Spatial and Temporal Variation of Atmospheric Particulate Matter in Bangalore: A Technology-Intensive Region in India

All of India’s megacities are experiencing acute air pollution problems due to the accelerated urbanization/industrialization and rapid economic growth. Nowadays, environmental pollution due to particulate matter is a major threat to human health and our regional air quality. Long-term air pollution data with the high spatial and temporal resolution are required to understand regional air quality and its effects on environmental degradation and human health. In view of the above, the particulate matter (PM2.5: particles with diameters less than 2.5 μm and PM10: particles with diameters less than 10 μm) were measured from January 2017 to March 2018 at five locations (PM2.5 at 3 sites and PM10: at 2 sites) across the Bangalore city, India. The measured concentrations indicated that PM2.5 and PM10 concentrations in Bangalore exceeded the World Health Organization’s air quality standards although the PM2.5 values did meet the Indian National Ambient Air Quality Standards (NAAQS). The PM10 NAAQS was exceeded at one site. Temporal patterns showed a strong evening peak at all sites and morning rush hour peaks of varying strength. Season peaks were observed in the winter or premonsoon seasons again with variations among the five sites. Lower pairwise correlation coefficients among the sites suggest that the PM sources were largely localized. The role of meteorological parameters (MP) was studied, and it was observed that MP play a vital role in the accumulation of PM2.5. During calm wind condition (WS < 0.5 m/s), the concentrations of PM2.5 has increased by 17%, indicating localized sources; however, in the case of PM10, it was opposite. Annually, the highest concentrations of PM2.5 (> 30 μg/ m3) and PM10 (> 75 μg/m3) over receptor side were observed during lower wind speeds (< 2 knots), which indicate that the transportation does not play any crucial role in higher concentrations of PM over Bangalore.