Exploring optical properties of absorbing aerosols using satellite-based observations over Pakistan

Abstract

Pakistan’s urban air is among the worst in the world, in terms of air quality with the major sources of air pollutants to be open biomass burning, motor vehicles and industries. Besides the local sources, transboundary air pollutants e.g., agriculture fires from India is one of the major sources in Pakistan. Atmospheric aerosol is of great implication as it plays a key role in the formation of clouds and fog. Also, it affects the budget of the Earth's radiation. The study aims to characterize the absorbing aerosols using optical properties (Angstrom exponent, Single scattering albedo and particle size distribution) retrieved from Aerosol Robotic Network (AERONET) site in Lahore. It also provides a database of satellite observations using observations from Moderate Resolution Imaging Spectroradiometer (MODIS), which were validated against AERONET observations. Both datasets found to have a high degree of correlation during the period of 2017-18. PM10 and PM2.5 concentrations were also measured at IESE-NUST site over Islamabad during the time period of Aug2017 to July2018. Back trajectories from Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model were used during the incidence of smog episodes in the regions of Punjab. It indicated that major agricultural waste burning in India leads to the deterioration of air quality of Pakistan due to smog episodes. Keywords— AOD, MODIS, AERONET, HYSPLIT.