Breathe with Caution: Exploring the Adverse Effect of Fine Particulate Matter (PM2.5) on Wildland Firefighters' Pulmonary Function and DNA Damage

Abstract Chiang Mai experiences severe pollution during wildfire season, and wildland firefighters are exposed to the hazards, particularly during fire suppression, including particulate matter. The adverse effects of wildfire smoke on respiratory health are a significant concern. This study aimed to investigate the potential adverse effects of PM2.5 exposure on the respiratory function and DNA damage of wildland firefighters. From January to May 2022 in Chiang Mai, this prospective cohort study assessed the health of wildland firefighters throughout pre-peak, peak, and post-peak ambient air pollution seasons. PM2.5 was measured at each forest fire station and from the Pollution Control Department data. Participants had general health exams, spirometry, and DNA damage analysis blood tests. Pair t-tests and multiple regression models were used to examine the connection between pulmonary function parameters (FVC, FEV1) and PM 2.5 concentration, with a significance level of P < 0.05. Thirty-three peak-season and twenty-one post-peak-season participants were enrolled. Four pre-peak-season wildland firefighters had FVC and FEV1 declines of > 15%. Multiple regression analysis showed a negative association between PM2.5 exposure and FVC% predicted (-2.81%, 95% CI: -5.27 to -0.34%, p = 0.027) and a marginally significant negative correlation with FVC (-114.38 ml, 95% CI: -230.36 to 1.59 ml, p = 0.053). Other pulmonary measures showed a non-significant downward trend. No significant changes in DNA damage were observed. Wildland firefighters experienced significant declines in pulmonary function associated with PM2.5 exposure. Spirometry is essential for surveillance and early detection of these respiratory issues during wildfire seasons.