Investigating the Spatiotemporal Distributions of NO2, SO2 and Their Association with NDVI in Lahore (Pakistan) and Its Adjoining Region of Punjab (India)

Developing country like Pakistan is severely affected by poor air quality and is globally ranked in third position for mortality cases caused by air pollution. Air Pollution is severely degrading the quality of air and climatic systems and is affecting the health of the people and plants. This study aimed to examine the spatiotemporal distributions of some selected air pollutants (NO2 and SO2) and their association with NDVI in Lahore and its adjoining regions from July 2018 to December 2020. The present study utilized air pollutants (NO2 and SO2) observations obtained from TROPOMI onboard Sentinel-5P, and NDVI retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra satellite. The mean annual high NO2 concentrations of 163.0 x 10(-6) mol m(-2), 160.0 x 10(-6) mol m(-2), and 154.0 x 10(-6) mol m(-2) were found over northwestern, central, and southern boundaries of Lahore, respectively, while the SO2 concentration of 315.4 x 10(-6) mol m(-2) was observed over the northwestern boundary of Lahore. Moreover, the mean annual NDVI ranging from 0.5 to 0.65 was observed in the east, northeast, southeast and outside the boundary of Lahore towards Amritsar. The monthly time series analyses show that the highest values of NO2, SO2 and NDVI are found to be 149 x 10(-6) & PLUSMN; 1.58 x 10(-5) (mole m(-2)), 544 x 10(-6) & PLUSMN; 1.68 x 10(-4) (mole m(-2)), and 0.670 & PLUSMN; 0.12 in January 2019, December 2020 and February 2019, respectively. The highest correlation between NO2 and SO2 with NDVI is found to be 0.95 and 0.87, respectively in the southwest, and southeast directions. These findings will be helpful for concerned departments such as Environmental Protection Agency (EPA) and Pakistan Agricultural Research Council (PARC), and the scientific community to formulate policies and take measures to mitigate the adverse effects of air pollution on the agricultural sector.