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Levels of short chain chlorinated paraffins in pine needles and bark and their vegetation-air partitioning in urban areas 全文
2015
Wang, Thanh | Yu, Junchao | Han, Shanlong | Wang, Yawei | Jiang, Guibin
Short chain chlorinated paraffins (SCCPs) have been of considerable concern in recent years due to their high production volumes, environmental persistency and potential for long range atmospheric transport. Vegetation can take up considerable amounts of semivolatile organic compounds from the atmosphere and can act as indicators of local contamination. Paired pine needles and bark were sampled around Beijing during winter and summertime to investigate the distribution of SCCPs in urban areas. Levels in bark samples ranged 5.79–37.5 μg/g on a lipid normalized basis (lw) with a geometric mean (GM) of 16.9 μg/g lw whereas levels were 3.03–40.8 (GM 11.8) μg/g lw for needles. Average congener group abundance profiles showed equal contribution of all four carbon groups (C10–13) in wintertime whereas higher abundances of C10 and C11 groups were found during summer. Uptake of SCCPs occurred mainly via kinetically limited gaseous deposition and particle bound deposition in the investigated area.
显示更多 [+] 显示较少 [-]Spatiotemporal distribution of carbonyl compounds in China 全文
2015
Ho, K.F. | Ho, Steven Sai Hang | Huang, R.-J. | Dai, W.T. | Cao, J.J. | Tian, Linwei | Deng, W.J.
A sampling campaign was carried out at nine Chinese cities in 2010/2011. Fifteen monocarbonyls (C# = 1–9) were quantified. Temperature is the rate-determining factor of the summertime carbonyl levels. The carbonyl emissions in winter are mainly driven by the primary anthropogenic sources like automobile. A molar ratio of propionaldehyde to nonaldehyde is a barometer of the impact of atmospheric vegetation emission which suggesting that strong vegetation emissions exist in summer and high propionaldehyde abundance is caused by fossil fuel combustion in winter. Potential health risk assessment of formaldehyde and acetaldehyde was conducted and the highest cumulative risks were observed at Chengdu in summer and Wuhan in winter. Because of the strong photochemical reaction and large amount of anthropogenic emissions, high concentrations of carbonyl compounds were observed in Chengdu. The use of ethanol-blended gasoline in Wuhan is the key reason of acetaldehyde emission and action should be taken to avoid potential health risks.
显示更多 [+] 显示较少 [-]Hourly differences in air pollution on the risk of asthma exacerbation 全文
2015
Kim, Jayeun | Kim, Ho | Kweon, Jung
We investigated the association between hourly differences in air pollution and asthma exacerbation in Korea using asthma-related emergency department data and verified seasonality and demographic modifiers with an hourly temporal resolution. We applied time-stratified case-crossover adjusted for weather and influenza; the lag was stratified as 1–6, 7–12, 13–18, 19–24, 25–48, and49–72 h. Odds ratios (95% confidence interval) per interquartile range increase were 1.05 (1.00–1.11) after 1–6 h for PM10–2.5 and 1.10 (1.04–1.16) after 19–24 h for O3. Effect size was 1.14 (1.06–1.22) at a 1–6 h lag in spring for PM10–2.5, and 1.25 (1.03–1.51) at a 25–48 h lag in winter for O3. O3 effects were age- and low socio-economic status-modified at a 7–12 h lag [1.25 (1.04–1.51)]. Increased PM10–2.5 and O3 increased the risk of asthma exacerbation; the effect of PM10–2.5 was most immediate.
显示更多 [+] 显示较少 [-]Application of chemometric analysis and self Organizing Map-Artificial Neural Network as source receptor modeling for metal speciation in river sediment 全文
2015
Pandey, Mayank | Pandey, Ashutosh Kumar | Mishra, Ashutosh | Tripathi, B.D.
