Assessing smog trends and sources of air pollutants across northeastern districts of Punjab, Pakistan using geospatial techniques

Air pollution is a severe environmental issue that threatens the health and safety of many people worldwide. Smog is one of the most severe effects of air pollution, affecting not only people's health but also the economy. The northeastern districts of Punjab province, Pakistan, have been facing a severe smog crisis for the past few years. This study was planned to investigate the sources and trends of air pollution in the major cities of Punjab's Northeastern Districts. MODIS products MOD14A2 and MOD08_M3 were used to identify fire events and Aerosol's Optical Depth respectively. MOD13Q1 NDVI and Landsat images were used to analyze deforestation and urbanization respectively. MERRA-2 and OMNO2d were used to detect amounts of PM2.5, SO2, CO2, CO and NO2. The findings of the study revealed an annual increase in industrial and vehicular emissions in Lahore and Faisalabad districts. Approximately 123 and 542 tons of PM2.5 were produced in the winter season within the vertical height of 1000 m from the surface over Lahore (1772 km(2)) and Faisalabad (5857 km(2)) districts respectively. CO2 concentration in the last decade has increased by 4% in these districts. Also, Hafizabad, Nankana Sahib, Narowal and Sheikhupura have shown higher amounts of residual burnings with time that are contributing to smog in North Punjab. NOAA's (National Oceanic and Atmospheric Administration) HYPSLIT was used to simulate air pollutant trajectories in the study area which showed smog moving to neighboring areas from the core source.