Organic compounds in aerosols from selected European sites - Biogenic versus anthropogenic sources

Science.gov (United States)

Alves, Célia; Vicente, Ana; Pio, Casimiro; Kiss, Gyula; Hoffer, Andras; Decesari, Stefano; Prevôt, André S. H.; Minguillón, María Cruz; Querol, Xavier; Hillamo, Risto; Spindler, Gerald; Swietlicki, Erik

2012-11-01

Atmospheric aerosol samples from a boreal forest (Hyytiälä, April 2007), a rural site in Hungary (K-puszta, summer 2008), a polluted rural area in Italy (San Pietro Capofiume, Po Valley, April 2008), a moderately polluted rural site in Germany located on a meadow (Melpitz, May 2008), a natural park in Spain (Montseny, March 2009) and two urban background locations (Zurich, December 2008, and Barcelona, February/March 2009) were collected. Aliphatics, polycyclic aromatic hydrocarbons, carbonyls, sterols, n-alkanols, acids, phenolic compounds and anhydrosugars in aerosols were chemically characterised by gas chromatography-mass spectrometry, along with source attribution based on the carbon preference index (CPI), the ratios between the unresolved and the chromatographically resolved aliphatics, the contribution of wax n-alkanes, n-alkanols and n-alkanoic acids from plants, diagnostic ratios of individual target compounds and source-specific markers to organic carbon ratios. In spite of transboundary pollution episodes, Hyytiälä registered the lowest levels among all locations. CPI values close to 1 for the aliphatic fraction of the Montseny aerosol suggest that the anthropogenic input may be associated with the transport of aged air masses from the surrounding industrial/urban areas, which superimpose the locally originated hydrocarbons with biogenic origin. Aliphatic and aromatic hydrocarbons in samples from San Pietro Capofiume reveal that fossil fuel combustion is a major source influencing the diel pattern of concentrations. This source contributed to 25-45% of the ambient organic carbon (OC) at the Po Valley site. Aerosols from the German meadow presented variable contributions from both biogenic and anthropogenic sources. The highest levels of vegetation wax components and biogenic secondary organic aerosol (SOA) products were observed at K-puszta, while anthropogenic SOA compounds predominated in Barcelona. The primary vehicular emissions in the Spanish

Fine and coarse PM composition and sources in rural and urban sites in Switzerland: local or regional pollution?

Science.gov (United States)

Minguillón, M C; Querol, X; Baltensperger, U; Prévôt, A S H

2012-06-15

The chemical composition and sources of ambient particulate matter (PM) in Switzerland were studied. PM(1) and PM(10) samples were collected in winter and summer at an urban background site in Zurich and a rural background site in Payerne. Concentrations of major and trace elements, NO(3)(-), SO(4)(2-), NH(4)(+), organic and elemental carbon were determined. A subsequent Positive Matrix Factorization (PMF) analysis was performed. PM(10) and PM(1) concentrations varied similarly at both sites, with average PM(10) concentrations 24-25 μg/m(3) and 13-14 μg/m(3) in winter and summer, respectively, and average PM(1) concentrations 12-17 μg/m(3) and 6-7 μg/m(3). The influence of local sources was found to be higher in winter. PM was dominated by nitrate and organic matter in winter, and by mineral matter and organic matter in summer. Trace element concentrations related to road traffic (Zn, Cu, Sb, Sn) were higher at Zurich. Concentrations of Tl and Cs, attributed to the influence of a glass industry, were higher at Payerne. The elements mainly present in the coarse fraction were those related to mineral matter and brake and tyre abrasion (Cu, Mn, Ti, Sb, Sr, Bi, Li, La, Nd), and those in the fine fraction were related to high temperature anthropogenic processes (Pb, As, Cd, Tl, Cs). Common PM(1) and PM(1-10) sources identified by PMF were: ammonium nitrate, present in winter, negligible in summer; ammonium sulfate+K(biomass burning)+road traffic; and road traffic itself, related to exhaust emissions in PM(1) and to road dust resuspension in PM(1-10). Size-fraction specific sources were: a PM(1) glass industry source characterized by Cs, Tl, Rb, Li and Na, only present in Payerne; a PM(1) background source characterized by V, Ni, sulfate and Fe; two PM(1-10) mineral-related sources, with higher contribution in summer; a PM(1-10) salt source; and a PM(1-10) organic source, with higher contribution in summer, attributed to bioaerosols. Copyright © 2012 Elsevier B

PM10 concentration levels at an urban and background site in Cyprus: the impact of urban sources and dust storms.

Science.gov (United States)

Achilleos, Souzana; Evans, John S; Yiallouros, Panayiotis K; Kleanthous, Savvas; Schwartz, Joel; Koutrakis, Petros

2014-12-01

Air quality in Cyprus is influenced by both local and transported pollution, including desert dust storms. We examined PM10 concentration data collected in Nicosia (urban representative) from April 1, 1993, through December 11, 2008, and in Ayia Marina (rural background representative) from January 1, 1999, through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM10 concentrations, meteorological records, and satellite data were used to identify dust storm days. We investigated long-term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM10 concentrations ranged from 50.4 to 63.8 μg/m3 and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m3 every year A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000-2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM10 was 24.0 (0.4) μg/m3. The study of yearly trends showed that PM10 levels in Nicosia decreased from 59.4 μg/m3 in 1993 to 49.0 μg/m3 in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m3, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM10 concentrations during desert dust storms were around 100 μg/m3 since 2000 and much higher in earlier years. Despite the large impact ofdust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM10 limit. Implications: This

Characteristics, sources and evolution of fine aerosol (PM1) at urban, coastal and forest background sites in Lithuania

Science.gov (United States)

Masalaite, A.; Holzinger, R.; Remeikis, V.; Röckmann, T.; Dusek, U.

2017-01-01

The chemical and isotopic composition of organic aerosol (OA) samples collected on PM1 filters was determined as a function of desorption temperature to investigate the main sources of organic carbon and the effects of photochemical processing on atmospheric aerosol. The filter samples were collected at an urban (54°38‧ N, 25°18‧ E), coastal (55°55‧ N, 21°00‧ E) and forest (55°27‧ N, 26°00' E) site in Lithuania in March 2013. They can be interpreted as winter-time samples because the monthly averaged temperature was -4 °C. The detailed chemical composition of organic compounds was analysed with a thermal desorption PTR-MS. The mass concentration of organic aerosol at the forest site was roughly by a factor of 30 lower than at the urban and coastal site. This fact could be an indication that in this cold month the biogenic secondary organic aerosol (SOA) formation was very low. Moreover, the organic aerosol collected at the forest site was more refractory and contained a larger fraction of heavy molecules with m/z > 200. The isotopic composition of the aerosol was used to differentiate the two main sources of organic aerosol in winter, i.e. biomass burning (BB) and fossil fuel (FF) combustion. Organic aerosol from biomass burning is enriched in 13C compared to OA from fossil fuel emissions. δ13COC values of the OA samples showed a positive correlation with the mass fraction of several individual organic compounds. Most of these organic compounds contained nitrogen indicating that organic nitrogen compounds formed during the combustion of biomass may be indicative of BB. Other compounds that showed negative correlations with δ13COC were possibly indicative of FF. These compounds included heavy hydrocarbons and were on the average less oxidized than the bulk organic carbon. The correlation of δ13COC and the O/C ratio was positive at low but negative at high desorption temperatures at the forest site. We propose that this might be due to

Understanding sediment sources in a peri-urban Mediterranean catchment using geochemical tracers

Science.gov (United States)

Ferreira, Carla; Walsh, Rory; Kikuchi, Ryunosuke; Blake, Will

2016-04-01

One of the main physical environmental impacts of urbanization is an increase in suspended sediment concentrations and loads, particularly in the constructional phase. Impacts in peri-urban catchments characterized by a mosaic of urban and non-urban landscape elements with varying roles in acting as sources and sinks of overland flow and slope wash have received little attention, particularly in Mediterranean environments. The present study uses a sediment 'fingerprinting' approach to determine the main sediment sources in the peri-urban Ribeira dos Covões catchment (6.2km2) in Portugal and how they change during storm events following contrasting antecedent weather. The catchment, rural until 1972, underwent discontinuous urbanization in 1973-1993, followed by an urban consolidation phase. Currently, its land-use is a complex mosaic of woodland (56%), urban (40%) and agricultural (4%) land parcels. Distinct urban patterns include some well-defined urban residential centres, but also areas of discontinuous urban sprawl. Since 2010, a major road was built and an enterprise park has been under construction, covering 1% and 5% of the catchment, respectively. The catchment has a Mediterranean climate. The geology comprises sandstone (56%), limestone (41%) and alluvial deposits (3%). Soils are generally deep (>3.0m), but shallow (urbanized and partly urbanized catchments, and to supporting them in designing and implementing effective land-use mosaics and site-specific measures to mitigate erosion.

Chemical mass balance source apportionment of PM10 and TSP in residential and industrial sites of an urban region of Kolkata, India.

Science.gov (United States)

Gupta, A K; Karar, Kakoli; Srivastava, Anjali

2007-04-02

Daily average PM(10) (particulate matter which passes through a size selective impactor inlet with a 50% efficiency cut-off at 10 microm aerodynamic diameter), TSP (total suspended particulate matter) and their chemical species mass concentrations were measured at residential and industrial sites of an urban region of Kolkata during November 2003-November 2004. Source apportionment using chemical mass balance model revealed that the most dominant source throughout the study period at residential site was coal combustion (42%), while vehicular emission (47%) dominates at industrial site to PM(10). Paved road, field burning and wood combustion contributed 21%, 7% and 1% at residential site, while coal combustion, metal industry and soil dust contributed 34%, 1% and 1% at industrial site, respectively, to PM(10) during the study period. The contributors to TSP included coal combustion (37%), soil dust (19%), road dust (17%) and diesel combustion (15%) at residential site, while soil dust (36%), coal combustion (17%), solid waste (17%), road dust (16%) and tyre wear (7%) at industrial site. Significant seasonal variations of the particulate matters have been observed during the study period. In the monitoring sites total carbon, organic carbon and iron were found to be the marker species of road dust, while organic carbon, total carbon, chloride and sulfate have been observed as the marker species of soil dust in TSP.

CADDIS Volume 2. Sources, Stressors and Responses: Urbanization - Energy Sources

Science.gov (United States)

Introduction to changes in basal energy sources with urbanization, overview of terrestrial leaf litter dynamics in urban streams, overview of how urbanization can affect primary production, respiration, and dissolved organic carbon quantity and quality.

Nitrogen sources, transport and processing in peri-urban floodplains

International Nuclear Information System (INIS)

Gooddy, D.C.; Macdonald, D.M.J.; Lapworth, D.J.; Bennett, S.A.; Griffiths, K.J.

2014-01-01

Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose. - Highlights: • Peri-urban floodplains have been found to

Nitrogen sources, transport and processing in peri-urban floodplains

Energy Technology Data Exchange (ETDEWEB)

Gooddy, D.C., E-mail: dcg@bgs.ac.uk [British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Macdonald, D.M.J.; Lapworth, D.J. [British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Bennett, S.A. [British Geological Survey, Keyworth, Nottingham NG12 5GG (United Kingdom); Griffiths, K.J. [British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB (United Kingdom)

2014-10-01

Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose. - Highlights: • Peri-urban floodplains have been found to

URBAN RAIN GAUGE SITING SELECTION BASED ON GIS-MULTICRITERIA ANALYSIS

OpenAIRE

Y. Fu; C. Jing; M. Du

2016-01-01

With the increasingly rapid growth of urbanization and climate change, urban rainfall monitoring as well as urban waterlogging has widely been paid attention. In the light of conventional siting selection methods do not take into consideration of geographic surroundings and spatial-temporal scale for the urban rain gauge site selection, this paper primarily aims at finding the appropriate siting selection rules and methods for rain gauge in urban area. Additionally, for optimization gauge loc...

Particle formation and growth at five rural and urban sites

Science.gov (United States)

Jeong, C.-H.; Evans, G. J.; McGuire, M. L.; Chang, R. Y.-W.; Abbatt, J. P. D.; Zeromskiene, K.; Mozurkewich, M.; Li, S.-M.; Leaitch, W. R.

2010-08-01

Ultrafine particle (UFP) number and size distributions were simultaneously measured at five urban and rural sites during the summer of 2007 in Ontario, Canada as part of the Border Air Quality and Meteorology Study (BAQS-Met 2007). Particle formation and growth events at these five sites were classified based on their strength and persistence as well as the variation in geometric mean diameter. Regional nucleation and growth events and local short-lived strong nucleation events were frequently observed at the near-border rural sites, upwind of industrial sources. Surprisingly, the particle number concentrations at one of these sites were higher than the concentrations at a downtown site in a major city, despite its high traffic density. Regional nucleation and growth events were favored during intense solar irradiance and in less polluted cooler drier air. The most distinctive regional particle nucleation and growth event during the campaign was observed simultaneously at all five sites, which were up to 350 km apart. Although the ultrafine particle concentrations and size distributions generally were spatially heterogeneous across the region, a more uniform spatial distribution of UFP across the five areas was observed during this regional nucleation event. Thus, nucleation events can cover large regions, contributing to the burden of UFP in cities and potentially to the associated health impacts on urban populations. Local short-lived nucleation events at the three near-border sites during this summer three-week campaign were associated with high SO2, which likely originated from US and Canadian industrial sources. Hence, particle formation in southwestern Ontario appears to often be related to anthropogenic gaseous emissions but biogenic emissions at times also contribute. Longer-term studies are needed to help resolve the relative contributions of anthropogenic and biogenic emissions to nucleation and growth in this region.

Source identification of PM2.5 at a port and an adjacent urban site in a coastal city of China: Impact of ship emissions and port activities.

Science.gov (United States)

Xu, Lingling; Jiao, Ling; Hong, Zhenyu; Zhang, Yanru; Du, Wenjiao; Wu, Xin; Chen, Yanting; Deng, Junjun; Hong, Youwei; Chen, Jinsheng

2018-09-01

Daily PM 2.5 samples were collected simultaneously at an urban site (UB) and a nearby port-industrial site (PI) on the coast of southeastern China from April 2015 to January 2016. The PM 2.5 mass concentration at the PI (51.9μgm -3 ) was significantly higher than that at the UB. The V concentration at the PI was also significantly higher and well-correlated to the urban value, which suggests that shipping emissions had a significant impact on the PI and, to a lesser extent, on the urban area. A positive matrix factorization (PMF) analysis showed that secondary aerosols were the dominant contribution of PM 2.5 at both sites (36.4% at the PI and 27.2% at the UB), while the contribution of industry and ship emissions identified by V, Mn, and Ba at the PI (26.1%) were double those at the UB. The difference in each source contribution among the trajectory clusters that included significant differences and insignificant differences from the UB to the PI provided insight into the role of local impacts. With regards to the UB, local potential sources play important roles in industry and ship emissions, traffic emissions, fugitive dust, and in their contributions to secondary aerosols. A conditional probability function further revealed that the ship emissions and port activities distributed in the NE, E, and SSE wind sectors were responsible for the source contributions of industry and ship emissions and secondary aerosols at the UB. This study provides an example of investigating the impact of ship emissions and port activities on the surrounding air environment using land-based measurements. Copyright © 2018 Elsevier B.V. All rights reserved.

URBAN RAIN GAUGE SITING SELECTION BASED ON GIS-MULTICRITERIA ANALYSIS

Directory of Open Access Journals (Sweden)

Y. Fu

2016-06-01

Full Text Available With the increasingly rapid growth of urbanization and climate change, urban rainfall monitoring as well as urban waterlogging has widely been paid attention. In the light of conventional siting selection methods do not take into consideration of geographic surroundings and spatial-temporal scale for the urban rain gauge site selection, this paper primarily aims at finding the appropriate siting selection rules and methods for rain gauge in urban area. Additionally, for optimization gauge location, a spatial decision support system (DSS aided by geographical information system (GIS has been developed. In terms of a series of criteria, the rain gauge optimal site-search problem can be addressed by a multicriteria decision analysis (MCDA. A series of spatial analytical techniques are required for MCDA to identify the prospective sites. With the platform of GIS, using spatial kernel density analysis can reflect the population density; GIS buffer analysis is used to optimize the location with the rain gauge signal transmission character. Experiment results show that the rules and the proposed method are proper for the rain gauge site selection in urban areas, which is significant for the siting selection of urban hydrological facilities and infrastructure, such as water gauge.

Aromatic hydrocarbons at urban, sub-urban, rural (8°52'N; 67°19'W) and remote sites in Venezuela

Science.gov (United States)

Holzinger, R.; Kleiss, B.; Donoso, L.; Sanhueza, E.

Using the novel on-line proton transfer reaction mass spectrometry (PTR-MS) technique, atmospheric concentrations of benzene, toluene, xylenes, and C 9-benzenes were measured in Caracas (urban), Altos de Pipe (sub-urban), Calabozo (rural) and Parupa (remote), during various campaigns in 1999 and 2000. Average daytime mixing ratios measured in Caracas are 1.1, 3.2, 3.7, and 2.7 nmol/mol for benzene, toluene, xylenes, and C 9-benzenes. At the sub-urban site, located only few km from Caracas, relatively low levels (˜20% of the levels measured in Caracas) of these aromatic hydrocarbons were observed. At the rural site during the dry season, higher concentrations of benzene (0.15 nmol/mol) were recorded, whereas those of toluene (0.08 nmol/mol) were lower during that time. The aromatic hydrocarbon ratios in the wet season (benzene: 0.08 nmol/mol; toluene: 0.09 nmol/mol) are consistent with an aged urban plume, whereas biomass burning emissions dominate during the dry season. From rural and urban [benzene]/[toluene] ratios a mean HO concentration of 2.6×10 6 molecules/cm 3 was estimated during the wet season. This value must be considered an overestimate because it does not account for background concentrations which are likely for benzene and toluene. At the remote "La Gran Sabana" region (Parupa) very low mixing ratios (0.031 and 0.015 nmol/mol for benzene and toluene) are showing the pristine region to be unaffected by local sources. From the [benzene]/[toluene] ratio we deduced, that "urban" air arriving from the coastline (350 km) is likely mixed with air containing some background of benzene and toluene. Urban emissions (automobiles) should be the major source of aromatic compounds, however, during the dry season biomass burning seems to make an important contribution.

Thia-arenes as source apportionment tracers for urban air particulate

International Nuclear Information System (INIS)

McCarry, B.E.; Allan, L.M.; Mehta, S.; Marvin, C.H.

1995-01-01

Over sixty respirable air particulate samples were selected from a large number of filters collected in Hamilton, Ontario, Canada. Depending on the wind direction these sites were either predominantly upwind or predominantly downwind of the industrial sources. The sixty filters were extracted and analyzed using GC-MS for a range of PAH and sulfur-containing PAH (thia-arenes). Various reference standards (coal tar, diesel exhaust, urban air particulate) and source samples (coke oven condensate) were analyzed as well. A set of air particulate samples collected in another city alongside a highway provided an urban vehicular air sample. Unique thia-arene profiles were noted in the reference and source samples which provided the basis for this source apportionment work; two main approaches were used: (1) analysis of alkylated derivatives of thia-arenes with a molecular mass of 184 amu and (2) analysis of 234 amu isomers. The diesel exhaust and urban vehicular samples gave identical profiles while the coal tar and coke oven samples also had identical profiles but in different respects. The air samples collected at samplers located upwind of the coke ovens showed thia-arene profiles which were similar to the profile observed with a diesel exhaust reference material. However, air samples collected downwind of the coke ovens were heavily loaded samples and resembled the coal tar coke and oven condensate samples

Atmospheric particulate mercury at the urban and forest sites in central Poland.

Science.gov (United States)

Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

2016-02-01

Particulate mercury concentrations were investigated during intensive field campaigns at the urban and forest sites in central Poland, between April 2013 and October 2014. For the first time, quantitative determination of total particulate mercury in coarse (PHg2.2) and fine (PHg0.7) aerosol samples was conducted in Poznań and Jeziory. The concentrations in urban fine and coarse aerosol fractions amounted to mercury concentrations. A strong impact of meteorological conditions (wind velocity, air mass direction, air temperature, and precipitation amount) on particulate mercury concentrations was also observed. In particular, higher variation and concentration range of PHg0.7 and PHg2.2 was reported for wintertime measurements. An increase in atmospheric particulate mercury during the cold season in the study region indicated that coal combustion, i.e., residential and industrial heating, is the main contribution factor for the selected particle size modes. Coarse particulate Hg at the urban site during summer was mainly attributed to anthropogenic sources, with significant contribution from resuspension processes and long-range transport. The highest values of PHg0.7 and PHg2.2 were found during westerly and southerly wind events, reflecting local emission from highly polluted areas. The period from late fall to spring showed that advection from the southern part of Poland was the main factor responsible for elevated Hg concentrations in fine and coarse particles in the investigated region. Moreover, September 2013 could be given as an example of the influence of additional urban activities which occurred approx. 10 m from the sampling site-construction works connected with replacement of the road surface, asphalting, etc. The concentrations of particulate Hg (>600.0 pg m(-3)) were much higher than during the following months when any similar situation did not occur. Our investigations confirmed that Hg in urban aerosol samples was predominantly related to local

Characteristics and diurnal variations of NMHCs at urban, suburban, and rural sites in the Pearl River Delta and a remote site in South China

Science.gov (United States)

Tang, J. H.; Chan, L. Y.; Chan, C. Y.; Li, Y. S.; Chang, C. C.; Liu, S. C.; Wu, D.; Li, Y. D.

The Pearl River Delta (PRD) is one of the most industrialized and urbanized regions in China. With rapid growth of the economy, it is suffering from deteriorating air quality. Non-methane hydrocarbons (NMHCs) were investigated at urban and suburban sites in Guangzhou (GZ), a rural site in PRD and a clean remote site in South China, in April 2005. Additional roadside samples in GZ and Qingxi (QX, a small industrial town in PRD), ambient air samples at the rooftop of a printing factory in QX and exhaust samples from liquefied petroleum gas (LPG)—fueled taxis in GZ were collected to help identify the source signatures of NMHCs. A large fraction of propane (47%) was found in exhaust samples from LPG-fueled taxis in GZ and extremely high levels of toluene (2.0-3.1 ppmv) were found at the rooftop of the printing factory in QX. Vehicular and industrial emissions were the main sources of NMHCs. The effect of vehicular emission on the ambient air varied among the three PRD sites. The impact of industrial emissions was widespread and they contributed greatly to the high levels of aromatic hydrocarbons, especially toluene, at the three PRD sites investigated. Leakage from vehicles fueled by LPG contributed mainly to the high levels of propane and n-butane at the urban GZ site. Ethane and ethyne from long-range transport and isoprene from local biogenic emission were the main contributors to the total hydrocarbons at the remote site. Diurnal variations of NMHCs showed that the contribution from vehicular emissions varied with traffic conditions and were more influenced by fresh emissions at the urban site and by aged air at the suburban and rural sites. Isoprene from biogenic emission contributed largely to the ozone formation potential (OFP) at the remote site. Ethene, toluene and m/ p-xylene were the main contributors to the OFP at the three PRD sites.

Comparison of the physical and chemical characteristics of fine road dust at different urban sites.

Science.gov (United States)

Lee, Kwang Yul; Batmunkh, Tsatsral; Joo, Hung Soo; Park, Kihong

2018-04-18

The size distribution and chemical components of a fine fraction (road dust collected at urban sites in Korea (Gwangju) and Mongolia (Ulaanbaatar) where distinct urban characteristics exist were measured. A clear bimodal size distribution was observed for the resuspended fine road dust at the urban sites in Korea. The first mode peaked at 100-110 nm, and the second peak was observed at 435-570 nm. Ultrafine mode (~30 nm) was found for the fine road dust at the Mongolia site, which was significantly affected by residential coal/biomass burning. The contribution of the water-soluble ions to the fine road dust was higher at the sites in Mongolia (15.8-16.8%) than at those in Korea (1.2-4.8%). Sulfate and chloride were the most dominant ionic species for the fine road dust in Mongolia. As (arsenic) was also much higher for the Mongolian road dust than the others. The sulfate, chloride, and As mainly come from coal burning activity, suggesting that coal and biomass combustion in Mongolia during the heating season should affect the size and chemical components of the fine road dust. Cu (copper) and Zn (zinc), carbonaceous particles (organic carbon [OC] and elemental carbon [EC]) increased at sites in Korea, suggesting that the fine road dust at these sites was significantly affected by the high volume of traffic (engine emission and brake/tire wear). Our results suggest that chemical profiles for road dust specific to certain sites should be applied to more accurately apportion road dust source contributing to the ambient particulate matter. Size and chemical characteristics of fine road dust at sites having distinct urban characteristics were examined. Residential coal and biomass burning and traffic affected physiochemical properties of the fine road dust. Different road dust profiles at different sites should be needed to determine the ambient PM2.5 sources more accurately.

Urban PM in Eastern Germany: Source apportionment and contributions from different spatial scales

Science.gov (United States)

van Pinxteren, D.; Fomba, K. W.; Mothes, F.; Spindler, G.; Herrmann, H.

2017-12-01

Understanding the contributions of particulate matter (PM) sources and the source areas impacting total PM levels in a city are important requirements for further developing clean air policies and efficient abatement strategies. This presentation reports on two studies in Eastern Germany providing a detailed picture of present-day urban PM sources and discriminating contributions of local, regional and long-range sources. The "Leipzig Aerosol 2013-15" study yielded contributions of 12 sources to coarse, fine, and ultrafine particles, resolved by Positive Matrix Factorization (PMF) from comprehensive chemical speciation of 5-stage Berner impactor samples at 4 different sites in the Leipzig area. Dominant winter-time sources were traffic exhaust and non-exhaust emissions, secondary aerosol formation, and combustion emissions from both biomass and coal burning with different relative importance in different particle size ranges. Local sources dominated PM levels in ultrafine and coarse particles (60% - 80%) while high mass concentrations in accumulation mode particles mainly resulted from regional import into the city (70%). The "PM-East" study compiled PM10 mass and constituents' concentrations at 10 urban and rural sites in Eastern Germany during winter 2016/17, which included a 3-week episode of frequent exceedances of the PM10 limit value. PMF source apportionment is performed for a subset of the sites, including the city of Berlin. Contributions from short-, mid-, and long-range sources, including trans-boundary pollution import from neighbouring countries, are quantitatively assessed by advanced back trajectory statistical methods. Data analysis in PM-East is ongoing and final results will be available by November. Funding is acknowledged from 4 federal states of Germany: Berlin Senate Department for Environment, Transport and Climate Protection; Saxon State Office for Environment, Agriculture and Geology; State Agency for Environment, Nature Conservation and

[A landscape ecological approach for urban non-point source pollution control].

Science.gov (United States)

Guo, Qinghai; Ma, Keming; Zhao, Jingzhu; Yang, Liu; Yin, Chengqing

2005-05-01

Urban non-point source pollution is a new problem appeared with the speeding development of urbanization. The particularity of urban land use and the increase of impervious surface area make urban non-point source pollution differ from agricultural non-point source pollution, and more difficult to control. Best Management Practices (BMPs) are the effective practices commonly applied in controlling urban non-point source pollution, mainly adopting local repairing practices to control the pollutants in surface runoff. Because of the close relationship between urban land use patterns and non-point source pollution, it would be rational to combine the landscape ecological planning with local BMPs to control the urban non-point source pollution, which needs, firstly, analyzing and evaluating the influence of landscape structure on water-bodies, pollution sources and pollutant removal processes to define the relationships between landscape spatial pattern and non-point source pollution and to decide the key polluted fields, and secondly, adjusting inherent landscape structures or/and joining new landscape factors to form new landscape pattern, and combining landscape planning and management through applying BMPs into planning to improve urban landscape heterogeneity and to control urban non-point source pollution.

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site during SAPUSS - diurnal variations and PMF receptor modelling

Science.gov (United States)

Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

2013-04-01

Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter Spain) during September-October 2010: an urban background site (UB) and a street canyon traffic road site (RS). Elements related to primary non-exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (regional sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non-exhaust brake dust (Fe-Cu) - 7%), and three types of industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%, percentages presented are average source contributions to the total elemental mass measured). The validity of the PMF solution of the PIXE data is supported by very good correlations with external single particle mass spectrometry measurements. Some important conclusions can be drawn about the PM2.5 mass fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with

Appreciating Site-Specific Qualities in Urban Harbours

DEFF Research Database (Denmark)

Reeh, Henrik

2015-01-01

of observa-tions from Marseille in southern France. After modernization and dislocation of its harbor territories in the early 20th century already, this city is currently taking important steps from industrial urbanism into cultural planning. This transformation allows for new and unprogrammed experiences......When “site-specificity” becomes a central value in city and harbor transformation, it soon proves necessary to address the ways in which scholars and professionals actually determine site-specific qualities in urban fabrics and social life. This paper delves into the above questions by means...

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site during SAPUSS – diurnal variations and PMF receptor modelling

Directory of Open Access Journals (Sweden)

M. Dall'Osto

2013-04-01

Full Text Available Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb were obtained by time (1 h and size (PM2.5 particulate matter 2.5 mass fraction simultaneously measured at the UB and RS sites: (1 the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2 by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3 a unique source of Pb-Cl (associated with combustion emissions is found to be the major (82% source of fine Cl in the urban agglomerate; (4 the mean diurnal variation of PM2.5 primary traffic non-exhaust brake dust (Fe-Cu suggests that this source is mainly emitted and not resuspended, whereas PM2.5 urban dust (Ca is found mainly resuspended by both traffic vortex and sea breeze; (5 urban dust (Ca is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing urban dust concentrations.

Atmospheric carbon tetrachloride in rural background and industry surrounded urban areas in Northern Iberian Peninsula: Mixing ratios, trends, and potential sources

International Nuclear Information System (INIS)

Blas, Maite de; Uria-Tellaetxe, Iratxe; Gomez, Maria Carmen; Navazo, Marino; Alonso, Lucio; García, Jose Antonio; Durana, Nieves; Iza, Jon; Ramón, Jarol Derley

2016-01-01

Latest investigations on atmospheric carbon tetrachloride (CTC) are focused on its ozone depleting potential, adverse effects on the human health, and radiative efficiency and Global Warming Potential as a greenhouse gas. CTC mixing ratios have been thoroughly studied since its restriction under the Montreal Protocol, mostly in remote areas with the aim of reporting long-term trends after its banning. The observed decrease of the CTC background mixing ratio, however, was not as strong as expected. In order to explain this behavior CTC lifetime should be adjusted by estimating the relative significance of its sinks and by identifying ongoing potential sources. Looking for possible sources, CTC was measured with high-time resolution in two sites in Northern Spain, using auto-GC systems and specifically developed acquisition and processing methodologies. The first site, Bilbao, is an urban area influenced by the surrounding industry, where measurements were performed with GC–MSD for a one-year period (2007–2008). The second site, at Valderejo Natural Park (VNP), is a rural background area where measurements were carried out with GC-FID and covering CTC data a nonsuccessive five-year period (2003–2005, 2010–2011, and 2014–2015 years). Median yearly CTC mixing ratios were slightly higher in the urban area (120 pptv) than in VNP (80–100 pptv). CTC was reported to be well mixed in the atmosphere and no sources were noticed to impact the rural site. The observed long-term trend in VNP was in agreement with the estimated global CTC emissions. In the urban site, apart from industrial and commercial CTC sources, chlorine-bleach products used as cleaning agents were reported as promotors of indoor sources. - Highlights: • A methodology was developed to measure CTC using GC-MSD and GC-FID. • CTC ongoing sources were noticed in an industry surrounded urban area. • No noticeable nearby CTC sources impacted the rural site. • Long-term CTC trend in agreement

Atmospheric carbon tetrachloride in rural background and industry surrounded urban areas in Northern Iberian Peninsula: Mixing ratios, trends, and potential sources

Energy Technology Data Exchange (ETDEWEB)

Blas, Maite de, E-mail: maite.deblas@ehu.eus [School of Engineering of Bilbao, University of the Basque Country UPV/EHU (Spain); Uria-Tellaetxe, Iratxe; Gomez, Maria Carmen [School of Engineering of Bilbao, University of the Basque Country UPV/EHU (Spain); Navazo, Marino [University College of Engineering of Vitoria-Gasteiz, University of the Basque Country UPV/EHU (Spain); Alonso, Lucio; García, Jose Antonio; Durana, Nieves; Iza, Jon; Ramón, Jarol Derley [School of Engineering of Bilbao, University of the Basque Country UPV/EHU (Spain)

2016-08-15

Latest investigations on atmospheric carbon tetrachloride (CTC) are focused on its ozone depleting potential, adverse effects on the human health, and radiative efficiency and Global Warming Potential as a greenhouse gas. CTC mixing ratios have been thoroughly studied since its restriction under the Montreal Protocol, mostly in remote areas with the aim of reporting long-term trends after its banning. The observed decrease of the CTC background mixing ratio, however, was not as strong as expected. In order to explain this behavior CTC lifetime should be adjusted by estimating the relative significance of its sinks and by identifying ongoing potential sources. Looking for possible sources, CTC was measured with high-time resolution in two sites in Northern Spain, using auto-GC systems and specifically developed acquisition and processing methodologies. The first site, Bilbao, is an urban area influenced by the surrounding industry, where measurements were performed with GC–MSD for a one-year period (2007–2008). The second site, at Valderejo Natural Park (VNP), is a rural background area where measurements were carried out with GC-FID and covering CTC data a nonsuccessive five-year period (2003–2005, 2010–2011, and 2014–2015 years). Median yearly CTC mixing ratios were slightly higher in the urban area (120 pptv) than in VNP (80–100 pptv). CTC was reported to be well mixed in the atmosphere and no sources were noticed to impact the rural site. The observed long-term trend in VNP was in agreement with the estimated global CTC emissions. In the urban site, apart from industrial and commercial CTC sources, chlorine-bleach products used as cleaning agents were reported as promotors of indoor sources. - Highlights: • A methodology was developed to measure CTC using GC-MSD and GC-FID. • CTC ongoing sources were noticed in an industry surrounded urban area. • No noticeable nearby CTC sources impacted the rural site. • Long-term CTC trend in agreement

Seasonal variations of dissolved organic carbon in precipitation over urban and forest sites in central Poland.

Science.gov (United States)

Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

2015-07-01

Spatial and temporal variability of carbon species in rainwater (bulk deposition) was studied for the first time at two sites located in urban area of Poznań City and protected woodland area (Jeziory), in central Poland, between April and December 2013. The mean concentration of total carbon (TC) for the first site was 5.86 mg L(-1), whereas for the second, 5.21 mg L(-1). Dissolved organic carbon (DOC) concentration accounted for, on average, 87 and 91 % of total carbon in precipitation at urban and non-urban sites, respectively. Significant changes in TC concentrations in rainwater were observed at both sites, indicating that atmospheric transformation, transport, and removal mechanisms of carbonaceous particles were affected by seasonal fluctuations in biogenic/anthropogenic emission and meteorological conditions (i.e., precipitation height and type, atmospheric transport). During the warm season, the DOC concentration in rainwater was mostly influenced by mixed natural and anthropogenic sources. In contrast, during the cold season, the DOC concentration significantly increased mainly as a result of anthropogenic activities, i.e., intensive coal combustion, domestic wood burning, high-temperature processes, etc. In addition, during the winter measurements, significant differences in mean DOC concentration (Kruskal-Wallis test, p urban and non-urban sites. These data imply that carbonaceous compounds are of crucial importance in atmospheric chemistry and should be considered as an important parameter while considering wet deposition, reactions with different substances, especially over polluted environments.

A GIS based screening tool for locating and ranking of suitable stormwater harvesting sites in urban areas.

Science.gov (United States)

Inamdar, P M; Cook, S; Sharma, A K; Corby, N; O'Connor, J; Perera, B J C

2013-10-15

There is the need to re-configure current urban water systems to achieve the objective of sustainable water sensitive cities. Stormwater represents a valuable alternative urban water source to reduce pressure on fresh water resources, and to mitigate the environmental impact of urban stormwater runoff. The selection of suitable urban stormwater harvesting sites is generally based on the judgement of water planners, who are faced with the challenge of considering multiple technical and socio-economic factors that influence the site suitability. To address this challenge, the present study developed a robust GIS based screening methodology for identifying potentially suitable stormwater harvesting sites in urban areas as a first pass for then more detailed investigation. The study initially evaluated suitability based on the match between harvestable runoff and demand through a concept of accumulated catchments. Drainage outlets of these accumulated catchments were considered as potential stormwater harvesting sites. These sites were screened and ranked under screening parameters namely demand, ratio of runoff to demand and weighted demand distance. The methodology described in this paper was successfully applied to a case study in Melbourne, Australia in collaboration with the local water utility. The methodology was found to be effective in supporting the selection of priority sites for stormwater harvesting schemes, as it provided the basis to identify, short-list and rank sites for further detailed investigation. The rapid identification of suitable sites for stormwater harvesting can assist planners in prioritising schemes in areas that will have the most impact on reducing potable water demand. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nitrogen sources, transport and processing in peri-urban floodplains.

Science.gov (United States)

Gooddy, D C; Macdonald, D M J; Lapworth, D J; Bennett, S A; Griffiths, K J

2014-10-01

Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose. Crown Copyright © 2014. Published by Elsevier B.V. All

Urban stormwater source control policies: why and how?

Directory of Open Access Journals (Sweden)

G. Petrucci

2014-09-01

Full Text Available Stormwater source control is becoming a common strategy for urban stormwater management in many countries. It relies on regulations or other policy instruments compelling or inciting implementation, for each new urban development, of small-scale facilities to locally store and manage stormwater. Local authorities that pioneered source control since the 1980s have already observed that small-scale facilities systematically implemented over a catchment are able to influence its hydrological behaviour. This capability is the main strength of source control, as it allows compensation for the negative effects of urbanization. Yet, it also represents its main risk: if initial decision-making is not sufficiently accurate, source control can produce long-term negative effects. Because of its current spreading, source control will acquire an increasing role as a driver of hydrological changes in urban catchments, and the directions of these changes depend on current policy-making practices. This paper presents an analysis and a critical discussion of the main objectives that policy-makers attribute to stormwater source control. The investigation is based on a sample of French case studies, completed by a literature review for international comparison. It identifies four main objectives, some typical of urban stormwater management and some more innovative: flood reduction, receiving waters protection, sustainable development, costs reduction. The discussion focuses on how current policy-making practices are able to translate these objectives in concrete policy instruments, and on which knowledge and tools could improve this process. It is shown that for some objectives, basic knowledge is available, but the creation of policy instruments which are effective at the catchment scale and adapted to local conditions is still problematic. For other objectives, substantial lacks of knowledge exist, casting doubts on long-term effectiveness of current policy

Sustainable Impact of Landfill Siting towards Urban Planning in Malaysia

Science.gov (United States)

Sin Tey, Jia; Goh, Kai Chen; Ern Ang, Peniel Soon

2017-10-01

Landfill is one of the most common, widely used waste management technique in Malaysia. The ever increasing of solid waste has made the role of landfill become prominent despite the negative impacts that caused by the landfill is unavoidable. The public and government regulations are getting more aware with the negative impacts that could be brought by the landfill towards the community. It led to the cultural shift to integrate the concept of sustainability into the planning of siting a landfill in an urban area. However, current urban planning tends to emphasize more on the environmental aspect instead of social and economic aspects. This is due to the existing planning guidelines and stakeholder’s understandings are more on the environmental aspect. This led to the needs of incorporating the concept of sustainability into the urban planning. Thus, this paper focuses on the industry stakeholders view on the negative impacts that will cause by the landfill towards the urban planning. The industry stakeholders are those who are related to the decision-making in the selection of a landfill site in the government department. The scope of the study is within the country of Malaysia. This study was conducted through the semi-structured interviews with a total of fifteen industry stakeholders to obtain their perspective on the issues of impacts of siting a landfill in the urban area. The data obtained was analysed using the software, QSR NVivo version 10. Results indicate that landfill bought significant sustainability-related impacts towards landfill siting in urban planning. The negative impacts stated by the respondents are categorized under all three sustainable aspects such as environmental, social and economic. Among the results are such as the pollution, such as the generation of leachate, the objection in siting a landfill site against by the public, and the negotiating and getting money contribution from local authorities. The results produced can be served

Source-receptor relationships for atmospheric mercury in urban Detroit, Michigan

Science.gov (United States)

Lynam, Mary M.; Keeler, Gerald J.

Speciated hourly mercury measurements were made in Detroit, Michigan during four sampling campaigns from 2000 to 2002. In addition, other chemical and meteorological parameters were measured concurrently. These data were analyzed using principal components analysis (PCA) in order to develop source receptor relationships for mercury species in urban Detroit. Reactive gaseous mercury (RGM) was found to cluster on two main factors; photochemistry and a coal combustion factor. Particulate phase mercury, Hg p, tended to cluster with RGM on the same factor. The photochemistry factor corroborates previous observations of the presence of RGM in highly oxidizing atmospheres and does not point to a specific source emission type. Instead, it likely represents local emissions and regional transport of photochemically processed air masses. The coal combustion factor is indicative of emissions from coal-fired power plants near the receptor site. Elemental mercury was found on a factor for combustion from automobiles and points to the influence these emissions have on the receptor site, which was located proximate to two major interstate highways and the largest border crossing in the United States. This analysis reveals that the receptor site which is located in an industrialized sector of the city of Detroit experienced impacts from both stationary and point sources of mercury that are both local and regional in nature.

Numerical Simulation of Dispersion from Urban Greenhouse Gas Sources

Science.gov (United States)

Nottrott, Anders; Tan, Sze; He, Yonggang; Winkler, Renato

2017-04-01

Cities are characterized by complex topography, inhomogeneous turbulence, and variable pollutant source distributions. These features create a scale separation between local sources and urban scale emissions estimates known as the Grey-Zone. Modern computational fluid dynamics (CFD) techniques provide a quasi-deterministic, physically based toolset to bridge the scale separation gap between source level dynamics, local measurements, and urban scale emissions inventories. CFD has the capability to represent complex building topography and capture detailed 3D turbulence fields in the urban boundary layer. This presentation discusses the application of OpenFOAM to urban CFD simulations of natural gas leaks in cities. OpenFOAM is an open source software for advanced numerical simulation of engineering and environmental fluid flows. When combined with free or low cost computer aided drawing and GIS, OpenFOAM generates a detailed, 3D representation of urban wind fields. OpenFOAM was applied to model scalar emissions from various components of the natural gas distribution system, to study the impact of urban meteorology on mobile greenhouse gas measurements. The numerical experiments demonstrate that CH4 concentration profiles are highly sensitive to the relative location of emission sources and buildings. Sources separated by distances of 5-10 meters showed significant differences in vertical dispersion of plumes, due to building wake effects. The OpenFOAM flow fields were combined with an inverse, stochastic dispersion model to quantify and visualize the sensitivity of point sensors to upwind sources in various built environments. The Boussinesq approximation was applied to investigate the effects of canopy layer temperature gradients and convection on sensor footprints.

Using trace element concentrations in Corbicula fluminea to identify potential sources of contamination in an urban river

International Nuclear Information System (INIS)

Loeffler Peltier, Gretchen; Meyer, Judith L.; Jagoe, Charles H.; Hopkins, William A.

2008-01-01

We used the biomonitor, Corbicula fluminea, to investigate the contributions of trace elements associated with different point sources and land uses in a large river. Trace elements were analyzed in tissues of clams collected from 15 tributary streams draining five land use or point source types: agriculture, forest, urban, coal-fired power plant (CFPP), and wastewater (WWTP). Clams from forested catchments had elevated Hg concentrations, and concentrations of arsenic and selenium were highest (5.0 ± 0.2 and 13.6 ± 0.9 μg g -1 dry mass (DM), respectively) in clams from CFPP sites. Cadmium concentrations were significantly higher in clams from urban and CFPP sites (4.1 ± 0.2 and 3.6 ± 0.9 μg g -1 DM, respectively). Non-metric multidimensional scaling (NMS) of tissue concentrations in clams clustered at CFPP and forest/agriculture sites at opposite ends of the ordination space, and the distribution of sites was driven by Cu, Zn, Cd, and Hg. - C. fluminea collected downstream of CFPPs had elevated tissue concentrations of trace elements

Quercus rubra-associated ectomycorrhizal fungal communities of disturbed urban sites and mature forests.

Science.gov (United States)

Karpati, Amy S; Handel, Steven N; Dighton, John; Horton, Thomas R

2011-08-01

The presence and quality of the belowground mycorrhizal fungal community could greatly influence plant community structure and host species response. This study tests whether mycorrhizal fungal communities in areas highly impacted by anthropogenic disturbance and urbanization are less species rich or exhibit lower host root colonization rates when compared to those of less disturbed systems. Using a soil bioassay, we sampled the ectomycorrhizal fungal (EMF) communities associating with Quercus rubra (northern red oak) seedlings in soil collected from seven sites: two mature forest reference sites and five urban sites of varying levels of disturbance. Morphological and polymerase chain reaction-restriction fragment length polymorphism analyses of fungi colonizing root tips revealed that colonization rates and fungal species richness were significantly lower on root systems of seedlings grown in disturbed site soils. Analysis of similarity showed that EMF community composition was not significantly different among several urban site soils but did differ significantly between mature forest sites and all but one urban site. We identified a suite of fungal species that occurred across several urban sites. Lack of a diverse community of belowground mutualists could be a constraint on urban plant community development, especially of late-successional woodlands. Analysis of urban EMF communities can add to our understanding of urban plant community structure and should be addressed during ecological assessment before pragmatic decisions to restore habitats are framed.

Source apportionment of size and time resolved trace elements and organic aerosols from an urban courtyard site in Switzerland

Directory of Open Access Journals (Sweden)

A. Richard

2011-09-01

Full Text Available Time and size resolved data of trace elements were obtained from measurements with a rotating drum impactor (RDI and subsequent X-ray fluorescence spectrometry. Trace elements can act as indicators for the identification of sources of particulate matter <10 μm (PM₁₀ in ambient air. Receptor modeling was performed with positive matrix factorization (PMF for trace element data from an urban background site in Zürich, Switzerland. Eight different sources were identified for the three examined size ranges (PM_1−0.1, PM_2.5−1 and PM_10−2.5: secondary sulfate, wood combustion, fire works, road traffic, mineral dust, de-icing salt, industrial and local anthropogenic activities. The major component was secondary sulfate for the smallest size range; the road traffic factor was found in all three size ranges. This trace element analysis is complemented with data from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS, assessing the PM₁ fraction of organic aerosols. A separate PMF analysis revealed three factors related to three of the sources found with the RDI: oxygenated organic aerosol (OOA, related to inorganic secondary sulfate, hydrocarbon-like organic aerosol (HOA, related to road traffic and biomass burning organic aerosol (BBOA, explaining 60 %, 22 % and 17 % of total measured organics, respectively. Since different compounds are used for the source classification, a higher percentage of the ambient PM₁₀ mass concentration can be apportioned to sources by the combination of both methods.

Childhood leukemia and residential proximity to industrial and urban sites

International Nuclear Information System (INIS)

García-Pérez, Javier; López-Abente, Gonzalo; Gómez-Barroso, Diana; Morales-Piga, Antonio; Pardo Romaguera, Elena; Tamayo, Ibon; Fernández-Navarro, Pablo

2015-01-01

Background: Few risk factors for the childhood leukemia are well established. While a small fraction of cases of childhood leukemia might be partially attributable to some diseases or ionizing radiation exposure, the role of industrial and urban pollution also needs to be assessed. Objectives: To ascertain the possible effect of residential proximity to both industrial and urban areas on childhood leukemia, taking into account industrial groups and toxic substances released. Methods: We conducted a population-based case–control study of childhood leukemia in Spain, covering 638 incident cases gathered from the Spanish Registry of Childhood Tumors and for those Autonomous Regions with 100% coverage (period 1990-2011), and 13,188 controls, individually matched by year of birth, sex, and autonomous region of residence. Distances were computed from the respective subject’s residences to the 1068 industries and the 157 urban areas with ≥10,000 inhabitants, located in the study area. Using logistic regression, odds ratios (ORs) and 95% confidence intervals (95%CIs) for categories of distance to industrial and urban pollution sources were calculated, with adjustment for matching variables. Results: Excess risk of childhood leukemia was observed for children living near (≤2.5 km) industries (OR=1.31; 95%CI=1.03–1.67) – particularly glass and mineral fibers (OR=2.42; 95%CI=1.49–3.92), surface treatment using organic solvents (OR=1.87; 95%CI=1.24–2.83), galvanization (OR=1.86; 95%CI=1.07–3.21), production and processing of metals (OR=1.69; 95%CI=1.22–2.34), and surface treatment of metals (OR=1.62; 95%CI=1.22–2.15) – , and urban areas (OR=1.36; 95%CI=1.02–1.80). Conclusions: Our study furnishes some evidence that living in the proximity of industrial and urban sites may be a risk factor for childhood leukemia. - Highlights: • We studied proximity to both industrial and urban sites on childhood leukemia. • We conducted a case–control study in

Childhood leukemia and residential proximity to industrial and urban sites

Energy Technology Data Exchange (ETDEWEB)

García-Pérez, Javier, E-mail: jgarcia@isciii.es [Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid (Spain); CIBER Epidemiología y Salud Pública (CIBERESP) (Spain); López-Abente, Gonzalo, E-mail: glabente@isciii.es [Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid (Spain); CIBER Epidemiología y Salud Pública (CIBERESP) (Spain); Gómez-Barroso, Diana, E-mail: dgomez@externos.isciii.es [CIBER Epidemiología y Salud Pública (CIBERESP) (Spain); National Center for Epidemiology, Carlos III Institute of Health, Madrid (Spain); Morales-Piga, Antonio, E-mail: amorales@isciii.es [Rare Disease Research Institute (IIER), Carlos III Institute of Health, Madrid (Spain); Consortium for Biomedical Research in Rare Diseases (CIBERER), Madrid (Spain); Pardo Romaguera, Elena, E-mail: elena.pardo@uv.es [Spanish Registry of Childhood Tumors (RETI-SEHOP), University of Valencia, Valencia (Spain); Tamayo, Ibon, E-mail: ibontama@gmail.com [Public Health Division of Gipuzkoa, BIODonostia Research Institute, Department of Health of the Regional Government of the Basque Country, Donostia (Spain); Fernández-Navarro, Pablo, E-mail: pfernandezn@isciii.es [Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid (Spain); CIBER Epidemiología y Salud Pública (CIBERESP) (Spain); and others

2015-07-15

Background: Few risk factors for the childhood leukemia are well established. While a small fraction of cases of childhood leukemia might be partially attributable to some diseases or ionizing radiation exposure, the role of industrial and urban pollution also needs to be assessed. Objectives: To ascertain the possible effect of residential proximity to both industrial and urban areas on childhood leukemia, taking into account industrial groups and toxic substances released. Methods: We conducted a population-based case–control study of childhood leukemia in Spain, covering 638 incident cases gathered from the Spanish Registry of Childhood Tumors and for those Autonomous Regions with 100% coverage (period 1990-2011), and 13,188 controls, individually matched by year of birth, sex, and autonomous region of residence. Distances were computed from the respective subject’s residences to the 1068 industries and the 157 urban areas with ≥10,000 inhabitants, located in the study area. Using logistic regression, odds ratios (ORs) and 95% confidence intervals (95%CIs) for categories of distance to industrial and urban pollution sources were calculated, with adjustment for matching variables. Results: Excess risk of childhood leukemia was observed for children living near (≤2.5 km) industries (OR=1.31; 95%CI=1.03–1.67) – particularly glass and mineral fibers (OR=2.42; 95%CI=1.49–3.92), surface treatment using organic solvents (OR=1.87; 95%CI=1.24–2.83), galvanization (OR=1.86; 95%CI=1.07–3.21), production and processing of metals (OR=1.69; 95%CI=1.22–2.34), and surface treatment of metals (OR=1.62; 95%CI=1.22–2.15) – , and urban areas (OR=1.36; 95%CI=1.02–1.80). Conclusions: Our study furnishes some evidence that living in the proximity of industrial and urban sites may be a risk factor for childhood leukemia. - Highlights: • We studied proximity to both industrial and urban sites on childhood leukemia. • We conducted a case–control study in

Aerosol composition of urban plumes passing over a rural monitoring site

International Nuclear Information System (INIS)

Ellestad, T.G.

1980-01-01

A field study conducted at a ground site 100 km north of St. Louis, Mo., to measure the aerosol composition and gaseous concentrations of urban plumes passing the site is discussed. Coarse and fine aerosol elemental concentrations, height scattering, meteorological data and concentrations of SO 2 , CO, O 3 , and NO-NO/sub x/ were measured and then analyzed together with data from associate investigators on fluorocarbon-11, total hydrocarbons, and size distributions. The results show that: (1) gaseous and elemental aerosol concentrations at the ground site 100 km from the St. Louis urban area were clearly influenced by the St. Louis urban plume, (2) the urban plumes of Chicago and Indianapolis, 350 km from the ground site, may have been detected, (3) sulfur compounds, presumably sulfates, accounted for 30-40% of the mass loading within the St. Louis urban plume, and resided almost entirely within the size range below 2.5 microns, (4) the most reliable urban-plume tracers in this study were fine Pb, fluorocarbon-11, total nonmethane hydrocarbons, and CO, and (5) over a period of several days, there may have been a regional buildup of fine S, light scattering, aerosol mass, O 3 , and NO/sub x/ and, to a lesser extent, CO and fluorocarbon-11

Observations of fine particulate nitrated phenols in four sites in northern China: concentrations, source apportionment, and secondary formation

Science.gov (United States)

Wang, Liwei; Wang, Xinfeng; Gu, Rongrong; Wang, Hao; Yao, Lan; Wen, Liang; Zhu, Fanping; Wang, Weihao; Xue, Likun; Yang, Lingxiao; Lu, Keding; Chen, Jianmin; Wang, Tao; Zhang, Yuanghang; Wang, Wenxing

2018-03-01

Filter samples of fine particulate matters were collected at four sites in northern China (urban, rural, and mountain) in summer and winter, and the contents of nine nitrated phenols were quantified in the laboratory with the use of ultra-high-performance liquid chromatography coupled with mass spectrometry. During the sampling periods, the concentrations of particulate nitrated phenols exhibited distinct temporal and spatial variation. On average, the total concentration of particulate nitrated phenols in urban Jinan in the wintertime reached 48.4 ng m-3, and those in the summertime were 9.8, 5.7, 5.9, and 2.5 ng m-3 in urban Jinan, rural Yucheng and Wangdu, and Mt. Tai, respectively. The elevated concentrations of nitrated phenols in wintertime and in urban areas demonstrate the apparent influences of anthropogenic sources. The positive matrix factorization receptor model was then applied to determine the origins of particulate nitrated phenols in northern China. The five major source factors were traffic, coal combustion, biomass burning, secondary formation, and aged coal combustion plume. Among them, coal combustion played a vital role, especially at the urban site in the wintertime, with a contribution of around 55 %. In the summertime, the observed nitrated phenols were highly influenced by aged coal combustion plumes at all of the sampling sites. Meanwhile, in remote areas, contributions from secondary formation were significant. Further correlation analysis indicates that nitrosalicylic acids were produced mostly from secondary formation that was dominated by NO2 nitration.

Identification of pollutant sources in a rapidly developing urban river catchment in China

Science.gov (United States)

Huang, Jingshui; Yin, Hailong; Jomma, Seifeddine; Rode, Michael; Zhou, Qi

2016-04-01

Rapid economic development and urbanization worldwide cause serious ecological and environmental problems. A typical region that is in transition and requires systemic research for effective intervention is the rapidly developing city of Hefei in central P. R. China. In order to investigate the sources of pollutants over a one-year period in Nanfei River catchment that drains the city of Hefei, discharges were measured and water samples were taken and measured along the 14km river section at 10 sites for 4 times from 2013 to 2014. Overflow concentrations of combined sewer and separate storm drains were also measured by selecting 15 rain events in 4 typical drainage systems. Loads and budgets of water and different pollutant sources i.e., wastewater treatment plant (WWTP) effluent, urban drainage overflow, unknown wastewater were calculated. The water balance demonstrated that >70% of the discharge originated from WWTP effluent. Lack of clean upstream inflow thereby is threatening ecological safety and water quality. Furthermore, mass fluxes calculations revealed that >40% of the COD (Chemical Oxygen Demand) loads were from urban drainage overflow because of a large amount of discharge of untreated wastewater in pumping stations during rain events. WWTP effluent was the predominant source of the total nitrogen loads (>60%) and ammonia loads (>45%). However, the total phosphorous loads from three different sources are similar (˜1/3). Thus, our research provided a basis for appropriate and prior mitigation strategies (state-of-art of WWTP upgrade, sewer systems modification, storm water regulation and storage capacity improvement, etc.) for different precedence-controlled pollutants with the limited infrastructure investments in these rapidly developing urban regions.

Nonpoint source pollution of urban stormwater runoff: a methodology for source analysis.

Science.gov (United States)

Petrucci, Guido; Gromaire, Marie-Christine; Shorshani, Masoud Fallah; Chebbo, Ghassan

2014-09-01

The characterization and control of runoff pollution from nonpoint sources in urban areas are a major issue for the protection of aquatic environments. We propose a methodology to quantify the sources of pollutants in an urban catchment and to analyze the associated uncertainties. After describing the methodology, we illustrate it through an application to the sources of Cu, Pb, Zn, and polycyclic aromatic hydrocarbons (PAH) from a residential catchment (228 ha) in the Paris region. In this application, we suggest several procedures that can be applied for the analysis of other pollutants in different catchments, including an estimation of the total extent of roof accessories (gutters and downspouts, watertight joints and valleys) in a catchment. These accessories result as the major source of Pb and as an important source of Zn in the example catchment, while activity-related sources (traffic, heating) are dominant for Cu (brake pad wear) and PAH (tire wear, atmospheric deposition).

Indoor/outdoor relationships, sources and cancer risk assessment of NPAHs and OPAHs in PM2.5 at urban and suburban hotels in Jinan, China

Science.gov (United States)

Li, Yanyan; Yang, Lingxiao; Chen, Xiangfeng; Jiang, Pan; Gao, Ying; Zhang, Junmei; Yu, Hao; Wang, Wenxing

2018-06-01

Paired indoor and outdoor measurements of 16 NPAHs and 5 OPAHs in PM2.5 were conducted at urban and suburban sites during January 2016 in Jinan, China. The concentrations of both indoor and outdoor NPAHs and OPAHs were higher at the urban site compared with the suburban site. 9N-ANT (16-42%), 2+3N-FLA (15-51%), 2N-PYR (6-20%), and 1N-PYR (4-6%) were the dominant NPAHs at all sites, and 9-FO (61-81%) was the most abundant OPAHs. Solid fuel combustion, motor vehicle exhausts, and secondary generation were the main sources of the PAH derivatives in this study area. The I/O ratios of 90% of NPAHs and OPAHs at the first urban indoor site (abbreviated as URI1, Green Tree Inn) and the suburban indoor site (abbreviated as SUI, the Seven Star Hotel) were Hotel), the I/O ratios of 2- and 3-ring NPAHs and OPAHs were >1.00, which was likely due to cooking activities occurring near the measurement site. Measurements of outdoor 2+3N-FLA/1N-PYR revealed mainly primary emission at the urban site and secondary sources at the suburban site, the average ratios were 3.76 and 12.22, respectively. The average ratio of 2+3N-FLA/2N-PYR at all sites was 3.3, indicating that the OH-initiated reaction was the dominant secondary formation pathway. Nighttime ratios of 2+3N-FLA/1N-PYR were significantly higher than the daytime ratios at all sites. The difference was especially pronounced during heavily polluted conditions at the suburban site, which suggests that heavy pollution and nighttime conditions promote secondary production. Additionally, the cancer risk was highest in urban outdoor (abbreviated as URO) when the population expose to the level as the outdoor air in the urban. The risk suggested that adults may be at a higher cancer risk.

