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Environmental Science and Pollution... Jan 2010Pakistan, during the last decade, has seen an extensive escalation in population growth, urbanization, and industrialization, together with a great increase in... (Review)
Review
BACKGROUND AND PURPOSE
Pakistan, during the last decade, has seen an extensive escalation in population growth, urbanization, and industrialization, together with a great increase in motorization and energy use. As a result, a substantial rise has taken place in the types and number of emission sources of various air pollutants. However, due to the lack of air quality management capabilities, the country is suffering from deterioration of air quality. Evidence from various governmental organizations and international bodies has indicated that air pollution is a significant risk to the environment, quality of life, and health of the population. The Government has taken positive steps toward air quality management in the form of the Pakistan Clean Air Program and has recently established a small number of continuous monitoring stations. However, ambient air quality standards have not yet been established. This paper reviews the data being available on the criteria air pollutants: particulate matter (PM), sulfur dioxide, ozone, carbon monoxide, nitrogen dioxide, and lead.
METHODS
Air pollution studies in Pakistan published in both scientific journals and by the Government have been reviewed and the reported concentrations of PM, SO(2), O(3), CO, NO(2), and Pb collated. A comparison of the levels of these air pollutants with the World Health Organization air quality guidelines was carried out.
RESULTS
Particulate matter was the most serious air pollutant in the country. NO(2) has emerged as the second high-risk pollutant. The reported levels of PM, SO(2), CO, NO(2), and Pb were many times higher than the World Health Organization air quality guidelines. Only O(3) concentrations were below the guidelines.
CONCLUSIONS
The current state of air quality calls for immediate action to tackle the poor air quality. The establishment of ambient air quality standards, an extension of the continuous monitoring sites, and the development of emission control strategies are essential.
Topics: Air; Air Pollutants; Environmental Monitoring; Pakistan; Particulate Matter; Risk Assessment; Time Factors
PubMed: 19575252
DOI: 10.1007/s11356-009-0217-2 -
Journal of Chromatography. A Jul 2000The use of sorbents in trapping volatile organic compounds in air for subsequent analysis is reviewed. Sorbents are classified in accordance with the mechanism used to... (Review)
Review
The use of sorbents in trapping volatile organic compounds in air for subsequent analysis is reviewed. Sorbents are classified in accordance with the mechanism used to recover the trapped compounds, either solvent or thermal desorption. The use of sorbents is contrasted with other sampling procedures, such as collecting whole air samples using canisters. New developments such as solid-phase microextraction are described. In particular, emphasis is placed on a holistic approach to sampling and analysis, and communication is encouraged between those who take samples in the field, and those who perform the analysis.
Topics: Adsorption; Air; Organic Chemicals; Reproducibility of Results; Volatilization
PubMed: 10941671
DOI: 10.1016/s0021-9673(00)00363-0 -
Journal of the Air & Waste Management... Jun 2010
Topics: Air; Air Pollutants; Air Pollution
PubMed: 20564990
DOI: 10.3155/1047-3289.60.6.642 -
Environmental Science and Pollution... Feb 2016Air quality depends mainly on changes in emission of pollutants and their precursors. Understanding its characteristics is the key to predicting and controlling air...
Air quality depends mainly on changes in emission of pollutants and their precursors. Understanding its characteristics is the key to predicting and controlling air quality. In this study, complex networks were built to analyze topological characteristics of air quality data by correlation coefficient method. Firstly, PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm) indexes of eight monitoring sites in Beijing were selected as samples from January 2013 to December 2014. Secondly, the C-C method was applied to determine the structure of phase space. Points in the reconstructed phase space were considered to be nodes of the network mapped. Then, edges were determined by nodes having the correlation greater than a critical threshold. Three properties of the constructed networks, degree distribution, clustering coefficient, and modularity, were used to determine the optimal value of the critical threshold. Finally, by analyzing and comparing topological properties, we pointed out that similarities and difference in the constructed complex networks revealed influence factors and their different roles on real air quality system.
Topics: Air; Air Pollutants; Beijing; Cluster Analysis; Environmental Monitoring; Neural Networks, Computer; Particle Size; Particulate Matter
PubMed: 26490943
DOI: 10.1007/s11356-015-5596-y -
Ying Yong Sheng Tai Xue Bao = the... Jun 2013Negative air ion (NAI) concentration is an important indicator comprehensively reflecting air quality, and has significance to human beings living environment. This... (Review)
Review
Negative air ion (NAI) concentration is an important indicator comprehensively reflecting air quality, and has significance to human beings living environment. This paper summarized the spatiotemporal distribution features of urban NAI concentration, and discussed the causes of these features based on the characteristics of the environmental factors in urban area and their effects on the physical and chemical processes of NAI. The temporal distribution of NAI concentration is mainly controlled by the periodic variation of solar radiation, while the spatial distribution of NAI concentration along the urban-rural gradient is mainly affected by the urban aerosol distribution, underlying surface characters, and urban heat island effect. The high NAI concentration in urban green area is related to the vegetation life activities and soil radiation, while the higher NAI concentration near the water environment is attributed to the water molecules that participate in the generation of NAI through a variety of ways. The other environmental factors can also affect the generation, life span, component, translocation, and distribution of NAI to some extent. To increase the urban green space and atmospheric humidity and to maintain the soil natural attributes of underlying surface could be the effective ways to increase the urban NAI concentration and improve the urban air quality.
