To Tackle India's Air Pollution, We Must Focus on Informal Sources
LUCAS ROJAS-MENDOZA, Srinidhi Balasubramanian, Chandra Venkataraman, Joshua S. Apte, University of California Berkeley
Abstract Number: 601
Working Group: Reducing Aerosol Exposure with Control Technologies and Interventions
Abstract
India has some of the highest PM2.5 concentrations globally, with significant geographic variation in exposure. Despite clear evidence of pollutant transport across regions and states, national mitigation strategies continue to focus primarily on urban areas. This study uses PAVITRA, an air quality assessment tool for South Asia, to quantify sectoral and spatial contributions to PM2.5 exposure at national, regional, state, and local scales. PAVITRA integrates the SMOG (Speciated Multi-pOllutant Generator) emissions inventory with InMAP, a reduced-complexity model derived from an optimized WRF-Chem simulation. Emissions are categorized into six sectors: three formal (heavy industry, energy, transport) and three informal (domestic, agriculture, small - medium industry), along with natural dust.
Our model shows a modest normalized mean bias (NMB) of 2.6%, a Pearson correlation coefficient (r) of 0.57, and an index of agreement (IoA) of 0.75. We conducted 2,500 simulations to estimate PM2.5 concentrations and population-weighted mean exposures from both primary PM2.5 and four precursor species: NH3, NOx, SOx, and VOCs. Results demonstrate substantial variation in sectoral contributions and the spatial distribution of emissions across India. Informal sources account for over 50% of PM2.5 exposure in 19 of 34 states, particularly in the Indo-Gangetic Plain, whereas formal sources dominate in southern regions.
We propose several mitigation strategies and evaluate their impacts across geographic scales. While controls on formal sectors remain important in high-exposure areas, reducing emissions from informal sources could substantially lower exposure across much of the country. Our findings emphasize the need for a multi-scale, multi-sector approach to air pollution management in India. We advocate targeting reductions in emissions from informal activities, such as household energy use and agricultural practices, within state-level strategies and underscore the utility of reduced-complexity models like InMAP for informing mitigation efforts and decision-making.