Carbonaceous and inorganic aerosols over a sub-urban site in peninsular India: Temporal variability and source characteristics

Science.gov (United States)

Aswini, A. R.; Hegde, Prashant; Nair, Prabha R.

2018-01-01

PM10 aerosol samples collected from a sub-urban site in Coimbatore during pre-monsoon, monsoon, post-monsoon and winter from 2014 to 2016 showed a large variability from 7.6 to 89 μg m- 3 with an annual average of 41 ± 21 μg m- 3 (N = 69). High abundance of PM10 and other components were recorded during winter and lowest during monsoon period. Total carbonaceous aerosols and water soluble ionic species contributed to 31% and 45% of PM10 mass respectively. SO42 - was the most abundant species (average 9.8 ± 4.8 μg m- 3) and constituted for 24% of total mass. Organic Carbon (OC) was the next most abundant species ranging from 1 to 16 μg m- 3 with an average of 7 ± 3.6 μg m- 3 accounting for 17% of PM10 mass concentration. POC (primary organic carbon) and SOC (secondary organic carbon) accounted for 56% and 44% of OC respectively. A major portion of OC ( 60%) was found to be water soluble. The correlation between OC and EC (elemental carbon) was found to be higher for night-time compared to daytime suggesting their origin from common sources during night-time. K+ was found to be strongly correlated with OC during night-time. WSOC showed good correlation with POC and K+ which was high especially during night-time. WSON (water soluble organic nitrogen) accounted for 34% of water soluble total nitrogen (WSTN). HCO3- exhibited significant positive correlation with Ca2 + during daytime indicating their crustal origin. The observations suggest that the region is influenced by biomass burning sources, however during day-time, secondary production and terrestrial sources (due to high temperature and wind) significantly influence the atmospheric aerosols over this region.

[Urban industrial contaminated sites: a new issue in the field of environmental remediation in China].

Science.gov (United States)

Liao, Xiao-Yong; Chong, Zhong-Yi; Yan, Xiu-Lan; Zhao, Dan

2011-03-01

Contamination of urban industrial lands is a new environmental problem in China during the process of upgrade of industrial structure and adjustment of urban layout. It restricts the safe re-use of urban land resources, and threatens the health of surrounding inhabitants. In the paper, the market potential of contaminated-site remediation was known through analysis of spatial distribution of urban industrial sites in China. Remediation technologies in the Occident which were suitable for urban industrial contaminated sites were discussed and compared to evaluate their superiority and inferiority. And then, some advices of remediation technologies for urban industrial contaminated sites in China were proposed.

Air ion concentrations in various urban outdoor environments

Science.gov (United States)

Ling, Xuan; Jayaratne, Rohan; Morawska, Lidia

2010-06-01

Atmospheric ions are produced by many natural and anthropogenic sources and their concentrations vary widely between different environments. There is very little information on their concentrations in different types of urban environments, how they compare across these environments and their dominant sources. In this study, we measured airborne concentrations of small ions, particles and net particle charge at 32 different outdoor sites in and around a major city in Australia and identified the main ion sources. Sites were classified into seven groups as follows: park, woodland, city centre, residential, freeway, power lines and power substation. Generally, parks were situated away from ion sources and represented the urban background value of about 270 ions cm -3. Median concentrations at all other groups were significantly higher than in the parks. We show that motor vehicles and power transmission systems are two major ion sources in urban areas. Power lines and substations constituted strong unipolar sources, while motor vehicle exhaust constituted strong bipolar sources. The small ion concentration in urban residential areas was about 960 cm -3. At sites where ion sources were co-located with particle sources, ion concentrations were inhibited due to the ion-particle attachment process. These results improved our understanding on air ion distribution and its interaction with particles in the urban outdoor environment.

Distinguishing spatiotemporal variability of sediment sources in small urbanized catchment as a response to urban expansion

Science.gov (United States)

Belyaev, Vladimir; Feoktistov, Artem; Huygens, Dries; Shamshurina, Eugenia; Golosov, Valentin

2014-05-01

Understanding hydrological response and geomorphic behavior of small catchments in urban environments, especially those experiencing urban expansion, represents serious and important problem which has not yet been given an adequate research attention. Urbanization exerts profound and diverse impacts on catchment characteristics, particularly by increasing surface runoff coefficients, peak flow discharges and rates of flash flood waves propagation as a result of widespread appearance of buildings and paved surfaces with practically zero infiltration capacities. Another essential influence of urbanization on small catchment hydrological regimes is associated with significant changes of natural topography (from relatively minor modifications such as grading of steeper slopes to complete transformations including total filling of gullies and small valleys, transfer of small streams from surface into underground pipes or collectors, etc.) combined with creation of systems of concrete-protected surface drainages and underground storm flow sewages. Such activities can result in substantial changes of runoff- and sediment-contributing areas for the remaining gullies and small valleys in comparison to the pre-urbanization conditions, causing dramatic increase of fluvial activity in some of those and much lower flow discharges in others. In addition, gullies and small valleys in urban settlements often become sites of dumping for both dry and liquid domestic and industrial wastes, thus being major pathways for dissolved and particle-bound pollutant transfer into perennial streams and rivers. All the problems listed require detailed hydrological and geomorphic investigations in order to provide sound basis for developing appropriate measures aimed to control and decrease urban erosion, sediment redistribution, pollution of water bodies, damage to constructions and communications. Recent advances in sediment tracing and fingerprinting techniques provide promising opportunities

Observations of fine particulate nitrated phenols in four sites in northern China: concentrations, source apportionment, and secondary formation

Directory of Open Access Journals (Sweden)

L. Wang

2018-03-01

Full Text Available Filter samples of fine particulate matters were collected at four sites in northern China (urban, rural, and mountain in summer and winter, and the contents of nine nitrated phenols were quantified in the laboratory with the use of ultra-high-performance liquid chromatography coupled with mass spectrometry. During the sampling periods, the concentrations of particulate nitrated phenols exhibited distinct temporal and spatial variation. On average, the total concentration of particulate nitrated phenols in urban Jinan in the wintertime reached 48.4 ng m−3, and those in the summertime were 9.8, 5.7, 5.9, and 2.5 ng m−3 in urban Jinan, rural Yucheng and Wangdu, and Mt. Tai, respectively. The elevated concentrations of nitrated phenols in wintertime and in urban areas demonstrate the apparent influences of anthropogenic sources. The positive matrix factorization receptor model was then applied to determine the origins of particulate nitrated phenols in northern China. The five major source factors were traffic, coal combustion, biomass burning, secondary formation, and aged coal combustion plume. Among them, coal combustion played a vital role, especially at the urban site in the wintertime, with a contribution of around 55 %. In the summertime, the observed nitrated phenols were highly influenced by aged coal combustion plumes at all of the sampling sites. Meanwhile, in remote areas, contributions from secondary formation were significant. Further correlation analysis indicates that nitrosalicylic acids were produced mostly from secondary formation that was dominated by NO2 nitration.

NORTH-EAST ROMANIA AS A FUTURE SOURCE OF TREES FOR URBAN PAVED ENVIRONMENTS IN NORTH-WEST EUROPE

Directory of Open Access Journals (Sweden)

SJÖMAN HENRIK

2009-12-01

Full Text Available Trees are an important feature of the urban environment. The problem today lies not in finding a wide range of well-adapted tree species for park environments, but in finding species suitable for urban paved sites. In terms of north-west Europe, it is unlikely that the limited native dendroflora will provide a large variety of tree species with high tolerance to the environmental stresses characterising urban paved sites in the region. However, other regions with a comparable climate but with a rich dendroflora can potentially provide new tree species and genera well-suited to the growing conditions at urban sites in north-west Europe. This paper examines the potential of a geographical area extending over north-east Romania and the Republic of Moldavia to supply suitable tree species for urban paved sites in Central and Northern Europe (CNE. The study involved comparing the temperature, precipitation, evapotranspiration and water runoff in the woodland area of Iasi, Romania, with those the current inner-city climate of Copenhagen, Denmark and those predicted for Copenhagen 2100. The latter included urban heat island effects and predicted global climate change. The results revealed similar pattern in summer water deficit and temperature between natural woodlands in Iasi and inner-city environment of Copenhagen today. On the other hand, there is a weak match between Iasi and the future Copenhagen. In order to match the future scenario of Copenhagen with the present situation in Iasi, a greater understanding in a early phase that the solution not only depends on suitable tree species, but also on technical solutions being developed in order to have trees in paved environments in the future. On the basis of precipitation and temperature data, natural woodlands in north-east Romania have the potential to be a source of suitable trees for urban paved environments in the CNE region, even for a future climate if other aspects in the planning of trees

Anatomical sites of colorectal cancer in a Semi-Urban Nigerian ...

African Journals Online (AJOL)

region from big urban cities have shown that the incidence of colorectal cancer is rising and with a proportionate right-ward shift. Objective: To assess the sub-site distribution and surgical treatment patterns of colorectal cancer in a semi-urban ...

Characteristics and Sources of Heavy Metals in PM2.5 during a Typical Haze Episode in Rural and Urban Areas in Taiyuan, China

Directory of Open Access Journals (Sweden)

Kankan Liu

2017-12-01

Full Text Available PM2.5 samples were collected in the rural and urban areas of Taiyuan, China during a typical haze episode and the heavy metals (Cr, Mn, Ni, Cu, Zn, As, Cd and Pb in PM2.5 were analyzed. The haze was characterized by start-up stage with a daily mean PM2.5 of 149.34 ± 52.33 and 146.73 ± 18.96 μg m−3 in the rural and urban sites, respectively, a peak stage (288.20 ± 12.43 and 323.44 ± 5.23 μg m−3, and a weakening stage (226.59 ± 12.43 and 195.60 ± 2.93 μg m−3. The concentrations of PM2.5 in the rural and urban sites in the peak stage were 5.9 and 5.5 times higher than those in the normal stage, respectively. The order of concentrations of heavy metals in PM2.5 at the rural and urban sites were the same and are listed as follows: Zn > Pb > Mn > Cr > Cu > Ni > Cd > As. Pb at the rural site, As at the urban site, and Cd at the both sites failed to meet the air quality standard. The concentrations of Pb and Zn were higher at the rural site than those at the urban site. Principal component analysis indicated that the main sources of heavy metals for the rural area were raw coal combustion and soil/road dust, and for the urban area were coal combustion/industrial emissions, road/soil dust, and vehicle emissions/oil combustion.

Urban wet deposition nitrate: a comparison to non-urban deposition

International Nuclear Information System (INIS)

Schultz, J.A.M.

1994-01-01

The concentration of nitrate in both wet and dry deposition has both increased historically and currently, and recently parallels emissions in NO x . Since NO x is produced in amounts comparable to SO 2 , it is an important contributor to acid deposition, and is produced in higher amounts in urban areas due to concentrated sources. Prior to to this study, national acid deposition monitoring networks in the United States have been and remain established in non-urban areas. This research study consisted of a comparison of precipitation sampling and analysis of wet deposition nitrate and pH for each deposition event in each of two urban sites over a 15 mo period. Also, a comparison of urban data and data generated at a nearby non-urban NADP site was made by examination of both monthly and seasonal data. This research suggests that national monitoring programs should consider inclusion of urban and non-urban monitoring sites in order to achieve a more representative regional assessment. 24 refs., 2 figs., 2 tabs

OPEN SOURCE APPROACH TO URBAN GROWTH SIMULATION

Directory of Open Access Journals (Sweden)

A. Petrasova

2016-06-01

Full Text Available Spatial patterns of land use change due to urbanization and its impact on the landscape are the subject of ongoing research. Urban growth scenario simulation is a powerful tool for exploring these impacts and empowering planners to make informed decisions. We present FUTURES (FUTure Urban – Regional Environment Simulation – a patch-based, stochastic, multi-level land change modeling framework as a case showing how what was once a closed and inaccessible model benefited from integration with open source GIS.We will describe our motivation for releasing this project as open source and the advantages of integrating it with GRASS GIS, a free, libre and open source GIS and research platform for the geospatial domain. GRASS GIS provides efficient libraries for FUTURES model development as well as standard GIS tools and graphical user interface for model users. Releasing FUTURES as a GRASS GIS add-on simplifies the distribution of FUTURES across all main operating systems and ensures the maintainability of our project in the future. We will describe FUTURES integration into GRASS GIS and demonstrate its usage on a case study in Asheville, North Carolina. The developed dataset and tutorial for this case study enable researchers to experiment with the model, explore its potential or even modify the model for their applications.

Five-year measurements of ambient ammonia and its relationships with other trace gases at an urban site of Delhi, India

Science.gov (United States)

Saraswati; Sharma, S. K.; Mandal, T. K.

2018-04-01

In this study, we present the 5-year measurements of ambient ammonia (NH3), oxides of nitrogen (NO and NO2) and carbon monoxide (CO) along with the meteorological parameters at an urban site of Delhi, India from January 2011 to December 2015. The average mixing ratios of ambient NH3, NO, NO2 and CO over the entire period of observations were recorded as 19.3 ± 4.4 (ppb), 20.1 ± 5.9 (ppb), 18.6 ± 4.6 (ppb) and 1.8 ± 0.5 (ppm), respectively. The mixing ratios of NH3, NO, NO2 and CO were recorded highest during winter season, followed by summer and monsoon season. In the present case, a substantial seasonal variation of NH3 was observed during all the seasons except NO, NO2 and CO. The results emphasized that the traffic could be one of the significant sources of ambient NH3 at the urban site of Delhi as illustrated by positive correlations of NH3 with traffic related pollutants (NO x and CO). Surface wind as well as back trajectory analysis also supports the road side traffic and agricultural activities at the nearby area indicating possible major sources of ambient NH3 at observational site. Trajectory analysis, potential source contribution function and concentration weighted trajectory analysis indicated the surrounding nearby areas (NCR, Haryana, Punjab, Rajasthan and Uttar Pradesh) as a significant source region of ambient NH3 at the observational site of Delhi.

Investigating Ammonia Emission Sources in a Coastal Urban Air Shed Using Stable Isotope Techniques

Science.gov (United States)

Berner, A.; Felix, J. D. D.

2017-12-01

For nearly 100 years, mankind has met the food demands of a growing population by commercially producing and consuming reactive nitrogen fertilizers. So much so, that now 40-60% of the population relies on them. This increase has drastically altered the global nitrogen (N) cycle. Specifically, ammonia (NH3) emissions to the atmosphere have increased, resulting in wet and dry NHx (NH3 + NH4+) deposition products that can be substantial sources of N to sensitive ecosystems. Excess N can wreak havoc on these environments, causing soil acidification, water body eutrophication, and decreases in biodiversity. Despite these effects, NH3 remains generally unregulated in the U.S. Should policymakers elect to regulate NH3, quantification of NH3 emission sources and transport is essential. This has proven to be particularly difficult in urban regions, where ambient NH3 may result from local urban sources and/or NH3 transport from rural agricultural sources. The presented work investigates potential NH3 emission sources within a South Texas coastal urban air shed, Corpus Christi, TX, U.S.A. Previous work has shown an increasing fine particulate matter (PM2.5) trend within the region, which may be attributable to NH3 emissions from a variety of local sources, including vehicle traffic, shipping traffic, the petrochemical industry, and/or surrounding agricultural cropland and livestock. NH3 was collected monthly at a set of 8 sites within the Corpus Christi air shed, analyzed for NH3 concentration and N isotopic composition (d15N-NH3), and compared to known isotopic compositions of NH3 sources. Low and seasonally variable d15N-NH3 values are associated with varying agricultural sources (fertilizer, livestock waste, etc.), while higher and more seasonally constant d15N-NH3 values are associated with non-agricultural sources (vehicles, industry, etc.). Several other physical and chemical atmospheric components (e.g. SO2, NO2, O3, PM2.5, temperature, relative humidity) were also

Characterization, source identification and apportionment of selected metals in TSP in an urban atmosphere.

Science.gov (United States)

Shah, Munir H; Shaheen, N; Jaffar, M

2006-03-01

To understand the metal distribution characteristics in the atmosphere of urban Islamabad, total suspended particulate (TSP) samples were collected on daily 12 h basis, at Quaid-i-Azam University campus, using high volume sampler. The TSP samples were treated with HNO(3)/HClO(4) based wet digestion method for the quantification of eight selected metals; Fe, Zn, Pb, Mn, Cr, Co, Ni and Cd by FAAS method. The monitoring period ran from June 2001 to January 2002, with a total of 194 samples collected on cellulose filters. Effects of different meteorological conditions such as temperature, relative humidity, wind speed and wind direction on selected metal levels were interpreted by means of multivariate statistical approach. Enhanced metal levels for Fe (930 ng/m(3)), Zn (542 ng/m(3)) and Pb (210 ng/m(3)) were found on the mean scale while Mn, Cr, Co and Ni emerged as minor contributors. Statistical correlation study was also conducted and a strong correlation was observed between Pb-Cr (r=0.611). The relative humidity showed some significant influence on atmospheric metal distribution while other meteorological parameters showed weak relationship with TSP metal levels. Regarding the origin of sources of heavy metals in TSP, the statistical procedure identified three source profiles; automobile emissions, industrial/metallurgical units, and natural soil dust. The metal levels were also compared with those reported for other parts of the world which showed that the metal levels in urban atmosphere of Islamabad are in exceedence than those of European industrial and urban sites while comparable with some Asian sites.

Assessment of light extinction at a European polluted urban area during wintertime: Impact of PM1 composition and sources.

Science.gov (United States)

Vecchi, R; Bernardoni, V; Valentini, S; Piazzalunga, A; Fermo, P; Valli, G

2018-02-01

In this paper, results from receptor modelling performed on a well-characterised PM 1 dataset were combined to chemical light extinction data (b ext ) with the aim of assessing the impact of different PM 1 components and sources on light extinction and visibility at a European polluted urban area. It is noteworthy that, at the state of the art, there are still very few papers estimating the impact of different emission sources on light extinction as we present here, although being among the major environmental challenges at many polluted areas. Following the concept of the well-known IMPROVE algorithm, here a tailored site-specific approach (recently developed by our group) was applied to assess chemical light extinction due to PM 1 components and major sources. PM 1 samples collected separately during daytime and nighttime at the urban area of Milan (Italy) were chemically characterised for elements, major ions, elemental and organic carbon, and levoglucosan. Chemical light extinction was estimated and results showed that at the investigated urban site it is heavily impacted by ammonium nitrate and organic matter. Receptor modelling (i.e. Positive Matrix Factorization, EPA-PMF 5.0) was effective to obtain source apportionment; the most reliable solution was found with 7 factors which were tentatively assigned to nitrates, sulphates, wood burning, traffic, industry, fine dust, and a Pb-rich source. The apportionment of aerosol light extinction (b ext,aer ) according to resolved sources showed that considering all samples together nitrate contributed at most (on average 41.6%), followed by sulphate, traffic, and wood burning accounting for 18.3%, 17.8% and 12.4%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Open Source Tools for Numerical Simulation of Urban Greenhouse Gas Emissions

Science.gov (United States)

Nottrott, A.; Tan, S. M.; He, Y.

2016-12-01

There is a global movement toward urbanization. Approximately 7% of the global population lives in just 28 megacities, occupying less than 0.1% of the total land area used by human activity worldwide. These cities contribute a significant fraction of the global budget of anthropogenic primary pollutants and greenhouse gasses. The 27 largest cities consume 9.9%, 9.3%, 6.7% and 3.0% of global gasoline, electricity, energy and water use, respectively. This impact motivates novel approaches to quantify and mitigate the growing contribution of megacity emissions to global climate change. Cities are characterized by complex topography, inhomogeneous turbulence, and variable pollutant source distributions. These features create a scale separation between local sources and urban scale emissions estimates known as the Grey-Zone. Modern computational fluid dynamics (CFD) techniques provide a quasi-deterministic, physically based toolset to bridge the scale separation gap between source level dynamics, local measurements, and urban scale emissions inventories. CFD has the capability to represent complex building topography and capture detailed 3D turbulence fields in the urban boundary layer. This presentation discusses the application of OpenFOAM to urban CFD simulations of natural gas leaks in cities. OpenFOAM is an open source software for advanced numerical simulation of engineering and environmental fluid flows. When combined with free or low cost computer aided drawing and GIS, OpenFOAM generates a detailed, 3D representation of urban wind fields. OpenFOAM was applied to model methane (CH4) emissions from various components of the natural gas distribution system, to investigate the impact of urban meteorology on mobile CH4 measurements. The numerical experiments demonstrate that CH4 concentration profiles are highly sensitive to the relative location of emission sources and buildings. Sources separated by distances of 5-10 meters showed significant differences in

Source identification and apportionment of heavy metals in urban soil profiles.

Science.gov (United States)

Luo, Xiao-San; Xue, Yan; Wang, Yan-Ling; Cang, Long; Xu, Bo; Ding, Jing

2015-05-01

Because heavy metals (HMs) occurring naturally in soils accumulate continuously due to human activities, identifying and apportioning their sources becomes a challenging task for pollution prevention in urban environments. Besides the enrichment factors (EFs) and principal component analysis (PCA) for source classification, the receptor model (Absolute Principal Component Scores-Multiple Linear Regression, APCS-MLR) and Pb isotopic mixing model were also developed to quantify the source contribution for typical HMs (Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn) in urban park soils of Xiamen, a representative megacity in southeast China. Furthermore, distribution patterns of their concentrations and sources in 13 soil profiles (top 20 cm) were investigated by different depths (0-5, 5-10, 10-20 cm). Currently the principal anthropogenic source for HMs in urban soil of China is atmospheric deposition from coal combustion rather than vehicle exhaust. Specifically for Pb source by isotopic model ((206)Pb/(207)Pb and (208)Pb/(207)Pb), the average contributions were natural (49%)>coal combustion (45%)≫traffic emissions (6%). Although the urban surface soils are usually more contaminated owing to recent and current human sources, leaching effects and historic vehicle emissions can also make deep soil layer contaminated by HMs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fossil and Contemporary Fine Carbon Fractions at 12 Rural and Urban Sites in the United States

Energy Technology Data Exchange (ETDEWEB)

Schichtel, B; Malm, W; Bench, G; Fallon, S; McDade, C; Chow, J

2007-03-01

Fine particulate matter collected at two urban, four near-urban, and six remote sites throughout the United States were analyzed for total carbon (TC) and radiocarbon ({sup 14}C). Samples were collected at most sites for both a summer and winter season. The radiocarbon was used to partition the TC into fossil and contemporary fractions. On average, contemporary carbon composed about half of the carbon at the urban, {approx}70-97% at near-urban, and 82-100% at remote sites. At Phoenix, Arizona, and Seattle, Washington, one monitor was located within the urban center and one outside to assess the urban excess over background concentrations. During the summer the urban and rural sites had similar contemporary carbon concentrations. However, during the winter the urban sites had more than twice the contemporary carbon measured at the neighboring sites, indicating anthropogenic contributions to the contemporary carbon. The urban fossil carbon was 4-20 times larger than the neighboring rural sites for both seasons. Organic (OC) and elemental carbon (EC) from TOR analysis were available. These and the radiocarbon data were used to estimate characteristic fossil and contemporary EC/TC ratios for the winter and summer seasons. These ratios were applied to carbon data from the Interagency Monitoring of Protected Visual Environments network to estimate the fraction of contemporary carbon at mostly rural sites throughout the United States. In addition, the ratios were used to develop a semiquantitative, lower bound estimate of secondary organic carbon (SOC) contribution to fossil and contemporary carbon. SOC accounted for more than one-third of the fossil and contemporary carbon.

A statistical intercomparison between "urban" and "rural" precipitation chemistry data from greater Manchester and two nearby secondary national network sites in the United Kingdom

Science.gov (United States)

Lee, David S.; Longhurst, James W. S.

Precipitation chemistry data from a dense urban monitoring network in Greater Manchester, northwest England, were compared with interpolated values from the U.K. secondary national acid deposition monitoring network for the year 1988. Differences were found to be small. However, when data from individual sites from the Greater Manchester network were compared with data from the two nearest secondary national network sites, significant differences were found using simple and complex statistical analyses. Precipitation chemistry at rural sites could be similar to that at urban sites, but the sources of some ions were thought to be different. The synoptic-scale gradients of precipitation chemistry, as shown by the secondary national network, also accounted for some of the differences.

Sediment sources and storages in the urbanizing South Creek catchment, Lake Macquarie, NSW

International Nuclear Information System (INIS)

Curtis, S.J.

1988-10-01

An investigation of the sediment source areas and sediment storages has been undertaken in the South Creek catchment, Lake Macquarie, NSW. Source areas have been examined by analyzing suspended sediment concentrations, field measurements and observations, and caesium-137 values. The caesium-137 technique and field measurements were used to study the sediment storages on the South Creek flood plain. Particle size analysis of sediments on the slopes and flood plain were undertaken to provide information on the efficiency of the sediment transport system. The results of these investigations indicate that the developing urban areas are the main sources of poorest water quality (in terms of suspended sediment) in the South Creek catchment. The open woodland, rural and established urban areas were minor sediment source areas, although the open woodland had the potential to become a major sediment source if disturbed by human activities. The developing urban areas had efficient sediment transport systems, while the open woodland and rural areas tended to deposit sediment locally. The upstream section of the flood plain was found to be storing more sediment than the downstream section. The study revealed that when urban development occurs on the steeper gradients of the South Creek catchment erosion processes are greatly accelerated and thus the developing urban area becomes the major source of poorest water quality in the catchment. The importance of the developing urban area as a sediment source needs to be considered in any future land developments in urbanizing drainage basins

Passerine migrant stopover duration and spatial behaviour at an urban stopover site

Science.gov (United States)

Seewagen, Chad L.; Slayton, Eric J.; Guglielmo, Christopher G.

2010-09-01

Migration routes of many Nearctic-Neotropical landbirds pass through the most urbanized regions of North America. Migrants are known to use urban habitats as stopover sites and often occur in cities at exceptional density; yet knowledge of migrant behaviour and ecology in such places is surprisingly limited. We radio-tracked ovenbirds ( Seiurus aurocapillus) during stopovers in a New York City park to obtain some of the first detailed information on how landbird migrants utilize an urban habitat as a stopover site. We examined fine-scale movement patterns, home range sizes, stopover durations, and how arrival condition affected each of these metrics. During both seasons, most birds moved widely throughout the site upon presumed arrival and then either continued migration that night or settled into a more defined area on subsequent days. Area usage varied markedly among individuals during both seasons, ranging 1-16 ha. Stopover durations averaged 3.0 days (range = 1-10 days) during spring and 2.9 days (range = 1-14 days) during autumn. Spatial behaviours and stopover durations were not influenced by arrival condition during spring, and during autumn only movement rates and displacement distances were significantly (negatively) condition-related. Our findings do not support previous assumptions that urban stopover habitats are only used by migrants briefly in times of urgency when alternatives are unavailable. At least half of the birds we studied stopped over for multiple days during both seasons, and bird movements were indicative of an ability to search for, locate, and occupy suitable micro-sites. Ovenbird behaviour in our study site was similar in many ways to what has been observed in recent telemetry studies of ovenbirds and other passerine migrants at various non-urban stopover sites.

Sediment sources in an urbanizing, mixed land-use watershed

Science.gov (United States)

Nelson, Erin J.; Booth, Derek B.

2002-07-01

The Issaquah Creek watershed is a rapidly urbanizing watershed of 144 km 2 in western Washington, where sediment aggradation of the main channel and delivery of fine sediment into a large downstream lake have raised increasingly frequent concerns over flooding, loss of fish habitat, and degraded water quality. A watershed-scale sediment budget was evaluated to determine the relative effects of land-use practices, including urbanization, on sediment supply and delivery, and to guide management responses towards the most effective source-reduction strategies. Human activity in the watershed, particularly urban development, has caused an increase of nearly 50% in the annual sediment yield, now estimated to be 44 tonnes km -2 yr -1. The main sources of sediment in the watershed are landslides (50%), channel-bank erosion (20%), and road-surface erosion (15%). This assessment characterizes the role of human activity in mixed-use watersheds such as this, and it demonstrates some of the key processes, particularly enhanced stream-channel erosion, by which urban development alters sediment loads.

Urban NH3 levels and sources in six major Spanish cities.

Science.gov (United States)

Reche, Cristina; Viana, Mar; Karanasiou, Angeliki; Cusack, Michael; Alastuey, Andrés; Artiñano, Begoña; Revuelta, M Aranzazu; López-Mahía, Purificación; Blanco-Heras, Gustavo; Rodríguez, Sergio; Sánchez de la Campa, Ana M; Fernández-Camacho, Rocío; González-Castanedo, Yolanda; Mantilla, Enrique; Tang, Y Sim; Querol, Xavier

2015-01-01

A detailed spatial and temporal assessment of urban NH3 levels and potential emission sources was made with passive samplers in six major Spanish cities (Barcelona, Madrid, A Coruña, Huelva, Santa Cruz de Tenerife and Valencia). Measurements were conducted during two different periods (winter-autumn and spring-summer) in each city. Barcelona showed the clearest spatial pattern, with the highest concentrations in the old city centre, an area characterised by a high population density and a dense urban architecture. The variability in NH3 concentrations did not follow a common seasonal pattern across the different cities. The relationship of urban NH3 with SO2 and NOX allowed concluding on the causes responsible for the variations in NH3 levels between measurement periods observed in Barcelona, Huelva and Madrid. However, the factors governing the variations in A Coruña, Valencia and Santa Cruz de Tenerife are still not fully understood. This study identified a broad variability in NH3 concentrations at the city-scale, and it confirms that NH3 sources in Spanish urban environments are vehicular traffic, biological sources (e.g. garbage containers), wastewater treatment plants, solid waste treatment plants and industry. The importance of NH3 monitoring in urban environments relies on its role as a precursor of secondary inorganic species and therefore PMX. Further research should be addressed in order to establish criteria to develop and implement mitigation strategies for cities, and to include urban NH3 sources in the emission inventories. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical characterization and source identification of PM2.5 at multiple sites in the Beijing-Tianjin-Hebei region, China

Science.gov (United States)

Huang, Xiaojuan; Liu, Zirui; Liu, Jingyun; Hu, Bo; Wen, Tianxue; Tang, Guiqian; Zhang, Junke; Wu, Fangkun; Ji, Dongsheng; Wang, Lili; Wang, Yuesi

2017-11-01

The simultaneous observation and analysis of atmospheric fine particles (PM2.5) on a regional scale is an important approach to develop control strategies for haze pollution. In this study, samples of filtered PM2.5 were collected simultaneously at three urban sites (Beijing, Tianjin, and Shijiazhuang) and at a regional background site (Xinglong) in the Beijing-Tianjin-Hebei (BTH) region from June 2014 to April 2015. The PM2.5 at the four sites was mainly comprised of organic matter, secondary inorganic ions, and mineral dust. Positive matrix factorization (PMF) demonstrated that, on an annual basis, secondary inorganic aerosol was the largest PM2.5 source in this region, accounting for 29.2-40.5 % of the PM2.5 mass at the urban sites; the second-largest PM2.5 source was motor vehicle exhaust, particularly in Beijing (24.9 %), whereas coal combustion was also a large source in Tianjin (12.4 %) and Shijiazhuang (15.5 %), with particular dominance in winter. Secondary inorganic aerosol plays a vital role in the haze process, with the exception of the spring haze in Shijiazhuang and Tianjin, for which the dust source was crucial. In addition to secondary transformations, local direct emissions (coal combustion and motor vehicle exhaust) significantly contribute to the winter haze at the urban sites. Moreover, with the aggravation of haze pollution, the OC / EC mass ratio of PM2.5 decreased considerably and the nitrate-rich secondary aerosol increased during all four seasons in Beijing, both of which indicate that local motor vehicle emissions significantly contribute to the severe haze episodes in Beijing. To assess the impacts of regional transport on haze pollution, the PMF results were further processed with backward-trajectory cluster analysis, revealing that haze pollution usually occurred when air masses originating from polluted industrial regions in the south prevailed and is characterized by high PM2.5 loadings with considerable contributions from secondary

Chemical characterization and source identification of PM2.5 at multiple sites in the Beijing–Tianjin–Hebei region, China

Directory of Open Access Journals (Sweden)

X. Huang

2017-11-01

Full Text Available The simultaneous observation and analysis of atmospheric fine particles (PM2.5 on a regional scale is an important approach to develop control strategies for haze pollution. In this study, samples of filtered PM2.5 were collected simultaneously at three urban sites (Beijing, Tianjin, and Shijiazhuang and at a regional background site (Xinglong in the Beijing–Tianjin–Hebei (BTH region from June 2014 to April 2015. The PM2.5 at the four sites was mainly comprised of organic matter, secondary inorganic ions, and mineral dust. Positive matrix factorization (PMF demonstrated that, on an annual basis, secondary inorganic aerosol was the largest PM2.5 source in this region, accounting for 29.2–40.5 % of the PM2.5 mass at the urban sites; the second-largest PM2.5 source was motor vehicle exhaust, particularly in Beijing (24.9 %, whereas coal combustion was also a large source in Tianjin (12.4 % and Shijiazhuang (15.5 %, with particular dominance in winter. Secondary inorganic aerosol plays a vital role in the haze process, with the exception of the spring haze in Shijiazhuang and Tianjin, for which the dust source was crucial. In addition to secondary transformations, local direct emissions (coal combustion and motor vehicle exhaust significantly contribute to the winter haze at the urban sites. Moreover, with the aggravation of haze pollution, the OC ∕ EC mass ratio of PM2.5 decreased considerably and the nitrate-rich secondary aerosol increased during all four seasons in Beijing, both of which indicate that local motor vehicle emissions significantly contribute to the severe haze episodes in Beijing. To assess the impacts of regional transport on haze pollution, the PMF results were further processed with backward-trajectory cluster analysis, revealing that haze pollution usually occurred when air masses originating from polluted industrial regions in the south prevailed and is characterized by high PM2.5 loadings with considerable

Predicting summer site occupancy for an invasive species, the common brushtail possum (Trichosurus vulpecula, in an urban environment.

Directory of Open Access Journals (Sweden)

Amy L Adams

Full Text Available Invasive species are often favoured in fragmented, highly-modified, human-dominated landscapes such as urban areas. Because successful invasive urban adapters can occupy habitat that is quite different from that in their original range, effective management programmes for invasive species in urban areas require an understanding of distribution, habitat and resource requirements at a local scale that is tailored to the fine-scale heterogeneity typical of urban landscapes. The common brushtail possum (Trichosurus vulpecula is one of New Zealand's most destructive invasive pest species. As brushtail possums traditionally occupy forest habitat, control in New Zealand has focussed on rural and forest habitats, and forest fragments in cities. However, as successful urban adapters, possums may be occupying a wider range of habitats. Here we use site occupancy methods to determine the distribution of brushtail possums across five distinguishable urban habitat types during summer, which is when possums have the greatest impacts on breeding birds. We collected data on possum presence/absence and habitat characteristics, including possible sources of supplementary food (fruit trees, vegetable gardens, compost heaps, and the availability of forest fragments from 150 survey locations. Predictive distribution models constructed using the programme PRESENCE revealed that while occupancy rates were highest in forest fragments, possums were still present across a large proportion of residential habitat with occupancy decreasing as housing density increased and green cover decreased. The presence of supplementary food sources was important in predicting possum occupancy, which may reflect the high nutritional value of these food types. Additionally, occupancy decreased as the proportion of forest fragment decreased, indicating the importance of forest fragments in determining possum distribution. Control operations to protect native birds from possum predation in

Coal-tar-based sealcoated pavement: a major PAH source to urban stream sediments.

Science.gov (United States)

Witter, Amy E; Nguyen, Minh H; Baidar, Sunil; Sak, Peter B

2014-02-01

We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (~1303 km(2)) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69-0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use. Copyright © 2013 Elsevier Ltd. All rights reserved.

Source Apportionment of the Size-Fractionated Urban Aerosols in and around Kolkata, India

Science.gov (United States)

Sarkar, Ujjaini; Haque, Monirul; Roy, Rajdeep; Chakraborty, Sanjoy

Our main objective was to estimate the heavy metals like the Lead, Mercury, Cadmium, Sodium, Potassium, Calcium, Aluminium, and Iron, in addition to ammonium, chloride, nitrate, and sulphate ions, by Atomic Absorption Spectrophotometry and Ion Chromatography and apportion the most probable sources using the Chemical Mass Balance Model. The three urban locations of Behala Chowrasta, Rabindra Sadan, and Shyam Bazaar Five Points were chosen within the city of Kolkata. One rural location was chosen at the Indian Institute of Technology campus, Kharagpur, a rural site in the Midnapur District of the state of West Bengal, India. The results look quite encouraging.

Local source impacts on primary and secondary aerosols in the Midwestern United States

Science.gov (United States)

Jayarathne, Thilina; Rathnayake, Chathurika M.; Stone, Elizabeth A.

2016-04-01

Atmospheric particulate matter (PM) exhibits heterogeneity in composition across urban areas, leading to poor representation of outdoor air pollutants in human exposure assessments. To examine heterogeneity in PM composition and sources across an urban area, fine particulate matter samples (PM2.5) were chemically profiled in Iowa City, IA from 25 August to 10 November 2011 at two monitoring stations. The urban site is the federal reference monitoring (FRM) station in the city center and the peri-urban site is located 8.0 km to the west on the city edge. Measurements of PM2.5 carbonaceous aerosol, inorganic ions, molecular markers for primary sources, and secondary organic aerosol (SOA) tracers were used to assess statistical differences in composition and sources across the two sites. PM2.5 mass ranged from 3 to 26 μg m-3 during this period, averaging 11.2 ± 4.9 μg m-3 (n = 71). Major components of PM2.5 at the urban site included organic carbon (OC; 22%), ammonium (14%), sulfate (13%), nitrate (7%), calcium (2.9%), and elemental carbon (EC; 2.2%). Periods of elevated PM were driven by increases in ammonium, sulfate, and SOA tracers that coincided with hot and dry conditions and southerly winds. Chemical mass balance (CMB) modeling was used to apportion OC to primary sources; biomass burning, vegetative detritus, diesel engines, and gasoline engines accounted for 28% of OC at the urban site and 24% of OC at the peri-urban site. Secondary organic carbon from isoprene and monoterpene SOA accounted for an additional 13% and 6% of OC at the urban and peri-urban sites, respectively. Differences in biogenic SOA across the two sites were associated with enhanced combustion activities in the urban area and higher aerosol acidity at the urban site. Major PM constituents (e.g., OC, ammonium, sulfate) were generally well-represented by a single monitoring station, indicating a regional source influence. Meanwhile, nitrate, biomass burning, food cooking, suspended dust, and

[Research on spatial differentiation of urban stormwater runoff quality by source area monitoring].

Science.gov (United States)

Li, Li-Qing; Zhu, Ren-Xiao; Guo, Shu-Gang; Yin, Cheng-Qing

2010-12-01

Runoff samples were collected from 14 source areas in Hanyang district during four rain events in an attempt to investigate the spatial differentiation and influencing factors of urban stormwater runoff quality. The outcomes are expected to offer practical guidance in sources control of urban runoff pollution. The results revealed that particle-bound proportion of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in stormwater runoff were 58% +/- 17%, 65% +/- 13% and 92% +/- 6%, respectively. The fractions of ammonia, nitrate and dissolved organic nitrogen were homogeneous in dissolved nitrogen composition. Urban surface function, traffic volume, land use, population density, and street sweeping practice are the main factors determining spatial differentiation of urban surface runoff quality. The highest magnitude of urban stormwater runoff pollution was expected in the old urban residential area, followed by general residential with restaurants, commercial and transport area, new developments and green land. In addition, the magnitude of road stormwater runoff pollution is positively correlated to traffic volume, in the following order: the first trunk road > the second trunk road > minor road. Street sweeping and critical source areas controls should be implemented to mitigate the adverse effects of urban stormwater runoff on receive waters.

Patterns and sources of particle-phase aliphatic and polycyclic aromatic hydrocarbons in urban and rural sites of western Greece

Science.gov (United States)

Kalaitzoglou, Maria; Terzi, Eleni; Samara, Constantini

Particle-bound aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs, respectively) were determined in the ambient air of the Eordea basin, in western Greece, where intensive coal burning for power generation takes place. Thirteen PAHs, n-alkanes (C 14-C 35), hopanes, and isoprenoid hydrocarbons (pristane and phytane) were determined in the total suspended particles collected from the atmosphere of four sites within the basin receiving potential impacts from various sources, such as fly ash, coal mining, automobile traffic, domestic heating, and agricultural or refuse burning. The same organic species were also determined in the fly ash generated in power stations, and in particulate emissions from open burning of biomass (dry corn leaves) and refuse burning. Organic particle sources were resolved using concentration diagnostic ratios and factor analysis (FA). A multivariate statistical receptor model (Absolute Principal Component Analysis, APCA) was finally employed to estimate the contribution of identified sources to the measured concentrations of organic pollutants. Four major sources for ambient PAHs and AHs were identified displaying variable contribution in different sites: (a) fossil fuel combustion, (b) biogenic emissions, (c) refuse burning, and (d) oil residues. Fuel combustion was the major source of ambient PAHs and an important source of n-alkanes in the range C 21-C 28. Oil residues were found to be the major source of low molecular weight n-alkanes (particularly the C 14-C 16), and an important source of pristane, phytane and UCM. Biogenic sources were primarily responsible for the high molecular weight n-alkanes explaining almost the entire concentration levels of homologues >C 32. Biomass burning was particularly important for the C 23-C 26n-alkanes. Despite the vicinity of certain sampling sites to power stations, coal fly ash was not identifiable as a source for ambient PAHs and AHs.

Perception of personal safety in urban recreation sites

Science.gov (United States)

Herbert W. Schroeder; L.M. Anderson

1984-01-01

Photograph of 17 urban recreation sites in Chicago and Atlanta were evaluated by college students (n = 68) in Illinois, Georgia, and Michigan, for either perceived security, scenic quality, or both. For most raters, high visibility and developed park features significantly enhanced perceived security. Scenic quality, on the other hand, was enhanced for the majority of...

Atmospheric polycyclic aromatic hydrocarbons in the urban environment: Occurrence, toxicity and source apportionment

International Nuclear Information System (INIS)

Mishra, Nitika; Ayoko, Godwin A.; Morawska, Lidia

2016-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) represent a major class of toxic pollutants because of their carcinogenic and mutagenic characteristics. People living in urban areas are regularly exposed to PAHs because of abundance of their emission sources. Within this context, this study aimed to: (i) identify and quantify the levels of ambient PAHs in an urban environment; (ii) evaluate their toxicity; and (iii) identify their sources as well as the contribution of specific sources to measured concentrations. Sixteen PAHs were identified and quantified in air samples collected from Brisbane. Principal Component Analysis – Absolute Principal Component Scores (PCA-APCS) was used in order to conduct source apportionment of the measured PAHs. Vehicular emissions, natural gas combustion, petrol emissions and evaporative/unburned fuel were the sources identified; contributing 56%, 21%, 15% and 8% of the total PAHs emissions, respectively, all of which need to be considered for any pollution control measures implemented in urban areas. - Highlights: • PAHs represent a major group of outdoor air pollutants. • Concentration levels of PAHS in urban schools ranged from 1.2 to 38 ng/m"3. • PCA–APCS technique used to identify sources of PAHs and their contributions. • Vehicular emissions (56%) were found to be the prominent sources of PAHs.

Carbon footprint of urban source separation for nutrient recovery.

Science.gov (United States)

Kjerstadius, H; Bernstad Saraiva, A; Spångberg, J; Davidsson, Å

2017-07-15

Source separation systems for the management of domestic wastewater and food waste has been suggested as more sustainable sanitation systems for urban areas. The present study used an attributional life cycle assessment to investigate the carbon footprint and potential for nutrient recovery of two sanitation systems for a hypothetical urban area in Southern Sweden. The systems represented a typical Swedish conventional system and a possible source separation system with increased nutrient recovery. The assessment included the management chain from household collection, transport, treatment and final return of nutrients to agriculture or disposal of the residuals. The results for carbon footprint and nutrient recovery (phosphorus and nitrogen) concluded that the source separation system could increase nutrient recovery (0.30-0.38 kg P capita -1 year -1 and 3.10-3.28 kg N capita -1 year -1 ), while decreasing the carbon footprint (-24 to -58 kg CO 2 -eq. capita -1 year -1 ), compared to the conventional system. The nutrient recovery was increased by the use of struvite precipitation and ammonium stripping at the wastewater treatment plant. The carbon footprint decreased, mainly due to the increased biogas production, increased replacement of mineral fertilizer in agriculture and less emissions of nitrous oxide from wastewater treatment. In conclusion, the study showed that source separation systems could potentially be used to increase nutrient recovery from urban areas, while decreasing the climate impact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of PM2.5 carbonaceous pollutants between an urban site in Shanghai and a background site in a coastal East China Sea island in summer: concentration, composition and sources.

Science.gov (United States)

Wang, Fengwen; Lin, Tian; Li, Yuanyuan; Guo, Zhigang; Rose, Neil L

2017-06-21

Nine paired samples of atmospheric particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM 2.5 ) were collected concurrently from an urban site in Shanghai, China and a background site in Huaniao Island (HNI) in the coastal East China Sea (ECS) between July 21 and 29, 2011. The samples were analyzed for 16 United States Environmental Protection Agency (USEPA) priority polycyclic aromatic hydrocarbons (PAHs), n-alkanes (20 species, C 14 -C 33 ), hopanes (10 species, C 29 -C 32 ), and steranes (12 species, C 27 -C 29 ). These two sites, approximately 66 km apart, are both on the pathway of land-based pollutants as they are transported to the ECS by seasonal winds. As expected, concentrations in Shanghai were higher (average: 8.4 and 67.8 ng m -3 for the 16 PAHs and n-alkanes, respectively) than those in HNI (average: 1.8 and 8.5 ng m -3 , respectively). The dominant contributor to the 16 PAHs in Shanghai was 5-6-ring PAHs (60.0%), whereas 2-3-ring PAHs contributed the most (72.5%) in HNI. Plant waxes contributed 45.7% and 25.9% of the n-alkanes in Shanghai and HNI, respectively, implying a relatively greater contribution from petroleum residues to the n-alkanes in HNI. Principal component analysis (PCA) and the compositions of hopanes and steranes highlighted a prominent contribution from traffic emissions to carbonaceous PM 2.5 aerosols. This study provides comprehensive details about the sources, formation, and transport of pollutants from eastern China to the coastal ECS.

Integrated site investigation and groundwater monitoring in an urban environment

Science.gov (United States)

Weatherl, R. K.

2017-12-01

Understanding groundwater dynamics around cities and other areas of human influence is of crucial importance for water resource management and protection, especially in a time of environmental and societal change. The human environment presents a unique challenge in terms of hydrological characterization, as the water cycle is generally artificialized and emissions of treated waste and chemical products into the surface- and groundwater system tend to disrupt the natural aqueous signature in significant ways. This project presents an integrated approach for robust characterization and monitoring of an urban aquifer which is actively exploited for municipal water supply. The study is carried out in the town of Fehraltorf, in the canton of Zürich, Switzerland. This particular town encompasses industrial and agricultural zones in addition to its standard urban setting. A minimal amount of data exist at this site, and the data that do exist are spatially and temporally sparse. Making use of traditional hydrogeological methods alongside evolving and emerging technologies, we aim to identify sources of contamination and to define groundwater flow and solute transport through space and time. Chemical and physical indicator parameters are identified for tracing contaminations including micropollutants and plant nutrients. Wireless sensors are installed for continuous on-line monitoring of essential parameters (electrical conductivity, temperature, water level). A wireless sensor network has previously been installed in the sewer system of the study site, facilitating investigation into interactions between sewer water and groundwater. Our approach illustrates the relations between land use, climate, rainfall dynamics, and the groundwater signature through time. At its conclusion, insights gained from this study will be used by municipal authorities to refine protective zones around pumping wells and to direct resources towards updating practices and replacing

Crowd Sourcing to Improve Urban Stormwater Management

Science.gov (United States)

Minsker, B. S.; Band, L. E.; Heidari Haratmeh, B.; Law, N. L.; Leonard, L. N.; Rai, A.

2017-12-01

Over half of the world's population currently lives in urban areas, a number predicted to grow to 60 percent by 2030. Urban areas face unprecedented and growing challenges that threaten society's long-term wellbeing, including poverty; chronic health problems; widespread pollution and resource degradation; and increased natural disasters. These are "wicked" problems involving "systems of systems" that require unprecedented information sharing and collaboration across disciplines and organizational boundaries. Cities are recognizing that the increasing stream of data and information ("Big Data"), informatics, and modeling can support rapid advances on these challenges. Nonetheless, information technology solutions can only be effective in addressing these challenges through deeply human and systems perspectives. A stakeholder-driven approach ("crowd sourcing") is needed to develop urban systems that address multiple needs, such as parks that capture and treat stormwater while improving human and ecosystem health and wellbeing. We have developed informatics- and Cloud-based collaborative methods that enable crowd sourcing of green stormwater infrastructure (GSI: rain gardens, bioswales, trees, etc.) design and management. The methods use machine learning, social media data, and interactive design tools (called IDEAS-GI) to identify locations and features of GSI that perform best on a suite of objectives, including life cycle cost, stormwater volume reduction, and air pollution reduction. Insights will be presented on GI features that best meet stakeholder needs and are therefore most likely to improve human wellbeing and be well maintained.

Variation at the DRD4 locus is associated with wariness and local site selection in urban black swans.

Science.gov (United States)

van Dongen, Wouter F D; Robinson, Randall W; Weston, Michael A; Mulder, Raoul A; Guay, Patrick-Jean

2015-12-11

Interactions between wildlife and humans are increasing. Urban animals are often less wary of humans than their non-urban counterparts, which could be explained by habituation, adaptation or local site selection. Under local site selection, individuals that are less tolerant of humans are less likely to settle in urban areas. However, there is little evidence for such temperament-based site selection, and even less is known about its underlying genetic basis. We tested whether site selection in urban and non-urban habitats by black swans (Cygnus atratus) was associated with polymorphisms in two genes linked to fear in animals, the dopamine receptor D4 (DRD4) and serotonin transporter (SERT) genes. Wariness in swans was highly repeatable between disturbance events (repeatability = 0.61) and non-urban swans initiated escape from humans earlier than urban swans. We found no inter-individual variation in the SERT gene, but identified five DRD4 genotypes and an association between DRD4 genotype and wariness. Individuals possessing the most common DRD4 genotype were less wary than individuals possessing rarer genotypes. As predicted by the local site selection hypothesis, genotypes associated with wary behaviour were over three times more frequent at the non-urban site. This resulted in moderate population differentiation at DRD4 (FST = 0.080), despite the sites being separated by only 30 km, a short distance for this highly-mobile species. Low population differentiation at neutrally-selected microsatellite loci and the likely occasional migration of swans between the populations reduces the likelihood of local site adaptations. Our results suggest that wariness in swans is partly genetically-determined and that wary swans settle in less-disturbed areas. More generally, our findings suggest that site-specific management strategies may be necessary that consider the temperament of local animals.

Using Social Media to Identify Sources of Healthy Food in Urban Neighborhoods.

Science.gov (United States)

Gomez-Lopez, Iris N; Clarke, Philippa; Hill, Alex B; Romero, Daniel M; Goodspeed, Robert; Berrocal, Veronica J; Vinod Vydiswaran, V G; Veinot, Tiffany C

2017-06-01

An established body of research has used secondary data sources (such as proprietary business databases) to demonstrate the importance of the neighborhood food environment for multiple health outcomes. However, documenting food availability using secondary sources in low-income urban neighborhoods can be particularly challenging since small businesses play a crucial role in food availability. These small businesses are typically underrepresented in national databases, which rely on secondary sources to develop data for marketing purposes. Using social media and other crowdsourced data to account for these smaller businesses holds promise, but the quality of these data remains unknown. This paper compares the quality of full-line grocery store information from Yelp, a crowdsourced content service, to a "ground truth" data set (Detroit Food Map) and a commercially-available dataset (Reference USA) for the greater Detroit area. Results suggest that Yelp is more accurate than Reference USA in identifying healthy food stores in urban areas. Researchers investigating the relationship between the nutrition environment and health may consider Yelp as a reliable and valid source for identifying sources of healthy food in urban environments.

Receptor modeling of C2─C7 hydrocarbon sources at an urban background site in Zurich, Switzerland: changes between 1993─1994 and 2005─2006

Directory of Open Access Journals (Sweden)

S. Reimann

2008-05-01

Full Text Available Hourly measurements of 13 volatile hydrocarbons (C2–C7 were performed at an urban background site in Zurich (Switzerland in the years 1993–1994 and again in 2005–2006. For the separation of the volatile organic compounds by gas-chromatography (GC, an identical chromatographic column was used in both campaigns. Changes in hydrocarbon profiles and source strengths were recovered by positive matrix factorization (PMF. Eight and six factors could be related to hydrocarbon sources in 1993–1994 and in 2005–2006, respectively. The modeled source profiles were verified by hydrocarbon profiles reported in the literature. The source strengths were validated by independent measurements, such as inorganic trace gases (NOx, CO, SO2, methane (CH4, oxidized hydrocarbons (OVOCs and meteorological data (temperature, wind speed etc.. Our analysis suggests that the contribution of most hydrocarbon sources (i.e. road traffic, solvents use and wood burning decreased by a factor of about two to three between the early 1990s and 2005–2006. On the other hand, hydrocarbon losses from natural gas leakage remained at relatively constant levels (−20%. The estimated emission trends are in line with the results from different receptor-based approaches reported for other European cities. Their differences to national emission inventories are discussed.

The Use of Principal Component Analysis for Source Identification of PM2.5 from Selected Urban and Regional Background Sites in Poland

Science.gov (United States)

Błaszczak, Barbara

2018-01-01

The paper reports the results of the measurements of water-soluble ions and carbonaceous matter content in the fine particulate matter (PM2.5), as well as the contributions of major sources in PM2.5. Daily PM2.5 samples were collected during heating and non-heating season of the year 2013 in three different locations in Poland: Szczecin (urban background), Trzebinia (urban background) and Złoty Potok (regional background). The concentrations of PM2.5, and its related components, exhibited clear spatiotemporal variability with higher levels during the heating period. The share of the total carbon (TC) in PM2.5 exceeded 40% and was primarily determined by fluctuations in the share of OC. Sulfates (SO42-), nitrates (NO3-) and ammonium (NH4+) dominated in the ionic composition of PM2.5 and accounted together 34% (Szczecin), 30% (Trzebinia) and 18% (Złoty Potok) of PM2.5 mass. Source apportionment analysis, performed by PCA-MLRA model (Principal Component Analysis - Multilinear Regression Analysis), revealed that secondary aerosol, whose presence is related to oxidation of gaseous precursors emitted from fuel combustion and biomass burning, had the largest contribution in observed PM2.5 concentrations. In addition, the contribution of traffic sources together with road dust resuspension, was observed. The share of natural sources (sea spray, crustal dust) was generally lower.

The Use of Principal Component Analysis for Source Identification of PM2.5 from Selected Urban and Regional Background Sites in Poland

Directory of Open Access Journals (Sweden)

Błaszczak Barbara

2018-01-01

Full Text Available The paper reports the results of the measurements of water-soluble ions and carbonaceous matter content in the fine particulate matter (PM2.5, as well as the contributions of major sources in PM2.5. Daily PM2.5 samples were collected during heating and non-heating season of the year 2013 in three different locations in Poland: Szczecin (urban background, Trzebinia (urban background and Złoty Potok (regional background. The concentrations of PM2.5, and its related components, exhibited clear spatiotemporal variability with higher levels during the heating period. The share of the total carbon (TC in PM2.5 exceeded 40% and was primarily determined by fluctuations in the share of OC. Sulfates (SO42-, nitrates (NO3- and ammonium (NH4+ dominated in the ionic composition of PM2.5 and accounted together ~34% (Szczecin, ~30% (Trzebinia and ~18% (Złoty Potok of PM2.5 mass. Source apportionment analysis, performed by PCA-MLRA model (Principal Component Analysis – Multilinear Regression Analysis, revealed that secondary aerosol, whose presence is related to oxidation of gaseous precursors emitted from fuel combustion and biomass burning, had the largest contribution in observed PM2.5 concentrations. In addition, the contribution of traffic sources together with road dust resuspension, was observed. The share of natural sources (sea spray, crustal dust was generally lower.

Triple oxygen isotopes indicate urbanization affects sources of nitrate in wet and dry atmospheric deposition

Science.gov (United States)

Nelson, David M.; Tsunogai, Urumu; Ding, Dong; Ohyama, Takuya; Komatsu, Daisuke D.; Nakagawa, Fumiko; Noguchi, Izumi; Yamaguchi, Takashi

2018-05-01

Atmospheric nitrate deposition resulting from anthropogenic activities negatively affects human and environmental health. Identifying deposited nitrate that is produced locally vs. that originating from long-distance transport would help inform efforts to mitigate such impacts. However, distinguishing the relative transport distances of atmospheric nitrate in urban areas remains a major challenge since it may be produced locally and/or be transported from upwind regions. To address this uncertainty we assessed spatiotemporal variation in monthly weighted-average Δ17O and δ15N values of wet and dry nitrate deposition during one year at urban and rural sites along the western coast of the northern Japanese island of Hokkaido, downwind of the East Asian continent. Δ17O values of nitrate in wet deposition at the urban site mirrored those of wet and dry deposition at the rural site, ranging between ˜ +23 and +31 ‰ with higher values during winter and lower values in summer, which suggests the greater relative importance of oxidation of NO2 by O3 during winter and OH during summer. In contrast, Δ17O values of nitrate in dry deposition at the urban site were lower (+19 - +25 ‰) and displayed less distinct seasonal variation. Furthermore, the difference between δ15N values of nitrate in wet and dry nitrate deposition was, on average, 3 ‰ greater at the urban than rural site, and Δ17O and δ15N values were correlated for both forms of deposition at both sites with the exception of dry deposition at the urban site. These results suggest that, relative to nitrate in wet and dry deposition in rural environments and wet deposition in urban environments, nitrate in dry deposition in urban environments forms from relatively greater oxidation of NO by peroxy radicals and/or oxidation of NO2 by OH. Given greater concentrations of peroxy radicals and OH in cities, these results imply that dry nitrate deposition results from local NOx emissions more so than wet

Atmospheric polycyclic aromatic hydrocarbons in the urban environment: Occurrence, toxicity and source apportionment.

