shallow-sea Modeler (4SM. This approach requires a trained practitioner, though, to produce its results within hours of downloading the raw image. The ideal raw image should be a “near-nadir” view, exhibit homogeneous atmosphere and water column, include some coverage of optically deep waters and bare land, and lend itself to quality removal of haze, atmospheric adjacency effect, and sun/sky glint.

  9. Water users associations and irrigation water pricing

    OpenAIRE

    Srđević, Zorica; Srđević, Bojan

    2012-01-01

    A brief review of contemporary discussion on irrigation water pricing and implementation of related strategies to collect annual fees is presented. Emphasis is on water pricing and its relation to water users associations' interests and real power. An example from Spain is provided to illustrate how contemporary multi-criteria analysis and its tools (AHP and TOPSIS) can be used to identify best irrigation water pricing and collection strategy; two water districts with 1500 farmers served as c...

  10. Catalytic Activity Studies of Vanadia/Silica–Titania Catalysts in SVOC Partial Oxidation to Formaldehyde: Focus on the Catalyst Composition

    Directory of Open Access Journals (Sweden)

    Niina Koivikko

    2018-02-01

    Full Text Available In this work, silica–titania supported catalysts were prepared by a sol–gel method with various compositions. Vanadia was impregnated on SiO2-TiO2 with different loadings, and materials were investigated in the partial oxidation of methanol and methyl mercaptan to formaldehyde. The materials were characterized by using N2 physisorption, X-ray diffraction (XRD, X-ray fluorescence spectroscopy (XRF, X-ray photoelectron spectroscopy (XPS, Scanning transmission electron microscope (STEM, NH3-TPD, and Raman techniques. The activity results show the high importance of an optimized SiO2-TiO2 ratio to reach a high reactant conversion and formaldehyde yield. The characteristics of mixed oxides ensure a better dispersion of the active phase on the support and in this way increase the activity of the catalysts. The addition of vanadium pentoxide on the support lowered the optimal temperature of the reaction significantly. Increasing the vanadia loading from 1.5% to 2.5% did not result in higher formaldehyde concentration. Over the 1.5%V2O5/SiO2 + 30%TiO2 catalyst, the optimal selectivity was reached at 415 °C when the maximum formaldehyde concentration was ~1000 ppm.

  11. Dataset of Building and Environment Publication in 2016, A reference method for measuring emissions of SVOCs in small chambers

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data presented in this data file is a product of a journal publication. The dataset contains DEHP air concentrations in the emission test chamber. This dataset...

  12. Water Pollution. Project COMPSEP.

    Science.gov (United States)

    Lantz, H. B., Jr.

    This is an introductory program on water pollution. Examined are the cause and effect relationships of water pollution, sources of water pollution, and possible alternatives to effect solutions from our water pollution problems. Included is background information on water pollution, a glossary of pollution terminology, a script for a slide script…

  13. Service water assistance program

    Energy Technology Data Exchange (ETDEWEB)

    Munchausen, J.H. [EPRI Plant Support Engineering, Charlotte, NC (United States)

    1995-09-01

    The Service Water Assistance Program was developed to provide utility service water system engineers with a mechanism to quickly and efficiently address service water issues. Since its inception, its ability to assist utilities has resulted in a reduction in the operations and maintenance costs associated with service water systems and has provided a medium for EPRI awareness of industry service water issues.

  14. Global water governance

    NARCIS (Netherlands)

    Gupta, J.; Falkner, R.

    2013-01-01

    Although (fresh) water challenges are primarily local in nature, globalization has led to feedback effects that make many water challenges global in nature. This chapter examines global water governance. It discusses four phases of water governance, argues that water governance is dispersed and

  15. Water technology for specific water usage.

    Science.gov (United States)

    Frimmel, Fritz H

    2003-01-01

    Water is the basis for life and culture. In addition to the availability of water its quality has become a major issue in industrialized areas and in developing countries as well. Water usage has to be seen as part of the hydrological cycle. As a consequence water management has to be sustainable. The aim of the contribution is to give water usage oriented quality criteria and to focus on the technical means to achieve them. Water is used for many purposes, ranging from drinking and irrigation to a broad variety of technical processes. Most applications need specific hygienic, chemical and/or physical properties. To meet these demands separation and reaction principles are applied. The reuse of water and the application of water treatment with little or no waste and by-product formation is the way to go. Membrane separation and advanced oxidation including catalytic reactions are promising methods that apply natural processes in sustainable technical performance. Thus elimination of specific water constituents (e.g. salts and metals, microorganisms) and waste water cleaning (e.g. pollutants, nutrients and organic water) can be done efficiently. Learning from nature and helping nature with appropriate technology is a convincing strategy for sustainable water management.

