Effective air quality management relies on a comprehensive understanding of source-receptor relationships. This study used the WRF-CMAQ model with the Integrated Source Apportionment Method (ISAM) and brute force method (BFM) to quantify the contributions of seven domestic anthropogenic emission sectors to PM 2.5 concentrations across distinct regions of Thailand. The investigated sectors included open biomass burning (OBB), residential (RES), industrial (IND), power generation (POW), road transport (ROAD), other transport (OTT), and other anthropogenic sources (OTA). Unclassified sources, such as transboundary transport and natural emissions, were categorized as ’Other’ (OTH). The results showed that the OTH sector was the major contributor to PM 2.5 levels at all receptor sites, especially in the rural Northern Region, where it accounted for up to 62.7% of concentrations. Conversely, domestic sources—specifically the IND, RES, and ROAD sectors—dominated pollution in the highly urbanized Bangkok Metropolitan Region and Saraburi. While domestic OBB was a major local contributor in the Northern Region, Khon Kaen, a key urban center, exhibited an intermediate pollution profile with notable contributions from both domestic sources and OBB. Differences between the ISAM and BFM results highlighted the non-linear atmospheric chemistry involved in secondary inorganic aerosol (SIA) formation. The analysis determined that Thailand is in an ammonia-rich regime, suggesting that controlling acidic precursors would be more effective for PM 2.5 reduction than targeting ammonia emissions. Ultimately, this study highlights the need for a multi-faceted air quality management approach that combines geographically tailored domestic policies with international cooperation to address transboundary pollution. • Transboundary and other sources are the primary PM2.5 contributors in all regions. • Domestic source profiles vary across regions. • Open biomass burning is the major domestic source in the Northern Region. • Industrial and residential emissions are the major domestic sources in urban areas. • Given Thailand’s ammonia-rich regime, acidic precursor control is the most effective.
Chantaraprachoom et al. (Sun,) studied this question.