Air pollution and hospital admissions for pneumonia in a subtropical city: Taipei, Taiwan.

This study was undertaken to determine whether there was an association between air pollutant 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 1996-2004. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single pollutant models, on warm days (>23 degrees C) statistically significant positive associations were found in all pollutants. On cool days (<23 degrees C), all pollutants were significantly associated with pneumonia admissions except SO(2). For the two-pollutant model, O(3) and NO(2) were significant in combination with each of the other 4 pollutants on warm days. On cool days, PM(10), CO, and O(3) remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient air pollutants increase the risk of hospital admissions for pneumonia.