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The variability of pollutants is an important factor in determining human exposure to the chemicals. This study presents the result of investigation of variability of Volatile organic compounds (VOCs) in urban area of Delhi, capital of India. Fifteen locations, in five categories namely residential, commercial, industrial, traffic intersections and petrol pump were monitored for one year every month during peak hours in morning and evening. Measurement focused on target VOCs as defined by USEPA. Variability was divided into measurement, spatial, temporal and temporal–spatial interaction components. Temporal component along with temporal–spatial interaction were found to be the major contributors to the variability of measured VOC concentrations. Need of continuous monitoring to capture short–term peak concentration and averages is evident.  相似文献   
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The present work attempts to identify VOC's in outdoor and indoor air in Mumbai City India. Ambient air was adsorbed on especially fabricated stainless steel cartridge packed with activated coconut charcoal at uniform flow rate. Qualitative identification of VOC's was done by thermally desorbing air from the cartridges and subsequent analysis on Varian GC-MS using NIST Library. The outdoor monitoring locations include residential area, commercial area, industrial, airport, petrol pumps, traffic junctions, arterial roads, highways, slums, parking area, service garages and municipal dump sites. The indoor locations comprised of air-conditioned and non air-conditioned offices, bedrooms, shops and instrumentation laboratory. The identified VOC's include aldehydes, ketones, polynuclear aromatic hydrocarbons, aromatic acids, oxygenated hydrocarbons, amines, esters and halogenated compounds. Thirteen VOCs in outdoor air and seven in indoor air amongst those identified, figure in the list of Hazardous Air Pollutants listed in Title III of the U.S. EPA Clean Air Act Amendments of 1990.  相似文献   
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Air pollution leads to serious negative impacts on health. Thephysical evidence is compelling. An attempt has been made inthis paper to establish dose-response relationship of AmbientAir Quality Index and human health, based on time spent by anindividual in different microenvironments during one day.Economic valuation of morbidity and mortality has been attemptedthrough lost salary approach. The results show that theavoidance cost is 29% of the total health damage cost.  相似文献   
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Extant species of the supraordinal mammal clade Euarchonta belong to the orders Primates, Scandentia, or Dermoptera. The fossil record of euarchontans suggests that they underwent their initial radiation during the Paleocene (65–55 million years ago) in North America, Eurasia, and Africa. The time and place of origin is poorly resolved due to lack of definitive fossils of euarchontan stem taxa. We describe a fragmentary humerus and two fragmentary ulnae from the latest Cretaceous of India that bear significantly on this issue. The fossils are tentatively referred to Deccanolestes cf. hislopi due to their small size and the fact that Deccanolestes is the only eutherian dental taxon to have been recovered from the same locality. The new fossils are used to evaluate the existing behavioral hypothesis that Deccanolestes was arboreal, and the competing phylogenetic hypotheses that Deccanolestes is a stem eutherian versus a stem euarchontan. The humerus resembles those of euarchontans in possessing a laterally keeled ulnar trochlea, a distinct zona conoidea, and a spherical capitulum. These features also suggest an arboreal lifestyle. The ulnar morphology is consistent with that of the humerus in reflecting an arboreal/scansorial animal. Detailed quantitative comparisons indicate that, despite morphological correlates to euarchontan-like arboreality, the humerus of Deccanolestes is morphologically intermediate between those of Cretaceous “condylarthran” mammals and definitive Cenozoic euarchontans. Additionally, humeri attributed to adapisoriculids are morphologically intermediate between those of Deccanolestes and definitive euarchontans. If adapisoriculids are euarchontans, as recently proposed, our results suggest that Deccanolestes is more basal. The tentative identification of Deccanolestes as a basal stem euarchontan suggests that (1) Placentalia began to diversify and Euarchonta originated before the Cretaceous–Tertiary boundary and (2) the Indian subcontinent, Eurasia, and Africa are more likely places of origin for Euarchonta than is North America.  相似文献   
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USEPA’s UNMIX, positive matrix factorization (PMF) and effective variance-chemical mass balance (EV-CMB) receptor models were applied to chemically speciated profiles of 125 indoor PM2.5 measurements, sampled longitudinally during 2012–2013 in low-income group households of Central India which uses solid fuels for cooking practices. Three step source apportionment studies were carried out to generate more confident source characterization. Firstly, UNMIX6.0 extracted initial number of source factors, which were used to execute PMF5.0 to extract source-factor profiles in second step. Finally, factor analog locally derived source profiles were supplemented to EV-CMB8.2 with indoor receptor PM2.5 chemical profile to evaluate source contribution estimates (SCEs). The results of combined use of three receptor models clearly describe that UNMIX and PMF are useful tool to extract types of source categories within small receptor dataset and EV-CMB can pick those locally derived source profiles for source apportionment which are analog to PMF-extracted source categories. The source apportionment results have also shown three fold higher relative contribution of solid fuel burning emissions to indoor PM2.5 compared to those measurements reported for normal households with LPG stoves. The previously reported influential source marker species were found to be comparatively similar to those extracted from PMF fingerprint plots. The comparison between PMF and CMB SCEs results were also found to be qualitatively similar. The performance fit measures of all three receptor models were cross-verified and validated and support each other to gain confidence in source apportionment results.  相似文献   
