Air pollution exposure and respiratory and cardiovascular emergency visits: A time-stratified case-crossover analysis in Taiwan.

Taiwan has undergone rapid urbanization and industrial expansion in recent years, which have significantly contributed to elevated levels of air pollution. This study examines the association between multiple air pollutants and emergency department (ED) visits for respiratory and cardiovascular diseases in selected counties and cities of Taiwan from 2015 to 2019. Using a time-stratified case-crossover approach and conditional logistic regression models adjusted for potential confounders, we analysed over 2,268,048 ED visits to assess the effects of pollutants like PM2.5, PM10, NO2, O3, and SO2 on disease-specific ED visits among residents living nearby coal-fired power plant. We also assessed effects modification by age (20-29 years, 30-59 years, and ≥ 60) and sex groups (male and female). Findings reveal that exposure to PM2.5 and PM10 at lag 5 was associated with increased asthma events, with odds ratios (ORs) of 1.13 (95 % CI: 1.03-1.23) for PM2.5 and 1.16 (95 % CI: 1.05-1.28) for PM10. Additionally, every 15 ppb increase in O3 was associated with increased asthma events at lag 0 (OR = 1.04, 95 % CI: 1.02-1.06). This study further demonstrates that a 1 ppb increase in NO2 was associated with increased ischemic heart disease (IHD) events at lag 1 (OR = 1.16, 95 % CI: 1.00-1.35), stroke at lag 0 (OR = 1.05, 95 % CI: 1.03-1.07), and ischemic stroke (IS) at lag 3 (OR = 1.27, 95 % CI: 1.05-1.49), respectively. These findings underscore the importance of continuous air quality monitoring to enhance the protection of sensitive populations.