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This research examines the impact of short-term wildfire smoke PM2.5 exposure on lung function in generally healthy young adults.

May 20, 2026

B97-08 Short-term Exposure to Wildfire Smoke PM2.5 and Lung Function in Generally Healthy Young Adults: The ALA Lung Health Cohort

Key Points

This research examines the impact of short-term wildfire smoke PM2.5 exposure on lung function in generally healthy young adults.
Analyzed 8,269 spirometry observations from 1,830 U.S. adults aged 25-35 years in the American Lung Association Lung Health Cohort.
Estimated daily wildfire smoke PM2.5 exposures using satellite-based models with 10 × 10 km spatial resolution.
Utilized generalized additive mixed models to assess associations between exposure and lung function, adjusted for relevant covariates.
Cumulative wildfire smoke exposure over lags 1-5 days associated with lower FEV1 (-25.9 mL; 95% CI: -45.7, -6.0) and FVC (-39.3 mL; 95% CI: -72.9, -6.4).
Moderate wildfire smoke exposure linked to lower FEV1 (-24.3 mL, 95% CI: -48.3, -0.4) and higher exposure further decreased FEV1 (-42.0 mL, 95% CI: -69.3, -14.6).
No significant association found with FEV1/FVC ratio.

Abstract

Abstract Rational Wildfires are increasing in frequency and intensity due to climate change, impairing air quality. While prior research has documented associations between wildfire smoke and asthma morbidity, there is limited evidence on the impact of wildfire smoke exposure on objective lung function in young, healthy adults. Methods We analyzed 8,269 spirometry observations from 1,830 U.S. adults aged 25-35 years in the national American Lung Association Lung Health Cohort, collected during warm seasons (April-October) from 2022-2024. Daily wildfire smoke PM2.5 exposures were estimated using high-resolution satellite-based models with 10 × 10 km spatial resolution. Wildfire smoke days were defined as any day when wildfire smoke PM2.5 0 µg/m³. To capture exposure intensity and potential dose-response relationships, smoke days were further categorized based on the wildfire PM2.5 distribution percentiles: low smoke days (25th percentile, 1.11 µg/m³), moderate smoke days (25th-75th percentile, 1.11-6.25 µg/m³), and high smoke days (75th percentile, 6.25-158 µg/m³). We estimated associations between wildfire smoke exposure (lags 1-7 days) and pre-bronchodilator lung function indices (forced expiratory volume in one second FEV1, forced vital capacity FVC, and FEV1/FVC ratio), using generalized additive mixed models with distributed lag non-linear modeling, adjusted for age, sex, BMI, height, education, and day of the week. Results The mean participant age was 29.5 years, and 65% were female. Overall, 62.3% of the warm season observations occurred on wildfire smoke days. Wildfire smoke PM2.5 exposure was associated with lower lung function, with attenuation at longer lags (Figure 1). Cumulative wildfire smoke exposure over lags 1-5 days were associated with lower FEV1 (-25.9 mL; 95% CI: -45.7, -6.0) and FVC (-39.3mL; 95% CI: -72.9, -6.4), while there was no significant association with FEV1/FVC ratio. There was evidence of a dose-response relationship: compared to non-smoke days, low wildfire smoke exposure was negatively but not significantly associated with lung function, whereas moderate exposure was associated with a lower FEV1 (-24.3 mL, 95% CI: -48.3, -0.4), and high smoke exposure was associated an even lower FEV1 (-42.0 mL, 95% CI: -69.3, -14.6), with a similar pattern for FVC. Conclusion Short-term exposure to wildfire smoke PM2.5 is associated with lower lung function in young healthy adults. These findings highlight the need for public health interventions and policies in the U.S. to mitigate the respiratory health impacts of increasing wildfire smoke exposure. This abstract is funded by: U01 HL 146408

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