Aerosol Optical Depth as a Proxy for Air Pollution in Bangladesh: Temporal Trends, Emission Drivers, and Implications for Public Health and Sustainable Development

Aerosol pollution constitutes a substantial risk to environmental health in South Asia, especially in Bangladesh, where rapid urbanization and industrial growth have exacerbated particulate emissions. This study examines 25 years (2000–2024) of MODIS Terra Aerosol Optical Depth (AOD) data to evaluate long-term trends in aerosol concentration in Bangladesh. Annual mean AOD values were obtained using Google Earth Engine and examined by linear regression, Mann–Kendall trend analysis, and Sen’s slope estimation in R. The results indicate a statistically significant upward trend in AOD, with mean values escalating from 0.49 in 2001 to 0.87 in 2024 (R² = 0.83; p < 0.001), implying a continual increase in atmospheric particle concentrations. Z-score analysis indicated that recent years, specifically 2023 and 2024, exhibited statistically significant increases in aerosol pollution. The rise in AOD is associated with both local and transboundary sources, such as automotive emissions, brick kilns, consumption of fossil fuels, and regional dust transport. These findings underscore the escalating public health risks associated with PM₂.₅ exposure and affirm the utility of AOD as a reliable proxy. The study emphasizes the imperative for targeted emission reduction measures, comprehensive planning, and improved monitoring systems to achieve Sustainable Development Goals (SDGs) related to health and urban resilience. Despite its limitations, especially the use of coarse-resolution AOD, the study provides essential evidence for informed decision-making and future research on aerosol pollution in Bangladesh.