Present study deals with the river Ganga water quality and its impact on metal speciation in its sediments. Concentration of physico-chemical parameters was highest in summer season followed by winter and lowest in rainy season. Metal speciation study in river sediments revealed that exchangeable, reducible and oxidizable fractions were dominant in all the studied metals (Cr, Ni, Cu, Zn, Cd, Pb) except Mn and Fe. High pollution load index (1.64–3.89) recommends urgent need of mitigation measures. Self-organizing Map-Artificial Neural Network (SOM-ANN) was applied to the data set for the prediction of major point sources of pollution in the river Ganga.
显示更多 [+] 显示较少 [-]Concentrations and origins of nitro-polycyclic aromatic hydrocarbons and oxy-polycyclic aromatic hydrocarbons in ambient air in urban and rural areas in northern China 全文
2015
Li, Wei | Wang, Chen | Shen, Huizhong | Su, Shu | Shen, Guofeng | Huang, Ye | Zhang, Yanyan | Chen, Yuanchen | Chen, Han | Lin, Nan | Zhuo, Shaojie | Zhong, Qirui | Wang, Xilong | Liu, Junfeng | Li, Bengang | Liu, Wenxin | Tao, Shu
Twelve nitro-PAHs (nPAHs) and four oxy-PAHs (oPAHs) were measured in air samples for 12 months at 18 sites in urban settings, rural villages, or rural fields in northern China. The nPAH concentrations were higher in urban areas (1.3 ± 1.3 ng/m3), and nPAH/parent PAH ratios were higher (suggesting important contributions from motor vehicles and secondary formation) in urban sites than in rural villages. oPAHs are primarily emitted from solid fuel combustion and motor vehicles, and similar oPAH concentrations were found in urban areas (23 ± 20 ng/m3) and rural villages (29 ± 24 ng/m3). The high numbers of motor vehicles in Beijing and intensive industrial activity in Taiyuan and Dezhou caused higher nPAH concentrations. No spatial trend in oPAH concentrations was found in the rural villages, because similar oPAH mixtures are emitted from solild fuel combustion. The nPAH and oPAH concentrations were higher in the winter, and correlated with residential energy consumption and precipitation.
显示更多 [+] 显示较少 [-]Searching for native tree species and respective potential biomarkers for future assessment of pollution effects on the highly diverse Atlantic Forest in SE-Brazil 全文
2015
Domingos, Marisa | Bulbovas, Patricia | Camargo, Carla Z.S. | Aguiar-Silva, Cristiane | Brandão, Solange E. | Dafré-Martinelli, Marcelle | Dias, Ana Paula L. | Engela, Marcela R.G.S. | Gagliano, Janayne | Moura, Barbara B. | Alves, Edenise S. | Rinaldi, Mirian C.S. | Gomes, Eduardo P.C. | Furlan, Claudia M. | Figueiredo, Ana Maria G.
This study summarizes the first effort to search for bioindicator tree species and respective potential biomarkers for future assessment of potential mixed pollution effects on the highly diverse Atlantic Forest in SE-Brazil. Leaves of the three most abundant species inventoried in a phytosociological survey (Croton floribundus, Piptadenia gonoacantha and Astronium graveolens) were collected in four forest remnants during winter and summer (2012). Their potential bioindicator attributes were highlighted using a screening of morphological, chemical and biochemical markers. The leaf surface structure and/or epicuticular wax composition pointed the accumulator properties of C. floribundus and P. gonoacantha. C. floribundus is a candidate for assessing potential accumulation of Cu, Cd, Mn, Ni, S and Zn. P. gonoacantha is a candidate to monitor polycyclic aromatic hydrocarbons. Increased levels of secondary metabolites and decreased antioxidant capacity in leaves of A. graveolens may support its value as a bioindicator for oxidative pollutants by visible dark stipplings.
