Particulate Air Pollution and Hospital Emergency Room Visits for Asthma in Seattle

TLDR

Short‑term exposure to respirable PM10 has been linked to asthma symptoms, medication use, hospitalizations, and increased chronic respiratory mortality. The study aimed to determine whether PM10 exposure increases asthma emergency room visits in Seattle. Daily asthma ER visit counts from eight Seattle hospitals were analyzed using Poisson regression models adjusted for weather, seasonality, demographics, and hospital factors. ER visits among people under 65 were significantly higher with higher PM10 levels, with a 30 µg/m³ increase raising risk by 12 % (RR = 1.12), and a 4‑day mean PM10 proved a stronger predictor; PM10 never exceeded 70 % of standards, underscoring the need for stricter particulate control.

Abstract

Recent studies have associated short-term exposure to respirable particulate matter (PM10) exposure with peak flow decrements, increased symptoms of respiratory irritation, increased use of asthma medications, and increased hospitalization for asthma. Increased mortality from chronic respiratory disease has also been reported. To help confirm whether PM10 exposure is a risk factor for the exacerbation of asthma, we compiled daily records of asthma emergency room visits from eight hospitals in the Seattle area. In Poisson regressions controlling for weather, season, time trends, age, hospital, and day of the week, the daily counts of emergency room visits for persons under age 65 were significantly associated with PM10 exposure on the previous day. The mean of the previous 4 days' PM10 was a better predictor (p < 0.005). The relative risk for a 30 µg/m3 increase in PM10 was 1.12 (95% confidence interval 1.20 to 1.04). Daily PM10 concentrations never exceeded 70% of the current ambient air quality standards during the period. The consistency of investigations of the health effects of PM10 suggest that increased attention should be given to the control of particulate matter air pollution.