Association of time-serial changes in ambient particulate matters (PMs) with respiratory emergency cases in Taipei's Wenshan District

<div><p>Ambient air pollution poses a significant risk for a group of common and often debilitating respiratory diseases, but its direct impact on cause-specific respiratory diseases using emergency room visit (ERV) as an indicator remains to be fully explored. In this study, we conducted a time-series study of ambient PM_2.5, NO₂, SO₂ and their association with ERV for asthma, COPD and pneumonia in a four-year time span. Relative risks for ERV as per log increase in the level of ambient pollutants with time lags of up to 10 days were calculated, using a generalized additive model of Poisson regression. Daily 24-h average concentrations of PM_2.5 and pollutant gases were obtained from a local Gutting air quality monitoring station. Results showed that the ERVs for pneumonia and asthma were associated with the level of PM_2.5. The effects of PM2.5 on the risk of ERV for asthma were found to be significant at lag days 1 and 2 with increasing risk of 4.34% [RR: 1.091; CI: 1.020–1.166 (95%)] and 3.58% [RR: 1.074; CI: 1.007–1.146 (95%)], respectively. The ERV for pneumonia was associated with the level of PM_2.5 at lag days 5, 6 and 7, with increasing risk of 1.92% [RR: 1.039; CI: 1.009–1.070 (95%)], 2.03% [RR: 1.041; CI: 1.009–1.075 (95%)], and 1.82% [RR: 1.037; CI: 1.001–1.075 (95%)], respectively. Further, PM_2.5, but not NO₂ and SO₂, posed a significant risk of ERV for asthma during spring at lag days 0, 1 and 2 (17.12%, RR: 1.408, CI: 1.075–1.238; 15.30%, RR: 1.358 CI: 1.158–1.166; 11.94%, RR: 1.165, CI: 1.004–1.121), which was particularly evident for those who were younger than 75 years of age. In contrast, only PM_2.5 was a significant risk of ERV for COPD, which was primarily for those who were younger than 75 years of age during summer season at lag days 3, 4 and 5. (26.66%, RR: 1.704, CI: 1.104–2.632; 26.99%; RR: 1.716, CI: 1.151–2.557; 24.09%; RR: 1.619, CI: 1.111–2.360). Collectively, these results suggested significant seasonal variation and differential time lag effects of PM_2.5 on ERV for asthma, COPD and pneumonia.</p>