Assessing Air Quality Dynamics In Kolkata Municipal Corporation: A Seasonal And Temporal Perspective

Abstract

This study assesses seasonal and temporal variations in air quality across the Kolkata Municipal Corporation (KMC) by comparing station-level concentrations of NO₂, PM₁₀, and SO₂ for 2003 and 2022. Thirteen monitoring stations and three seasonal windows (pre-monsoon, monsoon, post-monsoon) were analysed. AQI was computed to examine public-health implications and to identify spatial hotspots. Results reveal pronounced seasonal heterogeneity. Pre-monsoon shows a modest decline in NO₂ but significant increases in PM₁₀ and SO₂, driven by a few local hotspots. Monsoon displays unexpectedly higher PM₁₀ and AQI at many sites, suggesting strong local sources or resuspension that overcome wet scavenging. Post-monsoon exhibits the largest improvements: substantial reductions in both NO₂ and PM₁₀. The findings indicate partial success in controlling gaseous emissions but persistent or emerging particulate problems. The study suggests targeted, location-specific particulate mitigation, including dust suppression, construction controls, and systematic road maintenance, together with improved transparency of monitoring metadata.