SCHEDULED MAINTENANCE
Aerosol size distribution and mass concentration measurements in various cities of Pakistan
Abstract
During March and April 2010 aerosol inventories from four large cities in Pakistan were assessed in terms of particle size distributions (N), mass (M) concentrations, and particulate matter (PM) concentrations. These M and PM concentrations were obtained for Karachi, Lahore, Rawalpindi, and Peshawar from N concentrations using a native algorithm based on the Grimm model 1.109 dust monitor. The results have confirmed high N, M and PM concentrations in all four cities. They also revealed major contributions to the aerosol concentrations from the re-suspension of road dust, from sea salt aerosols, and from vehicular and industrial emissions. During the study period the 24 hour average PM10 concentrations for three sites in Karachi were found to be 461 μg m−3, 270 μg m−3, and 88 μg m−3, while the average values for Lahore, Rawalpindi and Peshawar were 198 μg m−3, 448 μg m−3, and 540 μg m−3, respectively. The corresponding 24 hour average PM2.5 concentrations were 185 μg m−3, 151 μg m−3, and 60 μg m−3 for the three sites in Karachi, and 91 μg m−3, 140 μg m−3, and 160 μg m−3 for Lahore, Rawalpindi and Peshawar, respectively. The low PM2.5/PM10 ratios revealed a high proportion of coarser particles, which are likely to have originated from (a) traffic, (b) other
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