Fine Particulate Air Pollution and Hospital Admissions for Asthma: A Case-Crossover Study in Taipei

Abstract

This study was undertaken to determine whether there was a correlation between fine particles (PM_2.5) levels and hospital admissions for asthma in Taipei, Taiwan. Hospital admissions for asthma and ambient air pollution data for Taipei were obtained for the period of 2006–2010. The relative risk of hospital admissions for asthma was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased asthma admissions were significantly associated with PM_2.5 levels both on warm days (>23°C) and cool days (<23°C), with an interquartile range rise associated with a 12% (95% CI = 6–18%) and 3% (95% CI = 0–8%) elevation in admissions for asthma, respectively. In the two-pollutant models, PM_2.5 levels remained significant for increased asthma admissions after inclusion of SO₂ or O₃ both on warm and cool days. This study provides evidence that higher levels of PM_2.5 elevate the risk of hospital admissions for asthma in Taiwan.