ABSTRACT
This study explores biomass burning impact on surface-level carbon monoxide (CO) using MOPITT satellite data during 2001–2017 over Lahore and Karachi and other megacities of South Asia, i.e., Delhi, Mumbai, Kolkata, and Dhaka. Also, MERRA-2 CO emission data have been used to identify CO emission hotspots. Fire and thermal anomalies, aerosol optical depth (AOD), Normalized Difference Vegetation Index (NDVI), and some selected meteorological parameters such as temperature, relative humidity, and wind speed have been used to map the spatial correlations with atmospheric CO in the study area. Three pre-monsoon large-scale crop residue burning events were identified during 2016 and 2017 to study their impacts on the air quality of Lahore and adjoining regions. In pre-monsoon, MERRA-2 CO emissions showed values up to 236 × 10−11 kg/m2/s in May 2012, followed by 220 × 10–11 kg/m2/s in May 2001, in Lahore. Karachi has the second-highest averaged value (74.4 × 10−11 kg/m2/s) after Kolkata (77 × 10−11 kg/m2/s). MOPITT CO retrievals over Karachi have shown the highest decreasing trend of −26.9%, followed by Lahore (−20.8%), during 2001–2017.
