State of air quality in twin cities of Pakistan: Islamabad and Rawalpindi

Imran Shahid, Farrukh Chishtie, Gufran Bulbul, Muhammad Zeeshaan Shahid, Shoaib Shafique, Arifa Lodhi

Abstract

Atmospheric pollution has emerged as a disaster in developing countries like Pakistan. The aim of this study was to observe and analyze the air quality status of the twin cities of Pakistan, Rawalpindi and Islamabad, with a combined population of 15 million. The concentration of criteria pollutants along with CO2 was measured at five different locations within these cities. Sampling was done for 24 h at each location using a mobile air quality monitoring lab. The overall concentrations of SO2, NOX and O3 were found to be within the permissible limits of the US-EPA standards and the National Environmental Quality Standards of Pakistan, with higher PM10 and CO2 concentrations at most locations. The highest concentrations of PM10 were observed at Saddar, Rawalpindi (184 µg m–3), while minimum values were observed at the Blue Area of Islamabad (121 µg m–3). The concentration of CO2 during the study period was found to be high in almost all locations, with Saddar, Rawalpindi, indicating the highest value (409 ppm). The concentrations of CO2 at the Blue Area and the National University of Science and Technology of Islamabad were observed to be as high as 385.3 and 246 ppm, respectively. The behavior of pollutants with different meteorological parameters was also studied. For source identification, backward air trajectories were also generated using the HYSPLIT model.

Keywords

PM10; ozone; twin cities; air quality; urban air pollution

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