Abstract
PM(2.5) is a critical air pollutant that significantly impacts human health and the environment. To develop effective air quality management and mitigation strategies, understanding PM(2.5) source attribution and associated health risks is essential. This study investigates the source attribution and health burden of PM(2.5) focusing on Mainland Thailand (MT), North Thailand (NT), and the Bangkok Metropolitan Region (BMR), using the WRF-Chem model and a brute-force method for source attribution. PM(2.5) contributions from biomass burning including both crop and non-crop burning are quantified, along with contributions from transportation, industry, energy, residential, and other anthropogenic sectors. This study focuses on the haze season (February-April) in 2019. Our research shows that in-domain foreign country's biomass burning is a major contributor to PM(2.5), accounting for 23%-38% of PM(2.5) concentrations in MT. In NT, non-crop burning within MT contributes the most (21%-36%) to PM(2.5) levels, while crop burning within MT has a minimal impact (less than 6%). In the BMR, PM(2.5) is strongly impacted by sources outside the model domain. Overall, industrial and transportation emissions are the most impactful anthropogenic sources. We further estimate the total health burden, associated with long-term PM(2.5) exposure during the haze season contributes to 46% of this PM(2.5) health burden in MT in 2019, 66% in NT, and 37% in the BMR. These findings suggest that reducing biomass burning within MT and from in-domain foreign countries during February-April could reduce the annual health burden in MT by up to 20%.