Science.gov (United States)

Mishra, Nitika; Ayoko, Godwin A; Morawska, Lidia

2016-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) represent a major class of toxic pollutants because of their carcinogenic and mutagenic characteristics. People living in urban areas are regularly exposed to PAHs because of abundance of their emission sources. Within this context, this study aimed to: (i) identify and quantify the levels of ambient PAHs in an urban environment; (ii) evaluate their toxicity; and (iii) identify their sources as well as the contribution of specific sources to measured concentrations. Sixteen PAHs were identified and quantified in air samples collected from Brisbane. Principal Component Analysis - Absolute Principal Component Scores (PCA-APCS) was used in order to conduct source apportionment of the measured PAHs. Vehicular emissions, natural gas combustion, petrol emissions and evaporative/unburned fuel were the sources identified; contributing 56%, 21%, 15% and 8% of the total PAHs emissions, respectively, all of which need to be considered for any pollution control measures implemented in urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sources and Potential Photochemical Roles of Formaldehyde in an Urban Atmosphere in South China

Science.gov (United States)

Wang, Chuan; Huang, Xiao-Feng; Han, Yu; Zhu, Bo; He, Ling-Yan

2017-11-01

Formaldehyde (HCHO) is an important intermediate in tropospheric photochemistry. However, study of its evolution characteristics under heavy pollution conditions in China is limited, especially for high temporal resolutions, making it difficult to analyze its sources and environmental impacts. In this study, ambient levels of HCHO were monitored using a proton-transfer reaction mass spectrometer at an urban site in the Pearl River Delta of China. Continuous monitoring campaigns were conducted in the spring, summer, fall, and winter in 2016. The highest averaged HCHO concentrations were observed in autumn (5.1 ± 3.1 ppbv) and summer (5.0 ± 4.4 ppbv), followed by winter (4.2 ± 2.2 ppbv) and spring (3.4 ± 1.6 ppbv). The daily maximum of HCHO occurs in the early afternoon and shows good correlations with O3 and the secondary organic aerosol tracer during the day, revealing close relationships between ambient HCHO and secondary formations in Shenzhen, especially in summer and autumn. The daytime HCHO is estimated to be the major contributor to O3 formation and OH radical production, indicating that HCHO plays a key role in the urban atmospheric photochemical reactions. Anthropogenic secondary formation was calculated to be the dominant source of HCHO using a photochemical age-based parameterization method, with an average proportion of 39%. The contributions of biogenic sources in summer (41%) and autumn (39%) are much higher than those in spring (26%) and winter (28%), while the contributions of anthropogenic primary sources in spring (20%) and winter (18%) are twice those in summer (9%) and autumn (9%).

Characteristics of particulate matter collected at an urban background site and a roadside site in Birmingham, United Kingdom

OpenAIRE

Taiwo, Adewale M.

2017-01-01

ABSTRACT This study was conducted to investigate the compositional characteristics of particulate matter (PM) collected both at an urban background site (Elms Road observational site, EROS) and a roadside site (Bristol Road observational site, BROS). PM samples were collected at the receptor sites between March 28 and April 11, 2012. Observed parameters included water-soluble ions (Cl-, NO- 3, SO4 2-, Na+, NH4 +, K+, Mg2+, Ca2+) and trace metals (V, Al, Cr, Mn, Fe, Zn, Cu, Sb, Ba, Pb). Result...

Quantification of source impact to PM using three-dimensional weighted factor model analysis on multi-site data

Science.gov (United States)

Shi, Guoliang; Peng, Xing; Huangfu, Yanqi; Wang, Wei; Xu, Jiao; Tian, Yingze; Feng, Yinchang; Ivey, Cesunica E.; Russell, Armistead G.

2017-07-01

Source apportionment technologies are used to understand the impacts of important sources of particulate matter (PM) air quality, and are widely used for both scientific studies and air quality management. Generally, receptor models apportion speciated PM data from a single sampling site. With the development of large scale monitoring networks, PM speciation are observed at multiple sites in an urban area. For these situations, the models should account for three factors, or dimensions, of the PM, including the chemical species concentrations, sampling periods and sampling site information, suggesting the potential power of a three-dimensional source apportionment approach. However, the principle of three-dimensional Parallel Factor Analysis (Ordinary PARAFAC) model does not always work well in real environmental situations for multi-site receptor datasets. In this work, a new three-way receptor model, called "multi-site three way factor analysis" model is proposed to deal with the multi-site receptor datasets. Synthetic datasets were developed and introduced into the new model to test its performance. Average absolute error (AAE, between estimated and true contributions) for extracted sources were all less than 50%. Additionally, three-dimensional ambient datasets from a Chinese mega-city, Chengdu, were analyzed using this new model to assess the application. Four factors are extracted by the multi-site WFA3 model: secondary source have the highest contributions (64.73 and 56.24 μg/m3), followed by vehicular exhaust (30.13 and 33.60 μg/m3), crustal dust (26.12 and 29.99 μg/m3) and coal combustion (10.73 and 14.83 μg/m3). The model was also compared to PMF, with general agreement, though PMF suggested a lower crustal contribution.

Chemical composition and source apportionment of PM10 at an urban background site in a high-altitude Latin American megacity (Bogota, Colombia).

Science.gov (United States)

Ramírez, Omar; Sánchez de la Campa, A M; Amato, Fulvio; Catacolí, Ruth A; Rojas, Néstor Y; de la Rosa, Jesús

2018-02-01

Bogota registers frequent episodes of poor air quality from high PM 10 concentrations. It is one of the main Latin American megacities, located at 2600 m in the tropical Andes, but there is insufficient data on PM 10 source contribution. A characterization of the chemical composition and the source apportionment of PM 10 at an urban background site in Bogota was carried out in this study. Daily samples were collected from June 2015 to May 2016 (a total of 311 samples). Organic carbon (OC), elemental carbon (EC), water soluble compounds (SO 4 2- , Cl - , NO 3 - , NH 4 + ), major elements (Al, Fe, Mg, Ca, Na, K, P) and trace metals (V, Cd, Pb, Sr, Ba, among others) were analyzed. The results were interpreted in terms of their variability during the rainy season (RS) and the dry season (DS). The data obtained revealed that the carbonaceous fraction (∼51%) and mineral dust (23%) were the main PM 10 components, followed by others (15%), Secondary Inorganic Compounds (SIC) (11%) and sea salt (0.4%). The average concentrations of soil, SIC and OC were higher during RS than DS. However, peak values were observed during the DS due to photochemical activity and forest fires. Although trace metals represented <1% of PM 10 , high concentrations of toxic elements such as Pb and Sb on RS, and Cu on DS, were obtained. By using a PMF model, six factors were identified (∼96% PM 10 ) including fugitive dust, road dust, metal processing, secondary PM, vehicles exhaust and industrial emissions. Traffic (exhaust emissions + road dust) was the major PM 10 source, accounting for ∼50% of the PM 10 . The results provided novel data about PM 10 chemical composition, its sources and its seasonal variability during the year, which can help the local government to define control strategies for the main emission sources during the most critical periods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multiple sources of boron in urban surface waters and groundwaters

Energy Technology Data Exchange (ETDEWEB)

Hasenmueller, Elizabeth A., E-mail: eahasenm@wustl.edu; Criss, Robert E.

2013-03-01

Previous studies attribute abnormal boron (B) levels in streams and groundwaters to wastewater and fertilizer inputs. This study shows that municipal drinking water used for lawn irrigation contributes substantial non-point loads of B and other chemicals (S-species, Li, and Cu) to surface waters and shallow groundwaters in the St. Louis, Missouri, area. Background levels and potential B sources were characterized by analysis of lawn and street runoff, streams, rivers, springs, local rainfall, wastewater influent and effluent, and fertilizers. Urban surface waters and groundwaters are highly enriched in B (to 250 μg/L) compared to background levels found in rain and pristine, carbonate-hosted streams and springs (< 25 μg/L), but have similar concentrations (150 to 259 μg/L) compared to municipal drinking waters derived from the Missouri River. Other data including B/SO{sub 4}{sup 2-}−S and B/Li ratios confirm major contributions from this source. Moreover, sequential samples of runoff collected during storms show that B concentrations decrease with increased discharge, proving that elevated B levels are not primarily derived from combined sewer overflows (CSOs) during flooding. Instead, non-point source B exhibits complex behavior depending on land use. In urban settings B is rapidly mobilized from lawns during “first flush” events, likely representing surficial salt residues from drinking water used to irrigate lawns, and is also associated with the baseflow fraction, likely derived from the shallow groundwater reservoir that over time accumulates B from drinking water that percolates into the subsurface. The opposite occurs in small rural watersheds, where B is leached from soils by recent rainfall and covaries with the event water fraction. Highlights: ► Boron sources and loads differ between urban and rural watersheds. ► Wastewaters are not the major boron source in small St. Louis, MO watersheds. ► Municipal drinking water used for lawn

Non-polar organic compounds as PM2.5 source tracers: Investigation of their sources and degradation in the Pearl River Delta, China

Science.gov (United States)

Wang, Q.; Feng, Y.; Huang, X. H. H.; Griffith, S.; Zhang, T.; Zhang, Q.; Wu, D.; Yu, J.

2016-12-01

Nonpolar organic compounds (NPOCs) including alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, and 1,3,5-triphenylbenzene, were quantified in PM2.5 samples at four sites in the Pearl River Delta (PRD) region, China over a two-year period from 2011 to 2012. The four sites include one industrial zone (Nanhai), one urban (Guangzhou), one urban outskirt (Dongguan) and one suburban (Nansha) locations. Some NPOCs are uniquely emitted from particular combustion sources, and thereby serving as convenient markers in source apportionment. Based on this multi-year and multi-site data set, spatial and seasonal variations, correlation analysis and ratio-ratio plots were used to investigate the source information and degradation of NPOC tracers. In summer, NPOCs showed distinct local emission characteristics, with urban sites having much higher concentrations than suburban site. In winter, regional transport was an important influence on NPOC levels, driving up concentrations at all sampling sites and diminishing an urban-suburban spatial gradient. The lighter NPOCs exhibited more prominent seasonal variations, suggesting their particle-phase abundance is more influenced by temperature, a critical factor in controlling the extent of semi-volatile organics partitioned into the aerosol phase. The heavier NPOCs, especially PAHs, showed negligible correlation among the four sites, suggesting more influence from local emissions. Ratio-ratio plots indicate photo-degradation and mixing of various sources for the NPOCs in the PRD. A positive matrix factorization (PMF) analysis of this large NPOC data set suggests that heavier NPOCs are more suitable source indicators than lighter NPOCs. Incorporating particle-phase light NPOC concentrations in PMF produces a separate factor, which primarily contains those light NPOCs and likely is not a source factor. Total NPOC concentrations predicted using Pankow partitioning theory were explored as PMF inputs, however, the PMF

Water-soluble components in PM10 aerosols over an urban and a suburban site in the city of Sfax (Tunisia)

OpenAIRE

AZRI, C.; MABROUK, C.; ABIDA, H.; MEDHIOUB, K.

2010-01-01

This study examines the influence of source and meteorological factors on the physico-chemical characteristics of atmospheric aerosols collected at two sampling sites, urban and suburban, in the city of Sfax (Tunisia) during the year of 2004. Atmospheric aerosols were further analyzed for their chemical composition and spatio-temporal evolution was investigated. Based on particle content distribution, the species studied were classified into distinct groups with different content and temporal...

A statistical intercomparison between 'urban' and 'rural' precipitation chemistry data from Greater Manchester and the two nearby secondary national network sites in the United Kingdom

Energy Technology Data Exchange (ETDEWEB)

Lee, D.S.; Longhurst, J.W.S. (Manchester Polytechnic, Manchester (United Kingdom). Acid Rain Information Centre, Dept. of Environmental and Graphical Studies)

1992-11-01

Precipitation chemistry data from a dense urban monitoring network in Greater Manchester, northwest England, were compared with interpolated values from the U.K. secondary national acid deposition monitoring network for the year 1988. Differences were found to be small. However, when data from individual sites from the Greater Manchester network were compared with data from the two nearest secondary national network sites, significant differences were found using simple and complex statistical analyses. Precipitation chemistry at rural sites could be similar to that at urban sites, but the sources of some ions were thought to be different. The synoptic-scale gradients of precipitation chemistry, as shown by the secondary national network, also accounted for some of the differences. 34 refs., 7 figs., 8 tabs.

Transplantation of epiphytic bioaccumulators (Tillandsia capillaris) for high spatial resolution biomonitoring of trace elements and point sources deconvolution in a complex mining/smelting urban context

Science.gov (United States)

Goix, Sylvaine; Resongles, Eléonore; Point, David; Oliva, Priscia; Duprey, Jean Louis; de la Galvez, Erika; Ugarte, Lincy; Huayta, Carlos; Prunier, Jonathan; Zouiten, Cyril; Gardon, Jacques

2013-12-01

Monitoring atmospheric trace elements (TE) levels and tracing their source origin is essential for exposure assessment and human health studies. Epiphytic Tillandsia capillaris plants were used as bioaccumulator of TE in a complex polymetallic mining/smelting urban context (Oruro, Bolivia). Specimens collected from a pristine reference site were transplanted at a high spatial resolution (˜1 sample/km2) throughout the urban area. About twenty-seven elements were measured after a 4-month exposure, also providing new information values for reference material BCR482. Statistical power analysis for this biomonitoring mapping approach against classical aerosols surveys performed on the same site showed the better aptitude of T. Capillaris to detect geographical trend, and to deconvolute multiple contamination sources using geostatistical principal component analysis. Transplanted specimens in the vicinity of the mining and smelting areas were characterized by extreme TE accumulation (Sn > Ag > Sb > Pb > Cd > As > W > Cu > Zn). Three contamination sources were identified: mining (Ag, Pb, Sb), smelting (As, Sn) and road traffic (Zn) emissions, confirming results of previous aerosol survey.

Managed Aquifer Recharge (MAR in Sustainable Urban Water Management

Directory of Open Access Journals (Sweden)

Declan Page

2018-02-01

Full Text Available To meet increasing urban water requirements in a sustainable way, there is a need to diversify future sources of supply and storage. However, to date, there has been a lag in the uptake of managed aquifer recharge (MAR for diversifying water sources in urban areas. This study draws on examples of the use of MAR as an approach to support sustainable urban water management. Recharged water may be sourced from a variety of sources and in urban centers, MAR provides a means to recycle underutilized urban storm water and treated wastewater to maximize their water resource potential and to minimize any detrimental effects associated with their disposal. The number, diversity and scale of urban MAR projects is growing internationally due to water shortages, fewer available dam sites, high evaporative losses from surface storages, and lower costs compared with alternatives where the conditions are favorable, including water treatment. Water quality improvements during aquifer storage are increasingly being documented at demonstration sites and more recently, full-scale operational urban schemes. This growing body of knowledge allows more confidence in understanding the potential role of aquifers in water treatment for regulators. In urban areas, confined aquifers provide better protection for waters recharged via wells to supplement potable water supplies. However, unconfined aquifers may generally be used for nonpotable purposes to substitute for municipal water supplies and, in some cases, provide adequate protection for recovery as potable water. The barriers to MAR adoption as part of sustainable urban water management include lack of awareness of recent developments and a lack of transparency in costs, but most importantly the often fragmented nature of urban water resources and environmental management.

Levels and Speciation of Platinum in Size-Fractionated Atmospheric Aerosol in Urban and Rural Sites across Europe

Science.gov (United States)

Shafer, Martin; Antkiewicz, Dagmara; Overdier, Joel; Schauer, James

2016-04-01

In this study we characterized the levels and speciation of platinum in a unique set of size-resolved atmospheric aerosol (PM) samples obtained from urban environments across Europe. From April-July 2012 we collected PM from roadside canyon, roadside motorway, and background urban sites in each of six European cities (Amsterdam, Frankfurt, London, Milan, Stockholm, and Thessaloniki). A Hi-Vol sampler was used to collect PM in three size classes (>PM7, PM7-PM3, PM3) and characterized for total platinum, soluble platinum (in a suite of physiologically relevant fluids - lung fluid (ALF), Gambles saline, 0.07M HCl, and MQ) and speciated forms (colloidal and anionic) within the soluble fractions. In addition we measured 50 other elements by SF-ICPMS, soluble ions by IC, and soluble organic carbon in the PM. Order-of-magnitude differences in air concentrations of total platinum were observed between urban sites, ranging from 4 to over 45 pg/m3; with a median level of 6 pg/m3. When platinum concentrations are normalized to PM mass the cross Europe and site-to-site variability was substantially reduced - a 3-fold variation from 200 to 600 ng/g was observed. Roadside canyon sites in London, Stockholm and Thessaloniki exhibited the highest concentrations; however levels at urban background sites were remarkably similar across the cities. Relatively consistent and low concentrations (1 to 2 pg/m3) of total platinum were observed at rural background sites across Europe. The contribution of coarse particles (>7 micron and 7-3 micron) to air concentrations of total platinum was very significant (>35% at nearly all sites). Soluble platinum fractions ranged from 2 to 6% (MQ to HCl) in rural background sites to 5 to 20% (MQ to HCl) in roadway canyon sites in London and Thessaloniki; with the extractable platinum fractions a strong function of pH. With the exception of urban canyon sites in London and Thessaloniki, soluble platinum concentrations in the fine aerosol (PM3) were all

Urbanization as Socioenvironmental Succession: The Case of Hazardous Industrial Site Accumulation.

Science.gov (United States)

Elliott, James R; Frickel, Scott

2015-05-01

This study rehabilitates concepts from classical human ecology and synthesizes them with contemporary urban and environmental sociology to advance a theory of urbanization as socioenvironmental succession. The theory illuminates how social and biophysical phenomena interact endogenously at the local level to situate urban land use patterns recursively and reciprocally in place. To demonstrate this theory we conduct a historical-comparative analysis of hazardous industrial site accumulation in four U.S. cities, using a relational database that was assembled for more than 11,000 facilities that operated during the past half century--most of which remain unacknowledged in government reports. Results show how three iterative processes--hazardous industrial churning, residential churning, and risk containment--intersect to produce successive socioenvironmental changes that are highly relevant to but often missed by research on urban growth machines, environmental inequality, and systemic risk.

Size distribution and sources of humic-like substances in particulate matter at an urban site during winter.

Science.gov (United States)

Park, Seungshik; Son, Se-Chang

2016-01-01

This study investigates the size distribution and possible sources of humic-like substances (HULIS) in ambient aerosol particles collected at an urban site in Gwangju, Korea during the winter of 2015. A total of 10 sets of size-segregated aerosol samples were collected using a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI), and the samples were analyzed to determine the mass as well as the presence of ionic species (Na(+), NH4(+), K(+), Ca(2+), Mg(2+), Cl(-), NO3(-), and SO4(2-)), water-soluble organic carbon (WSOC) and HULIS. The separation and quantification of the size-resolved HULIS components from the MOUDI samples was accomplished using a Hydrophilic-Lipophilic Balanced (HLB) solid phase extraction method and a total organic carbon analyzer, respectively. The entire sampling period was divided into two periods: non-Asian dust (NAD) and Asian dust (AD) periods. The contributions of water-soluble organic mass (WSOM = 1.9 × WSOC) and HULIS (=1.9 × HULIS-C) to fine particles (PM1.8) were approximately two times higher in the NAD samples (23.2 and 8.0%) than in the AD samples (12.8 and 4.2%). However, the HULIS-C/WSOC ratio in PM1.8 showed little difference between the NAD (0.35 ± 0.07) and AD (0.35 ± 0.05) samples. The HULIS exhibited a uni-modal size distribution (@0.55 μm) during NAD and a bimodal distribution (@0.32 and 1.8 μm) during AD, which was quite similar to the mass size distributions of particulate matter, WSOC, NO3(-), SO4(2-), and NH4(+) in both the NAD and AD samples. The size distribution characteristics and the results of the correlation analyses indicate that the sources of HULIS varied according to the particle size. In the fine mode (≤1.8 μm), the HULIS composition during the NAD period was strongly associated with secondary organic aerosol (SOA) formation processes similar to those of secondary ionic species (cloud processing and/or heterogeneous reactions) and primary emissions during the biomass burning period, and during

Three-dimensional geological modelling of anthropogenic deposits at small urban sites: a case study from Sheepcote Valley, Brighton, UK.

Science.gov (United States)

Tame, C; Cundy, A B; Royse, K R; Smith, M; Moles, N R

2013-11-15

Improvements in computing speed and capacity and the increasing collection and digitisation of geological data now allow geoscientists to produce meaningful 3D spatial models of the shallow subsurface in many large urban areas, to predict ground conditions and reduce risk and uncertainty in urban planning. It is not yet clear how useful this 3D modelling approach is at smaller urban scales, where poorly characterised anthropogenic deposits (artificial/made ground and fill) form the dominant subsurface material and where the availability of borehole and other geological data is less comprehensive. This is important as it is these smaller urban sites, with complex site history, which frequently form the focus of urban regeneration and redevelopment schemes. This paper examines the extent to which the 3D modelling approach previously utilised at large urban scales can be extended to smaller less well-characterised urban sites, using a historic landfill site in Sheepcote Valley, Brighton, UK as a case study. Two 3D models were generated and compared using GSI3D™ software, one using borehole data only, one combining borehole data with local geological maps and results from a desk study (involving collation of available site data, including ground contour plans). These models clearly delimit the overall subsurface geology at the site, and allow visualisation and modelling of the anthropogenic deposits present. Shallow geophysical data collected from the site partially validate the 3D modelled data, and can improve GSI3D™ outputs where boundaries of anthropogenic deposits may not be clearly defined by surface, contour or borehole data. Attribution of geotechnical and geochemical properties to the 3D model is problematic without intrusive investigations and sampling. However, combining available borehole data, shallow geophysical methods and site histories may allow attribution of generic fill properties, and consequent reduction of urban development risk and

Detection and Estimation of 2-D Distributions of Greenhouse Gas Source Concentrations and Emissions over Complex Urban Environments and Industrial Sites

Science.gov (United States)

Zaccheo, T. S.; Pernini, T.; Dobler, J. T.; Blume, N.; Braun, M.

2017-12-01

This work highlights the use of the greenhouse-gas laser imaging tomography experiment (GreenLITETM) data in conjunction with a sparse tomography approach to identify and quantify both urban and industrial sources of CO2 and CH4. The GreenLITETM system provides a user-defined set of time-sequenced intersecting chords or integrated column measurements at a fixed height through a quasi-horizontal plane of interest. This plane, with unobstructed views along the lines of sight, may range from complex industrial facilities to a small city scale or urban sector. The continuous time phased absorption measurements are converted to column concentrations and combined with a plume based model to estimate the 2-D distribution of gas concentration over extended areas ranging from 0.04-25 km2. Finally, these 2-D maps of concentration are combined with ancillary meteorological and atmospheric data to identify potential emission sources and provide first order estimates of their associated fluxes. In this presentation, we will provide a brief overview of the systems and results from both controlled release experiments and a long-term system deployment in Paris, FR. These results provide a quantitative assessment of the system's ability to detect and estimate CO2 and CH4 sources, and demonstrate its ability to perform long-term autonomous monitoring and quantification of either persistent or sporadic emissions that may have both health and safety as well as environmental impacts.

Measurements of gas and particle polycyclic aromatic hydrocarbons (PAHs) in air at urban, rural and near-roadway sites

Science.gov (United States)

Pratt, G. C.; Herbrandson, C.; Krause, M. J.; Schmitt, C.; Lippert, C. J.; McMahon, C. R.; Ellickson, K. M.

2018-04-01

We measured polycyclic aromatic hydrocarbons (PAHs) in gas and particle phases over two years using high volume samplers equipped with quartz fiber filters and XAD-4 at a rural site, an urban site, and a site adjacent to a heavily trafficked roadway. Overall results were generally as expected, in that concentrations increased from rural to urban to near-roadway sites, and PAHs with high vapor pressures (liquid subcooled, PoL) and low octanol-air partition coefficients (Koa) were mainly in the gas phase, while those with low PoL and high Koa were predominantly in the particle phase. Intermediate PAHs existed in both phases with the phase distribution following a seasonal pattern of higher gas phase concentrations in summer due to temperature effects. The overall pattern of phase distribution was consistent with PAH properties and ambient conditions and was similar at all three sites. The particle-bound fraction (ϕ) was well-described empirically by nonlinear regressions with log Koa and log PoL as predictors. Adsorption and absorption models underestimated the particle-bound fraction for most PAHs. The dual aerosol-air/soot-air model generally represented the gas-particle partitioning better than the other models across all PAHs, but there was a tendency to underestimate the range in the particle-bound fraction seen in measurements. There was a statistically insignificant tendency for higher PAHs in the particle phase at the near roadway site, and one piece of evidence that PAHs may be enriched on ultrafine particles at the near roadway site. Understanding the phase and particle size distributions of PAHs in highly polluted, high exposure microenvironments near traffic sources will help shed light on potential health effects.

Emo, love and god: making sense of Urban Dictionary, a crowd-sourced online dictionary.

Science.gov (United States)

Nguyen, Dong; McGillivray, Barbara; Yasseri, Taha

2018-05-01

The Internet facilitates large-scale collaborative projects and the emergence of Web 2.0 platforms, where producers and consumers of content unify, has drastically changed the information market. On the one hand, the promise of the 'wisdom of the crowd' has inspired successful projects such as Wikipedia, which has become the primary source of crowd-based information in many languages. On the other hand, the decentralized and often unmonitored environment of such projects may make them susceptible to low-quality content. In this work, we focus on Urban Dictionary, a crowd-sourced online dictionary. We combine computational methods with qualitative annotation and shed light on the overall features of Urban Dictionary in terms of growth, coverage and types of content. We measure a high presence of opinion-focused entries, as opposed to the meaning-focused entries that we expect from traditional dictionaries. Furthermore, Urban Dictionary covers many informal, unfamiliar words as well as proper nouns. Urban Dictionary also contains offensive content, but highly offensive content tends to receive lower scores through the dictionary's voting system. The low threshold to include new material in Urban Dictionary enables quick recording of new words and new meanings, but the resulting heterogeneous content can pose challenges in using Urban Dictionary as a source to study language innovation.

Apportionment of urban aerosol sources in Cork (Ireland) by synergistic measurement techniques.

Science.gov (United States)

Dall'Osto, Manuel; Hellebust, Stig; Healy, Robert M; O'Connor, Ian P; Kourtchev, Ivan; Sodeau, John R; Ovadnevaite, Jurgita; Ceburnis, Darius; O'Dowd, Colin D; Wenger, John C

2014-09-15

The sources of ambient fine particulate matter (PM2.5) during wintertime at a background urban location in Cork city (Ireland) have been determined. Aerosol chemical analyses were performed by multiple techniques including on-line high resolution aerosol time-of-flight mass spectrometry (Aerodyne HR-ToF-AMS), on-line single particle aerosol time-of-flight mass spectrometry (TSI ATOFMS), on-line elemental carbon-organic carbon analysis (Sunset_EC-OC), and off-line gas chromatography/mass spectrometry and ion chromatography analysis of filter samples collected at 6-h resolution. Positive matrix factorization (PMF) has been carried out to better elucidate aerosol sources not clearly identified when analyzing results from individual aerosol techniques on their own. Two datasets have been considered: on-line measurements averaged over 2-h periods, and both on-line and off-line measurements averaged over 6-h periods. Five aerosol sources were identified by PMF in both datasets, with excellent agreement between the two solutions: (1) regional domestic solid fuel burning--"DSF_Regional," 24-27%; (2) local urban domestic solid fuel burning--"DSF_Urban," 22-23%; (3) road vehicle emissions--"Traffic," 15-20%; (4) secondary aerosols from regional anthropogenic sources--"SA_Regional" 9-13%; and (5) secondary aged/processed aerosols related to urban anthropogenic sources--"SA_Urban," 21-26%. The results indicate that, despite regulations for restricting the use of smoky fuels, solid fuel burning is the major source (46-50%) of PM2.5 in wintertime in Cork, and also likely other areas of Ireland. Whilst wood combustion is strongly associated with OC and EC, it was found that peat and coal combustion is linked mainly with OC and the aerosol from these latter sources appears to be more volatile than that produced by wood combustion. Ship emissions from the nearby port were found to be mixed with the SA_Regional factor. The PMF analysis allowed us to link the AMS cooking organic

Urban sources and emissions of nitrous oxide and methane in southern California, USA

Science.gov (United States)

Townsend-Small, A.; Pataki, D.; Tyler, S. C.; Czimczik, C. I.; Xu, X.; Christensen, L. E.

2012-12-01

Anthropogenic activities have resulted in increasing levels of greenhouse gases, including carbon dioxide, methane, and nitrous oxide. While global and regional emissions sources of carbon dioxide are relatively well understood, methane and nitrous oxide are less constrained, particularly at regional scales. Here we present the results of an investigation of sources and emissions of methane and nitrous oxide in Los Angeles, California, USA, one of Earth's largest urban areas. The original goal of the project was to determine whether isotopes are useful tracers of agricultural versus urban nitrous oxide and methane sources. For methane, we found that stable isotopes (carbon-13 and deuterium) and radiocarbon are good tracers of biogenic versus fossil fuel sources. High altitude observations of methane concentration, measured continuously using tunable laser spectroscopy, and isotope ratios, measured on discrete flask samples using mass spectrometry, indicate that the predominant methane source in Los Angeles is from fossil fuels, likely from "fugitive" emissions from geologic formations, natural gas pipelines, oil refining, or power plants. We also measured nitrous oxide emissions and isotope ratios from urban (landscaping and wastewater treatment) and agricultural sources (corn and vegetable fields). There was no difference in nitrous oxide isotope ratios between the different types of sources, although stable isotopes did differ between nitrous oxide produced in oxic and anoxic wastewater treatment tanks. Our nitrous oxide flux data indicate that landscaped turfgrass emits nitrous oxide at rates equivalent to agricultural systems, indicating that ornamental soils should not be disregarded in regional nitrous oxide budgets. However, we also showed that wastewater treatment is a much greater source of nitrous oxide than soils regionally. This work shows that global nitrous oxide and methane budgets are not easily downscaled to regional, urban settings, which has

Characteristics of surface ozone and nitrogen oxides at urban, suburban and rural sites in Ningbo, China

Science.gov (United States)

Tong, Lei; Zhang, Huiling; Yu, Jie; He, Mengmeng; Xu, Nengbin; Zhang, Jingjing; Qian, Feizhong; Feng, Jiayong; Xiao, Hang

2017-05-01

Surface ozone (O3) is a harmful air pollutant that has attracted growing concern in China. In this study, the mixing ratios of O3 and nitrogen oxides (NOx) at three different sites (urban, suburban and rural) of Ningbo were continuously measured to investigate the spatiotemporal characteristics of O3 and its relationships with environmental variables. The diurnal O3 variations were characterized by afternoon maxima (38.7-53.1 ppb on annual average) and early morning minima (11.7-26.2 ppb) at all the three sites. Two seasonal peaks of O3 were observed in spring (April or May) and autumn (October) with minima being observed in winter (December). NOx levels showed generally opposite variations to that of O3 with diurnal and seasonal maxima occurring in morning/evening rush-hours and in winter, respectively. As to the inter-annual variations of air pollutants, generally decreasing and increasing trends were observed in NO and O3 levels, respectively, from 2012 to 2015 at both urban and suburban sites. O3 levels were positively correlated with temperature but negatively correlated with relative humidity and NOx levels. Significant differences in O3 levels were observed for different wind speeds and wind directions (p variation, higher levels of O3 were observed at the suburban and rural sites where less O3 was depleted by NO titration. In contrast, the urban site exhibited lower O3 but higher NOx levels due to the influence of traffic emissions. Larger amplitudes of diurnal and monthly O3 variations were observed at the suburban site than those at the urban and rural sites. In general, the O3 levels at the non-urban sites were more affected by the background transport, while both the local and regional contributions played roles in urban O3 variations. The annual average O3 mixing ratios (22.7-37.7 ppb) in Ningbo were generally similar to those of other regions around the world. However, the recommended air quality standards for O3 were often exceeded during warm

Chemical composition, sources and evolution processes of aerosol at an urban site in Yangtze River Delta, China during wintertime

Science.gov (United States)

Zhang, Yunjiang; Tang, Lili; Yu, Hongxia; Wang, Zhuang; Sun, Yele; Qin, Wei; Chen, Wentai; Chen, Changhong; Ding, Aijun; Wu, Jing; Ge, Shun; Chen, Cheng; Zhou, Hong-cang

2015-12-01

To investigate the composition, sources and evolution processes of submicron aerosol during wintertime, a field experiment was conducted during December 1-31, 2013 in urban Nanjing, a megacity in Yangtze River Delta of China. Non-refractory submicron aerosol (NR-PM1) species were measured with an Aerodyne Aerosol Chemical Speciation Monitor. NR-PM1 is dominated by secondary inorganic aerosol (55%) and organic aerosol (OA, 42%) during haze periods. Six OA components were identified by positive matrix factorization of the OA mass spectra. The hydrocarbon-like OA and cooking-related OA represent the local traffic and cooking sources, respectively. A highly oxidized factor related to biomass burning OA accounted for 15% of the total OA mass during haze periods. Three types of oxygenated OA (OOA), i.e., a less-oxidized OOA (LO-OOA), a more-oxidized OOA (MO-OOA), and a low-volatility OOA (LV-OOA), were identified. LO-OOA is likely associated with fresh urban secondary OA. MO-OOA likely represents photochemical products showing a similar diurnal cycle to nitrate with a pronounced noon peak. LV-OOA appears to be a more oxidized factor with a pronounced noon peak. The OA composition is dominated by secondary species, especially during haze events. LO-OOA, MO-OOA and LV-OOA on average account for 11%, (18%), 24% (21%) and 23% (18%) of the total OA mass for the haze (clean) periods respectively. Analysis of meteorological influence suggested that regional transport from the northern and southeastern areas of the city is responsible for large secondary and low-volatility aerosol formation.

Residential runoff as a source of pyrethroid pesticides to urban creeks

Energy Technology Data Exchange (ETDEWEB)

Weston, D.P. [Department of Integrative Biology, University of California, 3060 Valley Life Sciences Building, Berkeley, CA 94720-3140 (United States)], E-mail: dweston@berkeley.edu; Holmes, R.W. [Water Branch, California Department of Fish and Game, 830 S Street, Sacramento, CA 95811 (United States)], E-mail: rholmes@dfg.ca.gov; Lydy, M.J. [Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, 171 Life Sciences II, Carbondale, IL 62901 (United States)], E-mail: mlydy@siu.edu

2009-01-15

Pyrethroid pesticides occur in urban creek sediments at concentrations acutely toxic to sensitive aquatic life. To better understand the source of these residues, runoff from residential neighborhoods around Sacramento, California was monitored over the course of a year. Pyrethroids were present in every sample. Bifenthrin, found at up to 73 ng/L in the water and 1211 ng/g on suspended sediment, was the pyrethroid of greatest toxicological concern, with cypermethrin and cyfluthrin of secondary concern. The bifenthrin could have originated either from use by consumers or professional pest controllers, though the seasonal pattern of discharge from the drain was more consistent with professional use as the dominant source. Stormwater runoff was more important than dry season irrigation runoff in transporting pyrethroids to urban creeks. A single intense storm was capable of discharging as much bifenthrin to an urban creek in 3 h as that discharged over 6 months of irrigation runoff. - Pyrethroid insecticides regularly detected in residential runoff at toxicologically significant concentrations.

Residential runoff as a source of pyrethroid pesticides to urban creeks

International Nuclear Information System (INIS)

Weston, D.P.; Holmes, R.W.; Lydy, M.J.

2009-01-01

Pyrethroid pesticides occur in urban creek sediments at concentrations acutely toxic to sensitive aquatic life. To better understand the source of these residues, runoff from residential neighborhoods around Sacramento, California was monitored over the course of a year. Pyrethroids were present in every sample. Bifenthrin, found at up to 73 ng/L in the water and 1211 ng/g on suspended sediment, was the pyrethroid of greatest toxicological concern, with cypermethrin and cyfluthrin of secondary concern. The bifenthrin could have originated either from use by consumers or professional pest controllers, though the seasonal pattern of discharge from the drain was more consistent with professional use as the dominant source. Stormwater runoff was more important than dry season irrigation runoff in transporting pyrethroids to urban creeks. A single intense storm was capable of discharging as much bifenthrin to an urban creek in 3 h as that discharged over 6 months of irrigation runoff. - Pyrethroid insecticides regularly detected in residential runoff at toxicologically significant concentrations

Concentration and source identification of polycyclic aromatic hydrocarbons (PAHs) in PM10 of urban, industrial and semi-urban areas in Malaysia

Science.gov (United States)

Jamhari, Anas Ahmad; Sahani, Mazrura; Latif, Mohd Talib; Chan, Kok Meng; Tan, Hock Seng; Khan, Md Firoz; Mohd Tahir, Norhayati

2014-04-01

Particulate matter (PM10) associated with polycyclic aromatic hydrocarbons (PAHs) in ambient air were determined at two sites within the Klang Valley, Kuala Lumpur (urban, KL) and Petaling Jaya (industrial, PJ), and one site outside the Klang Valley, Bangi (semi-urban, BG). This study aimed to determine the concentration and distribution of PAHs in PM10 and the source of origin through principal component analysis (PCA) and diagnostic ratio analysis. This study also assessed the health risk from exposure to airborne BaPeq. PM10 samples were collected on glass fiber filter paper using a High Volume Sampler (HVS) for 24 h between September 2010 and April 2011. The filter papers with PM10 were extracted using dichloromethane-methanol (3:1), and analysis of 16 USEPA priority PAHs was determined using gas chromatography with mass spectra (GC-MS). Health risk assessment was estimated using toxic equivalency factors (TEFs) and incremental lifetime cancer risk (ILCR) which quantitatively estimate the exposure risk for age specific group. The results showed that the total PAHs concentrations throughout seasonal monsoons for KL, PJ and BG ranged from 1.33 ng m-3 to 2.97 ng m-3, 2.24 ng m-3 to 4.84 ng m-3 and 1.64 ng m-3 to 3.45 ng m-3 respectively. More than 80% of total PAHs consisted of 5-ring and 6-ring PAHs such as benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (IcP), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF) and benzo[g,h,i]perylene (BgP). The presence of benzo[g,h,i]perylene (BgP) with high concentration at all locations suggested a source indicator for traffic emission. PCA and diagnostic ratio analysis also suggested substantial contributions from traffic emission with minimal influence from coal combustion and natural gas emissions. The use of total BaPeq concentration provide a better estimation of carcinogenicity activities, where they contributed to more than 50% of the potential health risk. Health risk assessment showed that the estimated incremental

The near-source impacts of diesel backup generators in urban environments

Science.gov (United States)

Tong, Zheming; Zhang, K. Max

2015-05-01

Distributed power generation, located close to consumers, plays an important role in the current and future power systems. However, its near-source impacts in complex urban environments are not well understood. In this paper, we focused on diesel backup generators that participate in demand response (DR) programs. We first improved the micro-environmental air quality simulations by employing a meteorology processor, AERMET, to generate site-specific boundary layer parameters for the Large Eddy Simulation (LES) modeling. The modeling structure was then incorporated into the CTAG model to evaluate the environmental impacts of diesel backup generators in near-source microenvironments. We found that the presence of either tall upwind or downwind building can deteriorate the air quality in the near-stack street canyons, largely due to the recirculation zones generated by the tall buildings, reducing the near-stack dispersion. Decreasing exhaust momentum ratio (stack exit velocity/ambient wind velocity) draws more exhaust into the recirculation zone, and reduces the effective stack height, which results in elevated near-ground concentrations inside downwind street canyons. The near-ground PM2.5 concentration for the worst scenarios could well exceed 100 μg m-3, posing potential health risk to people living and working nearby. In general, older diesel backup generators (i.e., Tier 1, 2 or older) without the up-to-date emission control may significantly increase the pollutant concentration in the near-source street canyons if participating in DR programs. Even generators that comply with Tier-4 standards could lead to PM hotspots if their stacks are next to tall buildings. Our study implies that the siting of diesel backup generators stacks should consider not only the interactions of fresh air intake and exhaust outlet for the building housing the backup generators, but also the dispersion of exhaust plumes in the surrounding environment.

Methods of analysis for complex organic aerosol mixtures from urban emission sources of particulate carbon

International Nuclear Information System (INIS)

Mazurek, M.A.; Hildemann, L.M.; Simoneit, B.R.T.

1990-10-01

Organic aerosols comprise approximately 30% by mass of the total fine particulate matter present in urban atmospheres. The chemical composition of such aerosols is complex and reflects input from multiple sources of primary emissions to the atmosphere, as well as from secondary production of carbonaceous aerosol species via photochemical reactions. To identify discrete sources of fine carbonaceous particles in urban atmospheres, analytical methods must reconcile both bulk chemical and molecular properties of the total carbonaceous aerosol fraction. This paper presents an overview of the analytical protocol developed and used in a study of the major sources of fine carbon particles emitted to an urban atmosphere. 23 refs., 1 fig., 2 tabs

Siting Urban Agriculture as a Green Infrastructure Strategy for Land Use Planning in Austin, TX

Directory of Open Access Journals (Sweden)

Charles M. Rogers

2016-04-01

Full Text Available Green infrastructure refers to a type of land use design that mimics the natural water cycle by using the infiltration capacities of vegetation, soils, and other natural processes to mitigate stormwater runoff. As a multifunctional landscape, urban agriculture should be seen as a highly beneficial tool for urban planning not only because of its ability to function as a green stormwater management strategy, but also due to the multiple social and environmental benefits it provides. In 2012, the city of Austin adopted a major planning approach titled the “Imagine Austin Comprehensive Plan” (IACP outlining the city’s vision for future growth and land use up to 2039. The plan explicitly addresses the adoption of green infrastructure as a target for future land use with urban agriculture as a central component. Addressing this area of land use planning will require tools that can locate suitable areas within the city ideal for the development of green infrastructure. In this study, a process was developed to create a spatially explicit method of siting urban agriculture as a green infrastructure tool in hydrologically sensitive areas, or areas prone to runoff, in east Austin. The method uses geospatial software to spatially analyze open access datasets that include land use, a digital elevation model, and prime farmland soils. Through this method a spatial relationship can be made between areas of high surface runoff and where the priority placement of urban farms should be sited as a useful component of green infrastructure. Planners or geospatial analysts could use such information, along with other significant factors and community input, to aid decision makers in the placement of urban agriculture. This spatially explicit approach for siting potential urban farms, will support the integration of urban agriculture as part of the land use planning of Austin.

Oxidative potential of size-fractionated atmospheric aerosol in urban and rural sites across Europe.

Science.gov (United States)

Shafer, Martin M; Hemming, Jocelyn D C; Antkiewicz, Dagmara S; Schauer, James J

2016-07-18

In this study we applied several assays, an in vitro rat alveolar macrophage model, a chemical ROS probe (DTT, dithiothreitol), and cytokine induction (TNFα) to examine relationships between PM-induced generation of reactive oxygen species (ROS) and PM composition, using a unique set of size-resolved PM samples obtained from urban and rural environments across Europe. From April-July 2012, we collected PM from roadside canyon, roadside motorway, and background urban sites in each of six European cities and from three rural sites spanning the continent. A Hi-Vol sampler was used to collect PM in three size classes (PM>7, PM7-3, PM3) and PM was characterized for total elements, and oxidative activity quantified in unfiltered and filtered PM extracts. We measured a remarkable uniformity in air concentrations of ROS and especially DTT activity across the continent. Only a 4-fold difference was documented for DTT across the urban sites and a similar variance was documented for ROS, implying that chemical drivers of oxidative activity are relatively similar between sites. The ROS and DTT specific activity was greater at urban background sites (and also rural sites) than at urban canyon locations. PM3 dominated the size distribution of both ROS activity (86% of total) and DTT activity (76% of total), reflecting both the large contribution of PM3 to total PM mass levels and importantly the higher specific oxidative activity of the PM3 in comparison with the larger particles. The soluble fraction of total activity was very high for DTT (94%) as well as for ROS (64%) in the PM3. However in the larger PM size fractions the contributions of the insoluble components became increasingly significant. The dominance of the insoluble PM drivers of activity was particularly evident in the TNFα data, where the insoluble contribution to cytokine production could be 100-fold greater than that from soluble components. ROS and DTT activity were strongly correlated in the PM3 (r = 0

Emo, love and god: making sense of Urban Dictionary, a crowd-sourced online dictionary

Science.gov (United States)

McGillivray, Barbara

2018-01-01

The Internet facilitates large-scale collaborative projects and the emergence of Web 2.0 platforms, where producers and consumers of content unify, has drastically changed the information market. On the one hand, the promise of the ‘wisdom of the crowd’ has inspired successful projects such as Wikipedia, which has become the primary source of crowd-based information in many languages. On the other hand, the decentralized and often unmonitored environment of such projects may make them susceptible to low-quality content. In this work, we focus on Urban Dictionary, a crowd-sourced online dictionary. We combine computational methods with qualitative annotation and shed light on the overall features of Urban Dictionary in terms of growth, coverage and types of content. We measure a high presence of opinion-focused entries, as opposed to the meaning-focused entries that we expect from traditional dictionaries. Furthermore, Urban Dictionary covers many informal, unfamiliar words as well as proper nouns. Urban Dictionary also contains offensive content, but highly offensive content tends to receive lower scores through the dictionary’s voting system. The low threshold to include new material in Urban Dictionary enables quick recording of new words and new meanings, but the resulting heterogeneous content can pose challenges in using Urban Dictionary as a source to study language innovation. PMID:29892417

Stable carbon isotopes to monitor the CO2 source mix in the urban environment

Science.gov (United States)

Vogel, F. R.; Wu, L.; Ramonet, M.; Broquet, G.; Worthy, D. E. J.

2014-12-01

Urban areas are said to be responsible for approximately 71% of fossil fuel CO2 emissions while comprising only two percent of the land area [IEA, 2008]. This limited spatial expansion could facility a monitoring of anthropogenic GHGs from atmospheric observations. As major sources of emissions, cities also have a huge potential to drive emissions reductions. To effectively manage emissions, cities must however, first establish techniques to validate their reported emission statistics. A pilot study which includes continues 13CO2 data from calibrated cavity ring-down spectrometers [Vogel et al. 2013] of two "sister sites" in the vicinity of Toronto, Canada is contrasted to recent observations of 13CO2 observations in Paris during significant pollution events. Using Miller-Tans plots [Miller and Tans, 2003] for our multi-season observations reveals significant changes of the source signatures of night time CO2 emissions which reflect the importance of natural gas burning in Megacities (up to 80% of fossil fuel sources) and show-case the potential of future isotope studies to determine source sectors. Especially the winter data this approach seems suitable to determine the source contribution of different fuel types (natural gas, liquid fuels and coal) which can inform the interpretation of other Greenhouse Gases and air pollution levels.

Urban Malaria: Understanding its Epidemiology, Ecology, and Transmission across Seven Diverse ICEMR Network Sites

Science.gov (United States)

Wilson, Mark L.; Krogstad, Donald J.; Arinaitwe, Emmanuel; Arevalo-Herrera, Myriam; Chery, Laura; Ferreira, Marcelo U.; Ndiaye, Daouda; Mathanga, Don P.; Eapen, Alex

2015-01-01

A major public health question is whether urbanization will transform malaria from a rural to an urban disease. However, differences about definitions of urban settings, urban malaria, and whether malaria control should differ between rural and urban areas complicate both the analysis of available data and the development of intervention strategies. This report examines the approach of the International Centers of Excellence for Malaria Research (ICEMR) to urban malaria in Brazil, Colombia, India (Chennai and Goa), Malawi, Senegal, and Uganda. Its major theme is the need to determine whether cases diagnosed in urban areas were imported from surrounding rural areas or resulted from transmission within the urban area. If infections are being acquired within urban areas, malaria control measures must be targeted within those urban areas to be effective. Conversely, if malaria cases are being imported from rural areas, control measures must be directed at vectors, breeding sites, and infected humans in those rural areas. Similar interventions must be directed differently if infections were acquired within urban areas. The hypothesis underlying the ICEMR approach to urban malaria is that optimal control of urban malaria depends on accurate epidemiologic and entomologic information about transmission. PMID:26259941

Identifying the contribution of different urban highway air pollution sources

International Nuclear Information System (INIS)

Peace, H.; Owen, B.; Raper, D.W.

2004-01-01

This paper describes the methodology and results, and draws conclusions from a large-scale source apportionment study undertaken in a large urban conurbation in the northwest of England. Annual average oxides of nitrogen (NOx) emission and ambient air pollution contributions have been estimated for road traffic sources. Ground level air pollution concentrations were estimated over a 1552-km 2 area with a resolution of up to 20 m, using emissions estimates and the second generation ADMS-Urban Gaussian dispersion model. Road traffic emissions were split into car and motorcycles; heavy and light goods vehicles; and buses to represent domestic users; commercial users and bus companies. Car related emissions were split further in to journey lengths under 3 km; journeys between 3 and 8 km; and journeys over 8 km to represent journeys which could be either walked or cycled; journeys for which a bus can easily be used and other journeys. These source sections were chosen so that the relevant authorities could target key groups in terms of reducing air pollution. The results confirm that the areas most likely to exceed air quality objectives are typically close to main arterial routes and close to urban centres and that the major culprits of road traffic related air pollution are goods vehicles and car journeys over 8 km. The paper also discusses the implications of the results and suggests how these can be used in the assessment of actions to reduce air pollution concentrations

Identifying the contribution of different urban highway air pollution sources.

Science.gov (United States)

Peace, H; Owen, B; Raper, D W

2004-12-01

This paper describes the methodology and results, and draws conclusions from a large-scale source apportionment study undertaken in a large urban conurbation in the northwest of England. Annual average oxides of nitrogen (NOx) emission and ambient air pollution contributions have been estimated for road traffic sources. Ground level air pollution concentrations were estimated over a 1552-km(2) area with a resolution of up to 20 m, using emissions estimates and the second generation ADMS-Urban Gaussian dispersion model. Road traffic emissions were split into car and motorcycles; heavy and light goods vehicles; and buses to represent domestic users; commercial users and bus companies. Car related emissions were split further in to journey lengths under 3 km; journeys between 3 and 8 km; and journeys over 8 km to represent journeys which could be either walked or cycled; journeys for which a bus can easily be used and other journeys. These source sections were chosen so that the relevant authorities could target key groups in terms of reducing air pollution. The results confirm that the areas most likely to exceed air quality objectives are typically close to main arterial routes and close to urban centres and that the major culprits of road traffic related air pollution are goods vehicles and car journeys over 8 km. The paper also discusses the implications of the results and suggests how these can be used in the assessment of actions to reduce air pollution concentrations.

High-Resolution Source Parameter and Site Characteristics Using Near-Field Recordings - Decoding the Trade-off Problems Between Site and Source

Science.gov (United States)

Chen, X.; Abercrombie, R. E.; Pennington, C.

2017-12-01

Recorded seismic waveforms include contributions from earthquake source properties and propagation effects, leading to long-standing trade-off problems between site/path effects and source effects. With near-field recordings, the path effect is relatively small, so the trade-off problem can be simplified to between source and site effects (commonly referred as "kappa value"). This problem is especially significant for small earthquakes where the corner frequencies are within similar ranges of kappa values, so direct spectrum fitting often leads to systematic biases due to corner frequency and magnitude. In response to the significantly increased seismicity rate in Oklahoma, several local networks have been deployed following major earthquakes: the Prague, Pawnee and Fairview earthquakes. Each network provides dense observations within 20 km surrounding the fault zone, recording tens of thousands of aftershocks between M1 to M3. Using near-field recordings in the Prague area, we apply a stacking approach to separate path/site and source effects. The resulting source parameters are consistent with parameters derived from ground motion and spectral ratio methods from other studies; they exhibit spatial coherence within the fault zone for different fault patches. We apply these source parameter constraints in an analysis of kappa values for stations within 20 km of the fault zone. The resulting kappa values show significantly reduced variability compared to those from direct spectral fitting without constraints on the source spectrum; they are not biased by earthquake magnitudes. With these improvements, we plan to apply the stacking analysis to other local arrays to analyze source properties and site characteristics. For selected individual earthquakes, we will also use individual-pair empirical Green's function (EGF) analysis to validate the source parameter estimations.

Persistence of phlebotomine Leishmania vectors in urban sites of Catania (Sicily, Italy).

Science.gov (United States)

Lisi, Oscar; D'Urso, Vera; Vaccalluzzo, Valerio; Bongiorno, Gioia; Khoury, Cristina; Severini, Francesco; Di Muccio, Trentina; Gramiccia, Marina; Gradoni, Luigi; Maroli, Michele

2014-12-09

Pioneering research on "Mediterranean Kala-Azar" carried out by Adler and Theodor early in the past century (~1930s) had identified Catania city (Sicily) as a major focus of the disease nowadays known as zoonotic visceral leishmaniasis (VL). Despite the fact that disease in both humans and dogs has continued to be highly prevalent in the Catania province up to the present times, research on Leishmania vectors in this urban focus dates back to that distant period. This study aimed to evaluate the persistence and current composition of the sand fly fauna in urban environments of Catania in recent years, 2006 and 2013. In 2006 fifty-one suitable collecting sites were identified within 44 sub-units of a grid drawn to include the urban Catania area. In 2013 the survey was restricted to four of the most productive and representative sites resulting from the 2006 survey. In both periods 3 collections per month were performed using standard sticky traps set for 3 days in wall holes/cavities along public roads, from the end of April through December. 43/51 sites (84.3%) were found positive for sand flies. The 2006 collections accounted for a total of 4341 specimens including six species. Among competent Leishmania vector species, P. perniciosus was the most prevalent (36.5%) being identified in all sand fly-positive sites, with significant abundance in those of the old city centre. Other species of interest were P. sergenti (2.5%) and P. neglectus (1.5%). The 2013 survey produced 1130 sand flies, of which 39.5% were P. perniciosus, 1.6% P. sergenti and 0.7% P. neglectus. A search for Leishmania DNA in a small sample of 72 P. perniciosus females revealed 11% infection prevalence. Our findings from an old urban focus of leishmaniasis demonstrate that phlebotomine sand flies have adapted fairly well to the drastic environmental changes that have occurred in cities of the Western world in the past century and still represent a potential risk for Leishmania transmission.

Characterization of sources of lead in the urban air of Asia using ratios of stable lead isotopes

Energy Technology Data Exchange (ETDEWEB)

Mukai, H.; Furuta, N.; Fujii, T.; Ambe, Y.; Sakamoto, K.; Hashimoto, Y. (National Institute of Environmental Studies, Tsukuba (Japan). Environmental Chemistry Division)

1993-07-01

Airborne particulate matter was collected at urban sites in six Asian countries (Japan, South Korea, China, Thailand, Sri Lanka, and Indonesia), and the stable lead isotope ratios were measured. Some source-related materials, such as coal and leaded gasoline, were also analyzed and compared to the ratios observed in airborne lead. Airborne lead isotope ratios differed considerably from each other, and these differences corresponded to differences in the regional source of lead. Leaded gasoline was still the primary source of lead in some cities in Asia, and the lead isotope ratios were strongly influenced by those of leaded gasoline. In Chinese and Korean cities, however, the considerable effect from coal combustion and industrial activity was also observed in their isotope ratios, despite leaded gasoline use. On the other hand, only refuse incineration was a possible single source of lead in Japanese air from the view of lead isotope ratios. 49 refs., 13 figs., 3 tabs.

Forensic applications of nitrogen and oxygen isotopes in tracing nitrate sources in urban environments

Science.gov (United States)

Silva, S.R.; Ging, P.B.; Lee, R.W.; Ebbert, J.C.; Tesoriero, A.J.; Inkpen, E.L.

2002-01-01

Ground and surface waters in urban areas are susceptible to nitrate contamination from septic systems, leaking sewer lines, and fertilizer applications. Source identification is a primary step toward a successful remediation plan in affected areas. In this respect, nitrogen and oxygen isotope ratios of nitrate, in conjunction with hydrologic data and water chemistry, have proven valuable in urban studies from Austin, Texas, and Tacoma, Washington. In Austin, stream water was sampled during stremflow and baseflow conditions to assess surface and subsurface sources of nitrate, respectively. In Tacoma, well waters were sampled in adjacent sewered and un-sewered areas to determine if locally high nitrate concentrations were caused by septic systems in the un-sewered areas. In both studies, sewage was identified as a nitrate source and mixing between sewage and other sources of nitrate was apparent. In addition to source identification, combined nitrogen and oxygen isotopes were important in determining the significance of denitrification, which can complicate source assessment by reducing nitrate concentrations and increasing ??15N values. The two studies illustrate the value of nitrogen and oxygen isotopes of nitrate for forensic applications in urban areas. ?? Published by Elsevier Science Ltd. on behalf of AEHS.

Nonpolar organic compounds as PM2.5 source tracers: Investigation of their sources and degradation in the Pearl River Delta, China

Science.gov (United States)

Wang, Qiongqiong; Feng, Yongming; Huang, X. H. Hilda; Griffith, Stephen M.; Zhang, Ting; Zhang, Qingyan; Wu, Dui; Yu, Jian Zhen

2016-10-01

A group of nonpolar organic compounds (NPOCs) in five compound classes including alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, and 1,3,5-triphenylbenzene were quantified in samples of particulate matter of aerodynamic diameter less than 2.5 μm collected at four sites in the Pearl River Delta (PRD) region, China, over a 2 year period from 2011 to 2012. The four sites include industrial (Nanhai), urban (Guangzhou), urban outskirt (Dongguan), and suburban (Nansha) locations. Some NPOCs are uniquely emitted from particular combustion sources and thereby serving as markers in source apportionment. Based on this multiyear and multisite NPOC data set, spatial and seasonal variations, correlation analysis, and ratio-ratio plots were used to investigate the source information and degradation of NPOC tracers. In summer, NPOCs showed distinct local emission characteristics, with urban sites having much higher concentrations than suburban sites. In winter, regional transport was an important influence on NPOC levels, driving up concentrations at all sampling sites and diminishing an urban-suburban spatial gradient. The lighter NPOCs exhibited more prominent seasonal variations. Such spatiotemporal features suggest that their particle-phase abundance is more influenced by temperature, which is a critical factor in controlling the extent of semivolatile organics partitioned into the aerosol phase. The heavier NPOCs, especially PAHs, showed negligible correlation among the four sites, suggesting more influence from local emissions. Ratio-ratio plots indicate photodegradation and mixing of various sources for the NPOCs in the PRD. A positive matrix factorization (PMF) analysis of this large NPOC data set suggests that heavier NPOCs are more suitable source indicators than lighter NPOCs. Incorporating particle-phase light NPOC concentrations in PMF produces a separate factor, which primarily contains those light NPOCs and likely is not a source factor. Total

Nonpoint Source: Urban Areas

Science.gov (United States)

Urbanization increases the variety and amount of pollutants carried into our nation's waters. Pavement and compacted landscapes do not allow rain and snow melt to soak into the ground. List of typical pollutants from Urban runoff.

Storm water runoff-a source of emerging contaminants in urban streams

Science.gov (United States)

Xia, K.; Chen, C.; FitzGerald, K.; Badgley, B.

