Effects of fine particulate matter and its constituents on emergency room visits for asthma in southern Taiwan during 2008–2010: a population-based study

Abstract

This population-based study evaluated the short-term association between fine particulate matter (PM_2.5) concentrations and its constituents and hospital emergency room visits (ERVs) for asthma in southern Taiwan during the period 2008–2010. Data on hospital ERVs for asthma and ambient PM_2.5 levels and its constituents were obtained from the National Health Insurance Research database and the Environmental Protection Administration, respectively. The quasi-Poisson generalized additive model was used to explore the associations between PM_2.5 and hospital ERVs for asthma. During the study period, the average daily number of ERVs for asthma and mean 24-h average level of PM_2.5 was 20.0 and 39.4 μg m⁻³, respectively. The estimated effects of PM_2.5 on asthma ERVs fluctuated with increasing tendencies after adjusting for O₃ and attenuating tendencies after adjusting for NO₂, SO₂, and CO. Children were more susceptible than other age groups to the effects of PM_2.5 exposure on asthma ERVs, with the relative risks (RRs) for every 10 μg m⁻³ increase in PM_2.5 being 1.016 [95% confidence interval (CI) = 1.002–1.030] and 1.018 (95% CI = 1.002–1.034), respectively, at a lag 0 day (i.e., no lag days) and lag 0–1 days. The effect of PM_2.5 concentrations on asthma ERVs was similar in male and female. Furthermore, asthma ERVs was significantly associated with concentrations of nitrate (NO₃⁻), with the RR for each 1 μg m⁻³ increase in NO₃⁻ concentrations being 1.004 (95% CI = 1.001–1.007) at lag 0 day. In conclusion, both PM_2.5 concentrations and its chemical constituents are associated with ERVs for asthma; moreover, children were more susceptible to the effects of PM_2.5 in southern Taiwan. PM_2.5 constituent, nitrate, is more closely related to ERVs for asthma.

http://ift.tt/2q6vTJT