Mortality and economic burden of PM2.5 and NO2 in Thailand using satellite remote sensing and Random Forest algorithms

• Satellite–Machine Learning integration aids air quality policy in data-scarce areas. • PM 2.5 exposure associated with 20,487 deaths during 2018–2022. • NO 2 exposure linked to 15,394 deaths, mainly in urban areas. • Economic loss of PM 2.5 -related deaths is approximately 2,313 million THB yearly. • Economic loss of NO 2 -related deaths is approximately 1,738 million THB annually. Air pollution remains a leading environmental health problem in Thailand, where rapid urbanization, biomass burning, and industrial activity contribute to high concentrations of fine particulate matter (PM 2.5 ) and nitrogen dioxide (NO 2 ). However, most existing studies rely upon data from fixed-site monitoring stations, leaving large areas underrepresented. This study aimed to develop satellite-based Random Forest (RF) models to estimate daily concentrations of PM 2.5 and NO 2 across Thailand from 2018 to 2022 using Aerosol Optical Depth (AOD) data from Terra and Aqua satellites, and NO 2 from TROPOspheric Monitoring Instrument (TROPOMI) aboard the Sentinel-5 Precursor satellite. These estimated concentrations were then linked to health and economic impacts using concentration-response functions and the Value of Statistical Life (VSL). The RF models demonstrated high performance. For PM 2.5 , the model achieved R 2 of 0.94 and RMSE of 7.40 µg m -3 in training, and R 2 of 0.71 with RMSE of 15.09 µg m -3 in testing. For NO 2 , R 2 values were 0.94 and 0.73, with RMSE of 2.21 and 4.41 ppb, respectively. Nationwide mean concentrations during the study period were 29.51 ± 2.82 µg m -3 for PM 2.5 and 4.61 ± 0.81 ppb for NO 2 , with pronounced regional and seasonal contrasts. Specifically, PM 2.5 peaked in northern provinces during the dry season, while NO 2 levels were concentrated in Bangkok and industrial regions. Modeled concentrations were higher than ground-based averages as the model captures unmonitored high-pollution areas, particularly in the north. Long-term exposure to PM 2.5 and NO 2 was associated with 20,487 deaths (95% CI: 12,833–28,079) and 15,394 deaths (95% CI: 10,281–20,487), respectively, corresponding to economic losses of 2,313 million THB (95% CI: 1,449–3,171) and 1,738 million THB (95% CI: 1,161–2,313) annually, respectively. This study provides a reliable tool for nationwide air quality monitoring and health impact assessment and supports development of sustainable environmental and public health strategies.