2016-12-01

Emerging contaminants (ECs) that refers to prescription, over-the-counter, veterinary, and illicit drugs in addition to products intended to have primary effects on the human body, such as sunscreens and insect repellants. Historically municipal wastewater treatment effluent has been considered to be the main source of ECs in aquatic environment. However, recent investigations have suggested urban storm water runoff as an important source of ECs in the environment. The objective of this multi-year study was to investigate the occurrence of a wide range of ECs and the special and temporal change of 4-Nonlyphenol (4-NP), an endocrine disruptor, in a stream solely impacted by the storm water runoff from Blacksburg, VA. Urban land cover has doubled during the past 15 years surrounding this. Water and sediment samples were collected periodically along the stream during a 3-year period and analyzed for 4-NP using a gas chromatography/tandem mass spectrometry and for EC screening using an ultra- performance liquid chromatography/tandem mass spectrometry. In addition, human-associated Bacteroides sp. (HF183) was analyzed to explore possible cross contamination between the sewer system and storm water collection system of the city. Fifteen ECs were detected in water samples from various locations along the stream at estimated levels ranging from low ppt to low ppb. The levels of 4-NP in the storm water sediment samples, ranging from 30-1500 µg/kg (d.w.), positively correlated with the levels of Human-associated Bacteroides sp. (HF183) in the storm water. Our study suggested: 1) collective urban activity and leaky urban sewer systems are significant sources of ECs in storm water runoff that are often untreated or with minimum treatment before flowing into urban streams; and 2) sediment transport and re-suspension can further releases accumulated ECs back into stream water during rain events, resulting in occurrence of ECs downstream and possibly in the receiving river. This

Incineration of urban solid waste containing radioactive sources

Energy Technology Data Exchange (ETDEWEB)

Ronchin, G.P., E-mail: giulio.ronchin@mail.polimi.i [Dipartimento di Energia (Sezione nucleare - Cesnef), Politecnico di Milano, Via Ponzio 34/3, 20133 Milano (Italy); Campi, F.; Porta, A.A. [Dipartimento di Energia (Sezione nucleare - Cesnef), Politecnico di Milano, Via Ponzio 34/3, 20133 Milano (Italy)

2011-01-15

Incineration of urban solid waste accidentally contaminated by orphan sources or radioactive material is a potential risk for environment and public health. Moreover, production and emission of radioactive fumes can cause a heavy contamination of the plant, leading to important economic detriment. In order to prevent such a hazard, in February 2004 a radiometric portal for detection of radioactive material in incoming waste has been installed at AMSA (Azienda Milanese per i Servizi Ambientali) 'Silla 2' urban solid waste incineration plant of Milan. Radioactive detections performed from installation time up to December 2006 consist entirely of low-activity material contaminated from radiopharmaceuticals (mainly {sup 131}I). In this work an estimate of the dose that would have been committed to population, due to incineration of the radioactive material detected by the radiometric portal, has been evaluated. Furthermore, public health and environmental effects due to incineration of a high-activity source have been estimated. Incineration of the contaminated material detected appears to have negligible effects at all; the evaluated annual collective dose, almost entirely conferred by {sup 131}I, is indeed 0.1 man mSv. Otherwise, incineration of a 3.7 x 10{sup 10} Bq (1 Ci) source of {sup 137}Cs, assumed as reference accident, could result in a light environmental contamination involving a large area. Although the maximum total dose, owing to inhalation and submersion, committed to a single individual appears to be negligible (less than 10{sup -8} Sv), the environmental contamination leads to a potential important exposure due to ingestion of contaminated foods. With respect to 'Silla 2' plant and to the worst meteorological conditions, the evaluated collective dose results in 0.34 man Sv. Performed analyses have confirmed that radiometric portals, which are today mainly used in foundries, represent a valid public health and environmental

Perceptual assessment of quality of urban soundscapes with combined noise sources and water sounds.

Science.gov (United States)

Jeon, Jin Yong; Lee, Pyoung Jik; You, Jin; Kang, Jian

2010-03-01

In this study, urban soundscapes containing combined noise sources were evaluated through field surveys and laboratory experiments. The effect of water sounds on masking urban noises was then examined in order to enhance the soundscape perception. Field surveys in 16 urban spaces were conducted through soundwalking to evaluate the annoyance of combined noise sources. Synthesis curves were derived for the relationships between noise levels and the percentage of highly annoyed (%HA) and the percentage of annoyed (%A) for the combined noise sources. Qualitative analysis was also made using semantic scales for evaluating the quality of the soundscape, and it was shown that the perception of acoustic comfort and loudness was strongly related to the annoyance. A laboratory auditory experiment was then conducted in order to quantify the total annoyance caused by road traffic noise and four types of construction noise. It was shown that the annoyance ratings were related to the types of construction noise in combination with road traffic noise and the level of the road traffic noise. Finally, water sounds were determined to be the best sounds to use for enhancing the urban soundscape. The level of the water sounds should be similar to or not less than 3 dB below the level of the urban noises.

PM 10-bound polycyclic aromatic hydrocarbons: Concentrations, source characterization and estimating their risk in urban, suburban and rural areas in Kandy, Sri Lanka

Science.gov (United States)

Wickramasinghe, A. P.; Karunaratne, D. G. G. P.; Sivakanesan, R.

2011-05-01

Kandy, a world heritage city, is a rapidly urbanized area in Sri Lanka, with a high population density of ˜6000 hab km -2. As it is centrally located in a small valley of 26 km 2 surrounded by high mountains, emissions from the daily flow of >100,000 vehicles, most are old and poorly maintained, get stagnant over the study area with an increased emphasis on the associated health impacts. Particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) are considered to be major pollutants in vehicular emissions; while PAHs account for the majority of mutagenic potency of PM. The purpose of the current study is to determine the 8 h average concentrations of ambient PM 10 PAHs at twenty sites distributed in the urban, suburban and rural Kandy. Samples on glass micro fibre filters were collected with a high volume air sampler from July/2008 to March/2009, prepared through standard procedures and analyzed for PAHs by high performance liquid chromatography with ultraviolet visible detection. Further, the type and strength of possible anthropogenic emission sources that cause major perturbations to the atmosphere were assessed by traffic volume (24 h) counts and firewood mass burnt/d at each sampling site, with the subsequent societal impact through quantitative cancer risk assessment. The results can serve as a base set to assess the PAH sources, pollution levels and human exposure. Mean total concentrations of 16 prioritized PAHs (∑PAHs) ranged from 57.43 to 1246.12 ng m -3 with 695.94 ng m -3 in urban heavy traffic locations (U/HT), 105.55 ng m -3 in urban light traffic locations, 337.45 ng m -3 in suburban heavy traffic stations, 154.36 ng m -3 in suburban light traffic stations, 192.48 ng m -3 in rural high firewood burning area and 100.31 ng m -3 in rural low firewood burning area. The mean PM 10 concentration was 129 μg m -3 (55-221 μg m -3); which is beyond the WHO air quality standards. Polycyclic aromatic hydrocarbon signature and the spatial variation

Identification of the sources of primary organic aerosols at urban schools: A molecular marker approach

International Nuclear Information System (INIS)

Crilley, Leigh R.; Qadir, Raeed M.; Ayoko, Godwin A.; Schnelle-Kreis, Jürgen; Abbaszade, Gülcin; Orasche, Jürgen; Zimmermann, Ralf; Morawska, Lidia

2014-01-01

Children are particularly susceptible to air pollution and schools are examples of urban microenvironments that can account for a large portion of children's exposure to airborne particles. Thus this paper aimed to determine the sources of primary airborne particles that children are exposed to at school by analyzing selected organic molecular markers at 11 urban schools in Brisbane, Australia. Positive matrix factorization analysis identified four sources at the schools: vehicle emissions, biomass burning, meat cooking and plant wax emissions accounting for 45%, 29%, 16% and 7%, of the organic carbon respectively. Biomass burning peaked in winter due to prescribed burning of bushland around Brisbane. Overall, the results indicated that both local (traffic) and regional (biomass burning) sources of primary organic aerosols influence the levels of ambient particles that children are exposed at the schools. These results have implications for potential control strategies for mitigating exposure at schools. - Highlights: • Selected organic molecular markers at 11 urban schools were analyzed. • Four sources of primary organic aerosols were identified by PMF at the schools. • Both local and regional sources were found to influence exposure at the schools. • The results have implications for mitigation of children's exposure at schools. - The identification of the most important sources of primary organic aerosols at urban schools has implications for control strategies for mitigating children's exposure at schools

Urban domestic dog populations as a source of canine distemper virus for wild carnivores in the Coquimbo region of Chile.

Science.gov (United States)

Acosta-Jamett, G; Chalmers, W S K; Cunningham, A A; Cleaveland, S; Handel, I G; Bronsvoort, B M deC

2011-09-28

Urban areas can support dog populations dense enough to maintain canine distemper virus (CDV) and can be a source of infection for rural dogs and free-ranging carnivores. The aim of this study was to investigate the relationships between urban and rural domestic dog and wild carnivore populations and their effects on the epidemiology of CDV to explain retrospectively a CD outbreak in wild foxes in 2003. From 2005 to 2007 a cross-sectional household questionnaire survey was conducted in Coquimbo and Ovalle cities, in three towns and in rural sites along two transects from these cities to the Fray Jorge National Park (FJNP) in the Coquimbo region, Chile. Blood samples were collected from unvaccinated dogs at surveyed households and from free-ranging foxes in rural areas along the transects. The seroprevalence of CDV in domestic dogs was higher in urban than in rural areas and in the later was highest in dogs born before 2001-2002. The seroprevalence of CDV in foxes was higher in areas closer to human settlements. A high seroprevalence in dogs born before 2001-2002 further supports a link between CDV patterns in rural dog and fox populations. In our study area, urban dogs are proposed to be the source of CDV infection to wild carnivores. The large dog population size and density detected in Coquimbo and Ovalle provides optimal conditions for maintaining a large and dense susceptible population of dogs, which can act as a reservoir for highly infectious diseases and could have been the source of infection in the CD outbreak in wild foxes. Copyright © 2011 Elsevier B.V. All rights reserved.

Urban Malaria: Understanding its Epidemiology, Ecology, and Transmission Across Seven Diverse ICEMR Network Sites.

Science.gov (United States)

Wilson, Mark L; Krogstad, Donald J; Arinaitwe, Emmanuel; Arevalo-Herrera, Myriam; Chery, Laura; Ferreira, Marcelo U; Ndiaye, Daouda; Mathanga, Don P; Eapen, Alex

2015-09-01

A major public health question is whether urbanization will transform malaria from a rural to an urban disease. However, differences about definitions of urban settings, urban malaria, and whether malaria control should differ between rural and urban areas complicate both the analysis of available data and the development of intervention strategies. This report examines the approach of the International Centers of Excellence for Malaria Research (ICEMR) to urban malaria in Brazil, Colombia, India (Chennai and Goa), Malawi, Senegal, and Uganda. Its major theme is the need to determine whether cases diagnosed in urban areas were imported from surrounding rural areas or resulted from transmission within the urban area. If infections are being acquired within urban areas, malaria control measures must be targeted within those urban areas to be effective. Conversely, if malaria cases are being imported from rural areas, control measures must be directed at vectors, breeding sites, and infected humans in those rural areas. Similar interventions must be directed differently if infections were acquired within urban areas. The hypothesis underlying the ICEMR approach to urban malaria is that optimal control of urban malaria depends on accurate epidemiologic and entomologic information about transmission. © The American Society of Tropical Medicine and Hygiene.

Interpreting sensor measurements in dikes - experiences from UrbanFlood pilot sites

NARCIS (Netherlands)

Simm, J.; Jordan, D.; Topple, A.; Mokhov, I.; Pyayt, A.; Abdoun, T.; Bennett, V.; Broekhuijsen, J.; Meijer, R.; Klijn, F.; Schweckendiek, T.

2012-01-01

The UrbanFlood project is creating an Early Warning System framework that can be used to link sensors via the Internet to predictive models and emergency warning systems. The project includes four pilot sites to apply and validate at full scale the technology being developed in the project:

Contamination and source differentiation of Pb in park soils along an urban-rural gradient in Shanghai

International Nuclear Information System (INIS)

Li Hongbo; Yu Shen; Li Guilin; Deng Hong; Luo Xiaosan

2011-01-01

Urban soil Pb contamination is a great human health risk. Lead distribution and source in topsoils from 14 parks in Shanghai, China were investigated along an urban-rural gradient. Topsoils were contaminated averagely with 65 mg Pb kg -1 , 2.5 times higher than local soil background concentrations. HCl-extracts contained more anthropogenic Pb signatures than total sample digests as revealed by the higher 207/206 Pb and 208/206 Pb ratios in extracts (0.8613 ± 0.0094 and 2.1085 ± 0.0121 versus total digests 0.8575 ± 0.0098 and 2.0959 ± 0.0116). This suggests a higher sensitivity of HCl-extraction than total digestion in identifying anthropogenic Pb sources. Coal combustion emission was identified as the major anthropogenic Pb source (averagely 47%) while leaded gasoline emission contributed 12% overall. Urbanization effects were observed by total Pb content and anthropogenic Pb contribution. This study suggests that to reduce Pb contamination, Shanghai might have to change its energy composition to clean energy. - Highlights: → Coal combustion emission is identified as a main Pb source in Shanghai park soils. → HCl-extraction is sensitive in identifying anthropogenic isotope Pb sources. → Soil Pb contamination and its anthropogenic sources showed urbanization effects. - Coal combustion emission was identified as the main anthropogenic source of soil Pb contamination affecting Shanghai parks.

Influences of natural emission sources (wildfires and Saharan dust) on the urban organic aerosol in Barcelona (Western Mediterranean Basis) during a PM event.

Science.gov (United States)

van Drooge, Barend L; Lopez, Jordi F; Grimalt, Joan O

2012-11-01

The urban air quality in Barcelona in the Western Mediterranean Basin is characterized by overall high particulate matter (PM) concentrations, due to intensive local anthropogenic emissions and specific meteorological conditions. Moreover, on several days, especially in summer, natural PM sources, such as long-range transported Saharan dust from Northern Africa or wildfires on the Iberian Peninsula and around the Mediterranean Basin, may influence the levels and composition of the organic aerosol. In the second half of July 2009, daily collected PM(10) filter samples in an urban background site in Barcelona were analyzed on organic tracer compounds representing several emission sources. During this period, an important PM peak event was observed. Individual organic compound concentrations increased two to five times during this event. Although highest increase was observed for the organic tracer of biomass burning, the contribution to the organic aerosol was estimated to be around 6 %. Organic tracers that could be related to Saharan dust showed no correlation with the PM and OC levels, while this was the case for those related to fossil fuel combustion from traffic emissions. Moreover, a change in the meteorological conditions gave way to an overall increase of the urban background contamination. Long-range atmospheric transport of organic compounds from primary emissions sources (i.e., wildfires and Saharan dust) has a relatively moderate impact on the organic aerosol in an urban area where the local emissions are dominating.

Metal accumulation and performance of nestlings of passerine bird species at an urban brownfield site

Energy Technology Data Exchange (ETDEWEB)

Hofer, Charles; Gallagher, Frank J. [Department of Ecology, Evolution and Natural Resources, Rutgers, the State University of New Jersey, 14 College Farm Rd., New Brunswick, NJ 08901-8551 (United States); Holzapfel, Claus, E-mail: holzapfe@andromeda.rutgers.ed [Department of Biological Sciences, Rutgers, the State University of New Jersey, Newark, 195 University Ave., Newark, NJ 07102-1811 (United States)

2010-05-15

The use of passerine species as bioindicators of metal bioaccumulation is often underutilized when examining the wildlife habitat value of polluted sites. In this study we tested feathers of nestlings of two common bird species (house wren and American robin) for accumulation of Pb, Zn, As, Cr, Cu, Fe in comparison of a polluted, urban brownfield with a rural, unpolluted site. House wren nestlings at the study site accumulated significantly greater concentrations of all target metals except Zn. At the polluted site we found significant species differences of metal concentrations in feathers, with house wrens accumulating greater concentrations of Pb, Fe, and Zn but slightly lesser accumulations of Cr and Cu than American robins. Although house wren nestlings demonstrated significant accumulation of metals, these concentrations showed little effect on size metrics or fledge rates during the breeding season compared to nestlings from the control site. - Nestlings of birds in an urban brownfield accumulated soil contaminants but did not show signs of reduced breeding success or growth.

Metal accumulation and performance of nestlings of passerine bird species at an urban brownfield site

International Nuclear Information System (INIS)

Hofer, Charles; Gallagher, Frank J.; Holzapfel, Claus

2010-01-01

The use of passerine species as bioindicators of metal bioaccumulation is often underutilized when examining the wildlife habitat value of polluted sites. In this study we tested feathers of nestlings of two common bird species (house wren and American robin) for accumulation of Pb, Zn, As, Cr, Cu, Fe in comparison of a polluted, urban brownfield with a rural, unpolluted site. House wren nestlings at the study site accumulated significantly greater concentrations of all target metals except Zn. At the polluted site we found significant species differences of metal concentrations in feathers, with house wrens accumulating greater concentrations of Pb, Fe, and Zn but slightly lesser accumulations of Cr and Cu than American robins. Although house wren nestlings demonstrated significant accumulation of metals, these concentrations showed little effect on size metrics or fledge rates during the breeding season compared to nestlings from the control site. - Nestlings of birds in an urban brownfield accumulated soil contaminants but did not show signs of reduced breeding success or growth.

Atmospheric aerosol compositions and sources at two national background sites in northern and southern China

Science.gov (United States)

Zhu, Qiao; He, Ling-Yan; Huang, Xiao-Feng; Cao, Li-Ming; Gong, Zhao-Heng; Wang, Chuan; Zhuang, Xin; Hu, Min

2016-08-01

Although China's severe air pollution has become a focus in the field of atmospheric chemistry and the mechanisms of urban air pollution there have been researched extensively, few field sampling campaigns have been conducted at remote background sites in China, where air pollution characteristics on a larger scale are highlighted. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), together with an Aethalometer, was deployed at two of China's national background sites in northern (Lake Hongze site; 33.23° N, 118.33° E; altitude 21 m) and southern (Mount Wuzhi site; 18.84° N, 109.49° E; altitude 958 m) China in the spring seasons in 2011 and 2015, respectively, in order to characterize submicron aerosol composition and sources. The campaign-average PM1 concentration was 36.8 ± 19.8 µg m-3 at the northern China background (NCB) site, which was far higher than that at the southern China background (SCB) site (10.9 ± 7.8 µg m-3). Organic aerosol (OA) (27.2 %), nitrate (26.7 %), and sulfate (22.0 %) contributed the most to the PM1 mass at NCB, while OA (43.5 %) and sulfate (30.5 %) were the most abundant components of the PM1 mass at SCB, where nitrate only constituted a small fraction (4.7 %) and might have contained a significant amount of organic nitrates (5-11 %). The aerosol size distributions and organic aerosol elemental compositions all indicated very aged aerosol particles at both sites. The OA at SCB was more oxidized with a higher average oxygen to carbon (O / C) ratio (0.98) than that at NCB (0.67). Positive matrix factorization (PMF) analysis was used to classify OA into three components, including a hydrocarbon-like component (HOA, attributed to fossil fuel combustion) and two oxygenated components (OOA1 and OOA2, attributed to secondary organic aerosols from different source areas) at NCB. PMF analysis at SCB identified a semi-volatile oxygenated component (SV-OOA) and a low-volatility oxygenated

Multisite study of particle number concentrations in urban air.

Science.gov (United States)

Harrison, Roy M; Jones, Alan M

2005-08-15

Particle number concentration data are reported from a total of eight urban site locations in the United Kingdom. Of these, six are central urban background sites, while one is an urban street canyon (Marylebone Road) and another is influenced by both a motorway and a steelworks (Port Talbot). The concentrations are generally of a similar order to those reported in the literature, although higher than those in some of the other studies. Highest concentrations are at the Marylebone Road site and lowest are at the Port Talbot site. The central urban background locations lie somewhere between with concentrations typically around 20 000 cm(-3). A seasonal pattern affects all sites, with highest concentrations in the winter months and lowest concentrations in the summer. Data from all sites show a diurnal variation with a morning rush hour peak typical of an anthropogenic pollutant. When the dilution effects of windspeed are accounted for, the data show little directionality at the central urban background sites indicating the influence of sources from all directions as might be expected if the major source were road traffic. At the London Marylebone Road site there is high directionality driven by the air circulation in the street canyon, and at the Port Talbot site different diurnal patterns are seen for particle number count and PM10 influenced by emissions from road traffic (particle number count) and the steelworks (PM10) and local meteorological factors. Hourly particle number concentrations are generally only weakly correlated to NO(x) and PM10, with the former showing a slightly closer relationship. Correlations between daily average particle number count and PM10 were also weak. Episodes of high PM10 concentration in summer typically show low particle number concentrations consistent with transport of accumulation mode secondary aerosol, while winter episodes are frequently associated with high PM10 and particle number count arising from poor dispersion of

Impacts of urbanization on regional nonpoint source pollution: case study for Beijing, China.

Science.gov (United States)

Zhi, Xiaosha; Chen, Lei; Shen, Zhenyao

2018-04-01

Due to limits on available data, the effects of urban sprawl on regional nonpoint source pollution (NPS) have not been investigated over long time periods. In this paper, the characteristics of urban sprawl from 1999 to 2014 in Beijing were explored by analyzing historical land-use data. The Event Mean Concentration data have been collected from all available references, which were used to estimate the variation in urban NPSs. Moreover, the impacts of variation in urban sprawl on regional NPSs were qualified. The results indicated that the urbanization process showed different influences on pollutants, while COD and TN were identified as key NPS pollutants. Residential areas contributed more NPS pollutants than did roads, which played a tremendous role in the control of urban NPS. The results also suggested in part that the impact of urban sprawl on the variation of COD decreased while TN increased in Beijing during the study period. These results would provide insight into the impacts of urban sprawl on NPS variation over a long period, as well as the reference for reasonable urban planning directives.

Novel Deployment of Mobile Eddy Covariance Tower Observations Across Variations in the Built Environment in a Desert Urban Area

Science.gov (United States)

2015-11-03

buildings); (2) high-density urban site (asphalt-paved parking lot near a high-traffic intersection); and 3) suburban mesic landscape (turf grass with...University campuses: (1) xeric landscape (gravel cover and palo verde trees with drip-irrigation systems near tall buildings); (2) high-density urban site...classification of each source area. The xeric site and high-density urban site behave like a semiarid landscape , with high Bowen ratios (~3 and ~8 respectively

ARCHAEOBOTANY IN URBAN SITES: THE CASE OF MUTINA

Directory of Open Access Journals (Sweden)

R. Rinaldi

2013-04-01

Full Text Available The present paper aims to show the importance of analyzing plant macroremains from urban excavations. Organic materials preserved below the historical city in waterlogged conditions are a fundamental resource, and the study of seeds and fruits gives a good contribution to historical and archaeological research. Archaeobotany in urban contexts provides important results when the examined material comes from several excavations that "photograph" the territory over quite a long period. An overview of archaeobotanical analyses carried out on material from archaeological sites of Modena (Emilia-Romagna, from the 2nd century BC to the 6th century AD, made by the Laboratory of Palynology and Palaeobotany of the University of Modena and Reggio Emilia, is presented. The floristic list of seed/fruit analyses result is reported and interesting subject matters are tackled concerning both cultivated/cultivable plants (fruits and nuts, vegetables/aromatics/spices/medicinal plants, fibre and oil plants, cereals and pulses, flowers and other ornamental plants and wild plants of no obvious use, together with wetland plants which are rare and endangered species in Emilia-Romagna today.

Geochemistry and carbon isotopic ratio for assessment of PM10 composition, source and seasonal trends in urban environment.

Science.gov (United States)

Di Palma, A; Capozzi, F; Agrelli, D; Amalfitano, C; Giordano, S; Spagnuolo, V; Adamo, P

2018-08-01

Investigating the nature of PM 10 is crucial to differentiate sources and their relative contributions. In this study we compared the levels, and the chemical and mineralogical properties of PM 10 particles sampled in different seasons at monitoring stations representative of urban background, urban traffic and suburban traffic areas of Naples city. The aims were to relate the PM 10 load and characteristics to the location of the monitoring stations, to investigate the different sources contributing to PM 10 and to highlight PM 10 seasonal variability. Bulk analyses of chemical species in the PM 10 fraction included total carbon and nitrogen, δ 13 C and other 20 elements. Both natural and anthropogenic sources were found to contribute to the exceedances of the EU PM 10 limit values. The natural contribution was mainly related to marine aerosols and soil dust, as highlighted by X-ray diffractometry and SEM-EDS microscopy. The percentage of total carbon suggested a higher contribution of biogenic components to PM 10 in spring. However, this result was not supported by the δ 13 C values which were seasonally homogeneous and not sufficient to extract single emission sources. No significant differences, in terms of PM 10 load and chemistry, were observed between monitoring stations with different locations, suggesting a homogeneous distribution of PM 10 on the studied area in all seasons. The anthropogenic contribution to PM 10 seemed to dominate in all sites and seasons with vehicular traffic acting as a main source mostly by generation of non-exhaust emissions Our findings reinforce the need to focus more on the analysis of PM 10 in terms of quality than of load, to reconsider the criteria for the classification and the spatial distribution of the monitoring stations within urban and suburban areas, with a special attention to the background location, and to emphasize all the policies promoting sustainable mobility and reduction of both exhaust and not

Source apportionment of heavy metals and ionic contaminants in rainwater tanks in a subtropical urban area in Australia.

Science.gov (United States)

Huston, R; Chan, Y C; Chapman, H; Gardner, T; Shaw, G

2012-03-15

Due to prolonged droughts in recent years, the use of rainwater tanks in urban areas has increased in Australia. In order to apportion sources of contribution to heavy metal and ionic contaminants in rainwater tanks in Brisbane, a subtropical urban area in Australia, monthly tank water samples (24 sites, 31 tanks) and concurrent bulk deposition samples (18 sites) were collected during mainly April 2007-March 2008. The samples were analysed for acid-soluble metals, soluble anions, total inorganic carbon and total organic carbon, and characteristics such as total solid and pH. The Positive Matrix Factorisation model, EPA PMF 3.0, was used to apportion sources of contribution to the contaminants. Four source factors were identified for the bulk deposition samples, including 'crustal matter/sea salt', 'car exhausts/road side dust', 'industrial dust' and 'aged sea salt/secondary aerosols'. For the tank water samples, apart from these atmospheric deposition related factors which contributed in total to 65% of the total contaminant concentration on average, another six rainwater collection system related factors were identified, including 'plumbing', 'building material', 'galvanizing', 'roofing', 'steel' and 'lead flashing/paint' (contributing in total to 35% of the total concentration on average). The Australian Drinking Water Guideline for lead was exceeded in 15% of the tank water samples. The collection system related factors, in particular the 'lead flashing/paint' factor, contributed to 79% of the lead in the tank water samples on average. The concentration of lead in tank water was found to vary with various environmental and collection system factors, in particular the presence of lead flashing on the roof. The results also indicated the important role of sludge dynamics inside the tank on the quality of tank water. Copyright © 2011 Elsevier Ltd. All rights reserved.

Water Soluble Organic Nitrogen (WSON) in Ambient Fine Particles Over a Megacity in South China: Spatiotemporal Variations and Source Apportionment

Science.gov (United States)

Yu, Xu; Yu, Qingqing; Zhu, Ming; Tang, Mingjin; Li, Sheng; Yang, Weiqiang; Zhang, Yanli; Deng, Wei; Li, Guanghui; Yu, Yuegang; Huang, Zhonghui; Song, Wei; Ding, Xiang; Hu, Qihou; Li, Jun; Bi, Xinhui; Wang, Xinming

2017-12-01

Organic nitrogen aerosols are complex mixtures and important compositions in ambient fine particulate matters (PM2.5), yet their sources and spatiotemporal patterns are not well understood particularly in regions influenced by intensive human activities. In this study, filter-based ambient PM2.5 samples at four stations (one urban, two rural, plus one urban roadside) and PM samples from combustion sources (vehicle exhaust, ship emission, and biomass burning) were collected in the coastal megacity Guangzhou, south China, for determining water soluble organic nitrogen (WSON) along with other organic and inorganic species. The annual average WSON concentrations, as well as the ratios of WSON to water soluble total nitrogen, were all significantly higher at rural sites than urban sites. Average WSON concentrations at the four sites during the wet season were quite near each other, ranging from 0.41 to 0.49 μg/m3; however, they became 2 times higher at the rural sites than at the urban sites during the dry season. Five major sources for WSON were identified through positive matrix factorization analysis. Vehicle emission (29.3%), biomass burning (22.8%), and secondary formation (20.2%) were three dominant sources of WSON at the urban station, while vehicle emission (45.4%) and dust (28.6%) were two dominant sources at the urban roadside station. At the two rural sites biomass burning (51.1% and 34.1%, respectively) and secondary formation (17.8% and 30.5%, respectively) were dominant sources of WSON. Ship emission contributed 8-12% of WSON at the four sites. Natural vegetation seemed to have very minor contribution to WSON.

Urban nonpoint source pollution buildup and washoff models for simulating storm runoff quality in the Los Angeles County.

Science.gov (United States)

Wang, Long; Wei, Jiahua; Huang, Yuefei; Wang, Guangqian; Maqsood, Imran

2011-07-01

Many urban nonpoint source pollution models utilize pollutant buildup and washoff functions to simulate storm runoff quality of urban catchments. In this paper, two urban pollutant washoff load models are derived using pollutant buildup and washoff functions. The first model assumes that there is no residual pollutant after a storm event while the second one assumes that there is always residual pollutant after each storm event. The developed models are calibrated and verified with observed data from an urban catchment in the Los Angeles County. The application results show that the developed model with consideration of residual pollutant is more capable of simulating nonpoint source pollution from urban storm runoff than that without consideration of residual pollutant. For the study area, residual pollutant should be considered in pollutant buildup and washoff functions for simulating urban nonpoint source pollution when the total runoff volume is less than 30 mm. Copyright © 2011 Elsevier Ltd. All rights reserved.

On the simultaneous deployment of two single-particle mass spectrometers at an urban background and a roadside site during SAPUSS

Directory of Open Access Journals (Sweden)

M. Dall'Osto

2016-08-01

Full Text Available The aerosol time-of-flight mass spectrometer (ATOFMS provides size-resolved information on the chemical composition of single particles with high time resolution. Within SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies, continuous ATOFMS measurements of ambient particles were made simultaneously at two urban locations: urban background (UB site and roadside (RS site in the city of Barcelona (Spain from 17 September to 18 October 2010. Two different instrumental configurations were used: ATOFMS (TSI 3800 with a converging nozzle inlet (high efficiency at about 800–2000 nm at the UB site and ATOFMS (TSI 3800-100 with an aerodynamic lens inlet (high efficiency at about 300–700 nm at the RS site. This is the first time, to our knowledge, that two ATOFMS instruments have been deployed in the same field study. The different instrument configurations had an impact on the observed particle types at the two sites. Nevertheless, 10 particle types were detected at both locations, including local and regional elemental carbon (22.7–58.9 % of total particles, fresh and aged sea salt (1.0–14.6 %, local and regional nitrate-containing aerosols (3–11.6 %, local lead-containing metallic particles (0.1–0.2 %, and transported Fe-nitrate particles (0.8–2.5 %. The ATOFMS at the UB also characterized four particle types: calcium-containing dust (0.9 %, Saharan dust (1.3 %, vanadium-containing particles (0.9 %, and vegetative debris (1.7 %. By contrast, the high statistical counts of fine particles detected at the RS allowed identification of eight particle types. Four of these contained organic nitrogen of primary and secondary origin, which highlights the complex nature of the sources and processes that contribute to this aerosol chemical component. Aminium salts were found related to coarse sulfate-rich particle types, suggesting heterogeneous reaction mechanisms for their formation. The other four particle

Area-wide management of Aedes albopictus. Part 2: gauging the efficacy of traditional integrated pest control measures against urban container mosquitoes.

Science.gov (United States)

Fonseca, Dina M; Unlu, Isik; Crepeau, Taryn; Farajollahi, Ary; Healy, Sean P; Bartlett-Healy, Kristen; Strickman, Daniel; Gaugler, Randy; Hamilton, George; Kline, Daniel; Clark, Gary G

2013-12-01

Aedes (Stegomyia) albopictus (Skuse) is an important disease vector and biting nuisance. During the 2009 active season, six ∼1000-parcel sites were studied, three in urban and three in suburban areas of New Jersey, United States, to examine the efficacy of standard integrated urban mosquito control strategies applied area wide. Active source reduction, larviciding, adulticiding and public education (source reduction through education) were implemented in one site in each county, an education-only approach was developed in a second site and a third site was used as an untreated experimental control. Populations were surveyed weekly with BG-Sentinel traps and ovitraps. A substantial reduction in Ae. albopictus populations was achieved in urban sites, but only modest reductions in suburban sites. Education alone achieved significant reductions in urban adult Ae. albopictus. Egg catches echoed adult catches only in suburban sites. There are significant socioeconomic and climatic differences between urban and suburban sites that impact upon Ae. albopictus populations and the efficacy of the control methods tested. An integrated pest management approach can affect abundances, but labor-intensive, costly source reduction was not enough to maintain Ae. albopictus counts below a nuisance threshold. Nighttime adult population suppression using truck-mounted adulticides can be effective. Area-wide cost-effective strategies are necessary. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Temporal characteristics of black carbon concentrations and its potential emission sources in a southern Taiwan industrial urban area.

Science.gov (United States)

Cheng, Yu-Hsiang; Lin, Chi-Chi; Liu, Jyh-Jian; Hsieh, Cheng-Ju

2014-03-01

This study investigates the temporal characteristics of black carbon and its potential emission sources, as well as the fractions of BC in PM2.5 levels in Kaohsiung urban area, which is an industrial city in southern Taiwan. Concentrations of BC and PM2.5 are monitored continuously from March 2006 to February 2010, using an aethalometer and a tapered element oscillating microbalance monitor. Additionally, the presence of organic compounds (or UV enhanced species) in particles at the sampling site is determined using the Delta-C (UVBC-BC) value. According to long-term measurement results, BC and PM2.5 concentrations are 3.33 and 34.0 μg m(-3), respectively, in the Kaohsiung urban area. The ratio of BC/PM2.5 is approximately 11 %. Low concentration of BC and PM2.5 in the summer of this study period is mostly likely owing to meteorological conditions that favored dispersion of local air pollutants. Nevertheless, BC concentrations peaked markedly during morning hours (7:00-11:00), likely owing to local traffic congestion. Measurement results suggest that BC is released from local traffic activities and emitted from industrial activities at this sampling site. Additionally, Delta-C values are significantly higher than zero during January-March and November-December periods in this industrial urban area, implying that UV enhanced species can be observed. At this sampling site, these UV enhanced species do not only originate from household activity and solid waste burning but also release from industrial activities. The elevated Delta-C values during nighttime (18:00-6:00) in the autumn and winter seasons are likely related to those UV enhanced species in the atmosphere, which can be condensed on particle surface under low temperature conditions. According to long-term measurement results, significantly positive Delta-C values can be observed under temperatures industrial parks and a coal-fired power plant.

Classifying urban meteorological stations sites by 'local climate zones': Preliminary results for the city of Novi Sad (Serbia

Directory of Open Access Journals (Sweden)

Savić Stevan

2013-01-01

Full Text Available Conventional approach in the investigation of urban climate of Novi Sad has been done through simple urban-rural air temperature differences. These inter-urban air temperature differences showed how much is city warmer than its surroundings, so-called urban heat island (UHI effect. Temperature differences exist inside the city as well. To get to know the intensity of these intra-urban temperature differences, installation of meteorological stations in different parts of the city or mobile measurements are needed. In 2012 started IPA HUSRB project made by Department of Climatology and Landscape Ecology (University of Szeged and Faculty of Sciences (University of Novi Sad. The main goal of this project is the development and installation of wireless urban meteorological network (temperature and relative humidity sensors in Szeged and Novi Sad. Before the deployment of sensors, necessary metadata about each potential urban meteorological station site needs to be collected. Field work, collected metadata and Stewart and Oke climate-based classification system from 2012 were used for defining the potential urban meteorological stations sites on the territory of the city of Novi Sad (Serbia and its surroundings.

Dry deposition study using filter packs at a rural and an urban monitoring sites

International Nuclear Information System (INIS)

Siti Mariam Sumari; Rusdin Laiman; Kantasamy, Nesamalar; Sinyaw, S.U.

2008-01-01

Air samples were collected from 2004 to 2005 using four-staged filter packs at an urban site Petaling Jaya (PJ) and a rural-agricultural site Tanah Rata (TR). The samples were analysed for reactive gases consisting of NH 3 , HNO 3 , HCL and SO 2 while the aerosol components were analysed for SO 4 2- , NO 3 - , Cl - , Na + , K + , Ca 2+ , Mg 2+ and NH 4 + . For both PJ and TR, analysis indicates the dry deposition was dominated by the gaseous components. They range from about 78 % to 80 % of total compositions for urban PJ and 59 % to 63 % for rural TR. Among the four reactive gases, NH 3 is the most dominating component at both sites. Elevated NH 3 concentration in TR was mainly attributed to the use of nitrogenous fertilizer. For PJ high NH 3 could be due to local air pollution created by industries as well as agricultural activities. The acidic species associated with SO x and NO x are typically more abundant at PJ than TR. Their presence, and for most other chemical species, show similar increasing trend, and this reflect the growing use of fossil fuels associated with urbanization and industrialization, especially for PJ. (author)

Offal dumping sites influence the relative abundance and roosting site selection of Black Kites (Milvus migrans govinda) in urban landscape: a study from Kolkata metropolis, India.

Science.gov (United States)

Mazumdar, Subhendu; Ghose, Dipankar; Saha, Goutam Kumar

2017-12-14

Although Black Kites (Milvus migrans govinda) serve as major scavenging raptor in most of the urban areas, scientific studies on this important ecosystem service provider are almost non-existent in Indian context. The present study was carried out in a metropolis in eastern India to find out the factors influencing relative abundance and roosting site selection of Black Kites. Separate generalized linear models (GLMs) were performed considering encounter rate and roosting Black Kite abundance as response variables. The study conclusively indicated that encounter rates of Black Kites were significantly influenced by the presence of garbage dumps in its vicinity. Numbers of Black Kites were also higher in the roosting sites situated closer to garbage dumps and open spaces. In addition, expected counts of Black Kites significantly increased in roosting sites situated away from buildings and water bodies. However, built-up area and tree cover around the roosting sites had no influence on the abundance of Black Kites therein. With rapid urbanization and changing offal disposal patterns, our findings would be useful to ensure continued availability of food and roosting sites of Black Kites in urban areas.

Isotopic evidence for enhanced fossil fuel sources of aerosol ammonium in the urban atmosphere.

Science.gov (United States)

Pan, Yuepeng; Tian, Shili; Liu, Dongwei; Fang, Yunting; Zhu, Xiaying; Gao, Meng; Gao, Jian; Michalski, Greg; Wang, Yuesi

2018-04-20

The sources of aerosol ammonium (NH 4 + ) are of interest because of the potential of NH 4 + to impact the Earth's radiative balance, as well as human health and biological diversity. Isotopic source apportionment of aerosol NH 4 + is challenging in the urban atmosphere, which has excess ammonia (NH 3 ) and where nitrogen isotopic fractionation commonly occurs. Based on year-round isotopic measurements in urban Beijing, we show the source dependence of the isotopic abundance of aerosol NH 4 + , with isotopically light (-33.8‰) and heavy (0 to +12.0‰) NH 4 + associated with strong northerly winds and sustained southerly winds, respectively. On an annual basis, 37-52% of the initial NH 3 concentrations in urban Beijing arises from fossil fuel emissions, which are episodically enhanced by air mass stagnation preceding the passage of cold fronts. These results provide strong evidence for the contribution of non-agricultural sources to NH 3 in urban regions and suggest that priority should be given to controlling these emissions for haze regulation. This study presents a carefully executed application of existing stable nitrogen isotope measurement and mass-balance techniques to a very important problem: understanding source contributions to atmospheric NH 3 in Beijing. This question is crucial to informing environmental policy on reducing particulate matter concentrations, which are some of the highest in the world. However, the isotopic source attribution results presented here still involve a number of uncertain assumptions and they are limited by the incomplete set of chemical and isotopic measurements of gas NH 3 and aerosol NH 4 + . Further field work and lab experiments are required to adequately characterize endmember isotopic signatures and the subsequent isotopic fractionation process under different air pollution and meteorological conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization of atmospheric black carbon and co-pollutants in urban and rural areas of Spain

Science.gov (United States)

Becerril-Valle, M.; Coz, E.; Prévôt, A. S. H.; Močnik, G.; Pandis, S. N.; Sánchez de la Campa, A. M.; Alastuey, A.; Díaz, E.; Pérez, R. M.; Artíñano, B.

2017-11-01

A one-year black carbon (BC) experimental study was performed at three different locations (urban traffic, urban background, rural) in Spain with different equivalent BC (eBC) source characteristics by means of multi-wavelength Aethalometers. The Aethalometer model was used for the source apportionment study, based on the difference in absorption spectral dependence of emissions from biomass burning (bb) and fossil fuel (ff) combustion. Most studies use a single bb and ff absorption Ångström exponent (AAE) pair (AAEbb and AAEff), however in this work we use a range of AAE values associated with fossil fuel and biomass burning based on the available measurements, which represents more properly all conditions. A sensitivity analysis of the source specific AAE was carried out to determine the most appropriate AAE values, being site dependent and seasonally variable. Here we present a methodology for the determination of the ranges of AAEbb and AAEff by evaluating the correlations between the source apportionment of eBC using the Aethalometer model with four biomass burning tracers measured at the rural site. The best combination was AAEbb = [1.63-1.74] and AAEff = [0.97-1.12]. Mean eBC values (±SD) obtained during the period of study were 3.70 ± 3.73 μg m-3 at the traffic urban site, 2.33 ± 2.96 μg m-3 at the urban background location, and 2.61 ± 5.04 μg m-3 in the rural area. High contributions of eBC to the PM10 mass were found (values up to 21% in winter), but with high eBC/PM10 variability. The hourly mean eBCff and eBCbb concentrations varied from 0 to 51 μg m-3 and from 0 to 50 μg m-3 at the three sites, respectively, exhibiting distinct seasonal and daily patterns. The fossil fuel combustion was the dominant eBC source at the urban sites, while biomass burning dominated during the cold season (88% of eBCbb) in the rural area. Daily PM2.5 and PM10 samples were collected using high-volume air samplers and analyzed for OC and EC. Analysis of biomass

An integrated approach to assess heavy metal source apportionment in peri-urban agricultural soils

International Nuclear Information System (INIS)

Huang, Ying; Li, Tingqiang; Wu, Chengxian; He, Zhenli; Japenga, Jan; Deng, Meihua; Yang, Xiaoe

2015-01-01

Highlights: • Heavy metal source apportionment was conducted in peri-urban agricultural areas. • Precise and quantified results were obtained by using isotope ratio analysis. • The integration of IRA, GIS, PCA, and CA was proved to be more reliable. • Hg pollution was from the use of organic fertilizers in this area. - Abstract: Three techniques (Isotope Ratio Analysis, GIS mapping, and Multivariate Statistical Analysis) were integrated to assess heavy metal pollution and source apportionment in peri-urban agricultural soils. The soils in the study area were moderately polluted with cadmium (Cd) and mercury (Hg), lightly polluted with lead (Pb), and chromium (Cr). GIS Mapping suggested Cd pollution originates from point sources, whereas Hg, Pb, Cr could be traced back to both point and non-point sources. Principal component analysis (PCA) indicated aluminum (Al), manganese (Mn), nickel (Ni) were mainly inherited from natural sources, while Hg, Pb, and Cd were associated with two different kinds of anthropogenic sources. Cluster analysis (CA) further identified fertilizers, waste water, industrial solid wastes, road dust, and atmospheric deposition as potential sources. Based on isotope ratio analysis (IRA) organic fertilizers and road dusts accounted for 74–100% and 0–24% of the total Hg input, while road dusts and solid wastes contributed for 0–80% and 19–100% of the Pb input. This study provides a reliable approach for heavy metal source apportionment in this particular peri-urban area, with a clear potential for future application in other regions.

An integrated approach to assess heavy metal source apportionment in peri-urban agricultural soils

Energy Technology Data Exchange (ETDEWEB)

Huang, Ying; Li, Tingqiang; Wu, Chengxian [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); He, Zhenli [University of Florida, Institute of Food and Agricultural Sciences, Indian River Research and Education Center, Fort Pierce, FL 34945 (United States); Japenga, Jan; Deng, Meihua [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Yang, Xiaoe, E-mail: xeyang@zju.edu.cn [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

2015-12-15

Highlights: • Heavy metal source apportionment was conducted in peri-urban agricultural areas. • Precise and quantified results were obtained by using isotope ratio analysis. • The integration of IRA, GIS, PCA, and CA was proved to be more reliable. • Hg pollution was from the use of organic fertilizers in this area. - Abstract: Three techniques (Isotope Ratio Analysis, GIS mapping, and Multivariate Statistical Analysis) were integrated to assess heavy metal pollution and source apportionment in peri-urban agricultural soils. The soils in the study area were moderately polluted with cadmium (Cd) and mercury (Hg), lightly polluted with lead (Pb), and chromium (Cr). GIS Mapping suggested Cd pollution originates from point sources, whereas Hg, Pb, Cr could be traced back to both point and non-point sources. Principal component analysis (PCA) indicated aluminum (Al), manganese (Mn), nickel (Ni) were mainly inherited from natural sources, while Hg, Pb, and Cd were associated with two different kinds of anthropogenic sources. Cluster analysis (CA) further identified fertilizers, waste water, industrial solid wastes, road dust, and atmospheric deposition as potential sources. Based on isotope ratio analysis (IRA) organic fertilizers and road dusts accounted for 74–100% and 0–24% of the total Hg input, while road dusts and solid wastes contributed for 0–80% and 19–100% of the Pb input. This study provides a reliable approach for heavy metal source apportionment in this particular peri-urban area, with a clear potential for future application in other regions.

Contribution of biogenic and photochemical sources to ambient VOCs during winter to summer transition at a semi-arid urban site in India.

Science.gov (United States)

Sahu, L K; Tripathi, Nidhi; Yadav, Ravi

2017-10-01

This paper presents the sources and characteristics of ambient volatile organic compounds (VOCs) measured using PTR-TOF-MS instrument in a metropolitan city of India during winter to summer transition period. Mixing ratios of VOCs exhibited strong diurnal, day-to-day and episodic variations. Methanol was the most dominant species with monthly mean values of 18-22 pbbv. The emission ratios of VOCs relative to benzene calculated from nighttime data were used to estimate the relative contributions of vehicle exhaust and other sources. The increasing daytime ratios of oxygenated-VOCs (OVOCs)/benzene and isoprene/benzene from February to March indicates increasing contribution of photo-oxidation and biogenic sources. Daytime fractions of acetone (18%), acetaldehyde (15%) and isoprene (4.5%) to the sum of measured VOCs in March were higher than those in February. Variations of VOCs at lower temperatures (biogenic emissions. The emissions of OVOCs from vehicle exhaust were estimated to be smaller (20-40%) than those from other sources. The contributions of biogenic and secondary sources to OVOCs and isoprene increased by 10-15% from winter to summer. This study provides evidence that the winter-to-summer transition has an impact on sources and composition of VOCs in tropical urban areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

Urban Stormwater Temperature Surges: A Central US Watershed Study

Directory of Open Access Journals (Sweden)

Sean J. Zeiger

2015-10-01

Full Text Available Impacts of urban land use can include increased stormwater runoff temperature (Tw leading to receiving water quality impairment. There is therefore a need to target and mitigate sources of thermal pollution in urban areas. However, complex relationships between urban development, stormwater runoff and stream water heating processes are poorly understood. A nested-scale experimental watershed study design was used to investigate stormwater runoff temperature impacts to receiving waters in a representative mixed-use urbanizing watershed of the central US. Daily maximum Tw exceeded 35.0 °C (threshold for potential mortality of warm-water biota at an urban monitoring site for a total of five days during the study period (2011–2013. Sudden increases of more than 1.0 °C within a 15 min time interval of Tw following summer thunderstorms were significantly correlated (CI = 95%; p < 0.01 to cumulative percent urban land use (r2 = 0.98; n = 29. Differences in mean Tw between monitoring sites were significantly correlated (CI = 95%; p = 0.02 to urban land use practices, stream distance and increasing discharge. The effects of the 2012 Midwest USA drought and land use on Tw were also observed with maximum Tw 4.0 °C higher at an urban monitoring site relative to a rural site for 10.5 h. The current work provides quantitative evidence of acute increases in Tw related to urban land use. Results better inform land managers wishing to create management strategies designed to preserve suitable thermal stream habitats in urbanizing watersheds.

Incorporating Open Source Data for Bayesian Classification of Urban Land Use From VHR Stereo Images

NARCIS (Netherlands)

Li, Mengmeng; De Beurs, Kirsten M.; Stein, Alfred; Bijker, Wietske

2017-01-01

This study investigates the incorporation of open source data into a Bayesian classification of urban land use from very high resolution (VHR) stereo satellite images. The adopted classification framework starts from urban land cover classification, proceeds to building-type characterization, and

Molecular marker analysis as a guide to the sources of fine organic aerosols

International Nuclear Information System (INIS)

Rogge, W.F.; Cass, G.R.; Hildemann, L.M.; Simoneit, B.R.T.

1992-07-01

The molecular composition of fine particulate (D p ≥ 2 μm) organic aerosol emissions from the most important sources in the Los Angeles area has been determined. Likewise, ambient concentration patterns for more than 80 single organic compounds have been measured at four urban sites (West Los Angeles, Downtown Los Angeles, Pasadena, and Rubidoux) and at one remote offshore site (San Nicolas Island). It has been found that cholesterol serves as a marker compound for emissions from charbroilers and other meat cooking operations. Vehicular exhaust being emitted from diesel and gasoline powered engines can be traced in the Los Angeles atmosphere using fossil petroleum marker compounds such as steranes and pentacyclic triterpanes (e.g., hopanes). Biogenic fine particle emission sources such as plant fragments abraded from leaf surfaces by wind and weather can be traced in the urban atmosphere. Using distinct and specific source organic tracers or assemblages of organic compounds characteristic for the sources considered it is possible to estimate the influence of different source types at any urban site where atmospheric data are available

An experimental study of the impact of trees and urban form on the turbulent dispersion of heavy particles from near ground point sources

Science.gov (United States)

Stoll, R., II; Christen, A.; Mahaffee, W.; Salesky, S.; Therias, A.; Caitlin, S.

2017-12-01

Pollution in the form of small particles has a strong impact on a wide variety of urban processes that play an important role in the function of urban ecosystems and ultimately human health and well-being. As a result, a substantial body of research exists on the sources, sinks, and transport characteristics of urban particulate matter. Most of the existing experimental work examining point sources employed gases (e.g., SF6) as the working medium. Furthermore, the focus of most studies has been on the dispersion of pollutants far from the source location. Here, our focus is on the turbulent dispersion of heavy particles in the near source region of a suburban neighborhood. To this end, we conducted a series of heavy particle releases in the Sunset neighborhood of Vancouver, Canada during June, 2017. The particles where dispersed from a near ground point source at two different locations. The Sunset neighborhood is composed mostly of single dwelling detached houses and has been used in numerous previous urban studies. One of the release points was just upwind of a 4-way intersection and the other in the middle of a contiguous block of houses. Each location had a significant density of trees. A minimum of four different successful release events were conducted at each site. During each release, fluorescing micro particles (mean diameter approx. 30 micron) were released from ultrasonic atomizer nozzles for a duration of approximately 20 minutes. The particles where sampled at 50 locations (1.5 m height) in the area downwind of the release over distances from 1-15 times the mean canopy height ( 6 m) using rotating impaction traps. In addition to the 50 sampler locations, instantaneous wind velocities were measured with eight sonic anemometers distributed horizontally and vertically throughout the release area. The resulting particle plume distributions indicate a strong impact of local urban form in the near source region and a high degree of sensitivity to the local

Snowmelt Runoff: A New Focus of Urban Nonpoint Source Pollution

Science.gov (United States)

Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

2012-01-01

Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing cosntitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control. PMID:23202881

Snowmelt runoff: a new focus of urban nonpoint source pollution.

Science.gov (United States)

Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

2012-11-30

Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing constitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control.

Sources and contributions of wood smoke during winter in London

Science.gov (United States)

Crilley, Leigh; Bloss, William; Yin, Jianxin; Beddows, David; Harrison, Roy; Zotter, Peter; Prevot, Andre; Green, David

2014-05-01

Determining the contribution of wood smoke in large urban centres such as London is becoming increasingly important with the changing nature of domestic heating partly due to the installation of biomass burning heaters to meet renewable energy targets imposed by the EU and also a rise in so-called recreational burning for aesthetic reasons (Fuller et al., 2013). Recent work in large urban centres (London, Paris and Berlin) has demonstrated an increase in the contribution of wood smoke to ambient particles during winter that can at times exceed traffic emissions. In Europe, biomass burning has been identified as a major cause of exceedances of European air quality limits during winter (Fuller et al., 2013). In light of the changing nature of emissions in urban areas there is a need for on-going measurements to assess the impact of biomass burning in cities like London. Therefore we aimed to determine quantitatively the contribution of biomass burning in London and surrounding rural areas. We also aimed to determine whether local emissions or regional sources were the main source of biomass burning in London. Sources of wood smoke during winter in London were investigated at an urban background site (North Kensington) and two surrounding rural sites (Harwell and Detling) by analysing selected wood smoke chemical tracers. Concentrations of levoglucosan, elemental carbon (EC), organic carbon (OC) and K+ were generally well correlated, indicating a similar source of these species at the three sites. Based on the conversion factor for levoglucosan, mean wood smoke mass at Detling, North Kensington and Harwell was 0.78, 0.87 and 1.0 µg m-3, respectively. At all the sites, biomass burning was found to be a source of OC and EC, with the largest source of OC and EC found to be secondary organic aerosols and traffic emissions, respectively. Peaks in levoglucosan concentrations at the sites were observed to coincide with low ambient temperature, suggesting domestic heating as

Urban nonpoint source pollution buildup and washoff models for simulating storm runoff quality in the Los Angeles County

International Nuclear Information System (INIS)

Wang Long; Wei Jiahua; Huang Yuefei; Wang Guangqian; Maqsood, Imran

2011-01-01

Many urban nonpoint source pollution models utilize pollutant buildup and washoff functions to simulate storm runoff quality of urban catchments. In this paper, two urban pollutant washoff load models are derived using pollutant buildup and washoff functions. The first model assumes that there is no residual pollutant after a storm event while the second one assumes that there is always residual pollutant after each storm event. The developed models are calibrated and verified with observed data from an urban catchment in the Los Angeles County. The application results show that the developed model with consideration of residual pollutant is more capable of simulating nonpoint source pollution from urban storm runoff than that without consideration of residual pollutant. For the study area, residual pollutant should be considered in pollutant buildup and washoff functions for simulating urban nonpoint source pollution when the total runoff volume is less than 30 mm. - Highlights: → An improved urban NPS model was developed. → It performs well in areas where storm events have great temporal variation. → Threshold of total runoff volume for ignoring residual pollutant was determined. - An improved urban NPS model was developed. Threshold of total runoff volume for ignoring residual pollutant was determined.

Chemical characterization and source apportionment of size-resolved particles in Hong Kong sub-urban area

Science.gov (United States)

Gao, Yuan; Lee, Shun-Cheng; Huang, Yu; Chow, Judith C.; Watson, John G.

2016-03-01

Size-resolved particulate matter (PM) samples were collected with a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) at a sub-urban site (Tung Chung) in Hong Kong for four non-consecutive months representing four seasons from 2011 to 2012. Major chemical components were water-soluble anions (i.e., Cl-, NO3-, and SO42 -), cations (i.e., NH4+, Na+, K+, and Ca2 +), organic and elemental carbon and elements. Both chemical mass closure and positive matrix factorization (PMF) were employed to understand the chemical composition, resolve particle size modes, and evaluate the PM sources. Tri-modal size distributions were found for PM mass and major chemical components (e.g., SO42 -, NH4+, and OC). Mass median aerodynamic diameters (MMADs) with similar standard deviations (1.32 burning. Secondary SO42 - is also the most dominant component in the droplet mode, accounting for 23% of PM mass, followed by an industrial source (19%). Engine exhaust, secondary NO3-, and sea salt each accounted for 13-15% of PM mass. Sea salt and soil are the dominated sources in the coarse mode, accounting for 80% of coarse mass.

A new framework for modeling urban land expansion in peri-urban area by combining multi-source datasets and data assimilation

Science.gov (United States)

Zhang, Z.; Xiao, R.; Li, X.

2015-12-01

Peri-urban area is a new type region under the impacts of both rural Industrialization and the radiation of metropolitan during rapid urbanization. Due to its complex natural and social characteristics and unique development patterns, many problems such as environmental pollution and land use waste emerged, which became an urgent issue to be addressed. Study area in this paper covers three typical peri-urban districts (Pudong, Fengxian and Jinshan), which around the Shanghai inner city. By coupling cellular automata and multi-agent system model as the basic tools, this research focus on modelling the urban land expansion and driving mechanism in peri-urban area. The big data is aslo combined with the Bayesian maximum entropy method (BME) for spatiotemporal prediction of multi-source data, which expand the dataset of urban expansion models. Data assimilation method is used to optimize the parameters of the coupling model and minimize the uncertainty of observations, improving the precision of future simulation in peri-urban area. By setting quantitative parameters, the coupling model can effectively improve the simulation of the process of urban land expansion under different policies and management schemes, in order to provide scientificimplications for new urbanization strategy. In this research, we precise the urban land expansion simulation and prediction for peri-urban area, expand the scopes and selections of data acquisition measurements and methods, develop the new applications of the data assimilation method in geographical science, provide a new idea for understanding the inherent rules of urban land expansion, and give theoretical and practical support for the peri-urban area in urban planning and decision making.

Urban sprawl leaves its PAH signature

Science.gov (United States)

Van Metre, P.C.; Mahler, B.J.; Furlong, E.T.