  16. Water-polymer interaction during water uptake

    NARCIS (Netherlands)

    Baukh, V.; Huinink, H.P.; Adan, O.C.G.; Erich, S.J.F.; Ven, L.G.J. van der

    2011-01-01

    Water uptake by multilayer films plays an important role in their performance. Individual layers may consist of different polymeric phases. Understanding the water uptake in such systems requires knowledge of the water distribution, its state in the polymer, and influence on the polymeric phases.

  17. Water neutral: reducing and ofsetting water footprints

    NARCIS (Netherlands)

    Hoekstra, Arjen Ysbert

    2008-01-01

    During the past few years the concept of the ‘water footprint’ has started to receive recognition within governments, non-governmental organizations, businesses and media as a useful indicator of water use. The increased interest in the water-footprint concept has prompted the question about what

  18. Alles is water

    NARCIS (Netherlands)

    Wal, van der A.

    2013-01-01

    Inaugurele rede bij de aanvaarding van buitengewoon hoogleraarschap in Electrochemical Water Treatment. De aandachtsgebieden in zijn professoraat richten zich achtereenvolgens op: a) energiezuinige ontzouting van water, b) selectieve verwijdering van ionen uit water, c) terugwinning van waardevolle

  19. Transboundary water interaction III

    NARCIS (Netherlands)

    Zeitoun, Mark; Cascão, Ana Elisa; Warner, Jeroen; Mirumachi, Naho; Matthews, Nathanial; Menga, Filippo; Farnum, Rebecca

    2017-01-01

    This paper serves international water conflict resolution efforts by examining the ways that states contest hegemonic transboundary water arrangements. The conceptual framework of dynamic transboundary water interaction that it presents integrates theories about change and counter-hegemony to

  20. Chloramines in Drinking Water

    Science.gov (United States)

    Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. Chloramines provide longer-lasting disinfection as the water moves through pipes to consumers.

  1. Water Quality Monitoring

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Our water quality sampling program is to determine the quality of Moosehorn's lakes and a limited number of streams. Water quality is a measure of the body of water,...

  2. Water safety and drowning

    Science.gov (United States)

    ... among people of all ages. Learning and practicing water safety is important to prevent drowning accidents. ... Water safety tips for all ages include: Learn CPR . Never swim alone. Never dive into water unless ...

  3. Tsunamis: Water Quality

    Science.gov (United States)

    ... Transmission in Pet Shelters Protect Your Pets Tsunamis: Water Quality Language: English Español (Spanish) Recommend on Facebook ... about testing should be directed to local authorities. Water for Drinking, Cooking, and Personal Hygiene Safe water ...

  4. Bottled Water Basics

    Science.gov (United States)

    ... of dollars each year to buy it (Beverage Marketing Corporation, 2004) Some people drink bottled water as ... has been treated to meet the U.S. Pharmacopeia definition of purified water. Purified water is essentially free ...

  5. Hydrography - Water Resources

    Data.gov (United States)

    NSGIC Education | GIS Inventory — A Water Resource is a DEP primary facility type related to the Water Use Planning Program. The sub-facility types related to Water Resources that are included are:...

  6. Public Waters Inventory Maps

    Data.gov (United States)

    Minnesota Department of Natural Resources — This theme is a scanned and rectified version of the Minnesota DNR - Division of Waters "Public Waters Inventory" (PWI) maps. DNR Waters utilizes a small scale...

  7. Ecological Exposure Research: Water

    Science.gov (United States)

    Overview of ecological exposure water research, including invasive species, Functional Process Zones (FPZs), biomarkers, pharmaceuticals in water, headwater streams, DNA barcoding, wetland ecosystem services, and sediment remediation.

  8. Water Innovation and Technology

    Science.gov (United States)

    Water technologies are a specific sector that EPA works to address through the water technology cluster, aging infrastructure research, green infrastructure, and major industry meetings such as WEFTEC.

  9. Water Treatment Group

    Data.gov (United States)

    Federal Laboratory Consortium — This team researches and designs desalination, water treatment, and wastewater treatment systems. These systems remediate water containing hazardous c hemicals and...

