Health benefits of reducing ambient levels of fine particulate matter: a mortality impact assessment in Taiwan.

While numerous studies have found a relationship between long-term exposure to airborne fine particulate matter (PM_2.5) and higher risk of death, few investigations examined the contribution that a reduction of exposure to ambient PM_2.5 levels might exert on mortality rates. This study aimed to collect data on changes in annual average ambient levels of PM_2.5 from 2006 to 2020 and consequent health impact in public health in 65 municipalities in Taiwan. Avoidable premature mortality was used here as an indicator of adverse health impact or health benefits. Annual PM_2.5 levels were averaged for the years 2006, 2010, and 2020. In accordance with World Health Organization (WHO) methodology, differences were estimated in the number of deaths attributed to ambient PM_2.5 exposure which were derived from concentration-response data from prior epidemiological studies. PM_2.5 concentrations were found to have been decreased markedly throughout Taiwan over the two-decade study. As the PM_2.5 concentrations fell, so was the health burden as evidenced by number of deaths concomitantly reduced from 22.4% in 2006 to 8.47% in 2020. Data demonstrated that reducing annual mean levels of PM_2.5 to PM₁₀ ug/m³ was associated with decrease in the total burden of mortality, with a 2.22-13.18% fall in estimated number of PM_2.5-related deaths between 2006 and 2020. Based upon these results, these declines in ambient PM_2.5 levels were correlated with significant improvement in public health (health benefits) and diminished number of deaths in Taiwan.