显示更多 [+] 显示较少 [-]Source contributions and regional transport of primary particulate matter in China 全文
2015
Hu, Jianlin | Wu, Li | Zheng, Bo | Zhang, Qiang | He, Kebin | Chang, Qing | Li, Xinghua | Yang, Fumo | Ying, Qi | Zhang, Hongliang
A source-oriented CMAQ was applied to determine source sector/region contributions to primary particulate matter (PPM) in China. Four months were simulated with emissions grouped to eight regions and six sectors. Predicted elemental carbon (EC), primary organic carbon (POC), and PPM concentrations and source contributions agree with measurements and have significant spatiotemporal variations. Residential is a major contributor to spring/winter EC (50–80%), POC (60%–90%), and PPM (30–70%). For summer/fall, industrial contributes 30–50% for EC/POC and 40–60% for PPM. Transportation is more important for EC (20–30%) than POC/PPM (<5%). Open burning is important in summer/fall of Guangzhou and Chongqing. Dust contributes to 1/3–1/2 in spring/fall of Beijing, Xi'an and Chongqing. Based on sector–region combination, local residential/transportation and residential/industrial from Heibei are major contributors to spring PPM in Beijing. In summer/fall, local industrial is the largest. In winter, residential/industrial from local and Hebei account for >90% in Beijing.
显示更多 [+] 显示较少 [-]Humidity plays an important role in the PM2.5 pollution in Beijing 全文
2015
Cheng, Yuan | He, Ke-bin | Du, Zhen-yu | Zheng, Mei | Duan, Feng-kui | Ma, Yong-Liang
Heavily-polluted PM2.5 (fine particulate matter) episodes frequently impacting Beijing, especially during winter, have become a substantial concern. We found that during winter, the daily variation of PM2.5 in Beijing tracked the pattern of relative humidity (RH). With the increase of PM2.5 (or RH), water-soluble components (especially inorganic ions) became more abundant, and the water-soluble organic carbon to organic carbon ratios increased. The nitrate to sulfate ratios also exhibited dependence on RH, and were higher than those measured about a decade ago, consistent with the increasing trend of nitrogen oxides emissions. Surprisingly, the ratios of water-insoluble organic carbon to elemental carbon showed significant increase at high RH levels, presumably indicating the formation of secondary organic aerosol that is not soluble in water. In addition, humid winters were occasionally identified during 1996–2013 which are expected to be favorable for the formation of air pollution episodes with high PM2.5 concentrations.
显示更多 [+] 显示较少 [-]Composition and potential origin of marine debris stranded in the Western Indian Ocean on remote Alphonse Island, Seychelles 全文
2015
Duhec, Aurélie V. | Jeanne, Richard F. | Maximenko, Nikolai | Hafner, Jan
The abundance, composition, and potential sources of marine debris were investigated on remote Alphonse Island, during the austral winter 2013. A total of 4743 items, weighing 142kg, were removed from 1km of windward beach, facing the prevailing southeasterly trade winds. Our study demonstrates the prevalence of plastic debris as a world-wide marine contaminant. Characteristics of the debris suggest it originated primarily from land-based sources. To determine their potential geographic sources we used the Surface Current from Diagnostic model of near-surface ocean currents, forced by satellite sea level and wind data. While preliminary evidence indicated the Southeast Asia to be the main source of the flotsam, the model highlighted Somalia as another potential primary source. Our study concludes that most of the collected debris entered the sea as a result of inadequate waste management and demonstrates how anthropogenic waste can negatively impact even the most remote environments.
显示更多 [+] 显示较少 [-]Biomass burning emissions contaminate winter snowfalls in urban Beijing: A case study in 2012 全文
2015
You, Chao | Gao, Shaopeng | Xu, Chao
Three monosaccharide anhydrides levoglucosan, mannosan and galactosan were detected in winter snowfall samples of 2012 in urban Beijing. Concentrations of three isomers vary from 0.15 to 54.43ngmL−1, with an average value of 10.49ngmL−1. Levoglucosan is the most abundant component. Winter snowfalls are contaminated by biomass burning emissions seriously in urban Beijing. The main sources are softwood and crop residue burnings around Beijing from late autumn to early winter, while long-range transport of biomass burning emissions contribute more during the late winter. Concentrations of monosaccharide anhydrides in snowfall samples may be affected by both topography and the meteorological conditions around urban Beijing.
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