Trends and Insights into Sources of PM2.5 in Kolkata, India from Low Cost Sensor Network Data

V. FAYE MCNEILL, Siddharth Nobell, Arnab Majumdar, Shovon Mukherjee, Sukumar Chakravorty, Sanjoy Chatterjee, Soumitra Bose, Anindita Dutta, Sandhya Sethuraman, Vigneshwari Sivakumar, Daniel Westervelt, Sarbani Palit, Shairik Sengupta, Rakhi Basu, Columbia University

     Abstract Number: 676
     Working Group: Urban Aerosols

Abstract
We present results from two field-calibrated networks of low-cost ambient particulate matter sensors (LCS) in greater Kolkata, India operated between 2018-2019 and 2019-2021. In order to understand LCS performance in relation to local reference-grade PM2.5 monitors (RGMs) and to develop calibration functions, LCS were co-located with RGMs operated by the West Bengal Pollution Control Board at three locations. Data from the co-locations were used to calibrate the LCS network using random forest regression and multiple linear regression approaches. Measured relative humidity and temperature were significant model features. Cross-calibration between co-located LCS-RGM pairs was tested in order to demonstrate the strength of the field calibraiton approach. Seasonal diurnal trends and a high level of correlation across the hybrid LCS-RGM network suggest regional and secondary sources of PM2.5 dominate in Kolkata, despite significant local sources.