2000-01-01

The increasing vehicle traffic associated with urban sprawl in the United States is frequently linked to degradation of air quality, but its effect on aquatic sediment is less well-recognized. This study evaluates trends in PAHs, a group of contaminants with multiple urban sources, in sediment cores from 10 reservoirs and lakes in six U.S. metropolitan areas. The watersheds chosen represent a range in degree and age of urbanization. Concentrations of PAHs in all 10 reservoirs and lakes increased during the past 20-40 years. PAH contamination of the most recently deposited sediment at all sites exceeded sediment-quality guidelines established by Environment Canada, in some cases by several orders of magnitude. These results add a new chapter to the story told by previous coring studies that reported decreasing concentrations of PAHs after reaching highs in the 1950s. Concurrent with the increase in concentrations is a change in the assemblage of PAHs that indicates the increasing trends are driven by combustion sources. The increase in PAH concentrations tracks closely with increases in automobile use, even in watersheds that have not undergone substantial changes in urban land-use levels since the 1970s.The increasing vehicle traffic associated with urban sprawl in the United States is frequently linked to degradation of air quality, but its effect on aquatic sediment is less well-recognized. This study evaluates trends in PAHs, a group of contaminants with multiple urban sources, in sediment cores from 10 reservoirs and lakes in six U.S. metropolitan areas. The watersheds chosen represent a range in degree and age of urbanization. Concentrations of PAHs in all 10 reservoirs and lakes increased during the past 20-40 years. PAH contamination of the most recently deposited sediment at all sites exceeded sediment-quality guidelines established by Environment Canada, in some cases by several orders of magnitude. These results add a new chapter to the story told by

Atmospheric aerosol compositions and sources at two national background sites in northern and southern China

Directory of Open Access Journals (Sweden)

Q. Zhu

2016-08-01

Full Text Available Although China's severe air pollution has become a focus in the field of atmospheric chemistry and the mechanisms of urban air pollution there have been researched extensively, few field sampling campaigns have been conducted at remote background sites in China, where air pollution characteristics on a larger scale are highlighted. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, together with an Aethalometer, was deployed at two of China's national background sites in northern (Lake Hongze site; 33.23° N, 118.33° E; altitude 21 m and southern (Mount Wuzhi site; 18.84° N, 109.49° E; altitude 958 m China in the spring seasons in 2011 and 2015, respectively, in order to characterize submicron aerosol composition and sources. The campaign-average PM1 concentration was 36.8 ± 19.8 µg m−3 at the northern China background (NCB site, which was far higher than that at the southern China background (SCB site (10.9 ± 7.8 µg m−3. Organic aerosol (OA (27.2 %, nitrate (26.7 %, and sulfate (22.0 % contributed the most to the PM1 mass at NCB, while OA (43.5 % and sulfate (30.5 % were the most abundant components of the PM1 mass at SCB, where nitrate only constituted a small fraction (4.7 % and might have contained a significant amount of organic nitrates (5–11 %. The aerosol size distributions and organic aerosol elemental compositions all indicated very aged aerosol particles at both sites. The OA at SCB was more oxidized with a higher average oxygen to carbon (O ∕ C ratio (0.98 than that at NCB (0.67. Positive matrix factorization (PMF analysis was used to classify OA into three components, including a hydrocarbon-like component (HOA, attributed to fossil fuel combustion and two oxygenated components (OOA1 and OOA2, attributed to secondary organic aerosols from different source areas at NCB. PMF analysis at SCB identified a semi-volatile oxygenated

Temporal variability and sources of VOCs in urban areas of the eastern Mediterranean

Directory of Open Access Journals (Sweden)

C. Kaltsonoudis

2016-11-01

Full Text Available During the summer of 2012 volatile organic compounds (VOCs were monitored by proton transfer reaction mass spectrometry (PTR-MS in urban sites, in Athens and Patras, two of the largest cities in Greece. Also, during the winter of 2013, PTR-MS measurements were conducted in the center of the city of Athens. Positive matrix factorization (PMF was applied to the VOC measurements to gain insights about their sources. In summer most of the measured VOCs were due to biogenic and traffic emissions. Isoprene, monoterpenes, and several oxygenated VOCs (oVOCs originated mainly from vegetation either directly or as oxidation products. Isoprene average concentrations in Patras and Athens were 1 and 0.7 ppb respectively, while the monoterpene concentrations were 0.3 and 0.9 ppb respectively. Traffic was the main source of aromatic compounds during summer. For Patras and Athens the average concentrations of benzene were 0.1 and 0.2 ppb, of toluene 0.3 and 0.8 ppb, and of the xylenes 0.3 and 0.7 ppb respectively. Winter measurements in Athens revealed that biomass burning used for residential heating was a major VOC source contributing both aromatic VOCs and biogenic compounds such as monoterpenes. Several episodes related to biomass burning were identified and emission ratios (ERs and emission factors (EFs were estimated.

Registration for the Hanford Site: Sources of radioactive emissions

International Nuclear Information System (INIS)

Silvia, M.J.

1993-04-01

This Registration Application serves to renew the registration for all Hanford Site sources of radioactive air emissions routinely reported to the State of Washington Department of Health (DOH). The current registration expires on August 15, 1993. The Application is submitted pursuant to the Washington Administrative Code (WAC) Chapter 246--247, and is consistent with guidance provided by DOH for renewal. The Application subdivides the Hanford Site into six major production, processing or research areas. Those six areas are in the 100 Area, 200 East Area, 200 West Area, 300 Area, 400 Area, and 600 Area. Each major group of point sources within the six areas listed above is represented by a Source Registration for Radioactive Air Emissions form. Annual emissions. for the sources are listed in the ''Radionuclide Air Emissions Report for the Hanford Site,'' published annually. It is a requirement that the following Statement of Compliance be provided: ''The radioactive air emissions from the above sources do meet the emissions standards contained in Chapter 173-480-040 WAC, Ambient Air Quality Standards and Emissions Limits for Radionuclides. As the Statement of Compliance pertains to this submittal, the phrase ''above sources'' is to be understood as meaning the combined air emissions from all sources registered by this submittal

House Church: Investigating Chinese Urban Christians’ Choice of Religious Practicing Site in Wuhan, China

Directory of Open Access Journals (Sweden)

Junqiang Han

2018-03-01

Full Text Available In this paper, we discuss the reasons why urban Christians choose certain sites for religious activities and explain the rapid development of house churches in urban areas in China from the perspective of individual Christians, through survey data obtained by the Chinese Urban Research Center for Ethnic and Religious Affairs Management in the city of Wuhan. We found that Christians who attend religious activities in urban house churches are generally younger in age, higher in education level, and more likely to be working in independent, private, or foreign-invested enterprises. Further investigation reveals that “Three-Self churches” are few in number and poorly planned geographically, resulting in very limited service abilities, thus being far from satisfactory for all believers. Moreover, the activities of such churches are unvaried and lack attractiveness. On the other hand, in house churches, Christians are able to build tight-knit social networks and house churches are more competitively aware in the “religious market”, leading some urban Christians to choose house churches, thereby inciting the fast development of house churches in Chinese urban areas.

Volatile chemical products emerging as largest petrochemical source of urban organic emissions

Science.gov (United States)

McDonald, Brian C.; de Gouw, Joost A.; Gilman, Jessica B.; Jathar, Shantanu H.; Akherati, Ali; Cappa, Christopher D.; Jimenez, Jose L.; Lee-Taylor, Julia; Hayes, Patrick L.; McKeen, Stuart A.; Cui, Yu Yan; Kim, Si-Wan; Gentner, Drew R.; Isaacman-VanWertz, Gabriel; Goldstein, Allen H.; Harley, Robert A.; Frost, Gregory J.; Roberts, James M.; Ryerson, Thomas B.; Trainer, Michael

2018-02-01

A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)—including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products—now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements. We show that human exposure to carbonaceous aerosols of fossil origin is transitioning away from transportation-related sources and toward VCPs. Existing U.S. regulations on VCPs emphasize mitigating ozone and air toxics, but they currently exempt many chemicals that lead to secondary organic aerosols.

Electrical resistivity borehole measurements: application to an urban tunnel site

Science.gov (United States)

Denis, A.; Marache, A.; Obellianne, T.; Breysse, D.

2002-06-01

This paper shows how it is possible to use wells drilled during geotechnical pre-investigation of a tunneling site to obtain a 2-D image of the resistivity close to a tunnel boring machine. An experimental apparatus is presented which makes it possible to perform single and borehole-to-borehole electrical measurements independent of the geological and hydrogeological context, which can be activated at any moment during the building of the tunnel. This apparatus is first demonstrated through its use on a test site. Numerical simulations and data inversion are used to analyse the experimental results. Finally, electrical resistivity tomography and single-borehole measurements on a tunneling site are presented. Experimental results show the viability of the apparatus and the efficiency of the inverse algorithm, and also highlight the limitations of the electrical resistivity tomography as a tool for geotechnical investigation in urban areas.

Assessment of Urban Renenewal Studies in the Context of Florence's Old Industrial Sites

Directory of Open Access Journals (Sweden)

Elif Özlem Aydın

2013-06-01

Full Text Available In the periphery of the historic city center of Florence, which is a settlement in Middle Italy, considered the symbol of Renaissance period train stations, small scale industrial structures were built under the influence of spread of industrialization in Continental Europe in the 19th century. Industrial buildings whose original functions are being lost nowadays are restricted to examples which started being built in the 18 th century, however, shaped in the 19 th century and were being able to brought until today with the increased industrialization activities in the first half of the 20 th century. The necessity of developing new thoughts aiming to revitalize areas around the city center and to reshape Florence, which witnessed a segmented growth due to increased industrialization in the first half of 20 th century, according to urban planning principles from 1990's onwards has been realized. Within the scope of integrated planning developed in the recent years, old industrial areas located in the historical city center peripheries whose functions have been lost are determined as urban renovation sites. In this study, Old Leopolda Train Station, Fiat Belfiore and Fiat Novoli factory sites as well as renovation/transformation work executed in old slaughter house sites, located in the west border of historical city center of Florence, have been studied with the help of technical surveys, personal interviews or published projects. Two approaches have been encountered when urban renovation projects executed in these areas where mixed-use strategies are adopted are examined. These are:  Preservation of some of the historical structures in the area, and demolition of some to create areas for new uses,  Demolition of all structures in the site to create areas for new uses. Not encountered in Florence, but there also exist renovation examples where almost all structures in the area are preserved. The results of research and observations have

Alternative energy facility siting policies for urban coastal areas: executive summary of findings and policy recommendations

Energy Technology Data Exchange (ETDEWEB)

Morell, D; Singer, G

1980-11-01

An analysis was made of siting issues in the coastal zone, one of the nation's most critical natural resource areas and one which is often the target for energy development proposals. The analysis addressed the changing perceptions of citizens toward energy development in the coastal zone, emphasizing urban communities where access to the waterfront and revitalization of waterfront property are of interest to the citizen. The findings of this analysis are based on an examination of energy development along New Jersey's urban waterfront and along the Texas-Louisiana Gulf Coast, and on redevelopment efforts in Seattle, San Francisco, Boston, and elsewhere. The case studies demonstrate the significance of local attitudes and regional cooperation in the siting process. In highly urbanized areas, air quality has become a predominant concern among citizen groups and an influential factor in development of alternative energy facility siting strategies, such as consideration of inland siting connected by pipeline to a smaller coastal facility. The study addresses the economic impact of the permitting process on the desirability of energy facility investments, and the possible effects of the location selected for the facility on the permitting process and investment economics. The economic analysis demonstrates the importance of viewing energy facility investments in a broad perspective that includes the positive or negative impacts of various alternative siting patterns on the permitting process. Conclusions drawn from the studies regarding Federal, state, local, and corporate politics; regulatory, permitting, licensing, environmental assessment, and site selection are summarized. (MCW)

Novel human-associated Lachnospiraceae genetic markers improve detection of fecal pollution sources in urban waters.

Science.gov (United States)

Feng, Shuchen; Bootsma, Melinda; McLellan, Sandra L

2018-05-04

The human microbiome contains many organisms that could potentially be used as indicators of human fecal pollution. Here we report the development of two novel human-associated genetic marker assays that target organisms within the family Lachnospiraceae Next-generation sequencing of the V6 region of the 16S rRNA gene from sewage and animal stool samples identified 40 human-associated marker candidates with a robust signal in sewage and low or no occurrence in nonhuman hosts. Two were chosen for quantitative PCR (qPCR) assay development using longer sequences (V2 to V9 regions) generated from clone libraries. Validation of these assays, designated Lachno3 and Lachno12, was performed using fecal samples (n=55) from cat, dog, pig, cow, deer, and gull sources, and compared with established host-associated assays (Lachno2, and two Human Bacteroides assays; HB and HF183/BacR287). Each of the established assays cross-reacted with at least one other animal, including animals common in urban areas. Lachno3 and Lachno12 were primarily human-associated; however, Lachno12 demonstrated low levels of cross-reactivity with select cows, and non-specific amplification in pigs. This limitation may not be problematic when testing urban waters. These novel markers resolved ambiguous results from previous investigations in stormwater-impacted waters, demonstrating their utility. The complexity of the microbiome in humans and animals suggests no single organism is strictly specific to humans, and multiple complementary markers used in combination will provide the highest resolution and specificity for assessing fecal pollution sources. IMPORTANCE Traditional fecal indicator bacteria do not distinguish animal from human fecal pollution, which is necessary to evaluate health risks and mitigate pollution sources. Assessing urban areas is challenging since water can be impacted by sewage, which has a high likelihood of carrying human pathogens, as well as pet waste and urban wildlife. We

Emerging contaminants in urban groundwater sources in Africa.

Science.gov (United States)

Sorensen, J P R; Lapworth, D J; Nkhuwa, D C W; Stuart, M E; Gooddy, D C; Bell, R A; Chirwa, M; Kabika, J; Liemisa, M; Chibesa, M; Pedley, S

2015-04-01

The occurrence of emerging organic contaminants within the aquatic environment in Africa is currently unknown. This study provides early insights by characterising a broad range of emerging organic contaminants (n > 1000) in groundwater sources in Kabwe, Zambia. Groundwater samples were obtained during both the dry and wet seasons from a selection of deep boreholes and shallow wells completed within the bedrock and overlying superficial aquifers, respectively. Groundwater sources were distributed across the city to encompass peri-urban, lower cost housing, higher cost housing, and industrial land uses. The insect repellent DEET was ubiquitous within groundwater at concentrations up to 1.8 μg/L. Other compounds (n = 26) were detected in less than 15% of the sources and included the bactericide triclosan (up to 0.03 μg/L), chlorination by-products - trihalomethanes (up to 50 μg/L), and the surfactant 2,4,7,9-tetramethyl-5-decyne-4,7-diol (up to 0.6 μg/L). Emerging contaminants were most prevalent in shallow wells sited in low cost housing areas. This is attributed to localised vulnerability associated with inadequate well protection, sanitation, and household waste disposal. The five-fold increase in median DEET concentration following the onset of the seasonal rains highlights that more mobile compounds can rapidly migrate from the surface to the aquifer suggesting the aquifer is more vulnerable than previously considered. Furthermore it suggests DEET is potentially useful as a wastewater tracer in Africa. There was a general absence of personal care products, life-style compounds, and pharmaceuticals which are commonly detected in the aquatic environment in the developed world. This perhaps reflects some degree of attenuation within the subsurface, but could also be a result of the current limited use of products containing emerging contaminants by locals due to unaffordability and unavailability. As development and population increases in Africa, it is

Diffusion from a point source in an urban atmosphere

International Nuclear Information System (INIS)

Essa, K.S.M.; El-Otaify, M.S.

2005-01-01

In the present paper, a model for the diffusion of material from a point source in an urban atmosphere is incorporated. The plume is assumed to have a well-defined edge at which the concentration falls to zero. The vertical wind shear is estimated using logarithmic law, by employing most of the available techniques of stability categories. The concentrations estimated from the model were compared favorably with the field observations of other investigators

Off-site source recovery project case study: disposal of high activity cobalt 60 sources at the Nevada test site 2008

International Nuclear Information System (INIS)

Cocina, Frank G.; Stewart, William C.; Wald-Hopkins, Mark; Hageman, John P.

2009-01-01

The Off-Site Source Recovery Project has been operating at Los Alamos National Laboratory since 1998 to address the U.S. Department of Energy responsibility for collection and management of orphaned or disused radioactive sealed sources which may represent a risk to public health and national security if not properly managed.

An integrated approach to assess heavy metal source apportionment in peri-urban agricultural soils.

Science.gov (United States)

Huang, Ying; Li, Tingqiang; Wu, Chengxian; He, Zhenli; Japenga, Jan; Deng, Meihua; Yang, Xiaoe

2015-12-15

Three techniques (Isotope Ratio Analysis, GIS mapping, and Multivariate Statistical Analysis) were integrated to assess heavy metal pollution and source apportionment in peri-urban agricultural soils. The soils in the study area were moderately polluted with cadmium (Cd) and mercury (Hg), lightly polluted with lead (Pb), and chromium (Cr). GIS Mapping suggested Cd pollution originates from point sources, whereas Hg, Pb, Cr could be traced back to both point and non-point sources. Principal component analysis (PCA) indicated aluminum (Al), manganese (Mn), nickel (Ni) were mainly inherited from natural sources, while Hg, Pb, and Cd were associated with two different kinds of anthropogenic sources. Cluster analysis (CA) further identified fertilizers, waste water, industrial solid wastes, road dust, and atmospheric deposition as potential sources. Based on isotope ratio analysis (IRA) organic fertilizers and road dusts accounted for 74-100% and 0-24% of the total Hg input, while road dusts and solid wastes contributed for 0-80% and 19-100% of the Pb input. This study provides a reliable approach for heavy metal source apportionment in this particular peri-urban area, with a clear potential for future application in other regions. Copyright © 2015 Elsevier B.V. All rights reserved.

Commonness and ecology, but not bigger brains, predict urban living in birds.

Science.gov (United States)

Dale, Svein; Lifjeld, Jan T; Rowe, Melissah

2015-04-11

Several life history and ecological variables have been reported to affect the likelihood of species becoming urbanized. Recently, studies have also focused on the role of brain size in explaining ability to adapt to urban environments. In contrast, however, little is known about the effect of colonization pressure from surrounding areas, which may confound conclusions about what makes a species urban. We recorded presence/absence data for birds in 93 urban sites in Oslo (Norway) and compared these with species lists generated from 137 forest and 51 farmland sites surrounding Oslo which may represent source populations for colonization. We found that the frequency (proportion of sites where present) of a species within the city was strongly and positively associated with its frequency in sites surrounding the city, as were both species breeding habitat and nest site location. In contrast, there were generally no significant effects of relative brain mass or migration on urban occupancy. Furthermore, analyses of previously published data showed that urban density of birds in six other European cities was also positively and significantly associated with density in areas outside cities, whereas relative brain mass showed no such relationship. These results suggest that urban bird communities are primarily determined by how frequently species occurred in the surrounding landscapes and by features of ecology (i.e. breeding habitat and nest site location), whereas species' relative brain mass had no significant effects.

Polycyclic aromatic hydrocarbons (PAHs) concentration levels, pattern, source identification and soil toxicity assessment in urban traffic soil of Dhanbad, India.

Science.gov (United States)

Suman, Swapnil; Sinha, Alok; Tarafdar, Abhrajyoti

2016-03-01

Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019 μg g(-1) to 10.856 μg g(-1) with an average value of 3.488 μg g(-1). At control/rural site, average concentration of total PAHs was found to be 0.640 μg g(-1). PAH pattern was dominated by four- and five-ring PAHs (contributing >50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing >30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant+Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla+Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA+Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP+BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil. Copyright © 2015 Elsevier B.V. All rights reserved.

Concentrations and source apportionment of PM10 and associated elemental and ionic species in a lignite-burning power generation area of southern Greece.

Science.gov (United States)

Argyropoulos, G; Grigoratos, Th; Voutsinas, M; Samara, C

2013-10-01

Ambient concentrations of PM10 and associated elemental and ionic species were measured over the cold and the warm months of 2010 at an urban and two rural sites located in the lignite-fired power generation area of Megalopolis in Peloponnese, southern Greece. The PM10 concentrations at the urban site (44.2 ± 33.6 μg m(-3)) were significantly higher than those at the rural sites (23.7 ± 20.4 and 22.7 ± 26.9 μg m(-3)). Source apportionment of PM10 and associated components was accomplished by an advanced computational procedure, the robotic chemical mass balance model (RCMB), using chemical profiles for a variety of local fugitive dust sources (power plant fly ash, flue gas desulfurization wet ash, feeding lignite, infertile material from the opencast mines, paved and unpaved road dusts, soil), which were resuspended and sampled through a PM10 inlet onto filters and then chemically analyzed, as well as of other common sources such as vehicular traffic, residential oil combustion, biomass burning, uncontrolled waste burning, marine aerosol, and secondary aerosol formation. Geological dusts (road/soil dust) were found to be major PM10 contributors in both the cold and warm periods of the year, with average annual contribution of 32.6 % at the urban site vs. 22.0 and 29.0 % at the rural sites. Secondary aerosol also appeared to be a significant source, contributing 22.1 % at the urban site in comparison to 30.6 and 28.7 % at the rural sites. At all sites, the contribution of biomass burning was most significant in winter (28.2 % at the urban site vs. 14.6 and 24.6 % at the rural sites), whereas vehicular exhaust contribution appeared to be important mostly in the summer (21.9 % at the urban site vs. 11.5 and 10.5 % at the rural sites). The highest contribution of fly ash (33.2 %) was found at the rural site located to the north of the power plants during wintertime, when winds are favorable. In the warm period, the highest contribution of fly ash was found at the

Factors influencing buyers' willingness to offer price premiums for carbon credits sourced from urban forests

Science.gov (United States)

N.C. Poudyal; J.M. Bowker; J.P. Siry

2015-01-01

Marketing carbon offset credits generated by urban forest projects could help cities and local governments achieve their financial self-sufficiency and environmental sustainability goals. Understanding the value of carbon credits sourced from urban forests, and the factors that determine buyers’ willingness to pay a premium for such credits could benefit cities in...

Pollution source localization in an urban water supply network based on dynamic water demand.

Science.gov (United States)

Yan, Xuesong; Zhu, Zhixin; Li, Tian

2017-10-27

Urban water supply networks are susceptible to intentional, accidental chemical, and biological pollution, which pose a threat to the health of consumers. In recent years, drinking-water pollution incidents have occurred frequently, seriously endangering social stability and security. The real-time monitoring for water quality can be effectively implemented by placing sensors in the water supply network. However, locating the source of pollution through the data detection obtained by water quality sensors is a challenging problem. The difficulty lies in the limited number of sensors, large number of water supply network nodes, and dynamic user demand for water, which leads the pollution source localization problem to an uncertainty, large-scale, and dynamic optimization problem. In this paper, we mainly study the dynamics of the pollution source localization problem. Previous studies of pollution source localization assume that hydraulic inputs (e.g., water demand of consumers) are known. However, because of the inherent variability of urban water demand, the problem is essentially a fluctuating dynamic problem of consumer's water demand. In this paper, the water demand is considered to be stochastic in nature and can be described using Gaussian model or autoregressive model. On this basis, an optimization algorithm is proposed based on these two dynamic water demand change models to locate the pollution source. The objective of the proposed algorithm is to find the locations and concentrations of pollution sources that meet the minimum between the analogue and detection values of the sensor. Simulation experiments were conducted using two different sizes of urban water supply network data, and the experimental results were compared with those of the standard genetic algorithm.

Levels and sources of PAHs in selected sites from Portugal: biomonitoring with Pinus pinea and Pinus pinaster needles.

Science.gov (United States)

Ratola, Nuno; Amigo, José Manuel; Alves, Arminda

2010-04-01

Pine needle samples from two pine species (Pinus pinaster Ait. and Pinus pinea L.) were collected at 29 sites scattered throughout Portugal, in order to biomonitor the levels and trends of 16 polycyclic aromatic hydrocarbons (PAHs). The values obtained for the sum of all PAHs ranged from 76 to 1944 ng/g [dry weight (dw)]. Despite the apparent matrix similarities between both pine species, P. pinaster needles revealed higher mean entrapment levels than P. pinea (748 and 399 ng/g (dw) per site, respectively). The urban and industrial sites have the highest average of PAH incidence [for P. pinea, 465 and 433 ng/g (dw) per site, respectively, and for P. pinaster, 1147 and 915 ng/g (dw)], followed by the rural sites [233 ng/g and 711 ng/g (dw) per site, for P. pinea and P. pinaster, respectively]. The remote sites, both from P. pinaster needles, show the least contamination, with 77 ng/g (dw) per site. A predominance of 3-ring and 4-ring PAHs was observed in most samples, with phenanthrene having 30.1% of the total. Naphthalene prevailed in remote sites. Rainfall had no influence on the PAHs levels, but there was a relationship between higher wind speeds and lower concentrations. PAH molecular ratios revealed the influence of both petrogenic and pyrogenic sources.

Investigating diesel engines as an atmospheric source of isocyanic acid in urban areas

Directory of Open Access Journals (Sweden)

S. H. Jathar

2017-07-01

Full Text Available Isocyanic acid (HNCO, an acidic gas found in tobacco smoke, urban environments, and biomass-burning-affected regions, has been linked to adverse health outcomes. Gasoline- and diesel-powered engines and biomass burning are known to emit HNCO and hypothesized to emit precursors such as amides that can photochemically react to produce HNCO in the atmosphere. Increasingly, diesel engines in developed countries like the United States are required to use selective catalytic reduction (SCR systems to reduce tailpipe emissions of oxides of nitrogen. SCR chemistry is known to produce HNCO as an intermediate product, and SCR systems have been implicated as an atmospheric source of HNCO. In this work, we measure HNCO emissions from an SCR system-equipped diesel engine and, in combination with earlier data, use a three-dimensional chemical transport model (CTM to simulate the ambient concentrations and source/pathway contributions to HNCO in an urban environment. Engine tests were conducted at three different engine loads, using two different fuels and at multiple operating points. HNCO was measured using an acetate chemical ionization mass spectrometer. The diesel engine was found to emit primary HNCO (3–90 mg kg fuel−1 but we did not find any evidence that the SCR system or other aftertreatment devices (i.e., oxidation catalyst and particle filter produced or enhanced HNCO emissions. The CTM predictions compared well with the only available observational datasets for HNCO in urban areas but underpredicted the contribution from secondary processes. The comparison implied that diesel-powered engines were the largest source of HNCO in urban areas. The CTM also predicted that daily-averaged concentrations of HNCO reached a maximum of ∼ 110 pptv but were an order of magnitude lower than the 1 ppbv level that could be associated with physiological effects in humans. Precursor contributions from other combustion sources (gasoline and biomass

Investigating Diesel Engines as an Atmospheric Source of Isocyanic Acid in Urban Areas

Science.gov (United States)

Farmer, D.; Jathar, S.; Heppding, C.; Link, M.; Akherati, A.; Kleeman, M.; De Gouw, J. A.; Veres, P. R.; Roberts, J. M.

2017-12-01

Isocyanic acid (HNCO), an acidic gas found in tobacco smoke, urban environments and biomass burning-affected regions, has been linked to adverse health outcomes. Gasoline- and diesel-powered engines and biomass burning are known to emit HNCO and hypothesized to emit precursors such as amides that can photochemically react to produce HNCO in the atmosphere. Increasingly, diesel engines in developed countries like the United States are required to use Selective Catalytic Reduction (SCR) systems to reduce tailpipe emissions of oxides of nitrogen. SCR chemistry is known to produce HNCO as an intermediate product, and SCR systems have been implicated as an atmospheric source of HNCO. In this work, we measure HNCO emissions from an SCR system-equipped diesel engine and, in combination with earlier data, use a three-dimensional chemical transport model (CTM) to simulate the ambient concentrations and source/pathway contributions to HNCO in an urban environment. Engine tests were conducted at three different engine loads, using two different fuels and at multiple operating points. HNCO was measured using an acetate chemical ionization mass spectrometer. The diesel engine was found to emit primary HNCO (3-90 mg kg-fuel-1) but we did not find any evidence that the SCR system or other aftertreatment devices (i.e., oxidation catalyst and particle filter) produced or enhanced HNCO emissions. The CTM predictions compared well with the only available observational data sets for HNCO in urban areas but under-predicted the contribution from secondary processes. The comparison implied that diesel-powered engines were the largest source of HNCO in urban areas. The CTM also predicted that daily-averaged concentrations of HNCO reached a maximum of 110 pptv but were an order of magnitude lower than the 1 ppbv level that could be associated with physiological effects in humans. Precursor contributions from other combustion sources (gasoline and biomass burning) and wintertime conditions

Driving mechanism and sources of groundwater nitrate contamination in the rapidly urbanized region of south China

Science.gov (United States)

Zhang, Qianqian; Sun, Jichao; Liu, Jingtao; Huang, Guanxing; Lu, Chuan; Zhang, Yuxi

2015-11-01

Nitrate contamination of groundwater has become an environmental problem of widespread concern in China. We collected 899 groundwater samples from a rapidly urbanized area, in order to identify the main sources and driving mechanisms of groundwater nitrate contamination. The results showed that the land use has a significant effect on groundwater nitrate concentration (P population growth. This study revealed that domestic wastewater and industrial wastewater were the main sources of groundwater nitrate pollution. Therefore, the priority method for relieving groundwater nitrate contamination is to control the random discharge of domestic and industrial wastewater in regions undergoing rapid urbanization. Capsule abstract. The main driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth.

Factors influencing mobile source particulate matter emissions-to-exposure relationships in the Boston urban area.

Science.gov (United States)

Greco, Susan L; Wilson, Andrew M; Hanna, Steven R; Levy, Jonathan I

2007-11-15

Benefit-cost and regulatory impact analyses often use atmospheric dispersion models with coarse resolution to estimate the benefits of proposed mobile source emission control regulations. This approach may bias health estimates or miss important intra-urban variability for primary air pollutants. In this study, we estimate primary fine particulate matter (PM2.5) intake fractions (iF; the fraction of a pollutant emitted from a source that is inhaled by the population) for each of 23 398 road segments in the Boston Metro Core area to evaluate the potential for intra-urban variability in the emissions-to-exposure relationship. We estimate iFs using the CAL3QHCR line source model combined with residential populations within 5000 m of each road segment. The annual average values for the road segments range from 0.8 to 53 per million, with a mean of 12 per million. On average, 46% of the total exposure is realized within 200 m of the road segment, though this varies from 0 to 93% largely due to variable population patterns. Our findings indicate the likelihood of substantial intra-urban variability in mobile source primary PM2.5 iF that accounting for population movement with time, localized meteorological conditions, and street-canyon configurations would likely increase.

Source Estimation of Wintertime Soot Particles for an Urban Site Varanasi (25.30 N, 83.00 E) in Central Indo-Gangetic Plain Region

Science.gov (United States)

Singh, A. K.; Srivastava, M. K.; Dumka, U. C.; Singh, R. K.; Singh, R. S.; Tiwari, S.; Mehrotra, B. J.; Srivastava, A. K.

2017-12-01

Black carbon particles (BC: also called Soot) are formed by incomplete combustion of hydrocarbon based fuels (fossil fuel: coal, diesel, petrol, etc.) as well as due to burning of biomass and bio-fuels (wood, shrubs, dry leaves, etc.). Soot particles are warming agent to the atmosphere that gained wide attention in recent years due to their direct and indirect impacts on local, regional as well as global climate. The climatic effects due to soot are not well understood as indicated by large uncertainties in their climate forcing estimation, particularly in South and East Asian region, possibly due to unavailability of adequate database and information about the source. Measurement of wintertime BC mass concentrations for urban site in central IGP, `Varanasi' (25.30 N, 83.00 E), using a seven wavelength Aethalometer is reported in this work. Delta-C (=BC370 - BC880), which is an indicator of biomass/bio-fuels or residential coal burning is used to understand the source. Aethalometer based source apportionment model "Aethalometer model" was used to apportion the fossil fuel/traffic and wood/biomass burning mass concentration to the total BC mass. The preliminary results for representative month (January-2015) show that daily-average BC mass ranged from 4.47 to 20.70 μg m-3 (Average: 9.45 ± 4.15 μg m-3). The daily Absorption Ångström Exponent (AAE) and the ratio of BCff/BC and BCff/BCwb varied between 1.09 - 1.32, 0.67 - 0.92 and 2 - 40, respectively, due to the changes in BC emissions rates. The total BC, BC from fossil fuel (BCff) and BC from wood/biomass burning (BCwb) behaved in the remarkable diurnal pattern, behaving opposite to the mixing layer heights (MLHs). During daytime, MLHs are higher due to surface based solar warming and causes more volume of atmosphere for the BC dispersion. This phenomenon causes the surface measurement of lower BC mass during the daytime. The data is, however, still being processed for multi-year wintertime observations and the

Urban Conservation Policies and Plans for a World Heritage Site Case: Antique Pergamon City and its Multi-Layered Cultural Landscape

Science.gov (United States)

Tunçer, Mehmet

2017-10-01

Izmir’s Pergamon (Bergama) Antique City and Its Multi-Layered Cultural Landscape entered the UNESCO World Heritage List with the participation of 21 countries in the 38th World Heritage Committee Meeting held in Doha, Qatar’s capital in between 15 - 25 June 2014. Bergama became the 999th WORLD HERITAGE. Bergama, which has been in operation since 2010, has entered the list as a Multi-layered Cultural Landscape Area. The main purpose of this paper will explain and summarize of urban and archaeological conservation efforts for Pergamon since 1992 to 2014. In the paper also aimed to give the conservation policies of public administrations which mainly central /Ministry of Culture and Tourism, Ministry of Environment/ and local /Bergama Municipality, Gen. Directorate of Vakiflar. Turkey is one of the 10 original member states to establish UNESCO. 9 cities in Turkey are included in the UNESCO List of World Heritage Sites. Further, 23 sites have been nominated and are included in the tentative list. The activities aimed to include the district of Bergama in the UNESCO World Heritage List are ongoing in the years 2009-2014. All the efforts have been made carry this unique antique city to the UNESCO Heritage List at 2014. As an Urban Conservation Planner, I had a change of preparing the FIRST Conservation Aimed Plans and urban designs for Urban and Archaeological Sites of Pergamon together with my team, in the years between 1992-94. We prepared conservation aimed plans for all of the areas of Acropolis, Middle City and Ottoman period urban conservation areas. Urban and archaeological sites of Pergamon the ancient city today, which is over two thousand years old, where scientists, archaeologists, architects, art historians, urban planners, sculptors and similar arts and culture, men talk about admiration, write about and write praises, face to face some deterioration and destruction. As a conservation planner working on Pergamon since 1992, I’ will concentrate the

Influence of natural and novel organic carbon sources on denitrification in forest, degraded urban, and restored streams

Science.gov (United States)

Organic carbon is important in regulating ecosystem function, and its source and abundance may be altered by urbanization. We investigated shifts in organic carbon quantity and quality associated with urbanization and ecosystem restoration, and its potential effects on denitrific...

Assessing the representativeness of monitoring data from an urban intersection site in Central London, UK

Energy Technology Data Exchange (ETDEWEB)

Scaperdas, A.; Colvile, R.N. [Imperial College of Science, Technology and Medicine, London (United Kingdom). Centre for Environmental Technology

1999-02-01

The wind flow field around urban street-building configurations has an important influence on the microscale pollutant dispersion from road traffic, affecting overall dilution and creating localised spatial variations of pollutant concentration. As a result, the ``representatives`` of air quality measurements made at different urban monitoring sites can be strongly dependent on the interaction of the local wind flow field with the street-building geometry surrounding the monitor. The present study is an initial attempt to develop a method for appraising the significance of air quality measurements from urban monitoring sites, using a general application computational fluid dynamics (CFD) code to simulate small-scale flow and dispersion patterns around real urban building configurations. The main focus of the work was to evaluate routine CO monitoring data collected by Westminster City Council at an intersection of street canyons at Marylebone Road, Central London. Many monitors in the UK are purposely situated at urban canyon intersections, which are thought to be local ``hot spots`` of pollutant emissions, however very limited information exists in the literature on the flow and dispersion patterns associated with them. With the use of simple CFD simulations and the analysis of available monitoring data, it was possible to gain insights into the effect of wind direction on the small-scale dispersion patterns at the chosen intersection, and how that can influence the data captured by a monitor. It was found that a change in wind direction could result in an increase or decrease of monitored CO concentration of up to 80%, for a given level of traffic emissions and meteorological conditions. Understanding and de-coupling the local effect of wind direction from monitoring data using the methods presented in this work could prove a useful new tool for urban monitoring data interpretation. (author)

A multi-model approach to monitor emissions of CO2 and CO from an urban-industrial complex

Science.gov (United States)

Super, Ingrid; Denier van der Gon, Hugo A. C.; van der Molen, Michiel K.; Sterk, Hendrika A. M.; Hensen, Arjan; Peters, Wouter

2017-11-01

Monitoring urban-industrial emissions is often challenging because observations are scarce and regional atmospheric transport models are too coarse to represent the high spatiotemporal variability in the resulting concentrations. In this paper we apply a new combination of an Eulerian model (Weather Research and Forecast, WRF, with chemistry) and a Gaussian plume model (Operational Priority Substances - OPS). The modelled mixing ratios are compared to observed CO2 and CO mole fractions at four sites along a transect from an urban-industrial complex (Rotterdam, the Netherlands) towards rural conditions for October-December 2014. Urban plumes are well-mixed at our semi-urban location, making this location suited for an integrated emission estimate over the whole study area. The signals at our urban measurement site (with average enhancements of 11 ppm CO2 and 40 ppb CO over the baseline) are highly variable due to the presence of distinct source areas dominated by road traffic/residential heating emissions or industrial activities. This causes different emission signatures that are translated into a large variability in observed ΔCO : ΔCO2 ratios, which can be used to identify dominant source types. We find that WRF-Chem is able to represent synoptic variability in CO2 and CO (e.g. the median CO2 mixing ratio is 9.7 ppm, observed, against 8.8 ppm, modelled), but it fails to reproduce the hourly variability of daytime urban plumes at the urban site (R2 up to 0.05). For the urban site, adding a plume model to the model framework is beneficial to adequately represent plume transport especially from stack emissions. The explained variance in hourly, daytime CO2 enhancements from point source emissions increases from 30 % with WRF-Chem to 52 % with WRF-Chem in combination with the most detailed OPS simulation. The simulated variability in ΔCO :  ΔCO2 ratios decreases drastically from 1.5 to 0.6 ppb ppm-1, which agrees better with the observed standard

Phosphorus export across an urban to rural gradient in the Chesapeake Bay watershed

Science.gov (United States)

Shuiwang Duan; Sujay S. Kaushal; Peter Groffman; Lawrence E. Band; Kenneth Belt

2012-01-01

Watershed export of phosphorus (P) from anthropogenic sources has contributed to eutrophication in freshwater and coastal ecosystems. We explore impacts of watershed urbanization on the magnitude and export flow distribution of P along an urban-rural gradient in eight watersheds monitored as part of the Baltimore Ecosystem Study Long-Term Ecological Research site....

Robust remediation strategies at gas-work sites: a case of source recognition and source characterization

International Nuclear Information System (INIS)

Vries, P.O. de

2005-01-01

In The Netherlands there have been gasworks at about 260 to 270 locations. Most of these locations are or were heavily polluted with tar, ashes and cyanides and many of them belong to the locations where remediation actions have already been executed. It seems however that many of them also belong to the locations where remediation actions were not quite as successful as was expected. So, for many gas-work sites that were already 'remedied' in the 80's and early 90's of the foregoing century, new programs for site remediation are planned. Of course the mistakes from the past should now be avoided. The current remediation strategy in The Netherlands for gas-work sites can be comprised in four steps: 1 - removing spots in the top soil, 2 - removing spots with mobile components in the shallow subsoil, 3 - controlling spots with mobile components in the deep subsoil, 4 - creating a 'steady endpoint situation' in the plume. At many former gas-work sites real sources, i.e. in a physico-chemical sense, are not very well known. This can easily lead to insufficient removal of some or part of these sources and cause a longer delivery of contaminants to the groundwater plume, with higher endpoint concentrations, higher costs and more restrictions for future use. The higher concentrations and longer deliveries originating from not recognized or not localized sources are often not sufficiently compensated by the proposed plume management in current remediation strategies. Remediation results can be improved by using knowledge about the processes that determine the delivery of contaminants to the groundwater, the materials that cause these delivery and the locations at the site where these are most likely found. When sources are present in the deep subsoil or the exact localization of sources is uncertain, robust remediation strategies should be chosen and wishful thinking about removing sources with in situ techniques should be avoided. Robust strategies are probably less

Suburban Soils: Are they the answer in determining factors controlling non-point-source DOC and DON in urban surface waters?

Science.gov (United States)

Aitkenhead-Peterson, J. A.

2016-12-01

Generally the quality of urban streams has been attributed to storm water runoff and sewage effluent discharge. Recent work in the upper Trinity Basin downstream from the Dallas/Fort Worth metropolis, TX concluded that sewage effluent only contributed between 1 and 35% of DOC dependent upon the population of the watershed. Change from native to urban land use increased DOC exports to between 938 - 1840 kg km-2 yr-1relative to the 517 kg km-2 yr-1 expected from native land use. Where this excess DOC might come from in an urban ecosystem was addressed in a separate study examining water extractable DOC (WEDOC) and DON (WEDON) in soils of single-family home lawns in Chicago, IL, Frederick, MD, Bryan/College Station, TX and Galveston, TX. These cities were exposed to different sources of sodium. Time of exposure to sodium was considered on the assumption that as new sub-divisions are built, new soil or turfgrass sod is introduced to the site. Exposure times were 0-5, 6-10, 11-20, 21-30 and > 30 yr. Length of exposure time of the soil to the urban environment was significant among the four cities examined for DOC (p < 0.001), DON (p < 0.001), sodium adsorption ratio (p < 0.006) but not for sodium (p = 0.08) or exchangeable sodium percent (ESP) (p = 0.09). In all cities WEDON increased with urban exposure time and in all cities except Galveston WEDOC increased with urban exposure time. Sodium, regardless of its source, explained 60% of the variance in WEDOC and 54% of the variance in WEDON across all cities (n = 136). To determine what other factors might be involved in increasing WEDOC and WEDON losses from suburban soils, backward stepwise regression models were used. Across the four cities, time of urban exposure, soil saturated hydraulic conductivity (Ksat), NO3-N, NH4-N, S, PO4-P, Na, Cu, Ca, Fe and Zn produced a significant model for WEDOC (Adjusted r2 = 0.85; p < 0.001) and Ksat, pH, NH4-N, PO4-P, S, Alkalinity and Cu produced a significant model for WEDON

Identifying strategic sites for Green-Infrastructures (GI) to manage stormwater in a miscellaneous use urban African watershed

Science.gov (United States)

Selker, J. S.; Kahsai, S. K.

2017-12-01

Green Infrastructure (GI) or Low impact development (LID), is a land use planning and design approach with the objective of mitigating land development impacts to the environment, and is ever more looked to as a way to lessen runoff and pollutant loading to receiving water bodies. Broad-scale approaches for siting GI/LID have been developed for agricultural watersheds, but are rare for urban watersheds, largely due to greater land use complexity. And it is even more challenging when it comes to Urban Africa due to the combination of poor data quality, rapid and unplanned development, and civic institutions unable to reliably carry out regular maintenance. We present a spacio-temporal simulation-based approach to identify an optimal prioritization of sites for GI/LID based on DEM, land use and land cover. Optimization used is a multi-objective optimization tool along with an urban storm water management model (SWMM) to identify the most cost-effective combination of LID/GI. This was applied to an urban watershed in NW Kampala, Lubigi Catchment (notorious for being heavily flooded every year), with a miscellaneous use watershed in Uganda, as a case-study to demonstrate the approach.

A community survey of the pattern and determinants of household sources of energy for cooking in rural and urban south western, Nigeria.

Science.gov (United States)

Desalu, Olufemi Olumuyiwa; Ojo, Ololade Olusola; Ariyibi, Ebenezer Kayode; Kolawole, Tolutope Fasanmi; Ogunleye, Ayodele Idowu

2012-01-01

The use of solid fuels for cooking is associated with indoor pollution and lung diseases. The objective of the study was to determine the pattern and determinants of household sources of energy for cooking in rural and urban South Western, Nigeria. We conducted a cross sectional study of households in urban (Ado-Ekiti) and rural (Ido-Ekiti) local council areas from April to July 2010. Female respondents in the households were interviewed by trained interviewers using a semi-structured questionnaire. A total of 670 households participated in the study. Majority of rural dwellers used single source of energy for cooking (55.6%) and urban dwellers used multiple source of energy (57.8%). Solid fuel use (SFU) was higher in rural (29.6%) than in urban areas (21.7%). Kerosene was the most common primary source of energy for cooking in both urban and rural areas (59.0% vs.66.6%) followed by gas (17.8%) and charcoal (6.6%) in the urban areas, and firewood (21.6%) and charcoal (7.1%) in the rural areas. The use of solid fuel was strongly associated with lack of ownership of dwellings and larger household size in urban areas, and lower level of education and lower level of wealth in the rural areas. Kerosene was associated with higher level of husband education and modern housing in urban areas and younger age and indoor cooking in rural areas. Gas was associated with high income and modern housing in the urban areas and high level of wealth in rural areas. Electricity was associated with high level of education, availability of electricity and old age in urban and rural areas respectively. The use of solid fuel is high in rural areas, there is a need to reduce poverty and improve the use of cleaner source of cooking energy particularly in rural areas and improve lung health.

Prevalence and genotypes of Campylobacter jejuni from urban environmental sources in comparison with clinical isolates from children

DEFF Research Database (Denmark)

Ramonaite, Sigita; Kudirkiene, Egle; Tamuleviciene, Egle

2014-01-01

This study aimed to investigate the prevalence of Campylobacter jejuni in potential contamination sources that are not regularly monitored such as free-living urban pigeons and crows, dogs, cats and urban environmental water and to assess the possible impact on the epidemiology of campylobacterio......This study aimed to investigate the prevalence of Campylobacter jejuni in potential contamination sources that are not regularly monitored such as free-living urban pigeons and crows, dogs, cats and urban environmental water and to assess the possible impact on the epidemiology...... of campylobacteriosis in children using multilocus sequence typing (MLST). Campylobacter spp. were detected in 36.2 % of faecal samples of free-living urban birds and in 40.4 % of environmental water samples. A low prevalence of Campylobacter spp. was detected in dogs and cats, with 7.9 and 9.1 %, respectively. Further...

Atmospheric transport of urban-derived NHx: Evidence from nitrogen concentration and δ15N in epilithic mosses at Guiyang, SW China

International Nuclear Information System (INIS)

Liu Xueyan; Xiao Huayun; Liu Congqiang; Li Youyi; Xiao Hongwei

2008-01-01

Nitrogen concentration and δ 15 N in 175 epilithic moss samples were investigated along four directions from urban to rural sites in Guiyang, SW China. The spatial variations of moss N concentration and δ 15 N revealed that atmospheric N deposition is dominated by NH x -N from two major sources (urban sewage NH 3 and agricultural NH 3 ), the deposition of urban-derived NH x followed a point source pattern characterized by an exponential decline with distance from the urban center, while the agricultural-derived NH x was shown to be a non-point source. The relationship between moss N concentration and distance (y = 1.5e -0.13x + 1.26) indicated that the maximum transporting distance of urban-derived NH x averaged 41 km from the urban center, and it could be determined from the relationship between moss δ 15 N and distance [y = 2.54 ln(x) - 12.227] that urban-derived NH x was proportionally lower than agricultural-derived NH x in N deposition at sites beyond 17.2 km from the urban center. Consequently, the variation of urban-derived NH x with distance from the urban center could be modeled as y = 56.272e -0.116x - 0.481 in the Guiyang area. - Tissue N concentration and δ 15 N in epilithic mosses may be indicators for atmospheric transport of urban-derived NH x

Urbanization impact on sulfur content of groundwater revealed by the study of urban speleothem-like deposits: Case study in Paris, France.

Science.gov (United States)

Pons-Branchu, E; Roy-Barman, M; Jean-Soro, L; Guillerme, A; Branchu, P; Fernandez, M; Dumont, E; Douville, E; Michelot, J L; Phillips, A M

2017-02-01

Speleothem-like deposits that develop underground in urban areas are an archive of the environmental impact of anthropic activities that has been little studied so far. In this paper, the sulfate content in shallow groundwater from northern Paris (France) is compared with the sulfur content in two 300-year-old urban carbonate deposits that grew in a historical underground aqueduct. The present-day waters of the aqueduct have very high sulfur and calcium contents, suggesting pollution from gypsum dissolution. However, geological gypsum levels are located below the water table. Sulfur content was measured by micro-X-ray fluorescence in these very S-rich carbonate deposits (0.5 to 1% of S). A twofold S increase during the second half of the 1800s was found in both samples. These dates correspond to two major periods of urbanization above the site. We discus three possible S sources: anthropic sources (industries, fertilizers…), volcanic eruptions and input within the water through gypsum brought for urbanization above the studied site (backfill with quarry waste) since the middle of the 19th century. For the younger second half of the studied section, S input from gypsum brought during urbanization was confirmed by the study of isotopic sulfur composition (δ 34 S=+15.2‰ at the top). For the oldest part, several sulfur peaks could be related to early industrial activity in Paris, that caused high local air pollution, as reported in historical archives but also to historical gypsum extraction. This study provides information on the origin and timing of the very high SO 4 2- levels measured nowadays within the shallow groundwater, thus demonstrating the interest in using carbonate deposits in urban areas as a proxy for the history of urbanization or human activities and their impact on water bodies. Copyright © 2016 Elsevier B.V. All rights reserved.

[Transport and sources of runoff pollution from urban area with combined sewer system].

Science.gov (United States)

Li, Li-Qing; Yin, Cheng-Qing

2009-02-15

Sampling and monitoring of runoff and sewage water in Wuhan urban area with combined sewer system were carried out during the period from 2003 to 2006, to study the transport and sources of runoff pollution at the catchment scale coupled with environmental geochemistry method. The results showed a change in quality between the runoff entering the sewer network and the combined storm water flow at the sewer's outlet. A significant increase was observed in the concentrations of total suspended solids (TSS), volatile suspended solids (VSS), COD, TN, and TP, and in the proportion of COD linked to particles. During the runoff production and transport, the concentrations of TSS and COD increased from 18.7 mg/L and 37.0 mg/L in roof runoff, to 225.3 mg/L and 176.5 mg/L in street runoff, and to 449.7 mg/L and 359.9 mg/L in combined storm water flow, respectively. The proportion of COD linked to particles was increased by 18%. In addition, the total phosphorus (P) and iron (Fe) contents in urban ground dust, storm drain sediment, sewage sewer sediment and combined sewer sediment were measured to identify the potential sources of suspended solids in the combined flow. The urban ground dust andstorm drain sediment wererich in Fe, whereas the sewage sewer sediment was rich in P. The P/Fe ratios in these groups were significantly distinct and able to differentiate them. A calculation of the two storm events based on the P/Fe rations showed that 56% +/- 26% of suspended solids in combined flow came from urban ground and storm drain. The rest wer e originated from the sewage sewer sediments which deposited in combined sewer on the dry weather days and were eroded on the wet weather days. The combined sewer network not only acts as a transport system, but also constitutes a physicochemical reactor that degrades the quality of urban water. Reducing the in-sewer pollution stocks would effectively control urban runoff pollution.

Breeding performance of blue tits (Cyanistes cæruleus ultramarinus) in relation to lead pollution and nest failure rates in rural, intermediate, and urban sites in Algeria

International Nuclear Information System (INIS)

Brahmia, Zahra; Scheifler, Renaud; Crini, Nadia; Maas, Samuel; Giraudoux, Patrick; Benyacoub, Slim

2013-01-01

The breeding parameters and the egg and nestling morphology of Cyanistes caeruleus populations from rural, intermediate, and urban sites in Algeria and the relationships of those variables with lead contamination were studied during three consecutive years. Breeding success was explained only by predation and vandalism rates. Predation was higher in the rural area, whereas vandalism was higher in the urban site. The other measured breeding parameters and egg characteristics were relatively insensitive to study site. The morphology of urban nestlings exhibited a trend toward smaller body size and mass compared to individuals from intermediate and rural sites. Although lead concentrations were higher in the tissues of urban birds than in intermediate and rural individuals, we did not detect a clear influence of this variable on nestling morphology. We conclude that urbanization influenced blue tit breeding parameters through predation and vandalism and nestling morphology through mechanisms other than lead pollution. -- Highlights: ► Life history traits in relation to lead contamination were studied in blue tits from rural, industrial and urban sites. ► The study took place in Annaba, the fourth most populated city of Algeria, during 3 consecutive years. ► Breeding success depended on predation and vandalism, which were high in the rural and urban sites, respectively. ► Urban nestlings exhibited a trend toward smaller body size and mass, which was not explained by lead contamination. ► Urbanization influences breeding success and nestling morphology in blue tits through other mechanisms than lead pollution. -- Urbanization modifies the nestling morphology and breeding success of populations of the Algerian blue tit (Cyanistes caeruleus ultramarinus) through mechanisms other than lead pollution

Ultrastructural alterations in the mouse lung caused by real-life ambient PM10 at urban traffic sites

International Nuclear Information System (INIS)

Samara, Constantini; Kouras, Athanasios; Kaidoglou, Katerina; Emmanouil-Nikoloussi, Elpida-Niki; Simou, Chrysanthi; Bousnaki, Maria; Kelessis, Apostolos

2015-01-01

Current levels of ambient air particulate matter (PM) are associated with mortality and morbidity in urban populations worldwide. Nevertheless, current knowledge does not allow precise quantification or definitive ranking of the health effects of individual PM components and indeed, associations may be the result of multiple components acting on different physiological mechanisms. In this paper, healthy Balb/c mice were exposed to ambient PM 10 at a traffic site of a large city (Thessaloniki, northern Greece), in parallel to control mice that were exposed to filtered air. Structural damages were examined in ultrafine sections of lung tissues by Transmission Electronic Microscopy (TEM). Ambient PM 10 samples were also collected during the exposure experiment and characterized with respect to chemical composition and oxidative potential. Severe ultrastructural alterations in the lung tissue after a 10-week exposure of mice at PM 10 levels often exceeding the daily limit of Directive 2008/50/EC were revealed mainly implying PM-induced oxidative stress. The DTT-based redox activity of PM 10 was found within the range of values reported for traffic sites being correlated with traffic-related constituents. Although linkage of the observed lung damage with specific chemical components or sources need further elucidation, the magnitude of biological responses highlight the necessity for national and local strategies for mitigation of particle emissions from combustion sources. - Highlights: • Animal exposure to PM10 was conducted at a traffic site of a large city. • Chemical and toxicological characterization of PM10 was carried out. • Severe degenerative alterations in alveolar cells were revealed. • PM induced oxidative stress from carbonaceous species was suggested

Sources and characteristics of lead pollution in the urban environment of Guangzhou

International Nuclear Information System (INIS)

Duzgoren-Aydin, Nurdan S.

2007-01-01

Guangzhou, the capital of the southeastern province of Guangdong, is one of the largest and most rapidly developing industrial cities in China. In recent years its rapid economic development has brought great prosperity to the Pearl River Delta (PRD) region, but has also given rise to a wide variety of environmental problems. The current level of lead (Pb) contamination (75-926 mg/kg) in the surface environment of Guangzhou remains a major concern, even though the use of leaded petrol in the city was banned in 1997. The Pb isotope ratios ( 206 Pb/ 207 Pb min-max : 1.1612-1.1961 and 208 Pb/ 207 Pb min-max : 2.4495-2.4838) of the urban dusts from unconfined (road dusts and gully sediments) and relatively confined (vehicular tunnel) settings in Guangzhou remains in a relatively narrow range, comparable with those of the regional natural and anthropogenic sources. This study highlights the inherent shortcomings of the Pb isotope fingerprinting technique for provenancing Pb sources, as both the target media (urban dusts) and potential sources have similar and highly radiogenic Pb isotope values. This could not only lead to an overestimation of the effectiveness of phasing-out of leaded petrol, but also an underestimation of the ever-increasing relative contributions from other potential sources of pollution, including coal combustion, industrial emissions of local Pb-ores and non-additive Pb contents of crude oils. Re-suspended Pb-bearing particulates deposited from early vehicular exhaust emission of leaded petrol with distinctly low Pb isotope compositions are still an important source of Pb pollution in the region

Integrated GIS-Based Site Selection of Hillside Development for Future Growth of Urban Areas

Directory of Open Access Journals (Sweden)

Imtiaz Ahmed Chandio

2016-04-01

Full Text Available Urbanization is a challenging issue for developing countries, like Malaysia. Penang Island is one of the states of Malaysia selected as a study area where limited flat land exists. As a result, this would create urban environmental problems, such as unstable slopes and landslides due to uneven topography. The purpose of this study was to develop land suitability model for hillside development. Hence, this research aims land suitability analysis modelling for hillside development by using integrated GIS (Geographic Information System based MCDM (Multi-Criteria Decision Making approach. The hill land portion of Penang Island was selected for hillside site development using GIS and AHP (Analytic Hierarchy Process as a MCDM method for sustainable hillside development. This study found that 15% of land was highly suitable, 27% moderately suitable, 41% less suitable, and 17% not suitable. Therefore, this research can be consistently used by the concerned authorities for sustainable hillside urban planning and development. This approach can be used as a policy tool in decision making of urban planning and development.

Source apportionment of ambient volatile organic compounds in the Pearl River Delta, China: Part II

Science.gov (United States)

Liu, Ying; Shao, Min; Lu, Sihua; Chang, Chih-Chung; Wang, Jia-Lin; Fu, Linlin

The chemical mass balance receptor model was applied to the source apportionment of 58 hydrocarbons measured at seven sites in a field campaign that examined regional air quality in the Pearl River Delta (PRD) region in the fall of 2004. A total of 12 volatile organic compound (VOC) emission sources were considered, including gasoline- and diesel-powered vehicle exhausts, headspace vapors of gasoline and diesel fuel, vehicle evaporative emissions, liquid petroleum gas (LPG) leakage, paint vapors, asphalt emissions from paved roads, biomass combustion, coal combustion, the chemical industry, and petroleum refineries. Vehicle exhaust was the largest source of VOCs, contributing to >50% of ambient VOCs at the three urban sites (Guangzhou, Foshan, and Zhongshan). LPG leakage played an important role, representing 8-16% of emissions at most sites in the PRD. Solvent usage was the biggest emitter of VOCs at Dongguan, an industrial site, contributing 33% of ambient VOCs. Similarly, at Xinken, a non-urban site, the evaporation of solvents and coatings was the largest emission source, accounting for 31% of emissions, probably because it was downwind of Dongguan. Local biomass combustion was a noticeable source of VOCs at Xinken; although its contribution was estimated at 14.3%, biomass combustion was the third largest VOC source at this site.

Process evaluation of child health services at outreach sites during health and nutrition day (Mamta Day) in urban slums of Western India.

Science.gov (United States)

Mehta, Kedar; Pandya, Chandresh; Chavda, Paragkumar; Solanki, Dipak

2017-01-01

Health indicators of rural and urban India show a wide variation. Rural areas have received large focus in child health services, but on the flip side, urban areas have been the last to receive such attention. A cross-sectional study was conducted to include one randomly selected outreach session from all the 19 urban primary health centers of Vadodara city from April 2013 to May 2014. Nineteen session sites were observed for the process evaluation of three components of child health care, namely, "planning of Health and Nutrition Day," "availability of vaccines/logistics," and "direct observation of actual immunization process" at the site using a structured checklist. Most of the vaccines and logistics were present at all 19 sites visited, but adverse events following immunization kit were observed at ten sites (52%) only. Open vial policy, no-touch technique, and immediate cutting of syringe with hub cutter were implemented at all sites; however, completely filled Mamta Card was observed at 9 (47%) sites only. All four key messages were given at 5 (26%) sites only. Immunization services such as proper vaccine administration with no-touch technique and open vial policy were mainly focused; however, other services such as biomedical waste management, record keeping, and delivery of all four key messages need to be strengthened during Mamta Divas. Strengthening of other child health care services such as growth monitoring, Integrated Management of Neonatal and Childhood Illnesses, and referral services is required in urban areas.

Handling Imprecision in Qualitative Data Warehouse: Urban Building Sites Annoyance Analysis Use Case

Science.gov (United States)

Amanzougarene, F.; Chachoua, M.; Zeitouni, K.

2013-05-01

Data warehouse means a decision support database allowing integration, organization, historisation, and management of data from heterogeneous sources, with the aim of exploiting them for decision-making. Data warehouses are essentially based on multidimensional model. This model organizes data into facts (subjects of analysis) and dimensions (axes of analysis). In classical data warehouses, facts are composed of numerical measures and dimensions which characterize it. Dimensions are organized into hierarchical levels of detail. Based on the navigation and aggregation mechanisms offered by OLAP (On-Line Analytical Processing) tools, facts can be analyzed according to the desired level of detail. In real world applications, facts are not always numerical, and can be of qualitative nature. In addition, sometimes a human expert or learned model such as a decision tree provides a qualitative evaluation of phenomenon based on its different parameters i.e. dimensions. Conventional data warehouses are thus not adapted to qualitative reasoning and have not the ability to deal with qualitative data. In previous work, we have proposed an original approach of qualitative data warehouse modeling, which permits integrating qualitative measures. Based on computing with words methodology, we have extended classical multidimensional data model to allow the aggregation and analysis of qualitative data in OLAP environment. We have implemented this model in a Spatial Decision Support System to help managers of public spaces to reduce annoyances and improve the quality of life of the citizens. In this paper, we will focus our study on the representation and management of imprecision in annoyance analysis process. The main objective of this process consists in determining the least harmful scenario of urban building sites, particularly in dense urban environments.

