Climate change is affecting human health through more extreme weather, worsening chronic conditions, higher temperatures, malnutrition, biodiversity loss, and the spread of diseases. Wildfire smoke is a growing concern as wildfire seasons increase, especially in the United States. Children and people with respiratory disease are more at risk from smoke exposure. Pediatric asthma affects more than 4 million children in the U.S. This condition is especially high in the Northeast, including Vermont. In 2023, smoke from large wildfires in Canada spread into this region. There is limited information on how wildfire smoke affects areas new to wildfire. Â
A recent study published in Environmental Health aimed to investigate how wildfire smoke and higher levels of particulate matter (PM2.5) affect children’s asthma control during the 2023 Quebec wildfires using two approaches. In the first approach, researchers compared the asthma control in the summers of 2024, 2022, and 2023 throughout the year as a proxy for exposure to smoke. In the second approach, the authors analyzed the association between asthma control and ZIP-code PM2.5 level during the heavily smoke-affected summer of 2023. This retrospective study included asthma patients aged 3 to 21 years from outpatient hospital visits across upstate New York and Vermont. Asthma control was determined using the National Heart, Lung, and Blood Institute (NHLBI) test for respiratory and asthma control in kids (TRACK), and the Asthma Therapy Assessment Questionnaire (ATAQ) guidelines. Exposure to PM2.5 was estimated through national aeronautics and space administration (NASA) hazardous air quality ensemble system (HAQES) data.
A total of 1,217 patients were included in this cross-sectional study from 2022 (n = 324, male = 56.5%, female = 43.5%, New York = 20.4%, Vermont = 79.6%), 2023 (n = 421, male = 58.7%, female = 41.33%, New York = 24%, Vermont = 76%), and 2024 (n = 472, male = 55.1%, female = 44.7%, New York = 24.2%, Vermont = 75.9%), of which 77% were from Vermont. The mean age of included participants was 9±4.5 years for NHLBI (n = 995), 3.5±0.5 years for TRACK (n = 172), and 9.7±3.7 years for ATAQ (n = 923).  Â
This study demonstrated mixed evidence linking wildfire smoke exposure to worsening control. TRACK scores (lower scores indicate poorer control) were 7 points lower in 2022 vs 2023 (p = 0.048) and showed a similar, borderline difference between 2024 and 2023 (p = 0.054). ATAQ scores (higher score = worse control) were 0.4 points higher in 2022 than in 2023 (p = 0.020), with no significant difference compared with 2024 (p = 0.067). No significant differences were found using NHLBI guidelines for uncontrolled asthma when comparing 2023 to 2022, with p = 0.455 or 0.992. High pollen exposure was associated with lower ATAQ scores (p < 0.001).
Within the smoke-affected summer of 2023, PM smaller than 2.5 showed no significant association with NHLBI (β = 0.99, 95% confidence interval [CI]: 0.91 to 1.07; p = 0.716), ATAQ (β = -0.01, 95% CI: -0.07 to 0.05; p = 0.801), or TRACK (β = 1.09, 95% CI: -0.95 to 3.13; p = 0.290) outcomes. Across ZIP codes, a 4-week rolling mean PM2.5 ranged from 5.8 to 18 µg/m3, with the highest variability on June 29 and the lowest on August 20.
In conclusion, Wildfire smoke worsens pediatric asthma control, is inconsistently detected across tools, and is not reflected at the ZIP code level in PM2.5. Diverse assessments, research, and clinical collaboration are crucial as wildfire seasons intensify.Â
References: Maassel AK, Brochu P, Harder VS, et al. Wildfire smoke and pediatric asthma control in the Northeastern United States: a cross-sectional study. Environmental Health. 2025;24(1):91. doi:10.1186/s12940-025-01245-9
