Sector-segregated anthropogenic impacts on PM2.5 over western India based on regional air quality modeling

Air quality over western India is impacted by both regional emissions and transport from the Indo-Gangetic Plain (IGP). Effective mitigation requires identifying the dominant emission sectors that govern regional air quality during different seasons. In this regard, the present study examines the impact of emissions from major anthropogenic sectors (power, residential, transport and industries) on ambient fine particulate matter (PM_2.5)concentrations over the western Indian region. For this, high-resolution (12km x 12km) regional model (WRF-Chem v3.9.1) simulations have been conducted using the EDGAR v5.0 inventory for anthropogenic emissions. Simulations are conducted for the year 2019, for winter and post-monsoon seasons when PM_2.5 concentrations are typically elevated in this region, and anthropogenic emissions effects are the highest. During winter, the residential sector is seen to dominate, contributing 20% to PM_2.5 concentration over western India, followed by power (9%) and industry (∼8%). The trans-regional pollution from the IGP and central India is also dominated by residential emissions (25%), followed by the power sector (∼8%). In contrast to winter, the dominant source during post-monsoon is the power sector (∼14%), followed by the industry (∼12%) and the residential (∼9%) sectors. Trans-regional impact also shows a similar pattern and dominance of power (∼15%) and industrial (∼10%) sectors. This seasonal shift in the dominant sector is driven by the seasonal variation in emissions. The results also reveal large spatial heterogeneity in sectoral influence, highlighting that dominant emission sources vary at the local scale within western India in both seasons. The study offers model-based insights for more effective planning of regional air pollution mitigation in western India.