Mortality and emergency room visits associated with ambient particulate matter constituents in metropolitan Taipei

To evaluate the elderly mortality and all population emergency room visits (ERV) associated with exposing to particulate matter (PM) ≤10μm in aerodynamic diameter (PM10), PM2.5, and PM constituents in Taipei, Taiwan.

This study used a distributed lag nonlinear model with Poisson distribution to estimate cumulative 6-day (lags 0-5) relative risks (RRs) and confidence intervals (CIs) of mortality and ERV of all causes, circulatory diseases, and respiratory diseases associated with daily concentrations of PM10, PM2.5 and PM constituents (organic carbon (OC), elemental carbon (EC), nitrate and sulfate).

Mortality and ERVs were associated with PM concentrations and its constituents. The elderly all-cause mortality was significantly associated with nitrate concentrations (RR=1.12 (95% CI: 1.02, 1.23) at 1μg/m(3)) and OC higher than 15μg/m(3); and mortality from circulatory diseases was significantly associated with PM10 (RR=1.13 (95% CI: 1.02, 1.25) at 50μg/m(3)), PM2.5 (RR=1.16 (95% CI: 1.01, 1.34) at 30μg/m(3)), nitrate higher than 8μg/m(3), and sulfate (RR=1.31 (95% CI: 1.12, 1.54) at 7μg/m(3)). An increase in PM2.5 from 5μg/m(3) to 30μg/m(3) was associated with increased ERV risk of all causes and respiratory diseases with cumulative 6-day RRs of 1.12 (95% CI: 1.06, 1.18) and 1.27 (95% CI: 1.10, 1.46), respectively. All-cause ERV was significantly associated with concentrations of OC (RR=1.03 (95% CI: 1.00, 1.06) at 4μg/m(3)), EC (RR=1.08 (95% CI: 1.05, 1.12) at 2μg/m(3)), nitrate higher than 6μg/m(3), and sulfate higher than 8μg/m(3).

Ambient air quality management should regularly evaluate PM constituents and related health effects.