Aerosol size distribution and mass concentration measurements in various cities of Pakistan Khan Alam, * a Thomas Blaschke, a Pierre Madl, b Azam Mukhtar, c Majid Hussain, b Thomas Trautmann d and Said Rahman e Received 29th January 2011, Accepted 17th May 2011 DOI: 10.1039/c1em10086f 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 PM 10 concentrations for three sites in Karachi were found to be 461 mgm 3 , 270 mgm 3 , and 88 mgm 3 , while the average values for Lahore, Rawalpindi and Peshawar were 198 mgm 3 , 448 mgm 3 , and 540 mgm 3 , respectively. The corresponding 24 hour average PM 2.5 concentrations were 185 mg m 3 , 151 mgm 3 , and 60 mgm 3 for the three sites in Karachi, and 91 mgm 3 , 140 mgm 3 , and 160 mgm 3 for Lahore, Rawalpindi and Peshawar, respectively. The low PM 2.5 /PM 10 ratios revealed a high proportion of coarser particles, which are likely to have originated from (a) traffic, (b) other combustion sources, and (c) the re-suspension of road dust. Our calculated 24 hour averaged PM 10 and PM 2.5 concentrations at all sampling points were between 2 and 10 times higher than the maximum PM concentrations recommended by the WHO guidelines. The aerosol samples collected were analyzed for crustal elements (Al, Fe, Si, Mg, Ca) and trace elements (B, Ba, Cr, Cu, K, Na, Mn, Ni, P, Pb, S, Sr, Cd, Ti, Zn and Zr). The averaged concentrations for crustal elements ranged from 1.02  0.76 mgm 3 for Si at the Sea View location in Karachi to 74.96  7.39 mgm 3 for Ca in Rawalpindi, and averaged concentrations for trace elements varied from 7.0  0.75 ng m 3 for B from the SUPARCO location in Karachi to 17.84  0.30 mgm 3 for Na at the M. A. Jinnah Road location, also in Karachi. a Department of Geography and Geology, University of Salzburg, Hellbrunnerstrasse 34, Salzburg, 5020, Austria. E-mail: khan.alam@ stud.sbg.ac.at; Tel: +43-681-10787864 b Department of Materials Research and Physics, Division of Physics and Biophysics, University of Salzburg, Hellbrunnerstrasse 34, Salzburg, 5020, Austria c Institute of Chemical Technologies and Analytics, Vienna University of Technology, A-1060 Vienna, Austria d German Aerospace Center, Remote Sensing Technology Institute, Oberpfaffenhofen, 82234 Wessling, Germany e Pakistan Space and Upper Atmosphere Research Commission (SUPARCO), P.O. Box 8402, Off University Road, Karachi, 75270, Pakistan Environmental impact Aerosols—hot spots in urban environments: with the onset of the industrial revolution manmade aerosol concentrations frequently override naturally occurring background concentrations. Urban environments in particular are chronically immersed into a cocktail of airborne combustion products. Standard monitoring campaigns rely on measuring particle mass, which underestimates aerosol exposure to biota. On top of that the surfaces of aerosols act as vehicles onto which other compounds readily get attached. By using a standard optical particle counter, this study attempts to characterize both the numeric particle concentration of urban hot spots in Pakistan and to correlate these datasets to volume and mass concentrations along with a chemical fingerprint using ICP-MS. 1944 | J. Environ. Monit., 2011, 13, 1944–1952 This journal is ª The Royal Society of Chemistry 2011 Dynamic Article Links C < Journal of Environmental Monitoring Cite this: J. Environ. Monit., 2011, 13, 1944 www.rsc.org/jem PAPER