Meteorology-driven trends in PM2.5 concentrations and related health burden over India

Abstract

As a heavily polluted country, India has made great efforts on mitigating severe PM2.5 pollution during last several years. Quantifying meteorological impacts on PM2.5 pollution and related health burden is essential to accurately assess pollution control effects and therefore provides a reference for air quality policy in India. This study identifies meteorological influences on PM2.5 trends and related mortality during 2014–2021 in five Indian megacities (Chennai, Kolkata, Hyderabad, Mumbai, Delhi). Decreasing trends in PM2.5 concentrations are observed in all cities and seasons with the maximum trend of −7.24 μg m−3 yr−1 in Delhi during winter. Meteorology causes PM2.5 decreases in all cities and seasons with meteorology-driven downward trends of −6.51 ∼ −0.36 μg m−3 yr−1. Meteorology dominates PM2.5 decreases in Delhi during summer/monsoon and Chennai/Mumbai/Delhi during winter, where meteorology-driven PM2.5 trends contribute 65% ∼ 105% of observed PM2.5 decreases. Better ventilation condition is identified as the primary meteorological factor for PM2.5 decrease. Anthropogenic emissions almost play positive roles in improving India's PM2.5 air quality, confirming the effectiveness of pollution control measures in India during recent years. Meteorological conditions dominate decreases in PM2.5-related deaths in 25% of cities and seasons. The most significant meteorology-driven PM2.5-related mortality trend of −127.12 deaths yr−1 occurs in Delhi during winter.