The association between wildfire smoke exposure and asthma-specific medical care utilization in Oregon during the 2013 wildfire season

Wildfire smoke (WFS) increases the risk of respiratory hospitalizations. We evaluated the association between WFS and asthma healthcare utilization (AHCU) during the 2013 wildfire season in Oregon. WFS particulate matter ≤ 2.5 μm in diameter (PM 2.5 ) was estimated using a blended model of in situ monitoring, chemical transport models, and satellite-based data. Asthma claims and place of service were identified from Oregon All Payer All Claims data from 1 May 2013 to 30 September 2013. The association with WFS PM 2.5 was evaluated using time-stratified case-crossover designs. The maximum WFS PM 2.5 concentration during the study period was 172 µg/m 3 . A 10 µg/m 3 increase in WFS increased risk in asthma diagnosis at emergency departments (odds ratio [OR]: 1.089, 95% confidence interval [CI]: 1.043–1.136), office visit (OR: 1.050, 95% CI: 1.038–1.063), and outpatient visits (OR: 1.065, 95% CI: 1.029–1.103); an association was observed with asthma rescue inhaler medication fills (OR: 1.077, 95% CI: 1.065–1.088). WFS increased the risk for asthma morbidity during the 2013 wildfire season in Oregon. Communities impacted by WFS could see increases in AHCU for tertiary, secondary, and primary care.