Urban Forest and Rural Cities: Multi-sited Households, Consumption Patterns, and Forest Resources in Amazonia

Directory of Open Access Journals (Sweden)

Christine Padoch

2008-12-01

Full Text Available In much of the Amazon Basin, approximately 70% of the population lives in urban areas and urbanward migration continues. Based on data collected over more than a decade in two long-settled regions of Amazonia, we find that rural-urban migration in the region is an extended and complex process. Like recent rural-urban migrants worldwide, Amazonian migrants, although they may be counted as urban residents, are often not absent from rural areas but remain members of multi-sited households and continue to participate in rural-urban networks and in rural land-use decisions. Our research indicates that, despite their general poverty, these migrants have affected urban markets for both food and construction materials. We present two cases: that of açaí palm fruit in the estuary of the Amazon and of cheap construction timbers in the Peruvian Amazon. We find that many new Amazonian rural-urban migrants have maintained some important rural patterns of both consumption and knowledge. Through their consumer behavior, they are affecting the areal extent of forests; in the two floodplain regions discussed, tree cover is increasing. We also find changes in forest composition, reflecting the persistence of rural consumption patterns in cities resulting in increased demand for and production of açaí and cheap timber species.

The atmosphere as a source/sink of polychlorinated biphenyls to/from the Lower Duwamish Waterway Superfund site

International Nuclear Information System (INIS)

Apell, Jennifer N.; Gschwend, Philip M.

2017-01-01

Waterbodies polluted with polychlorinated biphenyls (PCBs) may cause the air in the surrounding area to become PCB-contaminated. Conversely, when a waterbody is located in or near an urban area, the deposition of atmospheric PCBs may act as a low-level, ongoing source of PCB contamination to that water. Distinguishing these situations is necessary to be protective of human populations and to guide efforts seeking to cleanup such aquatic ecosystems. To assess the situation at the Lower Duwamish Waterway (LDW) Superfund site, low-density polyethylene passive samplers were deployed in the summer of 2015 to quantify freely dissolved water and gaseous air concentrations of PCBs thereby enabling estimates of the direction and magnitude of air-water exchange of PCB congeners. For the sum of the 27 PCB congeners, average concentrations were 220 pg/m 3 (95% C.I.: 80–610) in the air and 320 pg/L (95% C.I.: 110–960) in the water. The sum of air-water exchange fluxes of these PCB congeners was estimated to be 68 ng/m 2 /day (95% C.I.: 30–148) into the lower atmosphere, contrasting with the reported wet and dry depositional flux of only 5.5 ng/m 2 /day (95% C.I.: 1–38) from the air into the water. Therefore, the atmosphere was ultimately a sink of PCBs from the LDW Superfund site, at least under 2015 summertime conditions. However, we conclude that air-water exchange of PCBs is likely only a minor sink of PCBs from the LDW and only a minor source of contamination to the region's local atmosphere. - Highlights: • Passive samplers were used to estimate air and water concentrations. • At this site, PCBs were being transported from the water into the local atmosphere. • Air-water exchange was likely only a minor sink of PCBs for the LDW site. • The LDW was likely only a minor source of PCBs to the local atmosphere. - Air-water exchange of PCBs from the LDW Superfund site, calculated using passive sampler data, was determined to be a minor sink of PCBs from

[Characterization and source apportionment of pollutants in urban roadway runoff in Chongqing].

Science.gov (United States)

Zhang, Qian-Qian; Wang, Xiao-Ke; Hao, Li-Ling; Hou, Pei-Qiang; Ouyang, Zhi-Yun

2012-01-01

By investigating surface runoff from urban roadway in Chongqing, we assessed the characteristics of surface runoff pollution and the effect of rainfall intensity and antecedent dry weather period on water quality. Using multivariate statistical analysis of data of runoff quality, potential pollutants discharged from urban roadway runoff were identified. The results show that the roadway runoff has high levels of COD, TP and TN, the EMC were 60.83-208.03 mg x L(-1), 0.47-1.01 mg x L(-1) and 2.07-5.00 mg x L(-1) respectively, being the main pollutants; The peaks of pollutant concentration are ahead of or synchronous with the peak of runoff volume; the peaks of pollutant concentrations are mostly occurred within 10 minutes of rainfall. The heavy metal concentrations fluctuate dentately during runoff proceeding. Two potential pollution sources to urban roadway runoff apportioned by using principal component analysis are: vehicle's traffic loss and atmospheric dry and wet deposition, and municipal wastes.

Noise source emissions, Richton Dome site, Mississippi

International Nuclear Information System (INIS)

1987-01-01

Noise source data and use factors for modeling the environmental noise environment expected from salt-site repository activity were provided by Battelle Columbus Division. This report has been prepared for the purpose of documenting the development of the data provided to the Repository Project Management (RPM) organization. The data provided encompasses all phases of activity, from site preparation through construction of the exploratory shaft facility (ESF). Noise environments expected from construction and operation of transportation corridors associated with the activity were also modeled. Data for the construction of transportation corridors were provided. The equipment inventory, including sound-power levels for each item is included as Appendix A. Emission source terms provided by Parsons Brinckerhoff/PB-KBB for the ESF were used as a basis for the noise source emission inventory development. Where available, research results containing complete spectra were used. In cases where complete data were not available, a sound-pressure spectrum was synthesized from a characteristic spectrum shape from a similar piece of equipment. For example, a front-shovel excavator might be approximated by data from a front-end loader of similar horsepower range. Sound-power-level spectra were then calculated from the sound-pressure-level data. 14 refs

On-site and laboratory evaluations of soundscape quality in recreational urban spaces

DEFF Research Database (Denmark)

Bjerre, Lærke Cecilie; Larsen, Thea Mathilde; Sørensen, Anna Josefine

2017-01-01

on site. Moreover, the availability of the visual context in the listening experiment had no significant effect on the ratings. The participants were overall more positive toward natural sound sources on site. Conclusion: The full immersion in the on-site nonacoustic context may be important when...

Source Apportionment of Volatile Organic Compounds in an Urban Environment at the Yangtze River Delta, China.

Science.gov (United States)

An, Junlin; Wang, Junxiu; Zhang, Yuxin; Zhu, Bin

2017-04-01

Volatile organic compounds (VOCs) were collected continuously during June-August 2013 and December 2013-February 2014 at an urban site in Nanjing in the Yangtze River Delta. The positive matrix factorization receptor model was used to analyse the sources of VOCs in different seasons. Eight and seven sources were identified in summer and winter, respectively. In summer and winter, the dominant sources of VOCs were vehicular emissions, liquefied petroleum gas/natural gas (LPG/NG) usage, solvent usage, biomass/biofuel burning, and industrial production. In summer, vehicular emissions made the most significant contribution to ambient VOCs (38%), followed by LPG/NG usage (20%), solvent usage (19%), biomass/biofuel burning (13%), and industrial production (10%). In winter, LPG/NG usage accounted for 36% of ambient VOCs, whereas vehicular emissions, biomass/biofuel burning, industrial production and solvent usage contributed 30, 18, 9, and 6%, respectively. The contribution of LPG/NG usage in winter was approximately four times that in summer, whereas the contribution from biomass/biofuel burning in winter was more than twice that in summer. The sources related to vehicular emissions and LPG/NG usages were important. Using conditional probability function analysis, the VOC sources were mainly associated with easterly, northeasterly and southeasterly directions, pointing towards the major expressway and industrial area. Using the propylene-equivalent method, paint and varnish (23%) was the highest source of VOCs in summer and biomass/biofuel burning (36%) in winter. Using the ozone formation potential method, the most important source was biomass/biofuel burning (32% in summer and 47% in winter). The result suggests that the biomass/biofuel burning and paint and varnish play important roles in controlling ozone chemical formation in Nanjing.

Determination of metallic elements in soils and plants in industrial and urban sites

Energy Technology Data Exchange (ETDEWEB)

Delearte, E; Nangniot, P; Impens, R

1973-01-01

The first phase of a program to study metals in soils and plants in industrial and urban sites is reported. The metals analyzed were copper, cobalt, nickel, zinc, lead, and cadmium. The soil samples were taken at increasing distances from potential emission sources with respect to dominant wind directions. Ubiquitous plants, such as Tussilago farfara L., Plantago major L., Mercurialis annua L., and Agrostis velgaris With. were used as samples for differential oscillopolarographic analyses. Soil samples taken around a zinc ore roasting plant showed very high zinc contents, and irregular distribution of cadmium and copper. Plant samples taken at different distances from the plant revealed rapid reduction of the copper, zinc, and cadmium levels with increasing distance. Very high concentrations of copper were found in plants around a petroleum refinery. Leaves of Aeer platanoides variety Schwedlerii in a town contained an average of 14.1 ppM copper, 0.7 ppM cobalt, 5.4 ppM nickel, 160 ppM zinc, 145 ppM lead, and 0.08 ppM cadmium, relative to the dry weight. The findings indicate that samples should be obtained over a period of sufficient length.

Polychlorinated naphthalenes in urban soils: analysis, concentrations, and relation to other persistent organic pollutants

International Nuclear Information System (INIS)

Krauss, Martin; Wilcke, Wolfgang

2003-01-01

Some of the first data on polychlorinated naphthalenes (PCNs) in soils are presented from a rural-urban-industrial gradient. - We determined the concentrations of 35 PCNs, 12 PCBs, and 20 PAHs in 49 urban topsoils under different land use (house garden, roadside grassland, alluvial grassland, park areas, industrial sites, agricultural sites) and in nine rural topsoils. The sums of concentrations of 35 PCNs (Σ35 PCNs) were -1 in urban soils and -1 in rural soils. The PCN, PCB, and PAH concentrations were highest at industrial sites and in house gardens. While rural soils receive PCNs, PCBs, and PAHs by common atmospheric deposition, there are site-specific sources of PCNs, PCBs, and PAHs for urban soils such as deposition of contaminated technogenic materials. The PCN, PCB, and PAH concentrations decreased from the central urban to the rural area. In the same order the contribution of lower chlorinated PCNs and PCBs increased because they are more volatile and subject to increased atmospheric transport. The PCNs 52+60, and 73 were more abundant in soil samples than in Halowax mixtures, indicating that combustion contributed to the PCN contamination of the soils

Particle characterization at rural, suburban and urban aerosol sampling sites in Hungary

International Nuclear Information System (INIS)

Borbely-Kiss, I.; Koltay, E.; Szabo, G.; Meszaros, E.; Molnar, A.; Bozo, L.

1994-01-01

The study of atmospheric aerosols originating from natural and anthropogenic processes is of basic importance for a detailed understanding of the physics and chemistry of the atmosphere. Particle Induced X-ray Emission (PIXE) technique has been used by the authors for studying regularly the elemental composition of rural, suburban, and urban aerosols collected at six sampling sites in Hungary. Observed data presented in terms of concentrations and regional signature values and evaluated wind sector partition and in transport modelling revealed the natural/anthropogenic contribution to the moderate air pollution here. Dry deposition velocities have been deduced for elements V, Cr, Mn, Co, Ni, Cu, Zn, Cd, and Pb. Model calculations based on annual emission data and observed elemental concentrations resulted in total dry and wet deposition masses of the above elements to the territory of the country. At the same time, deduced budget data for the emission and deposition of the constituents indicated whether the country represents a net source or a sink for the above mentioned elements in the regional aerosol transport between neighbouring countries. Evidences have been found for intrusion events of Saharan aerosol to the atmosphere of Hungary. Part of the data collected recently will be evaluated in the frame-work of an international co-ordinated research programme. (author)

Characterization of Organic Matter Sources within a Matrix of Land Use in Northeast Utah

Science.gov (United States)

Kelso, J. E.; Baker, M. A.

2017-12-01

Dynamics of organic matter (OM) sources in natural aquatic systems have been studied for decades, but urban studies have revealed additional, less studied, OM sources such as stormwater, lawn clippings, and wastewater effluent. Traditionally the OM pool in freshwater systems has been defined as a homogenous pool of varying size classes: course particulate, fine particulate and dissolved OM. Our goal was to identify and quantify the composition of fine particulate OM (FPOM), and dissolved OM (DOM) as derived from autochthonous, terrestrial, and potential anthropogenic sources. We hypothesized anthropogenic changes in land use have increased the proportion of autochthonous sources of OM. We sampled OM at 33 sites in four watersheds in northeast Utah that encompass a range of land uses. Stable isotopes of carbon, nitrogen, and deuterium were collected for all size classes of OM, and DOM was analyzed with a spectrofluorometer. Stable isotopes were used to estimate the proportion of autochthonous and terrestrial sources of OM. Fluorescence indices and a PARAFAC model were created from DOM excitation emission matrices (EEMs). FPOM appeared to be a mixture of autochthonous and terrestrial sources but overlap in endmember isotope values made quantifying the proportion of each source difficult. Higher deuterium values (-120 to -80‰) were associated with sites receiving wastewater effluent, while sites with agriculture, forest, and urban land use had lower deuterium isotope values (-200 to -110). DOM Excitation Emission Matrices were resolved into a 5-component PARAFAC model. The percent of protein-like DOM components tended to be higher in urban versus non-urban sites (mean 35%, S.D. 12% versus mean 25%, S.D. 15%). We concluded deuterium isotopes may be used as a tracer or wastewater effluent and DOM is composed of more labile, protein-like DOM with increased wastewater input. A greater understanding of the sources of OM can inform management and policy decisions aimed at

The hydrogeology of urbanization: The lost springs of Washington, D.C., late Tertiary and Quaternary sediments of D.C., and the Baltimore Long Term Ecological Research site (LTER): Chapter

Science.gov (United States)

Bhaskar, Aditi; Pavich, Milan J.; Sharp, John M.

2015-01-01

Urbanization is a major process now shaping the environment. This field trip looks at the hydrogeology of the general Washington, D.C., area and focuses on the city's lost springs. Until 150 years ago, springs and shallow dug wells were the main source of drinking water for residents of Washington, D.C. Celebrating the nation's bicentennial, Garnett P. Williams of the U.S. Geological Survey examined changes in water supply and water courses since 1776. He examined old newspaper files to determine the location of the city's springs. This field trip visits sites of some of these springs (few of which are now flowing), discusses the hydrologic impacts of urbanization and the general geological setting, and finishes with the Baltimore Long Term Ecological Research site at Dead Run and its findings. The field trip visits some familiar locations in the Washington, D.C., area, and gives insights into their often hidden hydrologic past and present.

Process evaluation of child health services at outreach sites during health and nutrition day (Mamta Day in urban slums of Western India

Directory of Open Access Journals (Sweden)

Kedar Mehta

2017-01-01

Full Text Available Introduction: Health indicators of rural and urban India show a wide variation. Rural areas have received large focus in child health services, but on the flip side, urban areas have been the last to receive such attention. Materials and Methods: A cross-sectional study was conducted to include one randomly selected outreach session from all the 19 urban primary health centers of Vadodara city from April 2013 to May 2014. Nineteen session sites were observed for the process evaluation of three components of child health care, namely, “planning of Health and Nutrition Day,” “availability of vaccines/logistics,” and “direct observation of actual immunization process” at the site using a structured checklist. Results: Most of the vaccines and logistics were present at all 19 sites visited, but adverse events following immunization kit were observed at ten sites (52% only. Open vial policy, no-touch technique, and immediate cutting of syringe with hub cutter were implemented at all sites; however, completely filled Mamta Card was observed at 9 (47% sites only. All four key messages were given at 5 (26% sites only. Conclusion: Immunization services such as proper vaccine administration with no-touch technique and open vial policy were mainly focused; however, other services such as biomedical waste management, record keeping, and delivery of all four key messages need to be strengthened during Mamta Divas. Strengthening of other child health care services such as growth monitoring, Integrated Management of Neonatal and Childhood Illnesses, and referral services is required in urban areas.

Speciated atmospheric mercury and its potential source in Guiyang, China

Science.gov (United States)

Fu, Xuewu; Feng, Xinbin; Qiu, Guangle; Shang, Lihai; Zhang, Hui

2011-08-01

Speciated atmospheric mercury (Hg) including gaseous elemental mercury (GEM), particulate Hg (PHg), and reactive gaseous Hg (RGM) were continuously measured at an urban site in Guiyang city, southwest China from August to December 2009. The averaged concentrations for GEM, PHg, and RGM were 9.72 ± 10.2 ng m -3, 368 ± 676 pg m -3, and 35.7 ± 43.9 pg m -3, respectively, which were all highly elevated compared to observations at urban sites in Europe and North America. GEM and PHg were characterized by similar monthly and diurnal patterns, with elevated levels in cold months and nighttime, respectively. In contrast, RGM did not exhibit clear monthly and diurnal variations. The variations of GEM, PHg, and RGM indicate the sampling site was significantly impacted by sources in the city municipal area. Sources identification implied that both residential coal burning and large point sources were responsible to the elevated GEM and PHg concentrations; whereas point sources were the major contributors to elevated RGM concentrations. Point sources played a different role in regulating GEM, PHg, and RGM concentrations. Aside from residential emissions, PHg levels was mostly affected by small-scale coal combustion boilers situated to the east of the sampling site, which were scarcely equipped or lacking particulate control devices; whereas point sources situated to the east, southeast, and southwest of the sampling played an important role on the distribution of atmospheric GEM and RGM.

Solid Waste Landfill Site Selection in the Sense of Environment Sensitive Sustainable Urbanization: Izmir, Turkey Case

Science.gov (United States)

TÜdeş, Şule; Kumlu, Kadriye Burcu Yavuz

2017-10-01

Each stage of the planning process should be based on the natural resource protection, in the sense of environmental sensitive and sustainable urban planning. Values, which are vital for the continuity of the life in the Earth, as soil, water, forest etc. should be protected from the undesired effects of the pollution and the other effects caused by the high urbanization levels. In this context, GIS-MCDM based solid waste landfill site selection is applied for Izmir, Turkey, where is a significant attraction place for tourism. As Multi criteria Decision Making (MCDM) technique, Analytical Hierarchy Process (AHP) is used. In this study, geological, tectonically and hydrological data, as well as agricultural land use, slope, distance to the settlement areas and the highways are used as inputs for AHP analysis. In the analysis stage, those inputs are rated and weighted. The weighted criteria are evaluated via GIS, by using weighted overlay tool. Therefore, an upper-scale analysis is conducted and a map, which shows the alternative places for the solid waste landfill sites, considering the environmental protection and evaluated in the context of environmental and urban criteria, are obtained.

Painted surfaces - Important sources of polychlorinated biphenyls (PCBs) contamination to the urban and marine environment

International Nuclear Information System (INIS)

Jartun, Morten; Ottesen, Rolf Tore; Steinnes, Eiliv; Volden, Tore

2009-01-01

A study of a large number of samples of flaking old paint from various buildings in Bergen, Norway (N = 68) suggests that paint may be the most important contemporary source of PCBs in this urban environment with concentrations of PCB 7 up to 3.39 g/kg. Twenty-three of the samples were collected from a single building, and the concentrations were found to vary over 3 orders of magnitude. In addition, 16 concrete samples from a large bridge previously coated with PCB-containing paint were collected and separated into outer- and inner samples indicating that PCBs are still present in high concentrations subsequent to renovation. PCBs were found in several categories of paint from wooden and concrete buildings, potentially introduced to the environment by natural weathering, renovation, and volatilization. Consequently, this dispersion may lead to increased levels of PCBs in urban atmospheres, soils, and harbor sediments where high concentrations have resulted in Governmental advice against consumption of certain seafood. - Paint from structures built during the period 1950-1970 may be the most important source of PCBs in an urban environment

Ultrastructural alterations in the mouse lung caused by real-life ambient PM{sub 10} at urban traffic sites

Energy Technology Data Exchange (ETDEWEB)

Samara, Constantini, E-mail: csamara@chem.auth.gr [Environmental Pollution Control Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 541 24 Thesaloniki (Greece); Kouras, Athanasios; Kaidoglou, Katerina [Environmental Pollution Control Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 541 24 Thesaloniki (Greece); Emmanouil-Nikoloussi, Elpida-Niki; Simou, Chrysanthi; Bousnaki, Maria [Laboratory of Histology-Embryology and Anthropology, School of Medicine, Aristotle University of Thessaloniki, 541 24 Thesaloniki (Greece); Kelessis, Apostolos [Environmental Department, Municipality of Thessaloniki, Kleanthous 18, 54 642 Thessaloniki (Greece)

2015-11-01

Current levels of ambient air particulate matter (PM) are associated with mortality and morbidity in urban populations worldwide. Nevertheless, current knowledge does not allow precise quantification or definitive ranking of the health effects of individual PM components and indeed, associations may be the result of multiple components acting on different physiological mechanisms. In this paper, healthy Balb/c mice were exposed to ambient PM{sub 10} at a traffic site of a large city (Thessaloniki, northern Greece), in parallel to control mice that were exposed to filtered air. Structural damages were examined in ultrafine sections of lung tissues by Transmission Electronic Microscopy (TEM). Ambient PM{sub 10} samples were also collected during the exposure experiment and characterized with respect to chemical composition and oxidative potential. Severe ultrastructural alterations in the lung tissue after a 10-week exposure of mice at PM{sub 10} levels often exceeding the daily limit of Directive 2008/50/EC were revealed mainly implying PM-induced oxidative stress. The DTT-based redox activity of PM{sub 10} was found within the range of values reported for traffic sites being correlated with traffic-related constituents. Although linkage of the observed lung damage with specific chemical components or sources need further elucidation, the magnitude of biological responses highlight the necessity for national and local strategies for mitigation of particle emissions from combustion sources. - Highlights: • Animal exposure to PM10 was conducted at a traffic site of a large city. • Chemical and toxicological characterization of PM10 was carried out. • Severe degenerative alterations in alveolar cells were revealed. • PM induced oxidative stress from carbonaceous species was suggested.

Vertical and horizontal variability of PM10 source contributions in Barcelona during SAPUSS

Science.gov (United States)

Brines, Mariola; Dall'Osto, Manuel; Amato, Fulvio; Cruz Minguillón, María; Karanasiou, Angeliki; Alastuey, Andrés; Querol, Xavier

2016-06-01

During the SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies) PM10 samples at 12-hour resolution were simultaneously collected at four monitoring sites located in the urban agglomerate of Barcelona (Spain). A total of 221 samples were collected from 20 September to 20 October 2010. The Road Site (RS) site and the Urban Background (UB) site were located at street level, whereas the Torre Mapfre (TM) and the Torre Collserola (TC) sites were located at 150 m a.s.l. by the sea side within the urban area and at 415 m a.s.l. 8 km inland, respectively. For the first time, we are able to report simultaneous PM10 aerosol measurements, allowing us to study aerosol gradients at both horizontal and vertical levels. The complete chemical composition of PM10 was determined on the 221 samples, and factor analysis (positive matrix factorisation, PMF) was applied. This resulted in eight factors which were attributed to eight main aerosol sources affecting PM10 concentrations in the studied urban environment: (1) vehicle exhaust and wear (2-9 µg m-3, 10-27 % of PM10 mass on average), (2) road dust (2-4 µg m-3, 8-12 %), (3) mineral dust (5 µg m-3, 13-26 %), (4) aged marine (3-5 µg m-3, 13-20 %), (5) heavy oil (0.4-0.6 µg m-3, 2 %), (6) industrial (1 µg m-3, 3-5 %), (7) sulfate (3-4 µg m-3, 11-17 %) and (8) nitrate (4-6 µg m-3, 17-21 %). Three aerosol sources were found to be enhanced at the ground levels (confined within the urban ground levels of the city) relative to the upper levels: (1) vehicle exhaust and wear (2.8 higher), (2) road dust (1.8 higher) and (3) local urban industries/crafts workshops (1.6 higher). Surprisingly, the other aerosol sources were relatively homogeneous at both horizontal and vertical levels. However, air mass origin and meteorological parameters also played a key role in influencing the variability of the factor concentrations. The mineral dust and aged marine factors were found to be a mixture of natural and

USING REMOTELY SENSED DATA FOR DOCUMENTATION OF ARCHAEOLOGICAL SITES IN NORTHEASTERN MESOPOTAMIA

Directory of Open Access Journals (Sweden)

E. Matoušková

2016-06-01

Full Text Available This paper introduces two archaeological sites documented during the MULINEM (The Medieval Urban Landscape in Northeastern Mesopotamia project. This project investigates the Late Sasanian and Islamic urban network in the land of Erbil, a historic province of Hidyab (Adiabene that is located in northern Iraq. The investigated sites are the two deserted cities of Makhmúr al-Quadíma and Al-Hadítha. It is assumed that these two sites used to form large cities with high business and cultural importance in the medieval period. The archaeological locations are endangered by various threats.The Al-Hadítha site seems to be under the control of the „Islamic state“ at the moment and Makhmúr al-Quadíma is located just next to the town of new Makhmúr that expands rapidly and without complex urban plans. Documentation of the archaeological sites has been done by using remotely sensed methods together with in-situ measurements (where available. FORMOSAT-2 data that has been gained through a research announcement: Free FORMOSAT-2 satellite imagery and when combined with other sources (recent and historical data it provides a powerful documentation tool. In-situ RPAS measurements and a DTM creation furnish a new source of highly valuable information. Influence of the political and security situation in Al-Hadítha will be analysed.

Using Remotely Sensed Data for Documentation of Archaeological Sites in Northeastern Mesopotamia

Science.gov (United States)

Matoušková, E.; Starková, L.; Pavelka, K.; Nováček, K.; Šedina, J.; Faltýnová, M.; Housarová, E.

2016-06-01

This paper introduces two archaeological sites documented during the MULINEM (The Medieval Urban Landscape in Northeastern Mesopotamia) project. This project investigates the Late Sasanian and Islamic urban network in the land of Erbil, a historic province of Hidyab (Adiabene) that is located in northern Iraq. The investigated sites are the two deserted cities of Makhmúr al-Quadíma and Al-Hadítha. It is assumed that these two sites used to form large cities with high business and cultural importance in the medieval period. The archaeological locations are endangered by various threats.The Al-Hadítha site seems to be under the control of the „Islamic state" at the moment and Makhmúr al-Quadíma is located just next to the town of new Makhmúr that expands rapidly and without complex urban plans. Documentation of the archaeological sites has been done by using remotely sensed methods together with in-situ measurements (where available). FORMOSAT-2 data that has been gained through a research announcement: Free FORMOSAT-2 satellite imagery and when combined with other sources (recent and historical data) it provides a powerful documentation tool. In-situ RPAS measurements and a DTM creation furnish a new source of highly valuable information. Influence of the political and security situation in Al-Hadítha will be analysed.

Using a source-receptor approach to characterise VOC behaviour in a French urban area influenced by industrial emissions. Part II: source contribution assessment using the Chemical Mass Balance (CMB) model.

Science.gov (United States)

Badol, Caroline; Locoge, Nadine; Galloo, Jean-Claude

2008-01-25

In Part I of this study (Badol C, Locoge N, Leonardis T, Gallo JC. Using a source-receptor approach to characterise VOC behaviour in a French urban area influenced by industrial emissions, Part I: Study area description, data set acquisition and qualitative data analysis of the data set. Sci Total Environ 2007; submitted as companion manuscript.) the study area, acquisition of the one-year data set and qualitative analysis of the data set have been described. In Part II a source profile has been established for each activity present in the study area: 6 profiles (urban heating, solvent use, natural gas leakage, biogenic emissions, gasoline evaporation and vehicle exhaust) have been extracted from literature to characterise urban sources, 7 industrial profiles have been established via canister sampling around industrial plants (hydrocarbon cracking, oil refinery, hydrocarbon storage, lubricant storage, lubricant refinery, surface treatment and metallurgy). The CMB model is briefly described and its implementation is discussed through the selection of source profiles and fitting species. Main results of CMB modellings for the Dunkerque area are presented. (1) The daily evolution of source contributions for the urban wind sector shows that the vehicle exhaust source contribution varies between 40 and 55% and its relative increase at traffic rush hours is hardly perceptible. (2) The relative contribution of vehicle exhaust varies from 55% in winter down to 30% in summer. This decrease is due to the increase of the relative contribution of hydrocarbon storage source reaching up to 20% in summer. (3) The evolution of source contributions with wind directions has confirmed that in urban wind sectors the contribution of vehicle exhaust dominate with around 45-55%. For the other wind sectors that include some industrial plants, the contribution of industrial sources is around 60% and could reach 80% for the sector 280-310 degrees , which corresponds to the most dense

Optimized spectroscopic scheme for enhanced precision CO measurements with applications to urban source attribution

Science.gov (United States)

Nottrott, A.; Hoffnagle, J.; Farinas, A.; Rella, C.

2014-12-01

Carbon monoxide (CO) is an urban pollutant generated by internal combustion engines which contributes to the formation of ground level ozone (smog). CO is also an excellent tracer for emissions from mobile combustion sources. In this work we present an optimized spectroscopic sampling scheme that enables enhanced precision CO measurements. The scheme was implemented on the Picarro G2401 Cavity Ring-Down Spectroscopy (CRDS) analyzer which measures CO2, CO, CH4 and H2O at 0.2 Hz. The optimized scheme improved the raw precision of CO measurements by 40% from 5 ppb to 3 ppb. Correlations of measured CO2, CO, CH4 and H2O from an urban tower were partitioned by wind direction and combined with a concentration footprint model for source attribution. The application of a concentration footprint for source attribution has several advantages. The upwind extent of the concentration footprint for a given sensor is much larger than the flux footprint. Measurements of mean concentration at the sensor location can be used to estimate source strength from a concentration footprint, while measurements of the vertical concentration flux are necessary to determine source strength from the flux footprint. Direct measurement of vertical concentration flux requires high frequency temporal sampling and increases the cost and complexity of the measurement system.

Seasonal variation and source estimation of organic compounds in urban aerosol of Augsburg, Germany

International Nuclear Information System (INIS)

Pietrogrande, Maria Chiara; Abbaszade, Guelcin; Schnelle-Kreis, Juergen; Bacco, Dimitri; Mercuriali, Mattia; Zimmermann, Ralf

2011-01-01

This study reports a general assessment of the organic composition of the PM 2.5 samples collected in the city of Augsburg, Germany in a summer (August-September 2007) and a winter (February-March 2008) campaign of 36 and 30 days, respectively. The samples were directly submitted to in-situ derivatisation thermal desorption gas chromatography coupled with time of flight mass spectrometry (IDTD-GC-TOFMS) to simultaneously determine the concentrations of many classes of molecular markers, such as n-alkanes, iso- and anteiso-alkanes, polycyclic aromatic hydrocarbons (PAHs), oxidized PAHs, n-alkanoic acids, alcohols, saccharides and others. The PCA analysis of the data identified the contributions of three emission sources, i.e., combustion sources, including fossil fuel emissions and biomass burning, vegetative detritus, and oxidized PAHs. The PM chemical composition shows seasonal trend: winter is characterized by high contribution of petroleum/wood combustion while the vegetative component and atmospheric photochemical reactions are predominant in the hot season. - Highlights: → 59 molecular markers were simultaneously determined by thermal desorption GC-MS. → Organic composition of urban PM 2.5 in Augsburg, Germany, was characterized. → Fossil fuel, vegetative detritus, coal/wood burning are the main sources. → Seasonal trends winter vs. summer were identified. - Organic composition of the urban PM 2.5 identifies seasonal trend of the main sources: fossil fuel and biomass combustion sources, vegetative detritus, atmospheric photochemical reactions.

Stream Nitrogen Inputs Reflect Groundwater Across a Snowmelt-Dominated Montane to Urban Watershed.

Science.gov (United States)

Hall, Steven J; Weintraub, Samantha R; Eiriksson, David; Brooks, Paul D; Baker, Michelle A; Bowen, Gabriel J; Bowling, David R

2016-02-02

Snowmelt dominates the hydrograph of many temperate montane streams, yet little work has characterized how streamwater sources and nitrogen (N) dynamics vary across wildland to urban land use gradients in these watersheds. Across a third-order catchment in Salt Lake City, Utah, we asked where and when groundwater vs shallow surface water inputs controlled stream discharge and N dynamics. Stream water isotopes (δ(2)H and δ(18)O) reflected a consistent snowmelt water source during baseflow. Near-chemostatic relationships between conservative ions and discharge implied that groundwater dominated discharge year-round across the montane and urban sites, challenging the conceptual emphasis on direct stormwater inputs to urban streams. Stream and groundwater NO3(-) concentrations remained consistently low during snowmelt and baseflow in most montane and urban stream reaches, indicating effective subsurface N retention or denitrification and minimal impact of fertilizer or deposition N sources. Rather, NO3(-) concentrations increased 50-fold following urban groundwater inputs, showing that subsurface flow paths potentially impact nutrient loading more than surficial land use. Isotopic composition of H2O and NO3(-) suggested that snowmelt-derived urban groundwater intercepted NO3(-) from leaking sewers. Sewer maintenance could potentially mitigate hotspots of stream N inputs at mountain/valley transitions, which have been largely overlooked in semiarid urban ecosystems.

Sources of mutagenic activity in urban fine particles

International Nuclear Information System (INIS)

Stevens, R.K.; Lewis, C.W.; Dzubay, T.G.; Cupitt, L.T.; Lewtas, J.

1990-01-01

Samples were collected during the winter of 1984-1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3-5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model

Sources of SOA gaseous precursors in contrasted urban environments: a focus on mono-aromatic compounds and intermediate volatility compounds

Science.gov (United States)

Salameh, Therese; Borbon, Agnès; Ait-Helal, Warda; Afif, Charbel; Sauvage, Stéphane; Locoge, Nadine; Bonneau, Stéphane; Sanchez, Olivier

2016-04-01

Among Volatile Organic Compounds (VOC), the mono-aromatic compounds so-called BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) and the intermediate volatility organic compounds (IVOC) with C>12 are two remarkable chemical families having high impact on health, as well as on the production of secondary pollutants like secondary organic aerosols (SOA) and ozone. However, the nature and relative importance of their sources and, consequently, their impact on SOA formation at urban scale is still under debate. On the one hand, BTEX observations in urban areas of northern mid-latitudes do not reconcile with emission inventories; the latter pointing to solvent use as the dominant source compared to traffic. Moreover, a recent study by Borbon et al. (2013) has shown an enrichment in the C7-C9 aromatic fraction in Paris atmosphere by a factor of 3 compared to other cities. Causes would be: (i) differences in gasoline composition, (ii) differences in vehicle fleet composition, and (iii) differences in solvent use related sources. On the other hand, many smog chamber studies have highlighted IVOCs as important SOA precursors over the last decade but their origin and importance in urban areas relative to other precursors like BTEX is still poorly addressed. Here we combined large VOC datasets to investigate sources of BTEX and IVOC in contrasted urban areas by source-receptor approaches and laboratory experiments. Ambient data include multi-site speciated ambient measurements of C2 to C17 VOCs (traffic, urban background, and tunnel) from air quality networks (ie. AIRPARIF in Paris) and intensive field campaigns (MEGAPOLI-Paris, TRANSEMED in Beirut and Istanbul, PHOTOPAQ in Brussels). Preliminary results for Paris suggest that traffic dominates BTEX concentrations while traffic and domestic heating for IVOC (>70%). In parallel, the detailed composition of the fuel liquid phase was determined at the laboratory for typical fuels distributed in Ile de France region (diesel, SP95

Nest site selection and breeding success in three Turdus thrush species coexisting in an urban environment

Czech Academy of Sciences Publication Activity Database

Mikula, P.; Hromada, M.; Albrecht, Tomáš; Tryjanowski, P.

2014-01-01

Roč. 49, č. 1 (2014), s. 83-92 ISSN 0001-6454 Institutional support: RVO:68081766 Keywords : breeding success * coexistence * nest-habitat partitioning * nest site selection * predation * synurbization * urban habitat * thrushes Subject RIV: EG - Zoology Impact factor: 0.745, year: 2014

Breeding performance of blue tits (Cyanistes cæruleus ultramarinus) in relation to lead pollution and nest failure rates in rural, intermediate, and urban sites in Algeria.

Science.gov (United States)

Brahmia, Zahra; Scheifler, Renaud; Crini, Nadia; Maas, Samuel; Giraudoux, Patrick; Benyacoub, Slim

2013-03-01

The breeding parameters and the egg and nestling morphology of Cyanistes caeruleus populations from rural, intermediate, and urban sites in Algeria and the relationships of those variables with lead contamination were studied during three consecutive years. Breeding success was explained only by predation and vandalism rates. Predation was higher in the rural area, whereas vandalism was higher in the urban site. The other measured breeding parameters and egg characteristics were relatively insensitive to study site. The morphology of urban nestlings exhibited a trend toward smaller body size and mass compared to individuals from intermediate and rural sites. Although lead concentrations were higher in the tissues of urban birds than in intermediate and rural individuals, we did not detect a clear influence of this variable on nestling morphology. We conclude that urbanization influenced blue tit breeding parameters through predation and vandalism and nestling morphology through mechanisms other than lead pollution. Copyright © 2012 Elsevier Ltd. All rights reserved.

Atmospheric organochlorine pesticides and polychlorinated biphenyls in urban areas of Nepal: spatial variation, sources, temporal trends, and long-range transport potential

Science.gov (United States)

Pokhrel, Balram; Gong, Ping; Wang, Xiaoping; Nath Khanal, Sanjay; Ren, Jiao; Wang, Chuanfei; Gao, Shaopeng; Yao, Tandong

2018-02-01

The study of persistent organic pollutants (POPs) in low-latitude tropical and subtropical urban cities is necessary to assess their local and global impacts on ecosystems and human health. Despite studies on levels of POPs in water, soils, and sediments, analysis of the distribution patterns, seasonality, and sources of POPs in urban regions of Nepal remain limited. Polyurethane foam (PUF)-based passive air samplers were deployed in three major cities in Nepal: Kathmandu (the capital city), Pokhara, and Hetauda (agricultural cities). Dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) were the dominant organochlorine pesticides in the atmosphere at all sites. The average concentrations of POPs were ∑ DDTs, 8.7-1.0 × 103 pg m-3; ∑ HCHs, 5.3-3.3 × 103 pg m-3; HCB, 5.8-3.4 × 102 pg m-3; ∑ endosulfan, BDL-51 pg m-3; and ∑ 6PCBs, 1.4-47 pg m-3. Isomer and metabolite ratio analyses suggested that the concentrations present were from both new and historical applications of the POPs. Vegetable production sites and their market places appeared to be the major DDT and HCH source areas. Higher atmospheric concentrations of DDT and HCH occurred during the pre-monsoon and monsoon seasons, and winter, respectively, closely associated with their local application for soil preparation and vegetable spraying. The estimated travel distances of the POPs (HCB, α-HCH, γ-HCH, and p, p'-DDT) under the Nepalese tropical climate were all above 1000 km, suggesting that high precipitation levels in the tropical climate were not enough to scavenge the POPs and that Nepal could be an important source region for POPs. Due to their close proximity and cold trapping (driven by low temperatures), the high Himalayas and the Tibetan Plateau are likely the key receptors of POPs emitted in Nepal. These results add to the information available on POPs from tropical developing countries.

Sources of aminomethylphosphonic acid (AMPA) in urban and rural catchments in Ontario, Canada: Glyphosate or phosphonates in wastewater?

International Nuclear Information System (INIS)

Struger, J.; Van Stempvoort, D.R.; Brown, S.J.

2015-01-01

Correlation analysis suggests that occurrences of AMPA in streams of southern Ontario are linked mainly to glyphosate in both urban and rural settings, rather than to wastewater sources, as some previous studies have suggested. For this analysis the artificial sweetener acesulfame was analyzed as a wastewater indicator in surface water samples collected from urban and rural settings in southern Ontario, Canada. This interpretation is supported by the concurrence of seasonal fluctuations of glyphosate and AMPA concentrations. Herbicide applications in larger urban centres and along major transportation corridors appear to be important sources of glyphosate and AMPA in surface water, in addition to uses of this herbicide in rural and mixed use areas. Fluctuations in concentrations of acesulfame and glyphosate residues were found to be related to hydrologic events. - Highlights: • Widespread occurrence of glyphosate and AMPA in surface waters of southern Ontario. • Linked to applications of glyphosate in urban and rural settings. • Supported by lack of correlation between AMPA and the wastewater tracer acesulfame. • Contrasts with view that AMPA found in the environment is derived from wastewater. • AMPA more persistent than glyphosate and both fluctuated with hydrological cycles. - The occurrence of AMPA in streams in southern Ontario is linked mainly to glyphosate rather than wastewater sources

Sensitivities Affecting Heat and Urban Heat Island Effect on Local Scale Projected to Neighborhood Scale in Baltimore, Maryland

Science.gov (United States)

Sze, C.; Zaitchik, B. F.; Scott, A.

2015-12-01

Urban regions are often impacted more by heat than adjacent rural areas, which is a phenomenon known as the urban heat island (UHI) effect. Urban areas are also highly heterogeneous and notoriously difficult to monitor using standard meteorological protocols—the hottest microclimates within a city often occur in locations that lack open, representative installation sites that are an adequate distance from buildings and direct heat sources. To investigate the challenges of monitoring urban heat, this study examines the sensitivity of temperature and humidity sensors currently used in a Baltimore UHI monitoring network to differences in sun exposure, material on which the data collecting instrument is attached, and land cover class of the vicinity. Sensitivity to sun exposure and attachment site can be interpreted as sources of uncertainty for urban heat monitoring, while sensitivity to land cover may reflect a true source of local temperature and humidity variability. In this study, we present results from a test deployment designed to assess the sensitivity of heat measurements to each of these three factors. We then apply these results to interpret measurements taken across the entire Baltimore UHI monitoring network. These results can then be used to improve heat measurements and more accurately represent and quantify the UHI effect on a broader scale, such as in neighborhoods or urban centers.

Noise source emissions, Deaf Smith County site, Texas

International Nuclear Information System (INIS)

1987-01-01

Noise source data and use factors for modeling the noise environment expected from salt site repository activity were provided by Battelle Columbus Division. This report has been prepared for the purpose of documenting the development of the data provided to the Repository Project Management (RPM) organization. The data provided encompass all phases of activity from site preparation through construction of the exploratory shaft facility (ESF). Noise environments expected from construction and operation of transportation corridors associated with the activity were also modeled. The equipment inventory, including sound-power levels for each item, is included. Emission source terms provided by Parsons Brinckerhoff/PB-KBB for the ESF were used as a basis for the noise-source emission inventory development. Where available, research results containing complete spectra were used. In cases where complete data were not available, a sound-pressure spectrum was synthesized from a characteristic spectrum shape from a similar piece of equipment. For example, a front-shovel excavator might be approximated by data from a front-end loader of similar horsepower range. Sound-power-level spectra were then calculated from the sound-pressure-level data. 2 refs

Non-invasive shallow seismic source comparison for hazardous waste site investigations

International Nuclear Information System (INIS)

Doll, W.E.

1994-01-01

Many commonly used shallow seismic sources are unacceptable for hazardous waste site investigations because they risk exhumation of contaminants in the soil, they add contaminants (e.g. lead) which are not allowed by regulations, or they add new migration paths for contaminants. Furthermore, recently developed high frequency vibrators for shallow investigations could be more effective at some sites than non-invasive impulsive sources because of their ability to tailor the source spectrum and reduce interference. The authors show preliminary results of a comparison test of eight non-invasive impulsive and swept sources in preparation for seismic reflection profiling on the Oak Ridge Reservation, Tennessee. Well log data are used to determine geologic contacts and to generate synthetic seismograms for the site. Common midpoint (CMP) seismic data for each source were collected at 95 geophone groups from 125 shot points along a 400m test line. Hydrophone data were obtained at 1.5m spacing between 61m and 133m depth in a hole near the center of the CMP line. As of March, 1994, brute stacks have been completed for three of the eight sources. Depth penetration is demonstrated in brute stacks and shot gathers, which show a 200ms reflector for all of the sources tested along portions of the line. Source effectiveness will also be evaluated by comparing images of several shallower reflectors (40--150ms) which are apparent in many of the records. Imaging of these reflectors appears to depend upon the ability of the source to generate sufficient high frequency energy (>100 Hz)

Receptor modeling for source apportionment of polycyclic aromatic hydrocarbons in urban atmosphere.

Science.gov (United States)

Singh, Kunwar P; Malik, Amrita; Kumar, Ranjan; Saxena, Puneet; Sinha, Sarita

2008-01-01

This study reports source apportionment of polycyclic aromatic hydrocarbons (PAHs) in particulate depositions on vegetation foliages near highway in the urban environment of Lucknow city (India) using the principal components analysis/absolute principal components scores (PCA/APCS) receptor modeling approach. The multivariate method enables identification of major PAHs sources along with their quantitative contributions with respect to individual PAH. The PCA identified three major sources of PAHs viz. combustion, vehicular emissions, and diesel based activities. The PCA/APCS receptor modeling approach revealed that the combustion sources (natural gas, wood, coal/coke, biomass) contributed 19-97% of various PAHs, vehicular emissions 0-70%, diesel based sources 0-81% and other miscellaneous sources 0-20% of different PAHs. The contributions of major pyrolytic and petrogenic sources to the total PAHs were 56 and 42%, respectively. Further, the combustion related sources contribute major fraction of the carcinogenic PAHs in the study area. High correlation coefficient (R2 > 0.75 for most PAHs) between the measured and predicted concentrations of PAHs suggests for the applicability of the PCA/APCS receptor modeling approach for estimation of source contribution to the PAHs in particulates.

Multi-Sensor Constrained Time Varying Emissions Estimation of Black Carbon: Attributing Urban and Fire Sources Globally

Science.gov (United States)

Cohen, J. B.

2015-12-01

The short lifetime and heterogeneous distribution of Black Carbon (BC) in the atmosphere leads to complex impacts on radiative forcing, climate, and health, and complicates analysis of its atmospheric processing and emissions. Two recent papers have estimated the global and regional emissions of BC using advanced statistical and computational methods. One used a Kalman Filter, including data from AERONET, NOAA, and other ground-based sources, to estimate global emissions of 17.8+/-5.6 Tg BC/year (with the increase attributable to East Asia, South Asia, Southeast Asia, and Eastern Europe - all regions which have had rapid urban, industrial, and economic expansion). The second additionally used remotely sensed measurements from MISR and a variance maximizing technique, uniquely quantifying fire and urban sources in Southeast Asia, as well as their large year-to-year variability over the past 12 years, leading to increases from 10% to 150%. These new emissions products, when run through our state-of-the art modelling system of chemistry, physics, transport, removal, radiation, and climate, match 140 ground stations and satellites better in both an absolute and a temporal sense. New work now further includes trace species measurements from OMI, which are used with the variance maximizing technique to constrain the types of emissions sources. Furthermore, land-use change and fire estimation products from MODIS are also included, which provide other constraints on the temporal and spatial nature of the variations of intermittent sources like fires or new permanent sources like expanded urbanization. This talk will introduce a new, top-down constrained, weekly varying BC emissions dataset, show that it produces a better fit with observations, and draw conclusions about the sources and impacts from urbanization one hand, and fires on another hand. Results specific to the Southeast and East Asia will demonstrate inter- and intra-annual variations, such as the function of

Multiple approaches to microbial source tracking in tropical northern Australia

KAUST Repository

Neave, Matthew

2014-09-16

Microbial source tracking is an area of research in which multiple approaches are used to identify the sources of elevated bacterial concentrations in recreational lakes and beaches. At our study location in Darwin, northern Australia, water quality in the harbor is generally good, however dry-season beach closures due to elevated Escherichia coli and enterococci counts are a cause for concern. The sources of these high bacteria counts are currently unknown. To address this, we sampled sewage outfalls, other potential inputs, such as urban rivers and drains, and surrounding beaches, and used genetic fingerprints from E. coli and enterococci communities, fecal markers and 454 pyrosequencing to track contamination sources. A sewage effluent outfall (Larrakeyah discharge) was a source of bacteria, including fecal bacteria that impacted nearby beaches. Two other treated effluent discharges did not appear to influence sites other than those directly adjacent. Several beaches contained fecal indicator bacteria that likely originated from urban rivers and creeks within the catchment. Generally, connectivity between the sites was observed within distinct geographical locations and it appeared that most of the bacterial contamination on Darwin beaches was confined to local sources.

Experiences with on-site power sources at KCB

Energy Technology Data Exchange (ETDEWEB)

Heijnen, B. M.A. [Borssele Nuclear Power Station, N.V. P.Z.E.M., Postbus 48, 4330 AA Middleburg (Netherlands)

1986-02-15

The design of the nuclear power station is of the late sixties. The experiences with the on-site power sources, signal processing and some of the resulting modifications of the design of the power plant are mentioned. In order to let the design satisfy as much as possible present ideas about safety, it was decided to realize a total new and Independent decay heat removal System. With this system a second independent on-site power System is at disposal in case of accident situations. (author)

Source contributions to PM2.5 and PM10 at an urban background and a street location

NARCIS (Netherlands)

Keuken, M. P.; Moerman, M.; Voogt, M.; Blom, M.; Weijers, E. P.; Rockmann, T.; Dusek, U.

The contribution of regional, urban and traffic sources to PM2.5 and PM10 in an urban area was investigated in this study. The chemical composition of PM2.5 and PM10 was measured over a year at a street location and up- and down-wind of the city of Rotterdam, the Netherlands. The C-14 content in EC

Source contributions to PM2.5 and PM10 at an urban background and a street location

NARCIS (Netherlands)

Keuken, M.P.; Moerman, M.M.; Voogt, M.H.

2013-01-01

The contribution of regional, urban and traffic sources to PM2.5 and PM10 in an urban area was investigated in this study. The chemical composition of PM2.5 and PM10 was measured over a year at a street location and up- and down-wind of the city of Rotterdam, the Netherlands. The 14C content in EC

Use of Proton-Transfer-Reaction Mass Spectrometry to Characterize Volatile Organic Compound Sources at the La Porte Super Site During the Texas Air Quality Study 2000

Energy Technology Data Exchange (ETDEWEB)

Karl, Thomas G.; Jobson, B Tom T.; Kuster, W. C.; Williams, Eric; Stutz, Jochen P.; Shetter, Rick; Hall, Samual R.; Goldan, P. D.; Fehsenfeld, Fred C.; Lindinger, Werner

2003-08-19

Proton-transfer-reaction mass spectrometry (PTR-MS) was deployed for continuous real-time monitoring of volatile organic compounds (VOCs) at a site near the Houston Ship Channel during the Texas Air Quality Study 2000. Overall, 28 ions dominated the PTR-MS mass spectra and were assigned as anthropogenic aromatics (e.g., benzene, toluene, xylenes) and hydrocarbons (propene, isoprene), oxygenated compounds (e.g., formaldehyde, acetaldehyde, acetone, methanol, C7 carbonyls), and three nitrogencontaining compounds (e.g., HCN, acetonitrile and acrylonitrile). Biogenic VOCs were minor components at this site. Propene was the most abundant lightweight hydrocarbon detected by this technique with concentrations up to 100+ nmol mol-1, and was highly correlated with its oxidation products, formaldehyde (up to ~40 nmol mol-1) and acetaldehyde (up to ~80 nmol/mol), with typical ratios close to 1 in propene-dominated plumes. In the case of aromatic species the high time resolution of the obtained data set helped in identifying different anthropogenic sources (e.g., industrial from urban emissions) and testing current emission inventories. A comparison with results from complimentary techniques (gas chromatography, differential optical absorption spectroscopy) was used to assess the selectivity of this on-line technique in a complex urban and industrial VOC matrix and give an interpretation of mass scans obtained by ‘‘soft’’ chemical ionization using proton-transfer via H3O+. The method was especially valuable in monitoring rapidly changing VOC plumes which passed over the site, and when coupled with meteorological data it was possible to identify likely sources.

Development of a concept for non-monetary assessment of urban ecosystem services at the site level.

Science.gov (United States)

Wurster, Daniel; Artmann, Martina

2014-05-01

Determining the performance of ecosystem services at the city or regional level cannot accurately take into account the fine differences between green or gray structures. The supply of regulating ecosystem services in, for instance, parks can differ as parks vary in their land cover composition. A comprehensive ecosystem service assessment approach also needs to reflect land use to consider the demands placed on ecosystem services, which are mostly neglected by current research yet important for urban planning. For instance, if a sealed surface is no longer used, it could be unsealed to improve ecosystem service supply. Because of these scientific shortcomings, this article argues for a conceptual framework for the non-monetary assessment of urban ecosystem services at the site scale. This paper introduces a standardized method for selecting representative sites and evaluating their supply of and demand on ecosystem services. The conceptual design is supplemented by examples of Salzburg, Austria.

Bacteriological assessment of urban water sources in Khamis Mushait Governorate, southwestern Saudi Arabia

Directory of Open Access Journals (Sweden)

Sh AlOtaibi Eed L

2009-03-01

Full Text Available Abstract Background Urban water sources of Khamis Mushait Governorate, southwestern Saudi Arabia, were studied to assess their bacteriological characteristics and suitability for potable purposes. A cross-sectional epidemiological method was adopted to investigate the four main urban water sources (i.e. bottled, desalinated, surface, and well water. These were sampled and examined between February and June 2007. Results A total of 95 water samples from bottled, desalinated, surface, and well water were collected randomly from the study area using different gathering and analysing techniques. The bacteriological examination of water samples included the most probable number of presumptive coliforms, faecal coliforms, and faecal streptococci (MPN/100 ml. The results showed that the total coliform count (MPN/100 ml was not detected in any samples taken from bottled water, while it was detected in those taken from desalinated, surface, and well water: percentages were 12.9, 80.0, and 100.0, respectively. Faecal coliforms were detected in desalinated, surface, and well water, with percentages of 3.23, 60.0 and 87.88, respectively. About 6.45% of desalinated water, 53.33% of surface water, and 57.58% of well water was found positive for faecal streptococci. Colonies of coliforms were identified in different micro-organisms with various percentages. Conclusion Water derived from traditional sources (wells showed increases in most of the investigated bacteriological parameters, followed by surface water as compared to bottled or desalinated water. This may be attributed to the fact that well and surface water are at risk of contamination as indicated by the higher levels of most bacteriological parameters. Moreover, well water is exposed to point sources of pollution such as septic wells and domestic and farming effluents, as well as to soil with a high humus content. The lower bacteriological characteristics in samples from bottled water indicate that

Tracking Reactive Nitrogen Sources, Chemistry and Deposition in Urban Environments Using Stable Isotopes

Science.gov (United States)

Hastings, M. G.; Clark, S. C.; Chai, J.; Joyce, E.; Miller, D. J.; Schiebel, H.; Walters, W.

2017-12-01

Reactive nitrogen (Nr) includes compounds such as nitrogen oxides (NOx, HONO), ammonia (NH3), nitrate (NO3-), ammonium (NH4+), and organic nitrates. These compounds serve major roles in controlling the composition of our atmosphere, and have a direct impact on ecosystem health and water quality. Our research is focused on using stable isotopes of Nr to investigate variations in sources, chemistry, atmospheric transport, and deposition. Our aim is to fingerprint distinct emission sources - such as vehicles, power plants, aircraft, agriculature, wildfires, and lightning - and track their influence in the environment. We have recently characterized vehicle emission plumes, emissions from agricultural soils under different management practices, and (in the near future) wildfire plumes in the western U.S. Our approach targets characterizing the isotopic composition of NOx, HONO, and NH3 at both the emissions source and the plume scale. In contrast to large ranges found for individual tailpipe emissions of NOx, on-road plumes in the U.S. have a mean δ15N of -4.7 ± 1.7‰. The plume scale approach integrates across the typical U.S. fleet giving a representative value that can be used for tracking the impact of this emission source in the environment. NH3 also tends towards a narrow isotopic range when considered at the roadside scale compared to individual vehicles. In agricultural settings, the isotopes of NOx and HONO released from soils under different fertilizer practices is typically very negative in δ15N (-40 to -10‰) and appears to vary most with soil N properties rather than meteorology. Our work is now extending to discern sources influencing Nr deposition in an urban area at the head of New England's largest estuary. National monitoring of N deposition shows decreases in NO3- (but not NH4+) deposition over the last two decades, following better controls on NOx emissions. Wet deposition collected in an urban area exhibits N concentrations that are often 3

Source apportionment of fine organic aerosol in Mexico City during the MILAGRO experiment 2006

Directory of Open Access Journals (Sweden)

E. A. Stone

2008-03-01

Full Text Available Organic carbon (OC comprises a large fraction of fine particulate matter (PM_2.5 in Mexico City. Daily and select 12-h PM_2.5 samples were collected in urban and peripheral sites in Mexico City from 17–30 March 2006. Samples were analyzed for OC and elemental carbon (EC using thermal-optical filter-based methods. Real-time water-soluble organic carbon (WSOC was collected at the peripheral site. Organic compounds, particularly molecular markers, were quantified by soxhlet extraction with methanol and dichloromethane, derivitization, and gas chromatography with mass spectrometric detection (GCMS. A chemical mass balance model (CMB based on molecular marker species was used to determine the relative contribution of major sources to ambient OC. Motor vehicles, including diesel and gasoline, consistently accounted for 49% of OC in the urban area and 32% on the periphery. The daily contribution of biomass burning to OC was highly variable, and ranged from 5–26% at the urban site and 7–39% at the peripheral site. The remaining OC unapportioned to primary sources showed a strong correlation with WSOC and was considered to be secondary in nature. Comparison of temporally resolved OC showed that contributions from primary aerosol sources during daylight hours were not significantly different from nighttime. This study provides quantitative understanding of the important sources of OC during the MILAGRO 2006 field campaign.

Quantification of human-associated fecal indicators reveal sewage from urban watersheds as a source of pollution to Lake Michigan

Science.gov (United States)

Olds, Hayley T.; Dila, Deborah K.; Bootsma, Melinda J.; Corsi, Steven; McLellan, Sandra L.

2016-01-01

Sewage contamination of urban waterways from sewer overflows and failing infrastructure is a major environmental and public health concern. Fecal coliforms (FC) are commonly employed as fecal indicator bacteria, but do not distinguish between human and non-human sources of fecal contamination. Human Bacteroides and humanLachnospiraceae, two genetic markers for human-associated indicator bacteria, were used to identify sewage signals in two urban rivers and the estuary that drains to Lake Michigan. Grab samples were collected from the rivers throughout 2012 and 2013 and hourly samples were collected in the estuary across the hydrograph during summer 2013. Human Bacteroides and human Lachnospiraceae were highly correlated with each other in river samples (Pearson’s r = 0.86), with average concentrations at most sites elevated during wet weather. These human indicators were found during baseflow, indicating that sewage contamination is chronic in these waterways. FC are used for determining total maximum daily loads (TMDLs) in management plans; however, FC concentrations alone failed to prioritize river reaches with potential health risks. While 84% of samples with >1000 CFU/100 ml FC had sewage contamination, 52% of samples with moderate (200–1000 CFU/100 ml) and 46% of samples with low (events and was highest during an event with a short duration of intense rain. This work demonstrates urban areas have unrecognized sewage inputs that may not be adequately prioritized for remediation by the TMDL process. Further analysis using these approaches could determine relationships between land use, storm characteristics, and other factors that drive sewage contamination in urban waterways.

