Decadal changes in premature mortality associated with exposure to outdoor PM2.5 in mainland Southeast Asia and the impacts of biomass burning and anthropogenic emissions

In mainland Southeast Asia (SEA), a rapid increase of fossil fuel consumption and massive particulate matter emissions from biomass burning (BB) are severely threatening the health of local inhabitants. In this study, surface PM2.5 data, satellite fire observations and emission inventories were integrated with the Global Exposure Mortality Model (GEMM) to estimate premature mortality attributable to PM(2.5 )exposure from 1990 through 2019 and to explore and quantify the health burden associated with BB and anthropogenic emissions in mainland SEA. BB in mainland SEA has remained intense over the past decades. Owing to a lack of effective control measures, emission inventory and satellite-observed data both showed that BB has markedly intensified in several regions, including northern Cambodia and northern Laos. The multiannual average (1997-2015) BB PM2.5 emission was 1.6 x 10(6) t/yr, which is much higher than that of anthropogenic (fossil fuel combustion) PM2.5 emission. GEMM results indicated that PM2.5-related premature mortality in mainland SEA more than doubled from 100 (95 % confidence interval [CI], 88-112) thousand in 1990 to 257 (95 % CI, 228-286) thousand in 2019. Decomposition analysis revealed that variations in population size and age structure also promoted this increase of PM2.5-related deaths. Given that mainland SEA is a rapidly developing region, it is expected that local public health will face increasing challenges due to population growth, population ageing, and increased anthropogenic emissions. Therefore, it is imperative for policymakers to consider these influential factors, set practical mitigation targets, and explore how to effectively and systematically combine BB with anthropogenic emission controls to maximize the health benefits.