US wildfires: Lower access to AC ups emergency care risk, finds study

People who have limited access to air-conditioning may be at higher risk of seeking emergency care for health problems following exposure to wildfire smoke, according to a new study led by the Boston University School of Public Health (BUSPH) in the US, as Los Angeles county battles the most destructive wildfires in its history.

The study suggested that US policies should prioritise equity and education regarding measures people can take to protect themselves from the harmful pollutants in wildfire smoke. Posted online ahead of publication in the journal Environmental Research: Health, the study found that exposure to fine particle matter (PM2.5) from wildfire smoke in California is associated with higher rates of emergency department visits for all causes, non-accidental causes, and respiratory disease. This risk varied by age and race, but was especially high for individuals who lived in areas with lower availability of air-conditioning.

“Depending on the type of system and filter used, air-conditioning may modify the impact of smoke exposure on human health,” said study lead and corresponding author Dr Jennifer Stowell, research scientist in climate and health at BUSPH. “California is perhaps the best example of this in the US, with bigger fires and longer fire seasons. An important next step will be to identify ways to better characterise access to air-conditioning.”

The findings come at a critical time as firefighters in Southern California continue to battle multiple wildfires that have been blazing in and around Los Angeles county since 7 January, Tuesday — including the Palisades fire, which is likely the largest and most destructive wildfire in the county’s history.

Health experts are urging residents who are not under evacuation orders and can safely remain in their homes to turn on air-conditioners and/or air purifiers if they have access to these devices. Despite this guidance, very little research has examined how the health effects of wildfire smoke exposure may differ based on individuals’ access to air-conditioning.

For the study, Dr Stowell and colleagues from BUSPH, Boston University College of Arts & Sciences (CAS), and the Health Effects Institute utilised a nationwide dataset of healthcare claims to assess more than 50,000 emergency department visits during the 2012-19 California wildfire seasons, which occurred from May to November each year.

People living in areas with lower availability of air-conditioning had a 22-per cent greater risk of visiting the emergency department for respiratory conditions associated with wildfire smoke exposure. The study indicates a need for stronger policy measures that can reduce the health risks associated with wildfire smoke exposure.