Traffic-Induced Air Pollution at Traffic Intersections in Dhaka: Seasonal Patterns and Associated Health Implications

Abstract

Air pollution, poses a serious environmental and health challenge in Bangladesh. It is necessary to understand the concentration and seasonal variation of particulate matter (PM) and gaseous pollutants at traffic intersections to assess their impact on public health. This study was conducted to measure the levels of PM (PM1.0, PM2.5, and PM10) and trace gases (CO2, NO2) at five traffic intersections in Dhaka, Bangladesh, with the aim of evaluating seasonal variations and associated health risks. Sampling was conducted during the winter (December 2023–January 2024) and pre-monsoon (April–May 2024). Results revealed higher PM concentrations during winter: PM1.0, PM2.5 and PM10 averaged 108.3 ± 14.0, 336.1 ± 68.3 and 449.2 ± 98.7 μgm-3, respectively, compared to lower values in the pre-monsoon (41.7 ± 8.6, 93.1 ± 20.1 and 151.9 ± 33.3 μgm-3). NO2 concentrations were higher during winter (0.13 ± 0.01 ppm) with oscillating diurnal variation and declined in pre-monsoon (0.10 ± 0.02 ppm), which exhibits a clear rising trend. CO2 levels remained steady around 790 ± 30 ppm throughout both seasons. Health risk assessment showed Hazard Quotient (HQ) values above 1 for NO2 (between 1.06 to 1.58), PM2.5 (between 0.89 to 4.78) and PM10 (between 0.82 to 5.31) posing severe risks to infants. The Hazard Ratio (HR) for CO2 ranged between 0.7 and 0.85, indicating no direct health effects. This study emphasizes the immediate need for specific mitigation strategies at traffic intersections to protect public health.