Evaluation of health benefits from reductions in PM2.5 national ambient air quality standards for Ratchaburi, Thailand

Thailand recently announced new national ambient air quality standards, reducing the PM2.5 limits from 50 µg/m³ to 37.5 µg/m³ for the 24-hr average and from 25 µg/m³ to 15 µg/m³ for the annual average. This study aimed to evaluate the potential health benefits of these changes in national ambient air quality standards for Ratchaburi. A health impact function was used to quantify the avoided health burdens, while the cost of illness and the value of a statistical life were used to estimate the associated monetary benefits for morbidity and mortality, respectively. The study covered the period from 2015 to 2019. For the new 24-hr standard, it was estimated that meeting these standards would avoid an additional 4,549 hospital visits and 62 deaths related to cardiovascular and respiratory diseases, resulting in a cumulative monetary gain of 29,992,561 USD. Meeting the new annual PM2.5 standards would avoid 21,495 hospital visits and 330 deaths related to cardiovascular and respiratory diseases, yielding a cumulative economic gain of 146,466,731 USD. The upgrade of the annual standard is projected to provide higher health and financial benefits than the 24-hr standard. It is recommended that this evaluation be extended to other provinces to assess the overall health and economic impact of the new PM2.5 standards across Thailand. Additionally, all provinces should prioritize meeting the new annual standards.