Measurement Of Atmospheric Dry Deposition Flux And Resultant Deposition Velocity Of Inorganic Pollutants In The Provincial Capital Of Punjab, Pakistan

摘要

Inorganic pollutants (IPs), such as Pb, Cu, Zn, and Cd, which are present at trace levels in the atmosphere, are a major group of air pollutants that play important role in atmospheric chemistry. The concentration of such pollutants in the atmosphere is harmful to human health. Data on levels of IPs in the outdoor ambient air is lacking in Pakistan. Knowledge of atmospheric deposition of these IPs in different areas would enable establishing background values that could be used to distinguish additional contributions/ releases when contamination events occur. This knowledge would also help to introduce a strategy to maintain pollution-free air quality. The present study deals with the assessment of atmospheric deposition of IPs at all nine municipal towns in the Lahore City, which is the provincial capital of Punjab province of Pakistan. Sampling work was carried out during March to June 2004. The results show that dry deposition fluxes and deposition velocities of Pb, Cu, Zn, and Cd varied from 7 ± 3 to 30 ± 6 kg km~(-2) yr~(-2), 3 ± 2 to 14 ± 6 kg km~(-2) yr~(-2), 11 ± 6 to 21 ± 9 kg km~(-2) yr~(-2), and 0.7 ± 0.4 to 3 ± 1 kg km~(-2) yr~(-2); and 0.4 to 1.4 cm s~(-1), 0.8 to 1.3 cm s~(-1), 0.3 to 0.8 cm s~(-1), and 0.05 to 0.6 cm s~(-1) respectively. No significant correlations were found between measured deposition fluxes, showing no common emission sources of these pollutants. The data generated in this study will provide baseline values for monitoring of air pollution in the future.