Long-Term Variability of Air Pollutants in the Indo-Gangetic Plain: Drivers, Trends, and Hotspots

Long-Term Variability of Air Pollutants in the Indo-Gangetic Plain: Drivers, Trends, and Hotspots

Abhishek Saxena

Saxenaabhishek85@gmail.com

This study examines seasonal, monthly, and yearly trends of sulfur dioxide (SO₂), black carbon (BC), carbon monoxide (CO), ozone (O₃), fine particulate matter (PM2.5), and methane (CH₄) across the Indo-Gangetic Plain (IGP) from 2010 to 2024 using MERRA-2 Reanalysis data (0.5° x 0.625° resolution). Elevated concentrations of SO₂, BC, CO, PM2.5, and CH₄ are observed during winter and post-monsoon months due to thermal inversions, stagnant conditions, and emissions from biomass burning and agriculture, while O₃ peaks during summer due to photochemical activity.

Yearly trends show declines in SO₂ and PM2.5 due to emission controls, while BC, CO, and CH₄ remain stable, and O₃ increases slightly with rising precursor emissions. The western IGP, particularly Punjab and Haryana, is identified as a hotspot for SO₂, BC, CO, PM2.5, and CH₄ in post-monsoon, with O₃ hotspots prevalent in summer. Correlations among pollutants vary seasonally, with stronger links in winter and weaker ones during monsoon. These findings highlight the need for targeted, multi-pollutant mitigation strategies tailored to seasonal and regional pollution dynamics in the IGP.