Wildfire Smoke and Cardiorespiratory Emergency Visits in New Mexico 2022: Sensitivity to Exposure Estimates and...

In 2022, New Mexico (NM) experienced a number of wildfires, including the state's largest, Calf Canyon/Hermit's Peak. This study aimed to evaluate how different exposure estimate methods and referent period selection impacted associations between wildfire smoke and health outcomes using a case-crossover study design. We investigated associations with exposure to fine particulate matter (PM_2.5) from wildfire smoke and cardiorespiratory-related emergency department (ED) visits in NM during 2022. Our study compared a range of exposure methods: (a) PM_2.5 from the Environmental Protection Agency (EPA) regulatory-grade monitors, (b) PM_2.5 from both the EPA regulatory-grade monitors and low-cost PurpleAir observations, (c) modeled 24-hr average wildfire smoke PM_2.5 from the Community Multiscale Air Quality Modeling System (CMAQ), and (d) CMAQ daily 1-hr maximum wildfire smoke PM_2.5. The magnitude and statistical significance of health outcome associations varied substantially across exposure estimates and referent period selections. CMAQ-based exposure estimates produced odds ratios with wider confidence intervals (CIs), while the product that leveraged both regulatory and bias-corrected PurpleAir measurements improved the PM_2.5 measurement spatial coverage and yielded epidemiological estimates with narrower CIs. This highlights the importance of low-cost sensors in rural regions. Our findings emphasize the need to critically assess the inputs used in epidemiological studies for accurate and meaningful results, emphasizing the need for careful consideration of exposure assessment methods and study design when evaluating wildfire smoke health impacts.