Inter-annual variability and distribution of aerosols during winters and aerosol optical thickness over Northeastern Pakistan

ir pollution during winters over north-eastern (NE) Pakistan (71–74.5 E, 28–34 N) is a major challenge that affects human health, climate and daily life. In this article, distribution of aerosols and its optical properties over the NE Pakistan during winter of 2007–2015 is analyzed by applying MERRA-2 model, satellite measurements and focusing on four megacities in the NE Pakistan (Lahore, Islamabad, Faisalabad and Multan). Over the past decade, the winter mean aerosol optical depth (AOD) values were in the range of 0.5–0.8, which is attributed to anthropogenic activities due to increase in urban development and economic growth in NE Pakistan. Average over winters from 2007–2015, over the for four mega cities, Islamabad, Lahore, Faisalabad and Multan, the concentrations of sulfate were 5.06, 14.09, 14.29, 16.22 µg m−3, BC, were 1.5, 4.69, 4.46 4.52 µg m−3 and OC, were, 5.85, 17.32, 16.99 and 17.29 µg m−3, respectively. Decrease in urban emissions and crop residue burning considered effective measures for better air quality in these population centers.Higher Education Commission (HEC) Pakistan (HEC- PBAIRP Winter Smog Project No. 22-17