  10. Hydrography - Water Bodies

    Data.gov (United States)

    California Department of Resources — The hydrography layer consists of flowing waters (rivers and streams), standing waters (lakes and ponds), and wetlands -- both natural and manmade. Two separate...

  11. World Water Day 2014 – Water & Energy

    Directory of Open Access Journals (Sweden)

    Wojciech Majewski

    2014-06-01

    Full Text Available World Water Day was established in 1992 at the United Nations conference – Environment and Development. It was approved to be held every year on 22 March under the heading, theme selected for a given year. The purpose of WWD was to draw the attention of societies, politicians and decision-makers to the fact that water is essential for life and for conducting economic and social activity. The first WWD was held in 1994 under the theme: Caring for our Water Resources is Everybody’s Business. For the subsequent 20 years, the WWD has been held under headings closely related to water and use of water resources. In 2014, the WWD subject has been extended by the issue of energy. It results from the fact that energy – just like water – is a factor essential for global economic and social development. Moreover, both these areas (water and energy are strictly related to each other and are interdependent.

  12. Coupling Mars' Dust and Water Cycles: Effects on Dust Lifting Vigor, Spatial Extent and Seasonality

    Science.gov (United States)

    Kahre, M. A.; Hollingsworth, J. L.; Haberle, R. M.; Montmessin, F.

    2012-01-01

    The dust cycle is an important component of Mars' current climate system. Airborne dust affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. Dust raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. Generally, a low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in dust loading are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading. Interactive dust cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the dust cycle by scavenging dust from atmosphere and by interacting with solar and infrared radiation

  13. 2010 Water & Aqueous Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Dor Ben-Amotz

    2010-08-13

    Water covers more than two thirds of the surface of the Earth and about the same fraction of water forms the total mass of a human body. Since the early days of our civilization water has also been in the focus of technological developments, starting from converting it to wine to more modern achievements. The meeting will focus on recent advances in experimental, theoretical, and computational understanding of the behavior of the most important and fascinating liquid in a variety of situations and applications. The emphasis will be less on water properties per se than on water as a medium in which fundamental dynamic and reactive processes take place. In the following sessions, speakers will discuss the latest breakthroughs in unraveling these processes at the molecular level: Water in Solutions; Water in Motion I and II; Water in Biology I and II; Water in the Environment I and II; Water in Confined Geometries and Water in Discussion (keynote lecture and poster winners presentations).

  14. China's water scarcity.

    Science.gov (United States)

    Jiang, Yong

    2009-08-01

    China has been facing increasingly severe water scarcity, especially in the northern part of the country. China's water scarcity is characterized by insufficient local water resources as well as reduced water quality due to increasing pollution, both of which have caused serious impacts on society and the environment. Three factors contribute to China's water scarcity: uneven spatial distribution of water resources; rapid economic development and urbanization with a large and growing population; and poor water resource management. While it is nearly impossible to adjust the first two factors, improving water resource management represents a cost-effective option that can alleviate China's vulnerability to the issue. Improving water resource management is a long-term task requiring a holistic approach with constant effort. Water right institutions, market-based approaches, and capacity building should be the government's top priority to address the water scarcity issue.

  15. Sustainability and Water

    Science.gov (United States)

    Sharma, Virender A.

    2009-07-01

    World's population numbered 6.1 billion in 2000 and is currently increasing at a rate of about 77 million per year. By 2025, the estimated total world population will be of the order of 7.9 billion. Water plays a central role in any systematic appraisal of life sustaining requirements. Water also strongly influences economic activity (both production and consumption) and social roles. Fresh water is distributed unevenly, with nearly 500 million people suffering water stress or serious water scarcity. Two-thirds of the world's population may be subjected to moderate to high water stress in 2025. It is estimated that by 2025, the total water use will increase by to 40%. The resources of water supply and recreation may also come under stress due to changes in climate such as water balance for Lake Balaton (Hungary). Conventional urban water systems such as water supply, wastewater, and storm water management are also currently going through stress and require major rethinking. To maintain urban water systems efficiently in the future, a flexibility approach will allow incorporation of new technologies and adaptation to external changes (for example society or climate change). Because water is an essential resource for sustaining health, both the quantity and quality of available water supplies must be improved. The impact of water quality on human health is severe, with millions of deaths each year from water-borne diseases, while water pollution and aquatic ecosystem destruction continue to rise. Additionally, emerging contaminants such as endocrine disruptor chemicals (EDCs), pharmaceuticals, and toxins in the water body are also of a great concern. An innovative ferrate(VI) technology is highly effective in removing these contaminants in water. This technology is green, which addresses problems associated with chlorination and ozonation for treating pollutants present in water and wastewater. Examples are presented to demonstrate the applications of ferrate