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Improper solid waste management leads to aesthetic and environmental problems. Emission ofvolatile organic compounds (VOCs) is one of the problems from uncontrolled dumpsite. VOCs are well known to be hazardous to human health and many of them are known or potential carcinogens. They also contribute to ozone formation at ground level and climate change as well. The qualitative and quantitative analysis of VOCs emitting from two municipal waste (MSW) disposal sites in Mumbai, India, namely Deonar and Malad, are presented in this paper. Air at dumpsites was sampled and analyzed on gas chromatography-mass spectrometry (GC-MS) in accordance with U.S. Environmental Protection Agency (EPA) TO-17 compendium method for analysis of toxic compounds. As many as 64 VOCs were qualitatively identified, among which 13 are listed under hazardous air pollutants (HAPs). Study of environmental distribution of a few major VOCs indicates that although air is the principal compartment of residence, they also get considerably partitioned in soil and vegetation. The CO2 equivalent of target VOCs from the landfills in Malad and Deonar shows that the total yearly emissions are 7.89E+03 and 8.08E+02 kg, respectively. The total per hour ozone production from major VOCs was found to be 5.34E-01 ppb in Deonar and 9.55E-02 ppb in Malad. The total carcinogenic risk for the workers in the dumpsite considering all target HAPs are calculated to be 275 persons in 1 million in Deonar and 139 persons in 1 million in Malad.  相似文献   
28.
Evaluation of Chitosan zerovalent Iron Nanoparticle (CIN) towards arsenic removal is presented. Addition of chitosan enhances the stability of Fe(0) nano particle. Prepared adsorbent was characterized by FT-IR, SEM EDX, BET and XRD. It was found that, with an initial dose rate of 0.5 g L−1, concentrations of As (III) and As (V) were reduced from 2 mg L−1 to <5 μg L−1 in less than 180 min and the adsorbent was found to be applicable in wide range of pH. Langmuir monolayer adsorption capacity was found to be 94 ± 1.5 mg g−1 and 119 ± 2.6 mg g−1 at pH 7 for As (III) and As (V) respectively. Major anions including sulfate, phosphate and silicate did not cause significant interference in the adsorption behavior of both arsenite and arsenate. The adsorbent was successfully recycled five times and applied to the removal of total inorganic arsenic from real life groundwater samples.  相似文献   
29.
During the months of October to November, many important festivals are celebrated in India. Celebration of these festivals are marked by extensive use of fireworks or pyrotechnics, bonfire, incense burning, open air community cooking, and temporary eateries using crude fuel such as coal, wood, kerosene, cow dung, burning of raw/semiwood, and coconut shells. The present study deals with the influence of these unregulated anthropogenic activities on ambient mixing level of volatile organic compounds (VOCs), especially some carbonyl compounds. The study was undertaken in the metropolitan city of Kolkata, India, with very high population density, which is even higher during festival period. The average total carbonyl level at different sites in Kolkata varied from 134.8 to 516.5 μg m?3 in pre-festival season, whereas in post-festival season the same varied from 252.2 to 589.3 μg m?3. Formaldehyde to acetaldehyde ratio altered from 0.62 in pre-festival season to 1.78 in post-festival season. Diurnal variation also altered, indicating variation in source composition of carbonyls. The total ozone forming potential calculated for all 14 carbonyls in pre-festival season increased by 35% in post-festival season. The effect of anthropogenic activities typical to the event of Diwali night characterized by intense execution of pyrotechnics resulted in significantly high level of carbonyl VOCs. Principal component analysis study for the event of Diwali shows clear contribution of the event on certain carbonyl VOCs. The results indicate elevated primary emissions of these pollutants and also their effect on formation of secondary pollutants. The study emphasizes the need of generating awareness among the communities in society as well as need for regulations to minimize the emissions and related hazards to the extent possible.

Implications: Altered anthropogenic activities typical of festival season including extensive use of pyrotechnics affect ambient level of volatile organic compounds, especially some carbonyls. Such activities have considerable effect on interspecies ratio and diurnal variation. They also affect formation of secondary pollutants such as tropospheric ozone. Principal component analysis (PCA) study shows clear contribution of the pyrotechnics execution on certain carbonyl VOCs. The findings emphasize the need of generating awareness in society and need for regulations to minimize the emissions.  相似文献   
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