Fine particulate air pollution and hospital admissions for pneumonia in a subtropical city: Taipei, Taiwan.

This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for pneumonia in Taipei, Taiwan. Hospital admissions for pneumonia and ambient air pollution data for Taipei were obtained for the period from 2006 to 2010. The relative risk of hospital admissions for pneumonia 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 numbers of admissions for pneumonia were significantly associated with higher PM2.5 levels both on warm days (>23°C) and on cool days (<23°C). This was accompanied by an interquartile range elevation correlated with a 12% (95% CI = 16%-13%) and 4% (95% CI = 3%-6%) rise in number of admissions for pneumonia, respectively. In the two-pollutant models, PM2.5 remained significant after inclusion of sulfur dioxide (SO₂) or ozone (O₃) both on warm and on cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for pneumonia.