MAPPING THE CONCENTRATION OF AIR POLLUTANTS USING GEOSPATIAL TECHNOLOGIES

Abstract

Expanded burning of non-renewable energy sources in current century is the basic reason of the vigorous variation in the climatic conditions. For example in recent past; Pakistan has faced some extreme atmospheric event likes Karachi Heatwave 2015, and Lahore Smog of November 2016. In this scenario, it was need of the hour to monitor various atmospheric pollutants. For the current study, concentrations of Aerosols, SO2 and NO2 are investigated for Punjab province Pakistan for years 2010 and 2016 using new generation satellite imagery like Moderate Resolution Spectro-radiometer (MODIS) and Ozone Monitoring Instrument (OMI). Results revealed that various cities of Punjab like Lahore, have significant increase in the Aerosols concentration over the six years interval. Monthly average maps from MODIS-determined aerosol optical depth (AOD) over Punjab with highest AOD concentration in summer season (May to July) both in 2010 and 2016 over Bahawalpur and Bahawalnagar districts. Lowest AOD concentration is observed in March 2010, August 2016 and September 2016 and a decrease of 12.26 % was observed in extreme months. Seasonal and spatial distributions were related to the dust, anthropogenic emissions, agricultural burning and low precipitation in summers. Mean monthly SO2 and NO2 maps were derived from OMI. Highest concentration (0.96 and 1.12 DU) of SO2 were observed during summer season (May to July) both in 2010 and 2016 over Gujranwala, Lahore and Rawalpindi. While lowest values (0.29 and 0.31 DU) were observed in winter season (January and February) with an increase of 6.5 % in extreme months. NO2 showed similar pattern like SO2; with highest concentration (8.04 E+15 molec/cm2 and 8.84 E+15 molec/cm2) were observed during summer season (May to July) both in 2010 and 2016 over Lahore, Gujranwala and Sheikhupura with an ii unusual higher value of 9.6 E+15 molec/cm2 in January 2010 over Lahore. While lowest values (3.03 E+15 molec/cm2 and 3.13 E+15 molec/cm2) were observed in winter season (January and November) with an increase of 12.77 % in extreme months over Lahore, Gujranwala, Nankana Sahib and Sheikhupura. The study reveals that there is a decrease of 12.26% in concentration of aerosols over Bahawalpur and Bahawalnagar districts in extreme months. While concentration of SO2 and NO2 in Punjab province from 2010 to 2016 increased by 6.5% and 12.77% respectively over Lahore, Gujranwala, Rawalpindi, Nankana Sahib and Sheikhupura.