Evaporative Coolers and Wildfire Smoke Exposure: A Climate Justice Issue in Hot, Dry Regions

During wildfires and extreme heat events, low-income families in dry regions must resort to evaporative coolers (ECs) that pull unfiltered outdoor air into the home, creating a health hazard to occupants.

This study, “Evaporative coolers and wildfire smoke exposure: a climate justice issue in hot, dry regions,” co-written by authors from PHI’s Tracking California and partners and published in Frontiers in Public Health, explores how to protect low-income communities from wildfire smoke pollution. Since ECs are disproportionately in low-income homes, addressing smoke intrusion through these devices is an environmental justice issue.

The community-engaged research project to reduce wildfire smoke in homes was conducted in California’s San Joaquin Valley in homes of Spanish-speaking agricultural workers. Although participants were pleased with the air cleaners and air filters offered free of charge, the air filtration solutions would be an ongoing cost to participants due to the need to replace the filters.

Methods

Study site
The Filtration for Respiratory Exposure to wildfire Smoke from Swamp Cooler Air (FRESSCA) study was an air quality experimental intervention study conducted from 2021 to 2023 in Fresno, Kings, and Kern counties in California’s SJV, a low-income agricultural area (Figure 1). This region has long, hot, dry summers with average daily maximum temperatures over 32 degrees Celsius (90 degrees Fahrenheit) (19). In 2021, the National Weather Service recorded more than 67 days above 37 degrees Celsius (100 degrees Fahrenheit) in Bakersfield, CA (Kern County) (20).

Measures

The FRESSCA project included community engagement, development of filtration strategies for ECs, and air quality monitoring inside homes to test various interventions. The study also included questionnaires about health status, home comfort, satisfaction with the EC and the filtration strategy, and a question about willingness-to-pay for effective filtration. The development and laboratory testing of the interventions is described elsewhere (21), and the indoor air monitoring data analysis is ongoing. Here we focus on findings related to participants’ health status, home comfort, satisfaction with the intervention, and willingness-to-pay for indoor air with reduced wildfire smoke.

Results

Participant characteristics

Participants from both study phases all identified as Hispanic/Latinx and primarily spoke Spanish at home (Table 1). The average age of the 2023 participants was 43 years (range 22–61). Eighty-three participants identified as female and five as male. Most of the participants were agricultural workers (64%) or working in food packaging or processing (17%), shown in Table 1. About two-thirds (65%) of participants had lived in their home for more than 5 years and 69% owned their home. Most of the participants (72%) received health insurance through Medi-Cal, 7% had private insurance and 21% were uninsured.

Conclusion

Temporary filtration solutions are feasible to reduce indoor wildfire smoke exposure through ECs. However, such solutions will likely need to combine external filtration and use of a HEPA indoor air cleaner and would need to be offered in the community at low-or no-cost to reduce barriers to adoption. More permanent solutions would also require significant cost subsidies; these include prioritizing homes with ECs in wildfire smoke exposed regions for replacement with heat pump technology or air conditioning. While this solution would reduce water consumption, it could increase energy use relative to ECs.

Originally published by Frontiers in Public Health