CARDIORESPIRATORY EFFECTS OF CONCENTRATED AMBIENT PM2.5: A Pilot Study Using Controlled Human Exposures

Ambient air quality of Islamabad, Pakistan, reveals that annual average mass concentration of particulate matter (PM 2.5 ) (∼45 to ∼95 μg m −3 ) and nitric oxide (NO) (∼41 to ∼120 μg m −3 ) exceeds the Pakistan's National Environmental Quality Standards (NEQS). The annual ozone (O 3 ) concentration is within the permissible limits; however, some of the hourly concentration exceeds the NEQS mostly during the summer months. Correlation studies suggest that carbon monoxide (CO) has a significant (p-value ≤ 0.01) positive correlation with NO and NO y ′ ; whereas, with O 3 , a significant (p-value ≤ 0.01) negative correlation is observed. The regression analysis estimates the background CO concentration to be ∼300 to ∼600 ppbv in Islamabad. The higher ratio of CO/NO (∼10) suggests that mobile sources are the major contributor to NO concentration. On the other hand, the ratio analysis of sulfur dioxide (SO 2 )/NO for Islamabad (∼0.011) indicates that the point sources are contributing to SO 2 in the city. NO and SO 2 correlation indicates contribution of direct sulfur emission sources. Ratios of [CO] to [NO] and [SO 2 ] to [NO], based on ambient air quality measurements, provide a test for emission inventories. The ratios of these pollutants in the available Islamabad emission inventories are consistent with ambient values for these pollutants. The correlation of PM 2.5 and NO suggests that a fraction of secondary PM 2.5 is produced by chemical conversion of NO into nitrates. The regional background O 3 concentration for Islamabad has been determined to be ∼31 ppbv. This study suggests that there is an increase in O 3 concentration with increases in photochemical conversion of NO to reservoir NO y ′ species.

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Measurements and analysis of air quality in Islamabad, Pakistan

Rasheed

Aneja

Aiyyer

et al. 2014

Earth's Future

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Controlled Exposures of Healthy and Asthmatic Volunteers to Concentrated Ambient Fine Particles in Los Angeles

Gong

Linn

Sioutas

et al. 2003

Inhalation Toxicology

133

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Information about health effects from controlled exposure to particulate matter (PM) air pollution is relatively limited but potentially critical in urban locations such as Los Angeles, where abundant mobile sources generate combustion-related particles. Nonsmoking healthy (n = 12) and asthmatic (n = 12) volunteers, age 18-45 yr, were exposed to concentrated ambient particulates (CAP) in the fine (PM(2.5)) size range at an average concentration of 174 micro g/m(3) (range 99-224), and to filtered air (FA). Exposures used a two-stage Harvard virtual-impactor concentrator and whole-body chamber and lasted 2 h with alternating rest-exercise periods. Neither group showed significant (p <.05) changes in spirometry or routine hematologic measurements attributable to CAP exposure, relative to FA. Both groups showed CAP-related decreases of columnar cells in postexposure induced sputum, slight changes in certain mediators of blood coagulability and systemic inflammation, and modest increases in parasympathetic stimulation of heart rate variability. Systolic blood pressure decreased in asthmatics and increased in healthy subjects during CAP exposure relative to FA. Cardiovascular (but not respiratory) symptoms increased slightly with CAP in both groups. In summary, the urban fine PM exposures elicited different biologic endpoints with statistically significant differences between CAP and FA. The observed changes in blood inflammation and heart-rate variability were consistent with systemic (rather than respiratory) effects reported from other laboratory and epidemiologic studies. Further studies involving other biologic endpoints, PM size modes, and risk factors will be needed to clarify these results.

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A novel application of capnography during controlled human exposure to air pollution

et al. 2006

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CARDIORESPIRATORY EFFECTS OF CONCENTRATED AMBIENT PM2.5: A Pilot Study Using Controlled Human Exposures

Cited by 5 publications

References 14 publications

Measurements and analysis of air quality in Islamabad, Pakistan

Measurements and analysis of air quality in Islamabad, Pakistan

Controlled Exposures of Healthy and Asthmatic Volunteers to Concentrated Ambient Fine Particles in Los Angeles

A novel application of capnography during controlled human exposure to air pollution

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