Concentrations and characteristics of organic carbon in surface water in Arizona: Influence of urbanization

Science.gov (United States)

Westerhoff, P.; Anning, D.

2000-01-01

Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (p TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (p<0.05). Reservoir outflows and wastewater-treatment plant effluent were higher in DOC concentration (p<0.05) and exhibited less variability in concentration than inflows to the reservoirs. Specific ultraviolet absorbance values at 254 nm were typically less than 2 m-1(milligram DOC per liter)-1 and lower than values found in most temperate-region rivers, but specific ultraviolet absorbance values increased during runoff events. Fluorescence measurements indicated that DOC in desert streams typically exhibit characteristics of autochthonous sources; however, DOC in unregulated upland rivers and desert streams experienced sudden shifts from autochthonous to allochthonous sources during runoff events. The urban water system (reservoir systems and wastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition.The influence of urbanization, becoming increasingly common in arid regions, on dissolved organic carbon (DOC) concentrations in surface water

CADDIS Volume 2. Sources, Stressors and Responses: Urbanization - Hydrology

Science.gov (United States)

hydrologic (or flow) changes associated with urbanization, baseflow changes associated with urbanization, water withdrawals and interbasin transfers associated with urbanization, biotic responses to hydrologic (or flow) changes associated with urbanization

Use of CFD modeling for estimating spatial representativeness of urban air pollution monitoring sites and suitability of their locations

International Nuclear Information System (INIS)

Santiago, J. L.; Martin, F.

2015-01-01

A methodology to estimate the spatial representativeness of air pollution monitoring sites is applied to two urban districts. This methodology is based on high resolution maps of air pollution computed by using Computational Fluid Dynamics (CFD) modelling tools. Traffic-emitted NO 2 dispersion is simulated for several meteorological conditions taking into account the effect of the buildings on air flow and pollutant dispersion and using a steady state CFD-RANS approach. From these results, maps of average pollutant concentrations for January -May 2011 are computed as a combination of the simulated scenarios. Two urban districts of Madrid City were simulated. Spatial representativeness areas for 32 different sites within the same district (including the site of the operative air quality stations) have been estimated by computing the portion of the domains with average NO 2 concentration differing less than a 20% of the concentration at each candidate monitoring site. New parameters such as the ratio AR between the representativeness area and the whole domain area or the representativeness index (IR) has been proposed to discuss and compare the representativeness areas. Significant differences between the spatial representativeness of the candidate sites of both studied districts have been found. The sites of the Escuelas Aguirre district have generally smaller representativeness areas than those of the Plaza de Castilla. More stations are needed to cover the Escuelas Aguirre district than for the Plaza de Castilla one. The operative air quality station of the Escuelas Aguirre district is less representative than the station of the Plaza de Castilla district. The cause of these differences seems to be the differences in urban structure of both districts prompting different ventilation. (Author)

Use of CFD modeling for estimating spatial representativeness of urban air pollution monitoring sites and suitability of their locations

Energy Technology Data Exchange (ETDEWEB)

Santiago, J. L.; Martin, F.

2015-07-01

A methodology to estimate the spatial representativeness of air pollution monitoring sites is applied to two urban districts. This methodology is based on high resolution maps of air pollution computed by using Computational Fluid Dynamics (CFD) modelling tools. Traffic-emitted NO{sub 2} dispersion is simulated for several meteorological conditions taking into account the effect of the buildings on air flow and pollutant dispersion and using a steady state CFD-RANS approach. From these results, maps of average pollutant concentrations for January -May 2011 are computed as a combination of the simulated scenarios. Two urban districts of Madrid City were simulated. Spatial representativeness areas for 32 different sites within the same district (including the site of the operative air quality stations) have been estimated by computing the portion of the domains with average NO{sub 2} concentration differing less than a 20% of the concentration at each candidate monitoring site. New parameters such as the ratio AR between the representativeness area and the whole domain area or the representativeness index (IR) has been proposed to discuss and compare the representativeness areas. Significant differences between the spatial representativeness of the candidate sites of both studied districts have been found. The sites of the Escuelas Aguirre district have generally smaller representativeness areas than those of the Plaza de Castilla. More stations are needed to cover the Escuelas Aguirre district than for the Plaza de Castilla one. The operative air quality station of the Escuelas Aguirre district is less representative than the station of the Plaza de Castilla district. The cause of these differences seems to be the differences in urban structure of both districts prompting different ventilation. (Author)

Use of CFD modeling for estimating spatial representativeness of urban air pollution monitoring sites and suitability of their locations

Energy Technology Data Exchange (ETDEWEB)

Santiago, J.L.; Martin, F.

2015-07-01

A methodology to estimate the spatial representativeness of air pollution monitoring sites is applied to two urban districts. This methodology is based on high resolution maps of air pollution computed by using Computational Fluid Dynamics (CFD) modelling tools. Traffic-emitted NO2 dispersion is simulated for several meteorological conditions taking into account the effect of the buildings on air flow and pollutant dispersion and using a steady state CFD-RANS approach. From these results, maps of average pollutant concentrations for January–May 2011 are computed as a combination of the simulated scenarios. Two urban districts of Madrid City were simulated. Spatial representativeness areas for 32 different sites within the same district (including the site of the operative air quality stations) have been estimated by computing the portion of the domains with average NO2 concentration differing less than a 20% of the concentration at each candidate monitoring site. New parameters such as the ratio AR between the representativeness area and the whole domain area or the representativeness index (IR) has been proposed to discuss and compare the representativeness areas. Significant differences between the spatial representativeness of the candidate sites of both studied districts have been found. The sites of the Escuelas Aguirre district have generally smaller representativeness areas than those of the Plaza de Castilla. More stations are needed to cover the Escuelas Aguirre district than for the Plaza de Castilla one. The operative air quality station of the Escuelas Aguirre district is less representative than the station of the Plaza de Castilla district. The cause of these differences seems to be the differences in urban structure of both districts prompting different ventilation. (Author)

Establishing a link between vehicular PM sources and PM measurements in urban street canyons.

Science.gov (United States)

Eisner, Alfred D; Richmond-Bryant, Jennifer; Wiener, Russell W; Hahn, Intaek; Drake-Richman, Zora E; Ellenson, William D

2009-12-01

The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study, conducted in Brooklyn, NY, USA, in 2005, was designed with multiple goals in mind, two of which were contaminant source characterization and street canyon transport and dispersion monitoring. In the portion of the study described here, synchronized wind velocity and azimuth as well as particulate matter (PM) concentrations at multiple locations along 33rd Street were used to determine the feasibility of using traffic emissions in a complex urban topography as a sole tracer for studying urban contaminant transport. We demonstrate in this paper that it is possible to link downwind concentrations of contaminants in an urban street canyon to the vehicular traffic cycle using Eigen-frequency analysis. In addition, multivariable circular histograms are used to establish directional frequency maxima for wind velocity and contaminant concentration.

Lead concentration distribution and source tracing of urban/suburban aquatic sediments in two typical famous tourist cities: Haikou and Sanya, China.

Science.gov (United States)

Dong, Zhicheng; Bao, Zhengyu; Wu, Guoai; Fu, Yangrong; Yang, Yi

2010-11-01

The content and spatial distribution of lead in the aquatic systems in two Chinese tropical cities in Hainan province (Haikou and Sanyan) show an unequal distribution of lead between the urban and the suburban areas. The lead content is significantly higher (72.3 mg/kg) in the urban area than the suburbs (15.0 mg/kg) in Haikou, but quite equal in Sanya (41.6 and 43.9 mg/kg). The frequency distribution histograms suggest that the lead in Haikou and in Sanya derives from different natural and/or anthropogenic sources. The isotopic compositions indicate that urban sediment lead in Haikou originates mainly from anthropogenic sources (automobile exhaust, atmospheric deposition, etc.) which contribute much more than the natural sources, while natural lead (basalt and sea sands) is still dominant in the suburban areas in Haikou. In Sanya, the primary source is natural (soils and sea sands).

Source contributions to PM2.5 and PM10 at an urban background and a street location

Science.gov (United States)

Keuken, M. P.; Moerman, M.; Voogt, M.; Blom, M.; Weijers, E. P.; Röckmann, T.; Dusek, U.

2013-06-01

The contribution of regional, urban and traffic sources to PM2.5 and PM10 in an urban area was investigated in this study. The chemical composition of PM2.5 and PM10 was measured over a year at a street location and up- and down-wind of the city of Rotterdam, the Netherlands. The 14C content in EC and OC concentrations was also determined, to distinguish the contribution from "modern" carbon (e.g., biogenic emissions, biomass burning and wildfires) and fossil fuel combustion. It was concluded that the urban background of PM2.5 and PM10 is dominated by the regional background, and that primary and secondary PM emission by urban sources contribute less than 15%. The 14C analysis revealed that 70% of OC originates from modern carbon and 30% from fossil fuel combustion. The corresponding percentages for EC are, respectively 17% and 83%. It is concluded that in particular the urban population living in street canyons with intense road traffic has potential health risks. This is due to exposure to elevated concentrations of a factor two for EC from exhaust emissions in PM2.5 and a factor 2-3 for heavy metals from brake and tyre wear, and re-suspended road dust in PM10. It follows that local air quality management may focus on local measures to street canyons with intense road traffic.

Cryptosporidium Source Tracking in the Potomac River Watershed▿

Science.gov (United States)

Yang, Wenli; Chen, Plato; Villegas, Eric N.; Landy, Ronald B.; Kanetsky, Charles; Cama, Vitaliano; Dearen, Theresa; Schultz, Cherie L.; Orndorff, Kenneth G.; Prelewicz, Gregory J.; Brown, Miranda H.; Young, Kim Roy; Xiao, Lihua

2008-01-01

To better characterize Cryptosporidium in the Potomac River watershed, a PCR-based genotyping tool was used to analyze 64 base flow and 28 storm flow samples from five sites in the watershed. These sites included two water treatment plant intakes, as well as three upstream sites, each associated with a different type of land use. The uses, including urban wastewater, agricultural (cattle) wastewater, and wildlife, posed different risks in terms of the potential contribution of Cryptosporidium oocysts to the source water. Cryptosporidium was detected in 27 base flow water samples and 23 storm flow water samples. The most frequently detected species was C. andersoni (detected in 41 samples), while 14 other species or genotypes, almost all wildlife associated, were occasionally detected. The two common human-pathogenic species, C. hominis and C. parvum, were not detected. Although C. andersoni was common at all four sites influenced by agriculture, it was largely absent at the urban wastewater site. There were very few positive samples as determined by Environmental Protection Agency method 1623 at any site; only 8 of 90 samples analyzed (9%) were positive for Cryptosporidium as determined by microscopy. The genotyping results suggest that many of the Cryptosporidium oocysts in the water treatment plant source waters were from old calves and adult cattle and might not pose a significant risk to human health. PMID:18776033

Biomonitoring of PAHs by using Quercus ilex leaves: Source diagnostic and toxicity assessment

Science.gov (United States)

De Nicola, Flavia; Claudia, Lancellotti; MariaVittoria, Prati; Giulia, Maisto; Anna, Alfani

2011-03-01

Quercus ilex L. leaves were sampled at nineteen urban sites and two remote sites in order to evaluate PAH contamination degree. One-, two- and three-year-old leaves were collected and leaf lipid content was measured to investigate the influence of leaf age and lipids in PAH accumulation. Some PAH diagnostic ratios, such as Ant/Ant + Phen, Flt/Flt + Pyr, B[a]A/B[a]A + Crys and IP/IP + B[g,h,i]P, were calculated. The results suggest that Q. ilex leaves are effective biomonitors of PAH air contamination: in fact, a great PAH accumulation in leaves from the urban areas, until 30-time higher compared to those from the remote sites, has been observed. At each site, the similar total PAH concentrations in leaves of different age, probably due to a canopy effect, indicate an ability of all leaf age classes to monitor local PAH concentrations in air, remarking practical implications for air biomonitoring. The findings suggest that PAH adsorption in Q. ilex leaves does not result limited by leaf lipid content. Moreover, this study demonstrates the source-diagnostic potential of Q. ilex leaves, because, in particular, the Flt/Flt + Pyr and IP/IP + B[g,h,i]P ratios indicate vehicular traffic as the main source of PAHs in the urban areas and wood combustion in the remote areas. Moreover, to distinguish biomass combustion source, a promising tracer PAH as DB[a,h]A could be used. The high contribution of DB[a,h]A to total PAH concentrations at the remote sites determines a high carcinogenic potential in this area, similar to that calculated for the urban area where the carcinogenic PAH concentrations in absolute values are often higher.

Estimation of PAHs dry deposition and BaP toxic equivalency factors (TEFs) study at Urban, Industry Park and rural sampling sites in central Taiwan, Taichung.

Science.gov (United States)

Fang, Guor-Cheng; Chang, Kuan-Foo; Lu, Chungsying; Bai, Hsunling

2004-05-01

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in gas phase and particle bound were measured simultaneously at industrial (INDUSTRY), urban (URBAN), and rural areas (RURAL) in Taichung, Taiwan. And the PAH concentrations, size distributions, estimated PAHs dry deposition fluxes and health risk study of PAHs in the ambient air of central Taiwan were discussed in this study. Total PAH concentrations at INDUSTRY, URBAN, and RURAL sampling sites were found to be 1650 +/- 1240, 1220 +/- 520, and 831 +/- 427 ng/m3, respectively. The results indicated that PAH concentrations were higher at INDUSTRY and URBAN sampling sites than the RURAL sampling sites because of the more industrial processes, traffic exhausts and human activities. The estimation dry deposition and size distribution of PAHs were also studied. The results indicated that the estimated dry deposition fluxes of total PAHs were 58.5, 48.8, and 38.6 microg/m2/day at INDUSTRY, URBAN, and RURAL, respectively. The BaP equivalency results indicated that the health risk of gas phase PAHs were higher than the particle phase at three sampling sites of central Taiwan. However, compared with the BaP equivalency results to other studies conducted in factory, this study indicated the health risk of PAHs was acceptable in the ambient air of central Taiwan.

Importance of data comparability for multi-year trends and source apportionment of NMHC concentrations observed in France

Science.gov (United States)

Sauvage, Stéphane; Waked, Antoine; Leonardis, Thierry; Locoge, Nadine

2017-04-01

Non Methane Hydrocarbon Compounds (NMHCs) are of interest due to their potential health impact and their key role in atmospheric processes as precursors of secondary pollutants such as ozone (O3) and secondary organic aerosols (SOA). Hourly measurements of 31 non-methane hydrocarbons (NMHCs) were carried out at three urban sites in France over the period of a decade. The trends analysis showed a significant yearly decrease in pollutant concentrations over the study period and for the majority of species in the range of -1 to -7% in accordance with the decrease of NMHC emissions in France (-5 to -9%). Concentrations of long-lived species such as ethane and propane which are known as tracers of distant sources and natural gas remained constant. These trends are consistent with those recently described at urban and background sites in the northern mid-latitudes and with emission inventories. They are compared with the ones reported for 3 French rural sites (EMEP). A year per year source apportionment study using PMF was also conducted for 2 of the urban sites over the period 2005-2013. Using source fingerprints, five common anthropogenic sources were identified for Paris and Strasbourg: traffic-exhaust emissions (21±5%, 18±5%), evaporative sources (17±4%, 24±7%), natural gas & background (22±5%, 25±5%), residential heating (17±4%, 17±5%) and solvent use (19±7%, 12±5%). Biogenic sources were also identified and accounted for 4±1% of the total measured NMHC's at both sites. Along the presentation, the robustness of these results will be discussed regarding the site representativeness, the data comparability, and the temporal variation of the data quality

Urban Noise Modelling in Boka Kotorska Bay

Directory of Open Access Journals (Sweden)

Aleksandar Nikolić

2014-04-01

Full Text Available Traffic is the most significant noise source in urban areas. The village of Kamenari in Boka Kotorska Bay is a site where, in a relatively small area, road traffic and sea (ferry traffic take place at the same time. Due to the specificity of the location, i.e. very rare synergy of sound effects of road and sea traffic in the urban area, as well as the expressed need for assessment of noise level in a simple and quick way, a research was conducted, using empirical methods and statistical analysis methods, which led to the creation of acoustic model for the assessment of equivalent noise level (Leq. The developed model for noise assessment in the Village of Kamenari in Boka Kotorska Bay quite realistically provides data on possible noise levels at the observed site, with very little deviations in relation to empirically obtained values.

Vertical and horizontal variability of PM10 source contributions in Barcelona during SAPUSS

Directory of Open Access Journals (Sweden)

M. Brines

2016-06-01

Full Text Available During the SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies PM10 samples at 12-hour resolution were simultaneously collected at four monitoring sites located in the urban agglomerate of Barcelona (Spain. A total of 221 samples were collected from 20 September to 20 October 2010. The Road Site (RS site and the Urban Background (UB site were located at street level, whereas the Torre Mapfre (TM and the Torre Collserola (TC sites were located at 150 m a.s.l. by the sea side within the urban area and at 415 m a.s.l. 8 km inland, respectively. For the first time, we are able to report simultaneous PM10 aerosol measurements, allowing us to study aerosol gradients at both horizontal and vertical levels. The complete chemical composition of PM10 was determined on the 221 samples, and factor analysis (positive matrix factorisation, PMF was applied. This resulted in eight factors which were attributed to eight main aerosol sources affecting PM10 concentrations in the studied urban environment: (1 vehicle exhaust and wear (2–9 µg m−3, 10–27 % of PM10 mass on average, (2 road dust (2–4 µg m−3, 8–12 %, (3 mineral dust (5 µg m−3, 13–26 %, (4 aged marine (3–5 µg m−3, 13–20 %, (5 heavy oil (0.4–0.6 µg m−3, 2 %, (6 industrial (1 µg m−3, 3–5 %, (7 sulfate (3–4 µg m−3, 11–17 % and (8 nitrate (4–6 µg m−3, 17–21 %. Three aerosol sources were found to be enhanced at the ground levels (confined within the urban ground levels of the city relative to the upper levels: (1 vehicle exhaust and wear (2.8 higher, (2 road dust (1.8 higher and (3 local urban industries/crafts workshops (1.6 higher. Surprisingly, the other aerosol sources were relatively homogeneous at both horizontal and vertical levels. However, air mass origin and meteorological parameters also played a key role in influencing the variability of the factor

Scheduling the Remediation of Port Hope: Logistical and Regulatory Challenges of a Multiple Site Urban Remediation Project - 13119

International Nuclear Information System (INIS)

Ferguson Jones, Andrea; Lee, Angela; Palmeter, Tim

2013-01-01

The Port Hope Project is part of the larger CAN$1.28 billion Port Hope Area Initiative (PHAI), a community-based program for the development and implementation of a safe, local, long-term management solution for historic Low-Level Radioactive Waste (LLRW) in the Municipalities of Port Hope and Clarington, Ontario, Canada. Atomic Energy of Canada (AECL) is the Project Proponent, Public Works and Government Services (PWGSC) is managing the procurement of services and the MMM Group Limited - Conestoga Rovers and Associates Joint Venture (MMM-CRA Joint Venture) is providing detailed design and construction oversight and administration services for the Project. The Port Hope Project includes the construction of a long-term waste management facility (LTWMF) in the Municipality of Port Hope and the remediation of 18 (eighteen) large-scale LLRW, numerous small-scale sites still being identified and industrial sites within the Municipality. The total volume to be remediated is over one million cubic metres and will come from sites that include temporary storage sites, ravines, beaches, parks, private commercial and residential properties and vacant industrial sites all within the urban area of Port Hope. Challenges that will need to be overcome during this 10 year project include: - Requirements stipulated by the Environmental Assessment (EA) that affect Project logistics and schedule. - Coordination of site remediation with the construction schedule at the LTWMF. - Physical constraints on transport routes and at sites affecting production rates. - Despite being an urban undertaking, seasonal constrains for birds and fish (i.e., nesting and spawning seasons). - Municipal considerations. - Site-specific constraints. - Site interdependencies exist requiring consideration in the schedule. Several sites require the use of an adjacent site for staging. (authors)

Scheduling the Remediation of Port Hope: Logistical and Regulatory Challenges of a Multiple Site Urban Remediation Project - 13119

Energy Technology Data Exchange (ETDEWEB)

Ferguson Jones, Andrea; Lee, Angela [MMM Group Limited, 100 Commerce Valley Drive West, Thornhill, Ontario, L3T 0A1 (Canada); Palmeter, Tim [Public Works and Government Services Canada, 4900 Yonge Street, Toronto, Ontario, M2N 6A6 (Canada)

2013-07-01

The Port Hope Project is part of the larger CAN$1.28 billion Port Hope Area Initiative (PHAI), a community-based program for the development and implementation of a safe, local, long-term management solution for historic Low-Level Radioactive Waste (LLRW) in the Municipalities of Port Hope and Clarington, Ontario, Canada. Atomic Energy of Canada (AECL) is the Project Proponent, Public Works and Government Services (PWGSC) is managing the procurement of services and the MMM Group Limited - Conestoga Rovers and Associates Joint Venture (MMM-CRA Joint Venture) is providing detailed design and construction oversight and administration services for the Project. The Port Hope Project includes the construction of a long-term waste management facility (LTWMF) in the Municipality of Port Hope and the remediation of 18 (eighteen) large-scale LLRW, numerous small-scale sites still being identified and industrial sites within the Municipality. The total volume to be remediated is over one million cubic metres and will come from sites that include temporary storage sites, ravines, beaches, parks, private commercial and residential properties and vacant industrial sites all within the urban area of Port Hope. Challenges that will need to be overcome during this 10 year project include: - Requirements stipulated by the Environmental Assessment (EA) that affect Project logistics and schedule. - Coordination of site remediation with the construction schedule at the LTWMF. - Physical constraints on transport routes and at sites affecting production rates. - Despite being an urban undertaking, seasonal constrains for birds and fish (i.e., nesting and spawning seasons). - Municipal considerations. - Site-specific constraints. - Site interdependencies exist requiring consideration in the schedule. Several sites require the use of an adjacent site for staging. (authors)

Source identification of heavy metals in peri-urban agricultural soils of southeast China: An integrated approach.

Science.gov (United States)

Hu, Wenyou; Wang, Huifeng; Dong, Lurui; Huang, Biao; Borggaard, Ole K; Bruun Hansen, Hans Christian; He, Yue; Holm, Peter E

2018-06-01

Intensive human activities, in particular agricultural and industrial production have led to heavy metal accumulation in the peri-urban agricultural soils of China threatening soil environmental quality and agricultural product security. A combination of spatial analysis (SA), Pb isotope ratio analysis (IRA), input fluxes analysis (IFA), and positive matrix factorization (PMF) model was successfully used to assess the status and sources of heavy metals in typical peri-urban agricultural soils from a rapidly developing region of China. Mean concentrations of Cd, As, Hg, Pb, Cu, Zn and Cr in surface soils (0-20 cm) were 0.31, 11.2, 0.08, 35.6, 44.8, 119.0 and 97.0 mg kg -1 , respectively, exceeding the local background levels except for Hg. Spatial distribution of heavy metals revealed that agricultural activities have significant influence on heavy metal accumulation in the surface soils. Isotope ratio analysis suggested that fertilization along with atmospheric deposition were the major sources of heavy metal accumulation in the soils. Based on the PMF model, the relative contribution rates of the heavy metals due to fertilizer application, atmospheric deposition, industrial emission, and soil parent materials were 30.8%, 33.0%, 25.4% and 10.8%, respectively, demonstrating that anthropogenic activities had significantly higher contribution than natural sources. This study provides a reliable and robust approach for heavy metals source apportionment in this particular peri-urban area with a clear potential for future application in other regions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparison of mosquito control programs in seven urban sites in Africa, the Middle East, and the Americas.

Science.gov (United States)

Impoinvil, Daniel E; Ahmad, Sajjad; Troyo, Adriana; Keating, Joseph; Githeko, Andrew K; Mbogo, Charles M; Kibe, Lydiah; Githure, John I; Gad, Adel M; Hassan, Ali N; Orshan, Laor; Warburg, Alon; Calderón-Arguedas, Olger; Sánchez-Loría, Victoria M; Velit-Suarez, Rosanna; Chadee, Dave D; Novak, Robert J; Beier, John C

2007-10-01

Mosquito control programs at seven urban sites in Kenya, Egypt, Israel, Costa Rica, and Trinidad are described and compared. Site-specific urban and disease characteristics, organizational diagrams, and strengths, weaknesses, obstacles and threats (SWOT) analysis tools are used to provide a descriptive assessment of each mosquito control program, and provide a comparison of the factors affecting mosquito abatement. The information for SWOT analysis is collected from surveys, focus-group discussions, and personal communication. SWOT analysis identified various issues affecting the efficiency and sustainability of mosquito control operations. The main outcome of our work was the description and comparison of mosquito control operations within the context of each study site's biological, social, political, management, and economic conditions. The issues identified in this study ranged from lack of inter-sector collaboration to operational issues of mosquito control efforts. A lack of sustainable funding for mosquito control was a common problem for most sites. Many unique problems were also identified, which included lack of mosquito surveillance, lack of law enforcement, and negative consequences of human behavior. Identifying common virtues and shortcomings of mosquito control operations is useful in identifying "best practices" for mosquito control operations, thus leading to better control of mosquito biting and mosquito-borne disease transmission.

Synthetic fibers in atmospheric fallout: A source of microplastics in the environment?

Science.gov (United States)

Dris, Rachid; Gasperi, Johnny; Saad, Mohamed; Mirande, Cécile; Tassin, Bruno

2016-03-15

Sources, pathways and reservoirs of microplastics, plastic particles smaller than 5mm, remain poorly documented in an urban context. While some studies pointed out wastewater treatment plants as a potential pathway of microplastics, none have focused on the atmospheric compartment. In this work, the atmospheric fallout of microplastics was investigated in two different urban and sub-urban sites. Microplastics were collected continuously with a stainless steel funnel. Samples were then filtered and observed with a stereomicroscope. Fibers accounted for almost all the microplastics collected. An atmospheric fallout between 2 and 355 particles/m(2)/day was highlighted. Registered fluxes were systematically higher at the urban than at the sub-urban site. Chemical characterization allowed to estimate at 29% the proportion of these fibers being all synthetic (made with petrochemicals), or a mixture of natural and synthetic material. Extrapolation using weight and volume estimates of the collected fibers, allowed a rough estimation showing that between 3 and 10 tons of fibers are deposited by atmospheric fallout at the scale of the Parisian agglomeration every year (2500 km(2)). These results could serve the scientific community working on the different sources of microplastic in both continental and marine environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of Pollution Patterns and Sources in a Semi-Arid Urban Stream

Directory of Open Access Journals (Sweden)

Vassiliki Markogianni

2018-03-01

Full Text Available The impact and occurrence of human-induced pollution sources have been investigated in one of the few remaining urban streams located in Attica, Greece. Baseline information is provided on the presence and concentration of physicochemical parameters, nutrients, total coliforms, hydrocarbons and phenols in 12 key points along the Pikrodafni stream. The aim was to evaluate the relative importance of key water quality variables and their sources. Indicator substances (i.e. concentrations of nitrate, ammonium, phosphate and total coliforms in certain stations indicating wastewater exposure; PAHs indicating petroleum sources successfully related the water quality variables to pollution sources. Furthermore, a pollution pressure map has been developed with the activities identified from in-situ visits and Google Earth surveys, while the statistical analysis (CA and PCA has contributed to the further exploration of the relative magnitude of pollution sources effects. Our results underline initially the importance of diffuse pollution management accompanied by the necessity for continuous environmental monitoring and the application of legal and environmental restoration actions if water quality is to be improved according to WFD 2000/60/EC.

Analysis of the sources and dynamic processes leading to the increase of atmospheric CO2, black carbon and other trace species during recent urban pollution events in the Paris megacity region : a synergy of resources provided by the IPSL OCAPI platform.

Science.gov (United States)

Xueref-Remy, I.; Foret, G.; Beekmann, M.; Brégonzio-Rozier, L.; Favez, O.; Gros, V.; Moreau-Guigon, E.; Vogel, F. R.; Belviso, S.; Ghersi, V.; Dupont, J. C.; Bodichon, R.; Cailteau-Fischbach, C.; Baisnee, D.; Peinado, F.; Haeffelin, M.; DeCola, P.; Turnbull, J. C.; Chelin, P.; Te, Y. V.; Formenti, P.; Doussin, J. F.; Gratien, A.; Desboeufs, K. V.; Ramage, K.; Jeseck, P.; Delmotte, M.; Ramonet, M.; Michoud, V.; Ravetta, F.

2016-12-01

Nowadays, more than 50% of the global population leave in urban centers which activities generate large anthropogenic emissions of CO2 (more than 70% of fossil fuel CO2 comes from urbanized/industrialized areas) and reactive gases that endanger our climate, the health of human beings and surrounding ecosystems. The worst situations are encountered during urban pollution events that usually form under anticyclonic conditions. Analyzing the contribution of the local and regional sources of urban CO2 and co-emitted species vs the remote ones, as well as the nature of these sources and the dynamical processes that lead to the building of such events can provide interesting knowledge for helping urban policy makers to better identify the role of anthropogenic/biogenic sources on the urban air composition and to take proper decisions in matter of CO2 and pollutants sources mitigation. With 12 million of people, Paris (France) is the second megacity in Europe. In 2016, two pollution events occured in the Paris region during which the instrumental platform OCAPI (http://observations.ipsl.fr/composition-atmospherique-en-idf.html) from IPSL (Institut Pierre Simon Laplace) was mobilized in collaboration with air quality governing actors (AIRPARIF, INERIS) to collect a bunch of observations. Five sites located in the urban, peri-urban and rural areas of Paris were equiped with in-situ analyzers (CO2, CO, black carbon, 13CO2, COS) ; Fourier transform spectrometers for column measurements (XCO2, XCO, XCOS), particle filters (for aerosols size and content analysis) ; air samples (levoglucosan, 14CO2, VOCs) ; and Lidar profilers (boundary layer height ; wind profiles). These data, combined with a backtrajectories analysis, give information about the dynamical processes that lead to the formation of the pollution events and on the contribution of local, regional and remote sources. The analysis of the correlations between the trace species and of the isotopic content of carbon in

Chemical control of vegetation on urban sites: agronomic and ecotoxicological aspects

International Nuclear Information System (INIS)

Zanin, G.; Otto, S.

1996-01-01

The problem of the chemical control of spontaneous vegetation on urban sites is tackled. A method is presented to identify the best herbicides under both the agronomic and ecotoxicological aspects. Selection of the herbicides from the agronomic point of view is on the basis of the qualitative characteristics of the vegetation (life-form types periodicity types botanical composition), surveyed at 5 different times on the year while selection from the environmental viewpoint is based on an evaluation integrated with a series of ecotoxicological indices. The best solution was tested in a pilot area and the contamination of the water compartment evaluated both on entering and leaving the water treatment works

Human-Scale Sustainability Assessment of Urban Intersections Based upon Multi-Source Big Data

Directory of Open Access Journals (Sweden)

Yuhuan Zhang

2017-07-01

Full Text Available To evaluate the sustainability of an enormous number of urban intersections, a novel assessment model is proposed, along with an indicator system and corresponding methods to determine the indicators. Considering mainly the demands and feelings of the urban residents, the three aspects of safety, functionality, and image perception are taken into account in the indicator system. Based on technologies such as street view picture crawling, image segmentation, and edge detection, GIS spatial data analysis, a rapid automated assessment method, and a corresponding multi-source database are built up to determine the indicators. The improved information entropy method is applied to obtain the entropy weights of each indicator. A case study shows the efficiency and applicability of the proposed assessment model, indicator system and algorithm.

Fossil and non-fossil sources of organic carbon (OC and elemental carbon (EC in Göteborg, Sweden

Directory of Open Access Journals (Sweden)

S. Szidat

2009-03-01

Full Text Available Particulate matter was collected at an urban site in Göteborg (Sweden in February/March 2005 and in June/July 2006. Additional samples were collected at a rural site for the winter period. Total carbon (TC concentrations were 2.1–3.6 μg m⁻³, 1.8–1.9 μg m⁻³, and 2.2–3.0 μg m⁻³ for urban/winter, rural/winter, and urban/summer conditions, respectively. Elemental carbon (EC, organic carbon (OC, water-insoluble OC (WINSOC, and water-soluble OC (WSOC were analyzed for ¹⁴C in order to distinguish fossil from non-fossil emissions. As wood burning is the single major source of non-fossil EC, its contribution can be quantified directly. For non-fossil OC, the wood-burning fraction was determined independently by levoglucosan and ¹⁴C analysis and combined using Latin-hypercube sampling (LHS. For the winter period, the relative contribution of EC from wood burning to the total EC was >3 times higher at the rural site compared to the urban site, whereas the absolute concentrations of EC from wood burning were elevated only moderately at the rural compared to the urban site. Thus, the urban site is substantially more influenced by fossil EC emissions. For summer, biogenic emissions dominated OC concentrations most likely due to secondary organic aerosol (SOA formation. During both seasons, a more pronounced fossil signal was observed for Göteborg than has previously been reported for Zurich, Switzerland. Analysis of air mass origin using back trajectories suggests that the fossil impact was larger when local sources dominated, whereas long-range transport caused an enhanced non-fossil signal. In comparison to other European locations, concentrations of levoglucosan and other monosaccharide anhydrides were low for the urban and the rural site in the area of Göteborg during winter.

Variational Iterative Refinement Source Term Estimation Algorithm Assessment for Rural and Urban Environments

Science.gov (United States)

Delle Monache, L.; Rodriguez, L. M.; Meech, S.; Hahn, D.; Betancourt, T.; Steinhoff, D.

2016-12-01

It is necessary to accurately estimate the initial source characteristics in the event of an accidental or intentional release of a Chemical, Biological, Radiological, or Nuclear (CBRN) agent into the atmosphere. The accurate estimation of the source characteristics are important because many times they are unknown and the Atmospheric Transport and Dispersion (AT&D) models rely heavily on these estimates to create hazard assessments. To correctly assess the source characteristics in an operational environment where time is critical, the National Center for Atmospheric Research (NCAR) has developed a Source Term Estimation (STE) method, known as the Variational Iterative Refinement STE algorithm (VIRSA). VIRSA consists of a combination of modeling systems. These systems include an AT&D model, its corresponding STE model, a Hybrid Lagrangian-Eulerian Plume Model (H-LEPM), and its mathematical adjoint model. In an operational scenario where we have information regarding the infrastructure of a city, the AT&D model used is the Urban Dispersion Model (UDM) and when using this model in VIRSA we refer to the system as uVIRSA. In all other scenarios where we do not have the city infrastructure information readily available, the AT&D model used is the Second-order Closure Integrated PUFF model (SCIPUFF) and the system is referred to as sVIRSA. VIRSA was originally developed using SCIPUFF 2.4 for the Defense Threat Reduction Agency and integrated into the Hazard Prediction and Assessment Capability and Joint Program for Information Systems Joint Effects Model. The results discussed here are the verification and validation of the upgraded system with SCIPUFF 3.0 and the newly implemented UDM capability. To verify uVIRSA and sVIRSA, synthetic concentration observation scenarios were created in urban and rural environments and the results of this verification are shown. Finally, we validate the STE performance of uVIRSA using scenarios from the Joint Urban 2003 (JU03

Potential for nutrient recovery and biogas production from blackwater, food waste and greywater in urban source control systems.

Science.gov (United States)

Kjerstadius, H; Haghighatafshar, S; Davidsson, Å

2015-01-01

In the last decades, the focus on waste and wastewater treatment systems has shifted towards increased recovery of energy and nutrients. Separation of urban food waste (FW) and domestic wastewaters using source control systems could aid this increase; however, their effect on overall sustainability is unknown. To obtain indicators for sustainability assessments, five urban systems for collection, transport, treatment and nutrient recovery from blackwater, greywater and FW were investigated using data from implementations in Sweden or northern Europe. The systems were evaluated against their potential for biogas production and nutrient recovery by the use of mass balances for organic material, nutrients and metals over the system components. The resulting indicators are presented in units suitable for use in future sustainability studies or life-cycle assessment of urban waste and wastewater systems. The indicators show that source control systems have the potential to increase biogas production by more than 70% compared with a conventional system and give a high recovery of phosphorus and nitrogen as biofertilizer. The total potential increase in gross energy equivalence for source control systems was 20-100%; the greatest increase shown is for vacuum-based systems.

Review on urban vegetation and particle air pollution - Deposition and dispersion

Science.gov (United States)

Janhäll, Sara

2015-03-01

Urban vegetation affects air quality through influencing pollutant deposition and dispersion. Both processes are described by many existing models and experiments, on-site and in wind tunnels, focussing e.g. on urban street canyons and crossings or vegetation barriers adjacent to traffic sources. There is an urgent need for well-structured experimental data, including detailed empirical descriptions of parameters that are not the explicit focus of the study. This review revealed that design and choice of urban vegetation is crucial when using vegetation as an ecosystem service for air quality improvements. The reduced mixing in trafficked street canyons on adding large trees increases local air pollution levels, while low vegetation close to sources can improve air quality by increasing deposition. Filtration vegetation barriers have to be dense enough to offer large deposition surface area and porous enough to allow penetration, instead of deflection of the air stream above the barrier. The choice between tall or short and dense or sparse vegetation determines the effect on air pollution from different sources and different particle sizes.

Polycyclic aromatic hydrocarbons (PAHs) in sediments from lake Lille Lungegårdsvannet in Bergen, western Norway; appraising pollution sources from the urban history.

Science.gov (United States)

Andersson, Malin; Klug, Martin; Eggen, Ola Anfin; Ottesen, Rolf Tore

2014-02-01

This study aims to determine the temporal character and concentration variability of polycyclic aromatic hydrocarbon (PAH) during the last 5,400 years in urban lake sediments through a combination of dating and chemo-stratigraphical correlation. We investigate the chemical history of the city of Bergen and determine the effect of specific point sources, as well as diffuse sources, and also help assess the risk of remediation plans. By using several organic compounds, metals and cyanide, we demonstrate the more accurate timing of sedimentation. The PAH results display very low concentrations in pre-industrial times, followed by a general increase that is punctuated by a few significant concentration increases. These most probably correspond to urban fires, domestic heating, gaswork activity and most recently due to traffic pollution. At the same depth as a significant rise in concentration from background levels occurred, the high relative occurrence of low-molecular-weight PAH-compounds, such as naphthalene, were replaced by heavier compounds, thus indicating a permanent change in source. The general observation, using ratios, is that the sources have shifted from pre-industrial pure wood and coal combustion towards mixed and petrogenic sources in more recent times. The (14)C dating provides evidence that the sedimentation rate stayed more-or-less constant for 4,500 years (from 7200 to 2700 calibrated years before present (calyr BP)), before isostatic uplift isolated the water body and the sedimentation rate decreased or sediments were eroded. The sediment input increased again when habitation and industrial activities encroached on the lake. The (14)C dating does not provide consistent data in that period, possibly due to the fact that the lake has been used as a waste site throughout the history of Bergen city. Therefore, results from (14)C dating from anthropogenically influenced sediments should be used with caution. © 2013.

CADDIS Volume 2. Sources, Stressors and Responses: Urbanization - Temperature

Science.gov (United States)

water temperature changes associated with urbanization, heated surface runoff associated with urbanization, how temperature changes associated with urbanization can affect stream biota, interactive effects of urbanizaiton and climate change.

Source characterization using compound composition and stable carbon isotope ratio of PAHs in sediments from lakes, harbor, and shipping waterway

International Nuclear Information System (INIS)

Kim, Moonkoo; Kennicutt, Mahlon C.; Qian, Yaorong

2008-01-01

Molecular compositions and compound specific stable carbon isotope ratios of polycyclic aromatic hydrocarbons (PAH) isolated from sediments were used to characterize possible sources of contamination at an urban lake, a harbor, a shipping waterway, and a relatively undisturbed remote lake in the northwest United States. Total PAH concentrations in urban lake sediments ranged from 66.0 to 16,500 μg g -1 dry wt. with an average of 2600 μg g -1 , which is ∼ 50, 100, and 400 times higher on average than PAH in harbor (48 μg g -1 on average), shipping waterway (26 μg g -1 ), and remote lake (7 μg g -1 ) sediments, respectively. The PAH distribution patterns, methyl phenanthrene/phenanthrene ratios, and a pyrogenic index at the sites suggest a pyrogenic origin for PAHs. Source characterization using principal component analysis and various molecular indices including C2-dibenzothiophenes/C2-phenanthrenes, C3-dibenzothiophenes/C3-phenanthrenes, and C2-chrysenes/C2-phenanthrenes ratios, was able to differentiate PAH deposited in sediments from the four sites. The uniqueness of the source of the sediment PAHs from urban lake was also illustrated by compound specific stable carbon isotope analysis. It was concluded that urban lake sediments are accumulating PAH from sources that are unique from contamination detected at nearby sites in the same watershed

Trends and sources for heavy metals in urban atmosphere

International Nuclear Information System (INIS)

Kemp, Kaare

2002-01-01

The concentrations of a number of heavy metals in the air in three Danish cities have been measured by means of PIXE for more than two decades. The well-known capability of PIXE for fast and efficient analysis of aerosol samples has been employed for analysis of daily samples from several sites during the whole period. The main sources are traffic, domestic heating and long-range transport. Source apportionment and trends for single metals are assessed by means of simple statistical methods. The most striking change has occurred for the Pb concentration, which is reduced by almost a factor of 100 following the reduction of the Pb content in petrol. The main source of Cu, Cr and Zn is the traffic. The concentrations of these elements have been slightly increasing. The concentrations for most of the other heavy metals, which originate mainly from sources outside the cities, have been decreasing

Trends and sources for heavy metals in urban atmosphere

Science.gov (United States)

Kemp, Kåre

2002-04-01

The concentrations of a number of heavy metals in the air in three Danish cities have been measured by means of PIXE for more than two decades. The well-known capability of PIXE for fast and efficient analysis of aerosol samples has been employed for analysis of daily samples from several sites during the whole period. The main sources are traffic, domestic heating and long-range transport. Source apportionment and trends for single metals are assessed by means of simple statistical methods. The most striking change has occurred for the Pb concentration, which is reduced by almost a factor of 100 following the reduction of the Pb content in petrol. The main source of Cu, Cr and Zn is the traffic. The concentrations of these elements have been slightly increasing. The concentrations for most of the other heavy metals, which originate mainly from sources outside the cities, have been decreasing.

Source term development for tritium at the Sheffield disposal site

International Nuclear Information System (INIS)

MacKenzie, D.R.; Barletta, R.E.; Smalley, J.F.; Kempf, C.R.; Davis, R.E.

1984-01-01

The Sheffield low-level radioactive waste disposal site, which ceased operation in 1978, has been the focus of modeling efforts by the NRC for the purpose of predicting long-term site behavior. To provide the NRC with the information required for its modeling effort, a study to define the source term for tritium in eight trenches at the Sheffield site has been undertaken. Tritium is of special interest since significant concentrations of the isotope have been found in groundwater samples taken at the site and at locations outside the site boundary. Previous estimates of tritium site inventory at Sheffield are in wide disagreement. In this study, the tritium inventory in the eight trenches was estimated by reviewing the radioactive shipping records (RSRs) for waste buried in these trenches. It has been found that the tritium shipped for burial at the site was probably higher than previously estimated. In the eight trenches surveyed, which amount to roughly one half the total volume and activity buried at Sheffield, approximately 2350 Ci of tritium from non-fuel cycle sources were identified. The review of RSRs also formed the basis for obtaining waste package descriptions and for contacting large waste generators to obtain more detailed information regarding these waste packages. As a result of this review and the selected generator contacts, the non-fuel cycle tritium waste was categorized. The tritium releases from each of these waste categories were modeled. The results of this modeling effort are presented for each of the eight trenches selected. 3 references, 2 figures

Siting Background Towers to Characterize Incoming Air for Urban Greenhouse Gas Estimation: A Case Study in the Washington, DC/Baltimore Area

Science.gov (United States)

Mueller, K.; Yadav, V.; Lopez-Coto, I.; Karion, A.; Gourdji, S.; Martin, C.; Whetstone, J.

2018-03-01

There is increased interest in understanding urban greenhouse gas (GHG) emissions. To accurately estimate city emissions, the influence of extraurban fluxes must first be removed from urban greenhouse gas (GHG) observations. This is especially true for regions, such as the U.S. Northeastern Corridor-Baltimore/Washington, DC (NEC-B/W), downwind of large fluxes. To help site background towers for the NEC-B/W, we use a coupled Bayesian Information Criteria and geostatistical regression approach to help site four background locations that best explain CO2 variability due to extraurban fluxes modeled at 12 urban towers. The synthetic experiment uses an atmospheric transport and dispersion model coupled with two different flux inventories to create modeled observations and evaluate 15 candidate towers located along the urban domain for February and July 2013. The analysis shows that the average ratios of extraurban inflow to total modeled enhancements at urban towers are 21% to 36% in February and 31% to 43% in July. In July, the incoming air dominates the total variability of synthetic enhancements at the urban towers (R2 = 0.58). Modeled observations from the selected background towers generally capture the variability in the synthetic CO2 enhancements at urban towers (R2 = 0.75, root-mean-square error (RMSE) = 3.64 ppm; R2 = 0.43, RMSE = 4.96 ppm for February and July). However, errors associated with representing background air can be up to 10 ppm for any given observation even with an optimal background tower configuration. More sophisticated methods may be necessary to represent background air to accurately estimate urban GHG emissions.

A multi-source dataset of urban life in the city of Milan and the Province of Trentino.

Science.gov (United States)

Barlacchi, Gianni; De Nadai, Marco; Larcher, Roberto; Casella, Antonio; Chitic, Cristiana; Torrisi, Giovanni; Antonelli, Fabrizio; Vespignani, Alessandro; Pentland, Alex; Lepri, Bruno

2015-01-01

The study of socio-technical systems has been revolutionized by the unprecedented amount of digital records that are constantly being produced by human activities such as accessing Internet services, using mobile devices, and consuming energy and knowledge. In this paper, we describe the richest open multi-source dataset ever released on two geographical areas. The dataset is composed of telecommunications, weather, news, social networks and electricity data from the city of Milan and the Province of Trentino. The unique multi-source composition of the dataset makes it an ideal testbed for methodologies and approaches aimed at tackling a wide range of problems including energy consumption, mobility planning, tourist and migrant flows, urban structures and interactions, event detection, urban well-being and many others.

δ(15)N and δ(18)O Reveal the Sources of Nitrate-Nitrogen in Urban Residential Stormwater Runoff.

Science.gov (United States)

Yang, Yun-Ya; Toor, Gurpal S

2016-03-15

Nitrogen (N) sources are widely distributed in the complex urban environment. High-resolution data elucidating N sources in the residential catchments are not available. We used stable isotopes of N and oxygen (O) of nitrate (δ(18)O-NO3(-) and δ(15)N-NO3(-)) along with δ(18)O and hydrogen (δD) of water (H2O) to understand the sources and transformations of N in residential stormwater runoff. Stormwater runoff samples were collected over 25 stormwater events at 5 min intervals using an autosampler installed at the residential catchment outlet pipe that drained 31 low-density homes with a total drainage area of 0.11 km(2). Bayesian mixing model results indicated that atmospheric deposition (range 43-71%) and chemical N fertilizers (range stormwater runoff and that there was a continuum of source changes during the stormwater events. Further, the NO3-N transport in the stormwater runoff from the residential catchment was driven by mixing of multiple sources and biotic (i.e., nitrification) processes. This work suggests that a better understanding of N transport and sources is needed to reduce N export and improve water quality in urban water systems.

Carbonaceous aerosols in Norwegian urban areas

Directory of Open Access Journals (Sweden)

K. E. Yttri

2009-03-01

Full Text Available Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM₁₀ and PM_2.5 concentrations of elemental carbon (EC, organic carbon (OC, water-insoluble organic carbon (WINSOC, and water-soluble organic carbon (WSOC are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan.

Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OC_p at the suburban site was equal to (for PM₁₀ or even higher (for PM_2.5 than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m⁻³. This finding indicates that exposure to primary combustion derived OC_p could be equally high in residential areas as in a city center. It is demonstrated that OC_p from wood burning (OC_wood accounted for almost all OC_p at the suburban site in winter, allowing a new estimate of the ratio TC_p/levoglucosan for both PM₁₀ and PM_2.5. Particulate carbonaceous material (PCM

Gis-Based Route Finding Using ANT Colony Optimization and Urban Traffic Data from Different Sources

Science.gov (United States)

Davoodi, M.; Mesgari, M. S.

2015-12-01

Nowadays traffic data is obtained from multiple sources including GPS, Video Vehicle Detectors (VVD), Automatic Number Plate Recognition (ANPR), Floating Car Data (FCD), VANETs, etc. All such data can be used for route finding. This paper proposes a model for finding the optimum route based on the integration of traffic data from different sources. Ant Colony Optimization is applied in this paper because the concept of this method (movement of ants in a network) is similar to urban road network and movements of cars. The results indicate that this model is capable of incorporating data from different sources, which may even be inconsistent.

Atmospheric organochlorine pesticides and polychlorinated biphenyls in urban areas of Nepal: spatial variation, sources, temporal trends, and long-range transport potential

Directory of Open Access Journals (Sweden)

B. Pokhrel

2018-02-01

Full Text Available The study of persistent organic pollutants (POPs in low-latitude tropical and subtropical urban cities is necessary to assess their local and global impacts on ecosystems and human health. Despite studies on levels of POPs in water, soils, and sediments, analysis of the distribution patterns, seasonality, and sources of POPs in urban regions of Nepal remain limited. Polyurethane foam (PUF-based passive air samplers were deployed in three major cities in Nepal: Kathmandu (the capital city, Pokhara, and Hetauda (agricultural cities. Dichlorodiphenyltrichloroethane (DDT and hexachlorocyclohexane (HCH were the dominant organochlorine pesticides in the atmosphere at all sites. The average concentrations of POPs were  ∑ DDTs, 8.7–1.0  ×  103 pg m−3;  ∑ HCHs, 5.3–3.3  ×  103 pg m−3; HCB, 5.8–3.4  ×  102 pg m−3;  ∑ endosulfan, BDL–51 pg m−3; and  ∑ 6PCBs, 1.4–47 pg m−3. Isomer and metabolite ratio analyses suggested that the concentrations present were from both new and historical applications of the POPs. Vegetable production sites and their market places appeared to be the major DDT and HCH source areas. Higher atmospheric concentrations of DDT and HCH occurred during the pre-monsoon and monsoon seasons, and winter, respectively, closely associated with their local application for soil preparation and vegetable spraying. The estimated travel distances of the POPs (HCB, α-HCH, γ-HCH, and p, p′-DDT under the Nepalese tropical climate were all above 1000 km, suggesting that high precipitation levels in the tropical climate were not enough to scavenge the POPs and that Nepal could be an important source region for POPs. Due to their close proximity and cold trapping (driven by low temperatures, the high Himalayas and the Tibetan Plateau are likely the key receptors of POPs emitted in Nepal. These results add to the information available on POPs from

Anthropogenic Carbon Pump in an Urbanized Estuary

Science.gov (United States)

Park, J. H.; Yoon, T. K.; Jin, H.; Begum, M. S.

2015-12-01

The importance of estuaries as a carbon source has been increasingly recognized over the recent decades. However, constraining sources of CO2 evasion from urbanized estuaries remains incomplete, particularly in densely populated river systems receiving high loads of organic carbon from anthropogenic sources. To account for major factors regulating carbon fluxes the tidal reach of the Han River estuary along the metropolitan Seoul, characterization of organic carbon in the main stem and major urban tributaries were combined with continuous, submersible sensor measurements of pCO2 at a mid-channel location over a year and continuous underway measurements using a submersible sensor and two equilibrator sytems across the estuarine section receiving urban streams. Single-site continuous measurements exhibited large seasonal and diurnal variations in pCO2, ranging from sub-ambient air levels to exceptionally high values approaching 10,000 ppm. Diurnal variations of pCO2 were pronounced in summer and had an inverse relationship with dissolved oxygen, pointing to a potential role of day-time algal consumption of CO2. Cruise measurements displayed sharp pCO2 pulses along the confluences of urban streams as compared with relatively low values along the upper estuary receiving low-CO2 outflows from upstream dams. Large downstream increases in pCO2, concurrent with increases in DOC concentrations and fluorescence intensities indicative of microbially processed organic components, imply a translocation and subsequent dilution of CO2 carried by urban streams and/or fast transformations of labile C during transit along downstream reaches. The unique combination of spatial and temporal continuous measurements of pCO2 provide insights on estuarine CO2 pulses that might have resulted from the interplay between high loads of CO2 and organic C of anthropogenic origin and their priming effects on estuarine microbial processing of terrigenous and algal organic matter.

Mass closure and source apportionment of PM2.5 by Positive Matrix Factorization analysis in urban Mediterranean environment

Science.gov (United States)

Mantas, E.; Remoundaki, E.; Halari, I.; Kassomenos, P.; Theodosi, C.; Hatzikioseyian, A.; Mihalopoulos, N.

2014-09-01

A systematic monitoring of PM2.5 was carried out during a period of three years (from February 2010 to April 2013) at an urban site, at the National Technical University of Athens campus. Two types of 24-h PM2.5 samples have been collected: 271 samples on PTFE and 116 samples on quartz filters. Daily PM2.5 concentrations were determined for both types of samples. Total sulfur, crustal origin elements and elements of a major crustal component (Al, Si, Fe, Ca, K, Mg, Ti) trace elements (Zn, Pb, Cu, Ni, P, V, Cr, Mn) and water soluble ions (Cl-, NO3-, SO42-, Na+, K+, NH4+, Ca2+, Mg2+) were determined on the PTFE samples. Organic carbon (OC), elemental carbon (EC) and water soluble ions were determined on the quartz samples. For the mass closure six components were considered: Secondary Inorganic Aerosol (SIA), Organic Matter (OM), Elemental Carbon (EC), Dust, Mineral anthropogenic component (MIN) and Sea Salt (SS). SIA and OM contributed in the mass of PM2.5 almost equally: 30-36% and 30% respectively. EC, SS and MIN accounted for 5, 4 and 3% respectively of the total PM2.5 mass. Dust accounted for about 3-5% in absence of dust transport event and reached a much higher percentage in case of dust transport event. These contributions justify at least 80% of the PM2.5 mass. Source apportionment analysis has been performed by Positive Matrix Factorization. The combination of the PMF results obtained by both data sets lead to the definition of six factors: 1. SO42-, NH4+, OC (industrial/regional sources, secondary aerosol) 2. EC, OC, K and trace metals (traffic and heating by biomass burning, locally emitted aerosol). 3. Ca, EC, OC and trace metals (urban-resuspended road dust reflecting exhaust emissions), 4. Secondary nitrates 5. Na, Cl (marine source) 6. Si, Al, Ti, Ca, Fe (Dust transported from Sahara). These factors reflect not only main sources contributions but also underline the key role of atmospheric dynamics and aerosol ageing processes in this Mediterranean

Source Reduction Effectiveness at Fuel Contaminated Sites, Technical Summary Report

National Research Council Canada - National Science Library

2000-01-01

This report assesses the degree to which various types or engineered source-reduction efforts at selected fuel-contaminated sites have resulted in decreasing concentrations of fuel constituents dissolved in groundwater...

Evaluation of nonpoint-source contamination, Wisconsin: Land-use and Best-Management-Practices inventory, selected streamwater-quality data, urban-watershed quality assurance and quality control, constituent loads in rural streams, and snowmelt-runoff analysis, water year 1994

Science.gov (United States)

Walker, J.F.; Graczyk, D.J.; Corsi, S.R.; Owens, D.W.; Wierl, J.A.

1995-01-01

The objective of the watershed-management evaluation monitoring program in Wisconsin is to evaluate the effectiveness of best-management practices (BMP) for controlling nonpoint-source contamination in rural and urban watersheds. This report is an annual summary of the data collected for the program by the U.S Geological Survey and a report of the results of several different detailed analyses of the data. A land-use and BMP inventory is ongoing for 12 evaluation monitoring projects to track the sources of nonpoint-source pollution in each watershed and to document implementation of BMP's that may cause changes in the water quality of streams. Updated information is gathered each year, mapped, and stored in a geographic-information-system data base. Summaries of data collected during water years 1989-94 are presented. A water year is the period beginning October 1 and ending September 30; the water year is designated by the calendar year in which it ends. Suspended-sediment and total-phosphorus data (storm loads and annual loads) are summarized for eight rural sites. For all sites, the annual suspended-sediment or suspended-solids load for water year 1993 exceeded the average for the period of data collection; the minimum annual loads were transported in water year 1991 or 1992. Continuous dissolved-oxygen data were collected at seven rural sites during water year 1994. Data for water years 1990-93 are summarized and plotted in terms of percentage of time that a particular concentration is equaled or exceeded. Dissolved-oxygen concentrations in four streams were less than 9 mg/L at least 50 percent of the time, a condition that fails to meet suggested criterion for coldwater streams. The dissolved-oxygen probability curve for one of the coldwater streams is markedly different than the curves for the other streams, perhaps because of differences in aquatic biomass. Blank quality-assurance samples were collected at two of the urban evaluation monitoring sites to

Quantitative characterization of urban sources of organic aerosol by high-resolution gas chromatography

International Nuclear Information System (INIS)

Hildemann, L.M.; Mazurek, M.A.; Cass, G.R.; Simoneit, B.R.T.

1991-01-01

Fine aerosol emissions have been collected from a variety of urban combustion sources, including an industrial boiler, a fireplace, automobiles, diesel trucks, gas-fired home appliances, and meat cooking operations, by use of a dilution sampling system. Other sampling techniques have been utilized to collect fine aerosol samples of paved road dust, brake wear, tire wear, cigarette smoke, tar pot emissions, and vegetative detritus. The organic matter contained in each of these samples has been analyzed via high-resolution gas chromatography. By use of a simple computational approach, a quantitative, 50-parameter characterization of the elutable fine organic aerosol emitted from each source type has been determined. The organic mass distribution fingerprints obtained by this approach are shown to differ significantly from each other for most of the source types tested, using hierarchical cluster analysis

Concentration patterns of agricultural pesticides and urban biocides in surface waters of a catchment of mixed land use

Science.gov (United States)

Stamm, C.; Wittmer, I.; Bader, H.-P.; Scheidegger, R.; Alder, A.; Lück, A.; Hanke, I.; Singer, H.

