Assessment of PM2.5 and PM10 Over Sri Lanka: Spatiotemporal Trends, Potential Source Regions, and Associated Health Effects

Abstract

This study analyzed particulate matter (PM_2.5 and PM₁₀) concentrations at 17 locations in Sri Lanka over 2 years (January 2021–December 2022); the effects of meteorological parameters on the PM, potential source regions for high PM, and the associated human health risk. The highest annual mean PM_2.5 (29.9 ± 19.4 µgm⁻³), PM₁₀ (55.8 ± 37.8 µgm⁻³) in 2022, and PM_2.5 (21.4 ± 7.8 µgm⁻³) and PM₁₀ (41.1 ± 14.8 µgm⁻³) in 2021 were reported in Jaffna and Kurunegala, respectively. Throughout both years, the PM concentrations were always higher than the World Health Organization guidelines. Seasonally, the Northeast monsoon experienced the highest average PM_2.5 (54.7 µgm⁻³) and PM₁₀ (104.2 µgm⁻³) in 2022, which may be attributed to low rainfall (∼4.5 mm), moderate temperature (∼26°C), and low wind speed (∼3 mph). The conditional bivariate probability function (CBPF) revealed probable sources to be motor vehicles (in Colombo, Galle, and Kurunegala), biomass burning (at all sites), textile units (in Colombo, Kurunegala), cement manufacturing plants (in Galle, Puttalam), and coal-fired power plants (in Puttalam). A period of 72-hr backward trajectories at 500, 1000, and 1500 m using the hybrid single-particle Lagrangian–integrated trajectory (HYSPLIT) revealed air mass pathways tracing back to eastern India and the Bay of Bengal, confirming transboundary pollutant movement into Sri Lanka. The health effects of PM_2.5 exposure were estimated via AirQ+, which revealed the highest mortality in Jaffna in 2022. The findings of this study provide valuable insights to local and national governments for appropriate policy intervention needed to manage air pollution in Sri Lanka, considering the health risks associated with PM_2.5 exposure.