A Decadal Assessment of PM_2.5 Pollution in Dhaka, Bangladesh (2015–2024): Pollution Severity, Temporal Variability, and Meteorological Associations

Fine particulate matter (PM_2.5) is a persistent air-quality problem in Dhaka, Bangladesh, and its severity and temporal variability calls for a long-term assessment. The present study reviewed PM_2.5 pollution between 2015 and 2024 and investigated the seasonal, interannual, and meteorological correlation. Daily air-quality and meteorological data were analysed with descriptive statistics, air-quality benchmark comparison, general linear model, Spearman correlation and linear regression for three monitoring stations. A total of 7,943 station-day observations were processed, with 6,268 having good daily PM_2.5 observations. Annual mean concentrations varied from 77.24 μg/m³ in 2017 to 108.74 μg/m³ in 2021, well above the annual guideline of 5 μg/m³ set by the World Health Organization. The concentrations differed significantly between seasons (p < 0.001) with higher levels found in winter season compared to monsoon season. The general linear model also indicated an interannual difference (p = 0.033), but no significant linear trend was observed by the linear regression (p = 0.797). Bivariate correlations were negative for temperature, relative humidity and wind speed, but none of these variables were statistically significant in the adjusted model. The findings indicate persistently high PM_2.5 concentrations and pronounced seasonal variation. To improve air quality in Dhaka, sustained emission controls, uniform monitoring and coordinated air quality management is required.