2009-04-01

Organic pesticides and biocides that are found in surface waters, can originate from agricultural and urban sources. For a long time, agricultural pesticides have received substantially more attention than biocidal compounds from urban use like material protection or in-can preservatives (cosmetics etc.). Recent studies however revealed that the amounts of urban biocides used may exceed those of agricultural pesticides. This study aims at comparing the input of several important pesticides and biocides into a small Swiss stream with a special focus on loss events triggered by rainfall. A set of 16 substances was selected to represent urban and agricultural sources. The selected substances are either only used as biocides (irgarol, isothiazolinones, IPBC), as pesticides (atrazine, sulcotrione, dichlofluanid, tolylfluanid) or have a mixed use (isoproturon, terbutryn, terbutylazine, mecoprop, diazinon, carbendazim) The study catchment has an area of 25 km2 and is inhabited by about 12'000 people. Four sampling sites were selected in the river system in order to reflect different urban and agricultural sources. Additionally, we sampled a combined sewer overflow, a rain sewer and the outflow of a wastewater treatment plant. At each site discharge was measured continuously from March to November 2007. During 16 rain events samples were taken by automatic devices at a high temporal resolution. The results, based on more than 500 analyzed samples, revealed distinct concentration patterns for different compounds and sources. Agricultural pesticides exhibited a strong seasonality as expected based on the application periods. During the first one or two rain events after application the concentrations reached up to several thousand ng/l during peak flow (atrazine, isoproturon). The temporal patterns of urban biocides were more diverse. Some compounds obviously stem from permanent sources independent of rainfall because they were found mostly in the outlet of the wastewater

Modern Urban Naming Practices: Strategic Approaches and Practical Solutions

Directory of Open Access Journals (Sweden)

Marina V. Golomidova

2017-11-01

Full Text Available The article looks at the problems of the naming of municipal facilities. The author analyzes the existing policy in assigning new names and renaming urban sites, describes the current strategic approaches to urban naming and proposes a new strategy based on congruity with the holistic image of the city. The current approaches to urban naming mark the predominating interest in the historical and cultural heritage of cities as a valuable source for the toponymic nomination shared both by native and foreign experts. However, this commitment to the past may run counter to the modern arrangement and perception of the urban space, as well as impede the city development prospects. From the standpoint of modern area marketing, names of urban sites are regarded as an information and communication resource highly relevant to the city image formation and promotion. In the author’s view, the benefits of adopting a new strategy may also resonate with the concept of “urbanonymic construction,” which is understood as sustainable and streamlined management policy aimed at the progressive implementation of long-term programs for individual urban site names consistency. The urbanonymic construction involves a normative, regulatory aspect; formation of the holistic city image that builds on its resource base, the symbolic capital, and the development strategy; definition of key characteristics of the city image which are most relevant to its positioning; identification of principal nominative themes for verbal representation of the city image; use of naming technologies to ensure the relevance of the name’s implications; testing and expert evaluation of new names. Drawing on domestic and foreign expertise in the same study field, a number of practical solutions for the creation of new urbanonyms are described.

Towards urban mobility designs

DEFF Research Database (Denmark)

Lanng, Ditte Bendix; Harder, Henrik; Jensen, Ole B.

2012-01-01

for the wayfarers who use the site. The data for our work concerns a transit site in the 1970s urban district of Aalborg Øst, Denmark. - We set out by introducing our approach to the site. - Second, we examine the functional layout of the transit site in Aalborg Øst and outline the design challenge which we......Functionalist traffic design aims at a rational organisation of movement from A to B in a segregated and uniform physical environment. Such urban areas have been criticized for being exclusively functional and lacking sensuous and social qualities. Recent research on mobilities challenges the more...... insights on functional urban planning, on embodied practices and experiences of wayfaring, and on concrete small scale design concerns. We emphasise an integrated design agenda for those ordinary transit sites which is concerned with functional issues as well as the quality of life on the ground...

Source, propagation and site effects: impact on mapping strong ground motion in Bucharest area

International Nuclear Information System (INIS)

Radulian, R.; Kuznetsov, I.; Panza, G.F.

2004-01-01

Achievements in the framework of the NATO SfP project 972266 focused on the impact of Vrancea earthquakes on the security of Bucharest urban area are presented. The problem of Bucharest city security to Vrancea earthquakes is discussed in terms of numerical modelling of seismic motion and intermediate term earthquake prediction. A hybrid numerical scheme developed by Faeh et al. (1990; 1993) for frequencies up to 1 Hz is applied for the realistic modelling of the seismic ground motion in Bucharest. The method combines the modal summation for the 1D bedrock model and the finite differences for the 2D local structure model. All the factors controlling the ground motion at the site are considered: source, propagation and site effects, respectively. The input data includes the recent records provided by the digital accelerometer network developed within the Romanian-German CRC461 cooperation programme and CALIXTO'99, VRANCEA'99, VRANCEA2001 experiments. The numerical simulation proves to be a powerful tool in mapping the strong ground motion for realistic structures, reproducing acceptably from engineering point of view the observations. A new model of the Vrancea earthquake scaling is obtained and implications for the determination of the seismic motion parameters are analyzed. The role of the focal mechanism and attenuation properties upon the amplitude and spectral content of the ground motion are outlined. CN algorithm is applied for predicting Vrancea earthquakes. Finally, implications for the disaster management strategy are discussed. (authors)

Spatial and temporal variability in urban fine particulate matter concentrations

International Nuclear Information System (INIS)

Levy, Jonathan I.; Hanna, Steven R.

2011-01-01

Identification of hot spots for urban fine particulate matter (PM 2.5 ) concentrations is complicated by the significant contributions from regional atmospheric transport and the dependence of spatial and temporal variability on averaging time. We focus on PM 2.5 patterns in New York City, which includes significant local sources, street canyons, and upwind contributions to concentrations. A literature synthesis demonstrates that long-term (e.g., one-year) average PM 2.5 concentrations at a small number of widely-distributed monitoring sites would not show substantial variability, whereas short-term (e.g., 1-h) average measurements with high spatial density would show significant variability. Statistical analyses of ambient monitoring data as a function of wind speed and direction reinforce the significance of regional transport but show evidence of local contributions. We conclude that current monitor siting may not adequately capture PM 2.5 variability in an urban area, especially in a mega-city, reinforcing the necessity of dispersion modeling and methods for analyzing high-resolution monitoring observations. - Highlights: →Fine particulate matter (PM 2.5 ) hot spots are hard to identify in urban areas. → Literature conclusions about PM 2.5 hot spots depend on study design and methods. → Hot spots are more likely for short-term concentrations at high spatial density. → Statistical methods illustrate local source impacts beyond regional transport. → Dispersion models and high-resolution monitors are both needed to find hot spots. - Fine particulate matter can vary spatially within large urban areas, in spite of the significant contribution from regional atmospheric transport.

Sources and geographical origins of fine aerosols in Paris (France)

International Nuclear Information System (INIS)

Bressi, M.; Nicolas, J.B.; Sciare, J.; Feron, A.; Nonnaire, N.; Petit, J.E.

2014-01-01

The present study aims at identifying and apportioning fine aerosols to their major sources in Paris (France) - the second most populated - larger urban zone - in Europe - and determining their geographical origins. It is based on the daily chemical composition of PM2.5 examined over 1 year at an urban background site of Paris (Bressi et al., 2013). Positive matrix factorization (EPA PMF3.0) was used to identify and apportion fine aerosols to their sources; bootstrapping was performed to determine the adequate number of PMF factors, and statistics (root mean square error, coefficient of determination, etc.) were examined to better model PM2.5 mass and chemical components. Potential source contribution function (PSCF) and conditional probability function (CPF) allowed the geographical origins of the sources to be assessed; special attention was paid to implement suitable weighting functions. Seven factors, namely ammonium sulfate (A.S.)-rich factor, ammonium nitrate (A.N.)-rich factor, heavy oil combustion, road traffic, biomass burning, marine aerosols and metal industry, were identified; a detailed discussion of their chemical characteristics is reported. They contribute 27, 24, 17, 14, 12, 6 and 1% of PM2.5 mass (14.7 μgm -3 ) respectively on the annual average; their seasonal variability is discussed. The A.S.- and A.N.-rich factors have undergone mid- or long-range transport from continental Europe; heavy oil combustion mainly stems from northern France and the English Channel, whereas road traffic and biomass burning are primarily locally emitted. Therefore, on average more than half of PM2.5 mass measured in the city of Paris is due to mid- or long-range transport of secondary aerosols stemming from continental Europe, whereas local sources only contribute a quarter of the annual averaged mass. These results imply that fine-aerosol abatement policies conducted at the local scale may not be sufficient to notably reduce PM2.5 levels at urban background sites

Radical budget and ozone chemistry during autumn in the atmosphere of an urban site in central China

Science.gov (United States)

Lu, Xingcheng; Chen, Nan; Wang, Yuhang; Cao, Wenxiang; Zhu, Bo; Yao, Teng; Fung, Jimmy C. H.; Lau, Alexis K. H.

2017-03-01

The ROx (=OH + HO2 + RO2) budget and O3 production at an urban site in central China (Wuhan) during autumn were simulated and analyzed for the first time using a UW Chemical Model 0-D box model constrained by in situ observational data. The daytime average OH, HO2, and RO2 concentrations were 2.2 × 106, 1.0 × 108, and 5.2 × 107 molecules cm-3, respectively. The average daytime O3 production rate was 8.8 ppbv h-1, and alkenes were the most important VOC species for O3 formation (contributing 45%) at this site. Our sensitivity test indicated that the atmospheric environment in Wuhan during autumn belongs to the VOC-limited regime. The daily average HONO concentration at this site during the study period reached 1.1 ppbv and played an important role in the oxidative capacity of the atmosphere. Without the source of excess HONO, the average daytime OH, HO2, RO2, and O3 production rates decreased by 36%, 26%, 27%, and 31% respectively. A correlation between the HONO to NO2 heterogeneous conversion efficiency and PM2.5 × SWR was found at this site; based on this relationship, if the PM2.5 concentration met the World Health Organization air quality standard (25 µg m-3), the O3 production rate in this city would decrease by 19% during late autumn. The burning of agricultural biomass severely affected the air quality in Wuhan during summer and autumn. Agricultural burning was found to account for 18% of the O3 formation during the study period. Our results suggest that VOC control and a ban on agricultural biomass burning should be considered as high-priority measures for improving the air quality in this region.

A source of energy : sustainable architecture and urbanism

Energy Technology Data Exchange (ETDEWEB)

Roestvik, Harald N.

2011-07-01

An update on the environmental challenges. Meant to inspire and be a source of energy.Tearing down myths and floodlighting paradoxes. Particularly relevant for students of architecture, architects and concerned citizens. Training tasks, recommendations for further source books and web sites, are included. From the content: Climate change and consensus, Population growth, Food production, The sustainable city, Transportation myths and facts, A mini history of environmental architecture, Architects' approach to sustainable design, The failure of western architects; a case study; China, The passive, zeb and plus energy building, Natural ventilation, Sustainable materials, Plastics in building, Nuclear energy, Solar energy, The grid of the future, Indoor climate and health. The sick building syndrome, Radon, Universal design, Paradoxes, Bullying techniques, Trust yourself, Timing, Which gateway will you choose?, On transience. (au)

Biomonitoring of atmospheric pollution by moss bags: Discriminating urban-rural structure in a fragmented landscape.

Science.gov (United States)

Capozzi, F; Giordano, S; Di Palma, A; Spagnuolo, V; De Nicola, F; Adamo, P

2016-04-01

In this paper we investigated the possibility to use moss bags to detect pollution inputs - metals, metalloids and polycyclic aromatic hydrocarbons (PAHs) - in sites chosen for their different land use (agricultural, urban/residential scenarios) and proximity to roads (sub-scenarios), in a fragmented conurbation of Campania (southern Italy). We focused on thirty-nine elements including rare earths. For most of them, moss uptake was higher in agricultural than in urban scenarios and in front road sites. Twenty PAHs were analyzed in a subset of agricultural sites; 4- and 5-ringed PAHs were the most abundant, particularly chrysene, fluoranthene and pyrene. Overall results indicated that investigated pollutants have a similar spatial distribution pattern over the entire study area, with road traffic and agricultural practices as the major diffuse pollution sources. Moss bags proved a very sensitive tool, able to discriminate between different land use scenarios and proximity to roads in a mixed rural-urban landscape. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methylmercury bioaccumulation in an urban estuary: Delaware River USA.

Science.gov (United States)

Buckman, Kate; Taylor, Vivien; Broadley, Hannah; Hocking, Daniel; Balcom, Prentiss; Mason, Rob; Nislow, Keith; Chen, Celia

2017-09-01

Spatial variation in mercury (Hg) and methylmercury (MeHg) bioaccumulation in urban coastal watersheds reflects complex interactions between Hg sources, land use, and environmental gradients. We examined MeHg concentrations in fauna from the Delaware River estuary, and related these measurements to environmental parameters and human impacts on the waterway. The sampling sites followed a north to south gradient of increasing salinity, decreasing urban influence, and increasing marsh cover. Although mean total Hg in surface sediments (top 4cm) peaked in the urban estuarine turbidity maximum and generally decreased downstream, surface sediment MeHg concentrations showed no spatial patterns consistent with the examined environmental gradients, indicating urban influence on Hg loading to the sediment but not subsequent methylation. Surface water particulate MeHg concentration showed a positive correlation with marsh cover whereas dissolved MeHg concentrations were slightly elevated in the estuarine turbidity maximum region. Spatial patterns of MeHg bioaccumulation in resident fauna varied across taxa. Small fish showed increased MeHg concentrations in the more urban/industrial sites upstream, with concentrations generally decreasing farther downstream. Invertebrates either showed no clear spatial patterns in MeHg concentrations (blue crabs, fiddler crabs) or increasing concentrations further downstream (grass shrimp). Best-supported linear mixed models relating tissue concentration to environmental variables reflected these complex patterns, with species specific model results dominated by random site effects with a combination of particulate MeHg and landscape variables influencing bioaccumulation in some species. The data strengthen accumulating evidence that bioaccumulation in estuaries can be decoupled from sediment MeHg concentration, and that drivers of MeHg production and fate may vary within a small region.

Parameter Estimation and Sensitivity Analysis of an Urban Surface Energy Balance Parameterization at a Tropical Suburban Site

Science.gov (United States)

Harshan, S.; Roth, M.; Velasco, E.

2014-12-01

Forecasting of the urban weather and climate is of great importance as our cities become more populated and considering the combined effects of global warming and local land use changes which make urban inhabitants more vulnerable to e.g. heat waves and flash floods. In meso/global scale models, urban parameterization schemes are used to represent the urban effects. However, these schemes require a large set of input parameters related to urban morphological and thermal properties. Obtaining all these parameters through direct measurements are usually not feasible. A number of studies have reported on parameter estimation and sensitivity analysis to adjust and determine the most influential parameters for land surface schemes in non-urban areas. Similar work for urban areas is scarce, in particular studies on urban parameterization schemes in tropical cities have so far not been reported. In order to address above issues, the town energy balance (TEB) urban parameterization scheme (part of the SURFEX land surface modeling system) was subjected to a sensitivity and optimization/parameter estimation experiment at a suburban site in, tropical Singapore. The sensitivity analysis was carried out as a screening test to identify the most sensitive or influential parameters. Thereafter, an optimization/parameter estimation experiment was performed to calibrate the input parameter. The sensitivity experiment was based on the "improved Sobol's global variance decomposition method" . The analysis showed that parameters related to road, roof and soil moisture have significant influence on the performance of the model. The optimization/parameter estimation experiment was performed using the AMALGM (a multi-algorithm genetically adaptive multi-objective method) evolutionary algorithm. The experiment showed a remarkable improvement compared to the simulations using the default parameter set. The calibrated parameters from this optimization experiment can be used for further model

Effect of urban climate on building integrated photovoltaics performance

International Nuclear Information System (INIS)

Tian Wei; Wang Yiping; Ren Jianbo; Zhu Li

2007-01-01

It is generally recognized that BIPV (building integrated photovoltaics) has the potential to become a major source of renewable energy in the urban environment. The actual output of a PV module in the field is a function of orientation, total irradiance, spectral irradiance, wind speed, air temperature, soiling and various system-related losses. In urban areas, the attenuation of solar radiation due to air pollution is obvious, and the solar spectral content subsequently changes. The urban air temperature is higher than that in the surrounding countryside, and the wind speed in urban areas is usually less than that in rural areas. Three different models of PV power are used to investigate the effect of urban climate on PV performance. The results show that the dimming of solar radiation in the urban environment is the main reason for the decrease of PV module output using the climatic data of urban and rural sites in Mexico City for year 2003. The urban PV conversion efficiency is higher than that of the rural PV system because the PV module temperature in the urban areas is slightly lower than that in the rural areas in the case. The DC power output of PV seems to be underestimated if the spectral response of PV in the urban environment is not taken into account based on the urban hourly meteorological data of Sao Paulo for year 2004

Spatial variability of trace elements and sources for improved exposure assessment in Barcelona

Science.gov (United States)

Minguillón, María Cruz; Cirach, Marta; Hoek, Gerard; Brunekreef, Bert; Tsai, Ming; de Hoogh, Kees; Jedynska, Aleksandra; Kooter, Ingeborg M.; Nieuwenhuijsen, Mark; Querol, Xavier

2014-06-01

Trace and major elements concentrations in PM10 and PM2.5 were measured at 20 sites spread in the Barcelona metropolitan area (1 rural background, 6 urban background, 13 road traffic sites) and at 1 reference site. Three 2-week samples per site and size fraction were collected during 2009 using low volume samplers, adding a total of 120 samples. Collected samples were analysed for elemental composition using Energy Dispersive X-ray fluorescence (XRF). EC, OC, and hopanes and steranes concentrations in PM2.5 were determined. Positive Matrix Factorisation (PMF) model was used for a source apportionment analysis. The work was performed as part of the ESCAPE project. Elements were found in concentrations within the usual range in Spanish urban areas. Mineral elements were measured in higher concentrations during the warm season, due to enhanced resuspension; concentrations of fueloil combustion elements were also higher in summer. Elements in higher concentration at the traffic sites were: Ba, Cr, Cu, Fe, Mn, Mo, Pb, Sn, Zn and Zr. Spatial variations related to non-traffic sources were observed for concentrations of Br, Cl, K, and Na (sea salt origin) and Ni, V and S (shipping emissions), which were higher at the coastal sites, as well as for Zn and Pb, higher at sites closer to industrial facilities. Five common sources for PM10 and PM2.5 were identified by PMF: road traffic (with tracers Ba, Cr, Cu, Fe, Mo and Zn); fueloil combustion (Ni and V); secondary sulphate; industry (Pb and Zn); and mineral source (Al, Ca, Mg, Si, Sr and Ti). A marine aerosol source, a mixture of sea salt with aged anthropogenic aerosols, was found only in PM10. EC, hopanes and steranes concentrations correlate strongly with the PM10 road traffic source contributions, being hence all attributed to the same source. OC may arise from other sources in addition to road traffic and have a high contribution of secondary OC. Significant spatial and temporal variation in the PM2.5 and PM10 elemental

Disparities in Prevalence of Cardiometablic Risk Factors in Rural, Urban-Poor, and Urban-Middle Class Women in India.

Directory of Open Access Journals (Sweden)

Indu Mohan

Full Text Available Urbanization is an important determinant of cardiovascular disease (CVD risk. To determine location-based differences in CVD risk factors in India we performed studies among women in rural, urban-poor and urban middle-class locations.Population-based cross-sectional studies in rural, urban-poor, and urban-middle class women (35-70 y were performed at multiple sites. We evaluated 6853 women (rural 2616, 5 sites; urban-poor 2008, 4 sites; urban middle-class 2229, 11 sites for socioeconomic, lifestyle, anthropometric and biochemical risk factors. Descriptive statistics are reported.Mean levels of body mass index (BMI, waist circumference, waist-hip ratio (WHR, systolic BP, fasting glucose and cholesterol in rural, urban-poor and urban-middle class women showed significantly increasing trends (ANOVAtrend, p 80 cm (28.3, 63.4, 61.9%, waist >90 cm (8.4, 31.4, 38.2%, waist hip ratio (WHR >0.8 (60.4, 90.7, 88.5, WHR>0.9 (13.0, 44.3, 56.1%, hypertension (31.6, 48.2, 59.0% and hypercholesterolemia (13.5, 27.7, 37.4% (Mantel Haenszel X2 ptrend <0.01. Inverse trend was observed for tobacco use (41.6, 19.6, 9.4%. There was significant association of hypertension, hypercholesterolemia and diabetes with overweight and obesity (adjusted R2 0.89-0.99.There are significant location based differences in cardiometabolic risk factors in India. The urban-middle class women have the highest risk compared to urban-poor and rural.

Variability of atmospheric carbonyl sulfide at a semi-arid urban site in western India.

Science.gov (United States)

Mallik, Chinmay; Chandra, Naveen; Venkataramani, S; Lal, Shyam

2016-05-01

Atmospheric carbonyl sulfide (COS) is a major precursor for sulfate aerosols that play a critical role in climate regulation. Recent studies have highlighted the importance of COS measurements as a reliable means to constrain biospheric carbon assimilation. In a scenario of limited availability of COS data around the globe, we present gas-chromatographic measurements of atmospheric COS mixing ratios over Ahmedabad, a semi-arid, urban region in western India. These measurements, being reported for the first time over an Indian site, enable us to understand the diurnal and seasonal variation in atmospheric COS with respect to its natural, anthropogenic and photochemical sources and sinks. The annual mean COS mixing ratio over Ahmedabad is found to be 0.83±0.43ppbv, which is substantially higher than free tropospheric values for the northern hemisphere. Inverse correlation of COS with soil and skin temperature, suggests that the dry soil of the semi-arid study region is a potential sink for atmospheric COS. Positive correlations of COS with NO2 and CO during post-monsoon and the COS/CO slope of 0.78pptv/ppbv reveals influence of diesel combustion and tire wear. The highest concentrations of COS are observed during pre-monsoon; COS/CO2 slope of 44.75pptv/ppmv combined with information from air mass back-trajectories reveal marshy wetlands spanning over 7500km(2) as an important source of COS in Ahmedabad. COS/CO2 slopes decrease drastically (8.28pptv/ppmv) during post-monsoon due to combined impact of biospheric uptake and anthropogenic emissions. Copyright © 2016 Elsevier B.V. All rights reserved.

A Meta-Analysis of Urban Climate Change Adaptation ...

Science.gov (United States)

The concentration of people, infrastructure, and ecosystem services in urban areas make them prime sites for climate change adaptation. While advances have been made in developing frameworks for adaptation planning and identifying both real and potential barriers to action, empirical work evaluating urban adaptation planning processes has been relatively piecemeal. Existing assessments of current experience with urban adaptation provide necessarily broad generalizations based on the available peer-reviewed literature. This paper uses a meta-analysis of U.S. cities’ current experience with urban adaptation planning drawing from 54 sources that include peer-reviewed literature, government reports, white papers, and reports published by non-governmental organizations. The analysis specifically evaluates the institutional support structures being developed for urban climate change adaptation. The results demonstrate that adaptation planning is driven by a desire to reduce vulnerability and often catalyzes new collaborations and coordination mechanisms in urban governance. As a result, building capacity for urban climate change adaptation planning requires a focus not only on city governments themselves but also on the complex horizontal and vertical networks that have arisen around such efforts. Existing adaptation planning often lacks attention to equity issues, social vulnerability, and the influence of non-climatic factors on vulnerability. Engaging city govern

GIS-BASED ROUTE FINDING USING ANT COLONY OPTIMIZATION AND URBAN TRAFFIC DATA FROM DIFFERENT SOURCES

Directory of Open Access Journals (Sweden)

M. Davoodi

2015-12-01

Full Text Available Nowadays traffic data is obtained from multiple sources including GPS, Video Vehicle Detectors (VVD, Automatic Number Plate Recognition (ANPR, Floating Car Data (FCD, VANETs, etc. All such data can be used for route finding. This paper proposes a model for finding the optimum route based on the integration of traffic data from different sources. Ant Colony Optimization is applied in this paper because the concept of this method (movement of ants in a network is similar to urban road network and movements of cars. The results indicate that this model is capable of incorporating data from different sources, which may even be inconsistent.

Modeling urban coastal flood severity from crowd-sourced flood reports using Poisson regression and Random Forest

Science.gov (United States)

Sadler, J. M.; Goodall, J. L.; Morsy, M. M.; Spencer, K.

2018-04-01

Sea level rise has already caused more frequent and severe coastal flooding and this trend will likely continue. Flood prediction is an essential part of a coastal city's capacity to adapt to and mitigate this growing problem. Complex coastal urban hydrological systems however, do not always lend themselves easily to physically-based flood prediction approaches. This paper presents a method for using a data-driven approach to estimate flood severity in an urban coastal setting using crowd-sourced data, a non-traditional but growing data source, along with environmental observation data. Two data-driven models, Poisson regression and Random Forest regression, are trained to predict the number of flood reports per storm event as a proxy for flood severity, given extensive environmental data (i.e., rainfall, tide, groundwater table level, and wind conditions) as input. The method is demonstrated using data from Norfolk, Virginia USA from September 2010 to October 2016. Quality-controlled, crowd-sourced street flooding reports ranging from 1 to 159 per storm event for 45 storm events are used to train and evaluate the models. Random Forest performed better than Poisson regression at predicting the number of flood reports and had a lower false negative rate. From the Random Forest model, total cumulative rainfall was by far the most dominant input variable in predicting flood severity, followed by low tide and lower low tide. These methods serve as a first step toward using data-driven methods for spatially and temporally detailed coastal urban flood prediction.

Characteristics and sources of nitrous acid in an urban atmosphere of northern China: Results from 1-yr continuous observations

Science.gov (United States)

Li, Dandan; Xue, Likun; Wen, Liang; Wang, Xinfeng; Chen, Tianshu; Mellouki, Abdelwahid; Chen, Jianmin; Wang, Wenxing

2018-06-01

Nitrous acid (HONO) is a key reservoir of the hydroxyl radical (OH) and plays a central role in the atmospheric chemistry. To understand the sources and impact of HONO in the polluted atmosphere of northern China, continuous measurements of HONO and related parameters were conducted from September 2015 to August 2016 at an urban site in Ji'nan, the capital city of Shandong province. HONO showed well-defined seasonal and diurnal variation patterns with clear wintertime and nighttime concentration peaks. Elevated HONO concentrations (e.g., over 5 ppbv) were frequently observed with a maximum value of 8.36 ppbv. The HONO/NOX ratios of direct vehicle emissions varied in the range of 0.29%-0.87%, with a mean value of 0.53%. An average NO2-to-HONO nighttime conversion frequency (khet) was derived to be 0.0068 ± 0.0045 h-1 from 107 HONO formation cases. A detailed HONO budget analysis suggests an unexplained daytime missing source of 2.95 ppb h-1 in summer, which is about seven times larger than the homogeneous reaction of NO with OH. The effect of HONO on OH production was also quantified. HONO photolysis was the uppermost source of local OH radical throughout the daytime. This study provides the year-round continuous record of ambient HONO in the North China Plain, and offers some insights into the characteristics, sources and impacts of HONO in the polluted atmospheres of China.

Comparison of mosquito control programs in seven urban sites in Africa, the Middle East, and the Americas

Science.gov (United States)

Impoinvil, Daniel E.; Ahmad, Sajjad; Troyo, Adriana; Keating, Joseph; Githeko, Andrew K.; Mbogo, Charles M; Kibe, Lydiah; Githure, John I.; Gad, Adel M.; Hassan, Ali N.; Orshan, Laor; Warburg, Alon; Calderón-Arguedas, Olger; Sánchez-Loría, Victoria M.; Velit-Suarez, Rosanna; Chadee, Dave D.; Novak, Robert J.; Beier, John C.

2007-01-01

Mosquito control programs at seven urban sites in Kenya, Egypt, Israel, Costa Rica, and Trinidad are described and compared. Site-specific urban and disease characteristics, organizational diagrams, and strengths, weaknesses, obstacles and threats (SWOT) analysis tools are used to provide a descriptive assessment of each mosquito control program, and provide a comparison of the factors affecting mosquito abatement. The information for SWOT analysis is collected from surveys, focus group discussions, and personal communication. SWOT analysis identified various issues affecting the efficiency and sustainability of mosquito control operations. The main outcome of our work was the description and comparison of mosquito control operations within the context of each study site’s biological, social, political, management, and economic conditions. The issues identified in this study ranged from lack of inter-sector collaboration to operational issues of mosquito control efforts. A lack of sustainable funding for mosquito control was a common problem for most sites. Many unique problems were also identified, which included lack of mosquito surveillance, lack of law enforcement, and negative consequences of human behavior. Identifying common virtues and shortcomings of mosquito control operations is useful in identifying “best practices” for mosquito control operations, thus leading to better control of mosquito biting and mosquito-borne disease transmission. PMID:17316882

Urban snow indicates pollution originating from road traffic.

Science.gov (United States)

Kuoppamäki, Kirsi; Setälä, Heikki; Rantalainen, Anna-Lea; Kotze, D Johan

2014-12-01

Traffic is a major source of pollutants in cities. In this well-replicated study we analysed a broad array of contaminants in snowpacks along roads of different traffic intensities. The majority of pollutants showed a similar pattern with respect to traffic intensity: pH and conductivity as well as concentrations of PAHs, total suspended solids, phosphorus and most heavy metals were higher next to high intensity roads compared to low intensity roads. These pollutant levels also decreased considerably up to 5 m distance from the roads. Furthermore, apart from nitrogen, these variables increased in concentration from control sites in urban forest patches to road bank sites next to roads of low, intermediate and high traffic intensities. The deposition pattern of various traffic-derived pollutants--whether gaseous or particle-bound--was the same. Such information can be useful for the purposes of managing pollutants in urban areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

76 FR 62451 - Avon Products, Inc., Including On-Site Leased Workers From Spherion/Source Right, Springdale...

Science.gov (United States)

2011-10-07

...., Including On-Site Leased Workers From Spherion/Source Right, Springdale, Ohio; Amended Certification... workers of the subject firm. The company reports that workers leased from Spherion/Source Right were...., including on-site leased workers from Spherion/Source Right, Springdale, Ohio, who became totally or...

Saline sewage treatment and source separation of urine for more sustainable urban water management.

Science.gov (United States)

Ekama, G A; Wilsenach, J A; Chen, G H

2011-01-01

While energy consumption and its associated carbon emission should be minimized in wastewater treatment, it has a much lower priority than human and environmental health, which are both closely related to efficient water quality management. So conservation of surface water quality and quantity are more important for sustainable development than green house gas (GHG) emissions per se. In this paper, two urban water management strategies to conserve fresh water quality and quantity are considered: (1) source separation of urine for improved water quality and (2) saline (e.g. sea) water toilet flushing for reduced fresh water consumption in coastal and mining cities. The former holds promise for simpler and shorter sludge age activated sludge wastewater treatment plants (no nitrification and denitrification), nutrient (Mg, K, P) recovery and improved effluent quality (reduced endocrine disruptor and environmental oestrogen concentrations) and the latter for significantly reduced fresh water consumption, sludge production and oxygen demand (through using anaerobic bioprocesses) and hence energy consumption. Combining source separation of urine and saline water toilet flushing can reduce sewer crown corrosion and reduce effluent P concentrations. To realize the advantages of these two approaches will require significant urban water management changes in that both need dual (fresh and saline) water distribution and (yellow and grey/brown) wastewater collection systems. While considerable work is still required to evaluate these new approaches and quantify their advantages and disadvantages, it would appear that the investment for dual water distribution and wastewater collection systems may be worth making to unlock their benefits for more sustainable urban development.

Ground motion measurements at the LBL Light Source site, the Bevatron and at SLAC

International Nuclear Information System (INIS)

Green, M.A.; Majer, E.I.; More, V.D.; O'Connell, D.R.; Shilling, R.C.

1986-12-01

This report describes the technique for measuring ground motion at the site of the 1.0 to 2.0 GeV Synchrotron Radiation Facility which was known as the Advanced Light Source (in 1983 when the measurements were taken). The results of ground motion measurements at the Light Source site at Building 6 at LBL are presented. As comparison, ground motion measurements were made at the Byerly Tunnel, the Bevatron, Blackberry Canyon, and SLAC at the Spear Ring. Ground Motion at the Light Source site was measured in a band from 4 to 100 Hz. The measured noise is primarily local in origin and is not easily transported through LBL soils. The background ground motion is for the most part less than 0.1 microns. Localized truck traffic near Building 6 and the operation of the cranes in the building can result in local ground motions of a micron or more for short periods of time. The background motion at Building 6 is between 1 and 2 orders of magnitude higher than ground motion in a quiet seismic tunnel, which is representative of quiet sites worldwide. The magnitude of the ground motions at SLAC and the Bevatron are comparable to ground motions measured at the Building 6 Light Source site. However, the frequency signature of each site is very different

Sources of some obsidian flakes from a Paleoindian site in Guatemala

International Nuclear Information System (INIS)

Stross, F.H.; Asaro, F.; Michel, H.V.; Gruhn, R.

1977-01-01

Neutron activation analysis was used to determine the chemical composition of sources of obsidian artifacts from the Paleoindian site of Los Tapiales in Guatemala with an occupation date of around 10,700 radiocarbon years ago. Three different sources were detected, all between 50 and 75 km from Los Tapiales. The predominant source represented in our ten samples was in the Rio Pixcaya area, and another was in the Tajumulco area. A third source, identified by comparison with other work, appears to be in the area of San Bartolome Milpas Altas

Investigation of source position uncertainties & balloon deformation in MammoSite brachytherapy on treatment effectiveness

International Nuclear Information System (INIS)

Bensaleh, S.

2010-01-01

The MammoSite ® breast high dose rate brachytherapy is used in treatment of early-stage breast cancer. The tumour bed volume is irradiated with high dose per fraction in a relatively small number of fractions. Uncertainties in the source positioning and MammoSite balloon deformation will alter the prescribed dose within the treated volume. They may also expose the normal tissues in balloon proximity to excessive dose. The purpose of this work is to explore the impact of these two uncertainties on the MammoSite dose distribution in the breast using dose volume histograms and Monte Carlo simulations. The Lyman–Kutcher and relative seriality models were employed to estimate the normal tissues complications associated with the MammoSite dose distributions. The tumour control probability was calculated using the Poisson model. This study gives low probabilities for developing heart and lung complications. The probability of complications of the skin and normal breast tissues depends on the location of the source inside the balloon and the volume receiving high dose. Incorrect source position and balloon deformation had significant effect on the prescribed dose within the treated volume. A 4 mm balloon deformation resulted in reduction of the tumour control probability by 24%. Monte Carlo calculations using EGSnrc showed that a deviation of the source by 1 mm caused approximately 7% dose reduction in the treated target volume at 1 cm from the balloon surface. In conclusion, accurate positioning of the 192 Ir source at the balloon centre and minimal balloon deformation are critical for proper dose delivery with the MammoSite brachytherapy applicator. On the basis of this study, we suggest that the MammoSite treatment protocols should allow for a balloon deformation of ≤2 mm and a maximum source deviation of ≤1 mm.

Spectral dependence of aerosol light absorption at an urban and a remote site over the Tibetan Plateau.

Science.gov (United States)

Zhu, Chong-Shu; Cao, Jun-Ji; Hu, Ta-Feng; Shen, Zhen-Xing; Tie, Xue-Xi; Huang, Hong; Wang, Qi-Yuan; Huang, Ru-Jin; Zhao, Zhu-Zi; Močnik, Griša; Hansen, Anthony D A

2017-07-15

We present a study of aerosol light absorption by using a 7-wavelength Aethalometer model AE33 at an urban site (Lhasa) and a remote site (Lulang) in the Tibetan Plateau. Approximately 5 times greater aerosol absorption values were observed at Lhasa (53±46Mm -1 at 370nm and 20±18Mm -1 at 950nm, respectively) in comparison to Lulang (15±19Mm -1 at 370nm and 4±5Mm -1 at 950nm, respectively). Black carbon (BC) was the dominant light absorbing aerosol component at all wavelengths. The brown carbon (BrC) absorption at 370nm is 32±15% of the total aerosol absorption at Lulang, whereas it is 8±6% at Lhasa. Higher value of absorption Ångström exponent (AAE, 370-950nm) was obtained for Lulang (1.18) than that for Lhasa (1.04) due to the presence of BrC. The AAEs (370-950nm) of BrC were directly extracted at Lulang (3.8) and Lhasa (3.3). The loading compensation parameters (k) increased with wavelengths for both sites, and lower values were obtained at Lulang than those observed at Lhasa for all wavelengths. This study underlines the relatively high percentage of BrC absorption contribution in remote area compared to urban site over the Tibetan Plateau. Copyright © 2017 Elsevier B.V. All rights reserved.

Identification and characterization of fine and coarse particulate matter sources in a middle-European urban environment

International Nuclear Information System (INIS)

Kertesz, Zs.; Szoboszlai, Z.; Angyal, A.; Dobos, E.; Borbely-Kiss, I.

2010-01-01

In this work a source apportionment study is presented which aimed to characterize the PM 2.5 and PM 2.5-10 sources in the urban area of Debrecen, East-Hungary by using streaker samples, IBA methods and positive matrix factorization (PMF) analysis. Samples of fine (PM 2.5 ) and coarse (PM 2.5-10 ) urban particulate matter were collected with 2 h time resolution in the frame of five sampling campaigns during 2007-2009 in different seasons in the downtown of Debrecen. Elemental concentrations from Al to Pb of over 1000 samples were obtained by particle induced X-ray emission (PIXE); concentrations of black carbon (BC) were determined with a smoke stain reflectometer. On this data base source apportionment was carried out by using the PMF method. Seven factors were identified for both size fractions, including soil dust, traffic, secondary aerosol - sulphates, domestic heating, oil combustion, agriculture and an unknown factor enriched with chlorine. Seasonal and daily variation of the different factors was studied as well as their dependence on meteorological parameters. Besides determining the time patterns characteristic to the city, several emission episodes were identified including a Saharan dust intrusion on 21st-24th May, 2008.

Contrasting responses of urban and rural surface energy budgets to heat waves explain synergies between urban heat islands and heat waves

International Nuclear Information System (INIS)

Li, Dan; Sun, Ting; Liu, Maofeng; Yang, Long; Wang, Linlin; Gao, Zhiqiu

2015-01-01

Heat waves (HWs) are projected to become more frequent and last longer over most land areas in the late 21st century, which raises serious public health concerns. Urban residents face higher health risks due to synergies between HWs and urban heat islands (UHIs) (i.e., UHIs are higher under HW conditions). However, the responses of urban and rural surface energy budgets to HWs are still largely unknown. This study analyzes observations from two flux towers in Beijing, China and reveals significant differences between the responses of urban and rural (cropland) ecosystems to HWs. It is found that UHIs increase significantly during HWs, especially during the nighttime, implying synergies between HWs and UHIs. Results indicate that the urban site receives more incoming shortwave radiation and longwave radiation due to HWs as compared to the rural site, resulting in a larger radiative energy input into the urban surface energy budget. Changes in turbulent heat fluxes also diverge strongly for the urban site and the rural site: latent heat fluxes increase more significantly at the rural site due to abundant available water, while sensible heat fluxes and possibly heat storage increase more at the urban site. These comparisons suggest that the contrasting responses of urban and rural surface energy budgets to HWs are responsible for the synergies between HWs and UHIs. As a result, urban mitigation and adaption strategies such as the use of green roofs and white roofs are needed in order to mitigate the impact of these synergies. (letter)

Source and Ecological Risk Characteristics of PAHs in Sediments from Qinhuai River and Xuanwu Lake, Nanjing, China

Directory of Open Access Journals (Sweden)

Zhenhua Zhao

2017-01-01

Full Text Available In order to investigate the residual characteristics, sources, and ecological risk of PAHs in sediment from urban rivers, the sediments of 15 typical sites from Qinhuai River and Xuanwu Lake, which are typical urban rivers and lake, were collected from October 2015 to July 2016; the sources of PAHs in sediment were also identified by several methods. Results showed that ∑PAHs concentration in sediment ranged from 796.2 ng/g to 10,470 ng/g with an average of 2,713.8 ng/g. High molecular weight PAHs with 4-5 rings were most prominent in the sediment during all four seasons. Source characterization studies based on the analysis of diagnostic ratio (triangular plot method, cluster analysis, and positive factor matrix analysis suggested that the PAHs of Qinhuai River Basin were mainly from pyrogenic origin (biomass and coal combustion and vehicular emission, and the petroleum source also cannot be ignored (specially in summer. Most individual PAHs occasionally affect the aquatic organisms. The highest benzo[a]pyrene-equivalent doses (BaPeq dose appear at the sites of sewage discharge and heavy traffic. So, the PAHs pollution sources of urban water body have obvious seasonal-dependent and human activities-dependent characteristics.

Monumental heritage exposure to urban black carbon pollution

Science.gov (United States)

Patrón, D.; Lyamani, H.; Titos, G.; Casquero-Vera, J. A.; Cardell, C.; Močnik, G.; Alados-Arboledas, L.; Olmo, F. J.

2017-12-01

In this study, aerosol light-absorption measurements obtained at three sites during a winter campaign were used to analyse and identify the major sources of Black Carbon (BC) particles in and around the Alhambra monument, a UNESCO World Heritage Site that receives over 2 million visitors per year. The Conditional Bivariate Probability Function and the Aethalometer model were employed to identify the main sources of BC particles and to estimate the contributions of biomass burning and fossil fuel emissions to the total Equivalent Black Carbon (EBC) concentrations over the monumental complex. Unexpected high levels of EBC were found at the Alhambra, comparable to those measured in relatively polluted European urban areas during winter. EBC concentrations above 3.0 μg/m3, which are associated with unacceptable levels of soiling and negative public reactions, were observed at Alhambra monument on 13 days from 12 October 2015 to 29 February 2016, which can pose a risk to its long-term conservation and may cause negative social and economic impacts. It was found that road traffic emissions from the nearby urban area and access road to the Alhambra were the main sources of BC particles over the monument. However, biomass burning emissions were found to have very small impact on EBC concentrations at the Alhambra. The highest EBC concentrations were observed during an extended stagnant episode associated with persistent high-pressure systems, reflecting the large impact that can have these synoptic conditions on BC over the Alhambra.

Impact of vegetable crop agriculture on anopheline agressivity and malaria transmission in urban and less urbanized settings of the South region of Cameroon.

Science.gov (United States)

Akono, Patrick Ntonga; Mbida, Jean Arthur Mbida; Tonga, Calvin; Belong, Philippe; Ngo Hondt, Odette Etoile; Magne, Gaëlle Tamdem; Peka, Marie Florence; Lehman, Leopold Gustave

2015-05-28

The use of inland valley swamps for vegetable crop agriculture contributes to food security in urban and less urbanized settings in Africa. The impact of this agriculture on aggressive mosquitoes' diversity and malaria transmission in central Africa is poorly documented. This study is aimed at assessing the impact of vegetable crop agriculture on these entomological parameters in urban and less urbanized settings of the forest area, south of Cameroon. The human bait technique was used for the capture of aggressive mosquitoes from January to December 2012. For three consecutive days each month, captures were performed on volunteers in hydro-agricultural and river bank sites of Akonolinga and Yaoundé. Physico-chemical characteristics of mosquito breeding sites were recorded. Molecular alongside morpho-taxonomic techniques were used for the identification of mosquito species; ELISA test was used to reveal Plasmodium falciparum infected mosquitoes through the detection of CSP. Mosquito diversity, aggressivity and malaria transmission in sites and settings were determined and compared. Biting rates were higher in hydro-agricultural sites of less urbanized and urban settings (31.8 b/p/n and 28.6 b/p/n respectively) than in river banks sites (6.83 b/p/n and 3.64 b/p/n respectively; p agricultural sites 2 species were captured in the urban setting versus 4 in the less urbanized setting, meanwhile in river bank sites, 3 species were captured in the urban setting versus 4 species in the less urbanized setting. An. nili s.s. was found in river banks only. An. hancocki was not found to insure Plasmodium falciparum Welch transmission. EIR in hydro-agricultural sites varied from 1.86 ib/p/n (urban area) to 2.13 ib/p/n (less urbanized area) with higher rates in April/May and August. Overall, EIR was higher in less urbanized areas (p agriculture (p = 0.2). These results highlight the need for specific preventive measures that take into account the ecological peculiarities

Feedback on the radiological management of a urban site contaminated with tritium

Energy Technology Data Exchange (ETDEWEB)

Leprieur, F.; Pierrard, O. [Institut de radioportection et de surete nucleaire - IRSN (France)

2014-07-01

Introduction: In November 2010, the IRSN is reached on a rare case of environmental tritium contamination on a site located in an urban area near Paris (Saint-Maur-des-Fosses - dpt 94). This contamination resulted from the presence in an enterprise's premises of an experimental device containing molecular sieve from the Valduc nuclear site, wrongly considered as un-used. First actions: IRSN has quickly performed an initial characterization of tritium contamination in the premises of the company and its close environment. The first results showed the existence of a strong local contamination (tritium activity> 150 000 Bq/m{sup 3} in air) and a important labeling in samples collected in the close vicinity of the company premises (between 1000 and 10000 Bq/kg f.w. in plants, between 500 and 1500 Bq/L in water). These results led IRSN to conduct multiple investigations: - tritium measurements on samples of water, air and plants collected in the area close to the building to know the importance and extent of environmental marking and follow its evolution over time. In this aim, 450 measurements were made between 2010 and 2013; - measurements of tritium in the urine of residents living near the contaminated building: the results showed traces of tritium for some of them but the assessments conducted by the IRSN from these results led to extremely low dosimetry estimates without consequences for the health of these people; - dosimetric evaluations of tritium exposure of employees and visitors of the company contaminated. Informing the public and stakeholders In November 2010, IRSN has collaborated with the mayor to facilitate early interventions in urban areas and in particular to facilitate contacts for access to private property. In this perspective, the IRSN participated in public meetings to explain the cause of this accident and the results of tritium measurements to residents. IRSN also published regularly on its web site briefing notes reflecting the results

Levels, Composition and Sources of PM in the Mexico City Metropolitan Area During the MILAGRO Campaign

Science.gov (United States)

Querol, X.; Pey, J.; Minguillon, M. C.; Perez, N.; Alastuey, A.; Moreno, T.; Bernabe, R.; Blanco, S.; Cardenas, B.

2007-05-01

Particle air pollution in urban agglomerations comes mostly from anthropogenic sources, mainly traffic, industrial processes, energy production, domestic and residential emissions, construction, but also a minor contribution from natural sources may be expected (bioaerosols, soil dust, marine aerosol). Once emitted into the atmosphere, this complex mixture of pollutants may be transformed as a function of the ambient conditions and the interaction among the different PM components, and also between PM components and gaseous pollutants. This system is especially complex in mega-cities due to the large emission volumes of PM components and gaseous precursors, the high variability and broad distribution of emission sources, and the possible long range transport of the polluted air masses. Speciation studies help to identify major sources of PM components with the end objective of applying plans and programs for PM pollution abatement. In this framework, concentration levels and compositions of particulate matter (PM2.5, PM10 and TSP) have been measured simultaneously at two sites in the Mexico City Metropolitan Area (T0 and CENICA) and at one site 50 km away from Mexico City (T1) during the MILAGRO campaign (1st to 31st March 2006). Spatial and time (day and night) variations have been analysed. Coarse fraction levels were higher at T1 than at CENICA and T0, contrary to what was expected. This was due to the important soil re-suspension at T1, contributing significantly to the crustal load. Moreover, crustal levels were higher during daytime than during nights at all sites, while some secondary compounds (sulphate and ammonium) presented an opposite trend. Regarding trace elements, levels of Pb, Zn and Cd were higher at T0 than at CENICA and T1, probably due to traffic contribution. Arsenic levels did not show a clear pattern, being alternatively higher at CENICA and T0. Two intense episodes of Hg particulate have been recorded, more noticeable at T1 than at the urban

Phase I Source Investigation, Heckathorn Superfund Site, Richmond, California

Energy Technology Data Exchange (ETDEWEB)

Kohn, Nancy P; Evans, Nathan R

2002-12-18

This report represents Phase I of a multi-phase approach to a source investigation of DDT at the Heckathorn Superfund Site, Richmond, California, the former site of a pesticide packaging plant, and the adjacent waterway, the Lauritzen Channel. Potential identified sources of contamination were from sloughed material from undredged areas (such as side banks) and from outfall pipes. Objectives of Phase I included the (1) evaluation of pesticide concentrations associated with discharge from outfalls, (2) identification of additional outfalls in the area, (3) identification of type, quantity, and distribution of sediment under the Levin pier, (4) quantification of pesticide concentrations in sediment under the pier, and (5) evaluation of sediment structure and slope stability under the pier. Field operations included the collection of sediment directly from inside the mouths of outfall pipes, when possible, or the deployment of specially designed particle traps where direct sampling was problematic. Passive water samplers were placed at the end of known outfall pipes and analyzed for DDT and other pesticides of concern. Underwater dive surveys were conducted beneath the Levin pier to document type, slope, and thickness of sediment. Samples were collected at locations of interest and analyzed for contaminants. Also sampled was soil from bank areas, which were suspected of potentially contributing to continued DDT contamination of the Lauritzen Channel through erosion and groundwater leaching. The Phase I Source Investigation was successful in identifying significant sources of DDT contamination to Lauritzen Channel sediment. Undredged sediment beneath the Levin pier that has been redistributed to the channel is a likely source. Two outfalls tested bear further investigation. Not as well-defined are the contributions of bank erosional material and groundwater leaching. Subsequent investigations will be based on the results of this first phase.

Source apportionment of organic compounds in Berlin using positive matrix factorization - assessing the impact of biogenic aerosol and biomass burning on urban particulate matter.

Science.gov (United States)

Wagener, Sandra; Langner, Marcel; Hansen, Ute; Moriske, Heinz-Jörn; Endlicher, Wilfried R

2012-10-01

Source apportionment of 13 organic compounds, elemental carbon and organic carbon of ambient PM(10) and PM(1) was performed with positive matrix factorization (PMF). Samples were collected at three sites characterized by different vegetation influences in Berlin, Germany in 2010. The aim was to determine organic, mainly biogenic sources and their impact on urban aerosol collected in a densely populated region. A 6-factor solution provided the best data fit for both PM-fractions, allowing the sources isoprene- and α-pinene-derived secondary organic aerosol (SOA), bio primary, primarily attributable to fungal spores, bio/urban primary including plant fragments in PM(10) and cooking and traffic emissions in PM(1), biomass burning and combustion fossil to be identified. With mean concentrations up to 2.6 μg Cm(-3), biomass burning dominated the organic fraction in cooler months. Concentrations for α-pinene-derived SOA exceeded isoprene-derived concentrations. Estimated secondary organic carbon contributions to total organic carbon (OC) were between 7% and 42% in PM(10) and between 11% and 60% in PM(1), which is slightly lower than observed for US- or Asian cities. Primary biogenic emissions reached up to 33% of OC in the PM(10)-fraction in the late summer and autumn months. Temperature-dependence was found for both SOA-factors, correlations with ozone and mix depth only for the α-pinene-derived SOA-factor. Latter indicated input of α-pinene from the borders, highlighting differences in the origin of the precursors of both factors. Most factors were regionally distributed. High regional distribution was found to be associated with stronger influence of ambient parameters and higher concentrations at the background station. A significant contribution of biogenic emissions and biomass burning to urban organic aerosol could be stated. This indicates a considerable impact on PM concentrations also in cities in a densely populated area, and should draw the attention

Relation Decomposing between Urbanization and Consumption of Water-Energy Sources

Science.gov (United States)

Wang, Y.; Xiao, W.; Wang, Y.; Zhao, Y.; Wang, J., , Dr; Jiang, D.; Wang, H.

2017-12-01

Abstract: Water resources and energy, important subsystems of city, are the basic guarantee for the normal operation of city, which play an important role to brace the urbanization. The interdependence between them are increasing along with the rapid development of China's economy. The relationship between urbanization and consumption of energy and water have become the focal point of the scholars, but the research have more attention to the impact of urbanization on two subsystems separately, and do not reveal the effects of urbanization on the water-energy nexus. Thus, there is little consideration upon the different characteristics of China's several regions in water and energy consumption in urbanization. In this paper, the STIRPAT model is built to reveal the relationship between urbanization and the consumption of water and energy. Also, the influence of urbanization on different main body of water and energy consumption are discussed. The different regional main factors of water and energy in the process of urbanization are identified through water and energy panel data of China's thirty provinces. Finally, through the regression analysis of total water consumption data of agriculture, industry, service industry with total energy consumption data, the relationship of water and energy in the process of urban development are analyzed.

The sources and fate of (210)Po in the urban air: A review.

Science.gov (United States)

Długosz-Lisiecka, Magdalena

2016-09-01

The origin of (210)Po activity and its fluctuations in the air are discussed in this paper. In the case of atmospheric aerosol samples, a comparison of the (210)Po/(210)Pb and (210)Bi/(210)Pb activity ratios makes it possible not only to determine aerosol residence times but also to appraise the contribution of the unsupported (210)Po coming from other sources than (222)Rn decay, such as human industrial activities, especially coal combustion. A simple mathematical method makes it possible to observe the seasonal fluctuations of the anthropogenic excess of (210)Po in the urban air. The average doses of (210)Po intake with food (including drinking water) and inhalation of urban aerosols are usually lower than those from (210)Po intake by cigarette smokers and negligible in comparison to total natural radiation exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Controls on Stormwater Runoff Quality and Quantity in Semi-arid, Urban Catchments

Science.gov (United States)

Gallo, E. L.; Brooks, P. D.; Lohse, K. A.

2009-12-01

Utilization of recharged urban runoff to complement municipal water supply has gained importance in arid regions where populations and their urban footprint continue to grow, and where water resources are scarce. However, our understanding of how runoff quantity and quality respond to urbanization in arid landscapes is largely incomplete and poses a challenge for water resources management. Here we address the question: What controls the hydrologic and hydrochemical responses of arid urban catchments? We collected water samples and stream stage data from 5 urban catchments of varied land uses (low, medium and high density residential, mixed and commercial land use) in southern Arizona during the summer rainfall seasons of 2007 and 2008. The most homogeneous catchments, as indicated by the index of landscape heterogeneity, were the least and most impervious, while the most heterogeneous sites had mid-range imperviousness. Hydrochemical responses were mixed, did not correlate with imperviousness or vegetation abundance, and were not strongly controlled by land use. Clustering analysis highlight hydrologic and sourcing controls on hydrochemistry, specifically conservative solute transport, land use specific and geologic solute sourcing and atmospheric deposition. Overall, water yields were surprisingly small (< 15%) and increased with imperviousness. Our data show that discharge responses were more sensitive to rainfall magnitude in homogeneous sites. We suggest that imperviousness and rainfall magnitude control water yields; whereas landscape heterogeneity may control a catchment’s sensitivity to generate runoff. The coupling of landscape and hydrology in controlling hydrochemistry is well illustrated by chloride (Cl), a non-reactive hydrologic tracer that was positively correlated with a large number of solutes such as ammonium, dissolved organic carbon, cadmium and zinc. We observed the highest concentrations and coefficients of variation of Cl at least and most

Effects of the spatial resolution of urban drainage data on nonpoint source pollution prediction.

Science.gov (United States)

Dai, Ying; Chen, Lei; Hou, Xiaoshu; Shen, Zhenyao

2018-03-14

Detailed urban drainage data are important for urban nonpoint source (NPS) pollution prediction. However, the difficulties in collecting complete pipeline data usually interfere with urban NPS pollution studies, especially in large-scale study areas. In this study, NPS pollution models were constructed for a typical urban catchment using the SWMM, based on five drainage datasets with different resolution levels. The influence of the data resolution on the simulation results was examined. The calibration and validation results of the higher-resolution (HR) model indicated a satisfactory model performance with relatively detailed drainage data. However, the performances of the parameter-regionalized lower-resolution (LR) models were still affected by the drainage data scale. This scale effect was due not only to the pipe routing process but also to changes in the effective impervious area, which could be limited by a scale threshold. The runoff flow and NPS pollution responded differently to changes in scale, primarily because of the difference between buildup and washoff and the more significant decrease in pollutant infiltration loss and the much greater increase of pollutant flooding loss while scaling up. Additionally, scale effects were also affected by the rainfall type. Sub-area routing between impervious and pervious areas could improve the LR model performances to an extent, and this approach is recommended to offset the influence of spatial resolution deterioration.

Characterization of occurrence, sources and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in a tropical urban catchment

International Nuclear Information System (INIS)

Chen, Huiting; Reinhard, Martin; Nguyen, Tung Viet; You, Luhua; He, Yiliang; Gin, Karina Yew-Hoong

2017-01-01

Understanding the sources, occurrence and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in the urban water cycle is important to protect and utilize local water resources. Concentrations of 22 target PFASs and general water quality parameters were determined monthly for a year in filtered water samples from five tributaries and three sampling stations of an urban water body. Of the 22 target PFASs, 17 PFASs were detected with a frequency >93% including PFCAs: C4-C12 perfluoroalkyl carboxylates, C4, C6, C8, and C10 perfluoroalkane sulfonates, perfluorooctane sulfonamides and perfluorooctane sulfonamide substances (FOSAMs), C10 perfluoroalkyl phosphonic acid (C10 PFPA), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) and C8/C8 perfluoroalkyl phosphinic acid (C8/C8-PFPIA). The most abundant PFASs in water were PFBS (1.4–55 ng/L), PFBA (1.0–23 ng/L), PFOS (1.5–24 ng/L) and PFOA (2.0–21 ng/L). In the tributaries, PFNA concentrations ranged from 1.2 to 87.1 ng/L except in the May 2013 samples of two tributaries, which reached 520 and 260 ng/L. Total PFAS concentrations in the sediment samples ranged from 1.6 to 15 ng/g d.w. with EtFOSAA, PFDoA, PFOS and PFDA being the dominant species. Based on water and sediment data, two types of sources were inferred: one-time or intermittent point sources and continuous non-point sources. FOSAMs and PFOS released continually from non-point sources, C8/C8 PFPIA, PFDoA and PFUnA was released from point sources. The highly water soluble short-chain PFASs including PFBA, PFPeA and PFBS remained predominantly in the water column. The factors governing solution phase concentrations appear to be compound hydrophobicity and sorption to suspended particles. Correlation of the dissolved phase concentrations with precipitation data suggested stormwater was a significant source of PFBA, PFBS, PFUnA and PFDoA. Negative correlations with precipitation indicated sources feeding FOSAA and FOSA directly into the tributaries

Occurrence and sources of natural and anthropogenic lipid tracers in surface soils from arid urban areas of Saudi Arabia

International Nuclear Information System (INIS)

Rushdi, Ahmed I.; Al-Mutlaq, Khalid F.; El-Mubarak, Aarif H.; Al-Saleh, Mohammed A.; El-Otaibi, Mubarak T.; Ibrahim, Sami M.M.; Simoneit, Bernd R.T.

2016-01-01

Soil particles contain a variety of natural and anthropogenic organic components, and in urban areas can be considered as local collectors of pollutants. Surface soil samples were taken from ten urban areas in Riyadh during early winter of 2007. They were extracted with dichloromethane-methanol mixture and the extracts were analyzed by gas chromatography-mass spectrometry. The major compounds were unresolved complex mixture (UCM), plasticizers, n-alkanes, carbohydrates, n-alkanoic acids, hopanes, n-alkanols, and sterols. Vegetation detritus was the major natural source of organic compounds (24.0 ± 15.7%) in samples from areas with less human activities and included n-alkanes, n-alkanoic acids, n-alkanols, sterols and carbohydrates. Vehicular emission products and discarded plastics were the major anthropogenic sources in the soil particles (53.3 ± 21.3% and 22.7 ± 10.7%, respectively). The anthropogenic tracers were UCM, plasticizers, n-alkanes, hopanes and traces of steranes. Vegetation and human activities control the occurrence and distribution of natural and anthropogenic extractable organic matter in this arid urban area. - Highlights: • Human activities influence the distribution of EOM in soils of urban arid regions. • Petroleum residues and plastics are the dominant anthropogenic input. • Low soil organic matter and moisture limit microbial/fungal alteration. - This work shows that human activities are critical factors that influence the characteristics and distribution of EOM in soils of arid urban regions.

Source contributions to PM{sub 2.5} and PM{sub 10} at an urban background and a street location

Energy Technology Data Exchange (ETDEWEB)