  16. Water Footprints and Sustainable Water Allocation

    Directory of Open Access Journals (Sweden)

    Arjen Y. Hoekstra

    2015-12-01

    Full Text Available Water Footprint Assessment (WFA is a quickly growing research field. This Special Issue contains a selection of papers advancing the field or showing innovative applications. The first seven papers are geographic WFA studies, from an urban to a continental scale; the next five papers have a global scope; the final five papers focus on water sustainability from the business point of view. The collection of papers shows that the historical picture of a town relying on its hinterland for its supply of water and food is no longer true: the water footprint of urban consumers is global. It has become clear that wise water governance is no longer the exclusive domain of government, even though water is and will remain a public resource with government in a primary role. With most water being used for producing our food and other consumer goods, and with product supply chains becoming increasingly complex and global, there is a growing awareness that consumers, companies and investors also have a key role. The interest in sustainable water use grows quickly, in both civil society and business communities, but the poor state of transparency of companies regarding their direct and indirect water use implies that there is still a long way to go before we can expect that companies effectively contribute to making water footprints more sustainable at a relevant scale.

  17. Water footprint of Ghana

    Science.gov (United States)

    Debrah, E. R.; Odai, S. N.; Annor, F. O.; Adjei, K. A.; van der Zaag, P.

    2009-04-01

    Water is used in almost all human endeavour. Unlike oil, water does not have a substitute. There are many factors that affect the water consumption pattern of people. These include climatic condition, income level and agricultural practices among others. The water footprint concept has been developed in order to have an indicator of water use in relation to its consumption by people. The water footprint of a country is defined as the volume of water needed for the production of the goods and services consumed by the inhabitants of the country (Chapagain and Hoekstra, 2008). Due to the bulky nature of water, it is not in its raw state a tradable commodity though it could be traded through the exchange of goods and services from one point to the other. Closely linked to the water footprint concept is the virtual water concept. Virtual water can be defined as the volume of water required to produce a commodity or service (Chapagain and Hoekstra, 2008 and Allan, 1999). The international trade of these commodities implies flows of virtual water over large distances. The water footprint of a nation can therefore be assessed by quantifying the use of domestic water resources, taking out the virtual water flow that leaves the country and adding the virtual water flow that enters the country to it. This research focuses on the assessment and analysis of the water footprints of Ghana considering only the consumptive component of the water footprint. In addition to livestock, 13 crops were considered, 4 of which were cash crops. Data was analysed for the year 2001 to 2005 The most recent framework for the analysis of water footprint is offered by Chapagain and Hoekstra. This was adopted for the study. The water footprint calculations show that the water footprint of Ghana is about 20011 Gm³/yr. Base on this the average water footprint of a Ghanaian is 823 m³/cap/yr. Not only agricultural crops but also other products require water for their manufacture, aluminium being a

  18. Water, the intangible element

    NARCIS (Netherlands)

    Schotting, R.J.

    2009-01-01

    Water is the key to life. No living creature can survive without water. Too much water or polluted water are serious threats to mankind. Managing this intangible element is complex, not only in wet deltaic regions but also in the (semi-)arid regions of the world. Combined efforts of the

  19. Exploratorium: Exploring Water.

    Science.gov (United States)

    Brand, Judith, Ed.

    2001-01-01

    This issue of Exploratorium focuses on water and its varied uses in our environment. Articles include: (1) "Adventures with Water" (Eric Muller); (2) "Water: The Liquid of Life" (Karen E. Kalumuck); (3) "Water-Drop Projector" (Gorazd Planinsic); (4) "Waterways and Means" (Pearl Tesler); (5) "Explore Natural Phenomena in the Museum--and Just…

  20. Urbanizing rural waters

    NARCIS (Netherlands)

    Hommes, Lena; Boelens, Rutgerd

    2017-01-01

    This article studies how urbanization processes and associated rural-urban water transfers in the Lima region (Peru) create water control hierarchies that align the municipal drinking water company, hydropower plants and rural communities on unequal positions. By scrutinizing the history of water