PM sensors as an indicator of overall air quality: Pre-COVID and COVID periods

Jai Prakash; Shruti Choudhary; Ramesh Raliya; Tandeep Chadha; Jiaxi Fang; Pratim Biswas

doi:10.1016/j.apr.2022.101594

PM sensors as an indicator of overall air quality: Pre-COVID and COVID periods

Atmos Pollut Res. 2022 Nov;13(11):101594. doi: 10.1016/j.apr.2022.101594. Epub 2022 Nov 9.

Authors

Jai Prakash^{1

2}, Shruti Choudhary^{1

3}, Ramesh Raliya¹, Tandeep Chadha⁴, Jiaxi Fang⁴, Pratim Biswas^{1

3}

Affiliations

¹ Aerosol and Air Quality Research Laboratory, Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St Louis, MO, 63130, USA.
² Department of Atmospheric Science, School of Earth Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305 817, Rajasthan, India.
³ Department of Chemical Environmental and Materials Engineering, University of Miami, FL 33146, USA.
⁴ Applied Particle Technology, St Louis, MO, 63110, USA.

Abstract

Nowadays, there has been a substantial proliferation in the use of low-cost particulate matter (PM) sensors and facilitating as an indicator of overall air quality. However, during COVID-19 epidemics, air pollution sources have been deteriorated significantly, and given offer to evaluate the impact of COVID-19 on air quality in the world's most polluted city: Delhi, India. To address low-cost PM sensors, this study aimed to a) conduct a long-term field inter-comparison of twenty-two (22) low-cost PM sensors with reference instruments over 10-month period (evaluation period) spanning months from May 2019 to February 2020; b) trend of PM mass and number count; and c) probable local and regional sources in Delhi during Pre-CVOID (P-COVID) periods. The comparison of low-cost PM sensors with reference instruments results found with R² ranging between 0.74 and 0.95 for all sites and confirm that PM sensors can be a useful tool for PM monitoring network in Delhi. Relative reductions in PM_2.5 and particle number count (PNC) due to COVID-outbreaks showed in the range between (2-5%) and (4-13%), respectively, as compared to the P-COVID periods. The cluster analysis reveals air masses originated ∼52% from local, while ∼48% from regional sources in P-COVID and PM levels are encountered 47% and 66-70% from local and regional sources, respectively. Overall results suggest that low-cost PM sensors can be used as an unprecedented aid in air quality applications, and improving non-attainment cities in India, and that policy makers can attempt to revise guidelines for clean air.

Keywords: COVID-19; Field comparison; Low-cost PM sensors; Outbreaks; PM2.5; Particle number count.