The Effects of Wildfires and Related Air Pollution on Cardiorespiratory Health of Firefighters and Other High-Risk Occupational Groups- A Systematic Review

Abstract

Background: The frequency and intensity of wildfires are rising as a result of climate change, and exposure to wildfire smoke poses major health risks to the general public. Significant dangers to the heart and lungs have been associated with fine particulate matter (PM2.5) and other pollutants emitted during fires. Workers who are frequently exposed to high levels of smoke and other harmful substances, like firefighters, first responders, agricultural workers, and construction workers may particularly be at risk for health problems. Despite mounting concern, little is known about how air pollution from wildfires affects the cardiorespiratory health of high-risk occupational groups.

Objective: To systematically identify and evaluate the available data and summarize the information concerning the association between wildfires and related air pollution on cardiorespiratory health of different potentially affected occupational groups.

Methodology: A systematic literature search was conducted in MEDLINE and EMBASE via the Ovid interface, Google Scholar was manually searched. The search focused on studies published in English between 2015 and 2024 that examined the cardiorespiratory health effects of wildfire and wildfire related air pollution in occupational groups- firefighters, construction workers, agricultural workers, and first responders. Rayyan was used to perform full-text and title/abstract screening. Included studies were only original research publications that satisfied the PEO (Population, Exposure, Outcome) criterias. Risk of bias was assessed using the Critical Appraisal Skills Programme (CASP) checklist for Cohort and cross sectional studies, and a customized checklist was developed for the modelling study. Based on assessments at the qualitative domain level, studies were classified as having a low, moderate, or high risk of bias.

Results: Out of 966 screened articles, five met the inclusion criteria, all focusing on wildland firefighters. No eligible studies were found for other high-risk occupational groups. There was variation in the design and quality of the included studies; some evaluated short-term respiratory impacts, while others modelled or clinically measured long-term respiratory or cardiovascular outcomes. Short- and long-term health hazards are there for firefighters who are exposed to wildfire smoke. Long-term exposure was associated with a 2.84 fold higher odds of hypertension, a 16–30% increase in lifetime cardiovascular mortality risk, and up to 43% higher risk of lung cancer mortality among firefighters. 67.9% of firefighters experienced restricted respiratory patterns after just one season.

Conclusions: Wildfire smoke exposure is associated with adverse cardiorespiratory outcomes among firefighters, including increased risks of hypertension and respiratory impairment. To provide focused health protection and policy interventions, research should be expanded to include other high-risk occupational categories.

Key words: Climate change, wildfire, wildfire smoke, air pollution, cardiorespiratory health, cardiovascular disease, respiratory disease, fire fighters, occupational groups, agricultural workers, construction workers, first responders.

Background: The frequency and intensity of wildfires are rising as a result of climate change, and exposure to wildfire smoke poses major health risks to the general public. Significant dangers to the heart and lungs have been associated with fine particulate matter (PM2.5) and other pollutants emitted during fires. Workers who are frequently exposed to high levels of smoke and other harmful substances, like firefighters, first responders, agricultural workers, and construction workers may particularly be at risk for health problems. Despite mounting concern, little is known about how air pollution from wildfires affects the cardiorespiratory health of high-risk occupational groups.

Objective: To systematically identify and evaluate the available data and summarize the information concerning the association between wildfires and related air pollution on cardiorespiratory health of different potentially affected occupational groups.

Methodology: A systematic literature search was conducted in MEDLINE and EMBASE via the Ovid interface, Google Scholar was manually searched. The search focused on studies published in English between 2015 and 2024 that examined the cardiorespiratory health effects of wildfire and wildfire related air pollution in occupational groups- firefighters, construction workers, agricultural workers, and first responders. Rayyan was used to perform full-text and title/abstract screening. Included studies were only original research publications that satisfied the PEO (Population, Exposure, Outcome) criterias. Risk of bias was assessed using the Critical Appraisal Skills Programme (CASP) checklist for Cohort and cross sectional studies, and a customized checklist was developed for the modelling study. Based on assessments at the qualitative domain level, studies were classified as having a low, moderate, or high risk of bias.

Results: Out of 966 screened articles, five met the inclusion criteria, all focusing on wildland firefighters. No eligible studies were found for other high-risk occupational groups. There was variation in the design and quality of the included studies; some evaluated short-term respiratory impacts, while others modelled or clinically measured long-term respiratory or cardiovascular outcomes. Short- and long-term health hazards are there for firefighters who are exposed to wildfire smoke. Long-term exposure was associated with a 2.84 fold higher odds of hypertension, a 16–30% increase in lifetime cardiovascular mortality risk, and up to 43% higher risk of lung cancer mortality among firefighters. 67.9% of firefighters experienced restricted respiratory patterns after just one season.

Conclusions: Wildfire smoke exposure is associated with adverse cardiorespiratory outcomes among firefighters, including increased risks of hypertension and respiratory impairment. To provide focused health protection and policy interventions, research should be expanded to include other high-risk occupational categories.

Key words: Climate change, wildfire, wildfire smoke, air pollution, cardiorespiratory health, cardiovascular disease, respiratory disease, fire fighters, occupational groups, agricultural workers, construction workers, first responders.