Rafi Bin Shahadat, Sayma Sultana Keya, Md Tushar Ali
Ambient particulate pollution remains a major health concern in Bangladesh, yet its spatial, temporal, meteorological, and health-risk characteristics across Bangladesh remain insufficiently characterized. This study assessed PM2.5 and PM10 concentrations recorded at 16 Department of Environment continuous monitoring stations across Bangladesh during 2018-2025. Annual, monthly, and seasonal variability were evaluated using descriptive statistics, non-parametric comparisons, Spearman correlation, and Seasonal Mann-Kendall and tests. Kriging interpolation was used only for exploratory visualization because of limited predictive performance. Health risks were assessed using Excess Lifetime Cancer Risk (ELCR) for PM2.5 and Hazard Quotient (HQ) for both particulate matters. All stations exceeded the Bangladesh National Ambient Air Quality Standards and WHO Air Quality Guidelines in every year. Network-wide annual mean PM2.5 decreased from 91.54 µg/m3 in 2018 to 77.64 µg/m3 in 2025 (- 15.2%), while PM10 decreased from 155.7 to 132.3 µg/m3 (- 15.0%), although both trends were non-monotonic and rebounded after the 2020 minimum. A pronounced seasonal pattern was observed, with mean winter concentrations approximately 4.2 and 3.0 times higher than monsoon concentrations for PM2.5 and PM10, respectively. PM concentrations were generally negatively associated with temperature, relative humidity, wind speed, and rainfall, which indicates strong meteorological control. Most seasonal trends were statistically nonsignificant, which suggested that interannual variability rather than a consistent nationwide trend. Mean ELCR for PM2.5 ranged from 0.476 to 0.950, while mean HQ values were 3.60 and 2.73 for PM2.5 and PM10, respectively. These findings support stronger particulate emission controls, expanded air-quality monitoring, and seasonally targeted interventions to reduce population exposure across Bangladesh.