Topics: Air; Air Ionization; Anions; China; Cities; Ecosystem; Environmental Monitoring; Spatio-Temporal Analysis
PubMed: 24066568
DOI: No ID Found -
Proceedings of the National Academy of... May 2012
Topics: Air; Air Pollution; Carbon Dioxide
PubMed: 22538823
DOI: 10.1073/pnas.1200990109 -
Environmental Pollution (Barking, Essex... Jan 2016CicLAvia in Los Angeles, CA is the open streets program that closes streets to motorized vehicles and invites people to walk, run, play or ride their bicycles on these...
CicLAvia in Los Angeles, CA is the open streets program that closes streets to motorized vehicles and invites people to walk, run, play or ride their bicycles on these streets, allowing them to experience the city in a new way and get exercise at the same time. Since the events reduce the motorized traffic flow, which is a significant source of air pollution, on the streets, it is reasonable to hypothesize that the CicLAvia events can reduce the concentrations of traffic-emitted air pollutants during the road closure. This study is the first experiment to test this hypothesis. The on-road and community-wide ultrafine particle (UFP) and PM2.5 were measured on the Event-Sunday (October 5th, 2014) and the Pre- and Post- Sundays (September 28(th) and October 12(th), 2014). Data analysis results showed the on-road UFP and PM2.5 reduction was 21% and 49%, respectively, and the community-wide PM2.5 reduction was 12%.
Topics: Air; Air Pollutants; Environmental Monitoring; Los Angeles; Particle Size; Particulate Matter; Vehicle Emissions
PubMed: 26493865
DOI: 10.1016/j.envpol.2015.09.010 -
European Journal of Protistology Aug 2021Cercozoa and Oomycota contain a huge biodiversity and important pathogens of forest trees and other vegetation. We analyzed air dispersal of these protistan phyla with...
Cercozoa and Oomycota contain a huge biodiversity and important pathogens of forest trees and other vegetation. We analyzed air dispersal of these protistan phyla with an air sampler near-ground (~2 m) and in tree crowns (~25 m) of three tree species (oak, linden and ash) in a temperate floodplain forest in March (before leafing) and May (after leaf unfolding) 2019 with a cultivation-independent high-throughput metabarcoding approach. We found a high diversity of Cercozoa and Oomycota in air samples with 122 and 81 OTUs, respectively. Especially oomycetes showed a significant difference in community composition between both sampling dates. Differences in community composition between air samples in tree canopies and close to the ground were however negligible, and also tree species identity did not affect communities in air samples, indicating that the distribution of protistan propagules through the air was not spatially restricted in the forest ecosystem. OTUs of plant pathogens, whose host species did not occur in the forest, demonstrate dispersal of propagules from outside the forest biome. Overall, our results lead to a better understanding of the stochastic processes of air dispersal of protists and protistan pathogens, a prerequisite to understand the mechanisms of their community assembly in forest ecosystems.
Topics: Air; Biodiversity; Ecosystem; Eukaryota; Trees
PubMed: 34090087
DOI: 10.1016/j.ejop.2021.125805 -
Journal of the Air Pollution Control... Jun 1975
Topics: Air; Air Pollution; Mass Behavior; Smoking; United States
PubMed: 1141547
DOI: 10.1080/00022470.1975.10470122 -
The Science of the Total Environment Aug 2006This study examined the concentrations of carbon monoxide, carbon dioxide, TVOC, TSP, PM(10), PM(2.5), PM(1), benzene, toluene and xylene in passenger cars of the...
This study examined the concentrations of carbon monoxide, carbon dioxide, TVOC, TSP, PM(10), PM(2.5), PM(1), benzene, toluene and xylene in passenger cars of the Beijing Ground Railway Transit System (Line No. 13). This system connects the northern suburb and downtown, and is equipped with air-conditioned passenger cars. In-train air quality monitoring was performed in both summer (July and August) and winter (December). To obtain representative data, the sampling design considered both rush and regular hours, urban and suburban areas, as well as the number of passengers. Meanwhile, questionnaires were distributed to the passengers. The monitoring results indicated that, overall, the air quality in the passenger cars was acceptable with a few exceptions, which is consistent with the passengers' perception. Concentrations of some air pollutants showed significant seasonal variations and had the significant difference between rush hour and regular hour. Furthermore, the in-train air quality was greatly influenced by the number of passengers. This paper describes the experimental design, and presents the preliminary results.
Topics: Air; Air Conditioning; Air Pollutants; China; Environmental Monitoring; Motor Vehicles; Quality Control; Seasons; Urbanization
PubMed: 16516274
DOI: 10.1016/j.scitotenv.2006.01.007