Analysis of PM2.5 Exposure Trends in Indian State Capitals between 2015-16 - an Environmental Justice and Equity Perspective

Abstract

Introduction: Exposure to high levels of ambient particulate matter is a key risk factor for ill health in India with the Global burden of Disease ranking it the 3rd largest contributor to DALYs in 2016. Regulatory-grade monitoring, remains scarce outside a handful of major metropolitan centres, and this contributes to poor awareness of the scale and geography of the problem, and hampers documentation of health effects. It also contributes to a Delhi-centric approach to air pollution problem-solving, to the detriment of other parts of the country where exposure could be higher. Methods: We collected regulatory data on PM2.5 published by the Central Pollution Control Board for the years 2015-16 for all Indian State capitals. Annual and seasonal average PM2.5 was calculated for each city and region (South, West, Central, Indo-Gangetic Plain, and East). For periods where direct PM2.5 measurements were unavailable, station-specific or city-specific PM2.5/PM10 ratios were used to derive PM2.5 data. We also documented the number of stations per city and the data availability by station for all these state capitals.Results: Only one state capital (Aizawl) met WHO guidelines for annual average exposure, with 8 others meeting the more relaxed National Ambient Air Quality Standards. The central region registered the highest average PM2.5 levels, with little variation across seasons, compared with the IGP or other regions which exhibited strong seasonal variations in PM2.5 levels. The eastern region showed the lowest PM2.5 levels. Monitoring capacity and data availability across cities and regions varied greatly from. Conclusions: The Central Indian region has the highest exposure to ambient air pollution. In spite of it being a hub for the mining, power and steel industries, monitoring capacity in this region is scarce. Consequently, there is little discussion about the potential health impacts here. We believe this represents an environmental justice and equity issue.