Drivers of PM<sub>2.5</sub> Episodes and Exceedance in India: A Synthesis From the COALESCE Network
Chandra Venkataraman, Abhinav Anand, Sujit Maji, Neeldip Barman, Dewashish Tiwari, Kaushik Muduchuru, Arushi Sharma, Ganesh Gupta, Ankur Bhardwaj, Diksha Haswani, Delwin Pullokaran, Kajal Yadav, Ramya Sunder Raman, Mohd Imran, Gazala Habib, Taveen Singh Kapoor, Anurag Gupta, Renuka Sharma, Harish C. Phuleria, Adnan Mateen Qadri, Gyanesh Kumar Singh, Tarun Gupta, Abisheg Dhandapani, R. Naresh Kumar, Sauryadeep Mukherjee, Abhijit Chatterjee, Shahadev Rabha, Binoy K. Saikia, Prasenjit Saikia, Dilip Ganguly, Pooja Chaudhary, Baerbel Sinha, Sayantee Roy, Akila Muthalagu, Asif Qureshi, Lian Yang, G. Pandithurai, L. K. Prasad, Sadashiva Murthy BM, Sandeep Singh Duhan, Jitender Singh Laura, Anil Kumar Chhangani, Tanveer Ahmad Najar, Arshid Jehangir, Amit P. Kesarkar, Vikas Singh
Abstract
Abstract Emission sources influencing high particulate air pollution levels and related mortality in India have been studied earlier on country‐wide and sub‐national scales. Here, we use novel data sets of emissions (for 2019) and observations created under the Carbonaceous Aerosol Emissions, Source Apportionment, and Climate Impacts network in India (Venkataraman et al., 2020, https://doi.org/10.1175/bams‐d‐19‐0030.1 ) in WRF‐Chem simulations to evaluate drivers of high PM 2.5 levels during episodes and in airsheds with different pollution levels. We identify airsheds in “extreme” (110–140 μg/m 3 ), “severe” (80–110 μg/m 3 ) and “significant” (40–80 μg/m 3 ) exceedance of the Indian annual ambient air quality standard (National Ambient Air Quality Standards [NAAQS]) of 40 μg/m 3 for PM 2.5 . We find that primary organic matter and anthropogenic mineral matter (largely coal fly‐ash) drive high PM 2.5 levels, both annually and during high PM 2.5 episodes. PM 2.5 episodes are driven by organic aerosol in north India (Mohali) in wintertime but are additionally influenced by mineral matter and secondary inorganics in central (Bhopal), south India (Mysuru) and eastern India (Shyamnagar). Across airsheds in exceedance of the NAAQS and during high PM 2.5 episodes, primary PM 2.5 emissions arise largely from the residential sector (50%–75%). Formal sector emissions (industry, thermal power and transport; 40%–55%) drive airshed and episode scale PM 2.5 exceedance in northern and eastern India. Agricultural residue burning emissions predominate (50%–75%) on episode scales, both in northern and central India, but not on annual scales. Interestingly, residential sector emissions strongly influence (60%–90%) airsheds in compliance with the NAAQS (annual mean PM 2.5 < 40 μg/m 3 ), implying the need for modern residential energy transitions for the reduction of ambient air pollution across India.