Extreme heat, smoke from wildfires harm low-income, non-white communities most, study finds

Extreme heat and smoke from wildfires are independently harmful to the human body, but together their impact on the cardiovascular and respiratory systems is more dangerous and affects some communities more than others.

A study published Friday in the journal Scientists progress said climate change is increasing the frequency of both risks, particularly in California. The authors found that the combined damage from extreme heat and smoke inhalation from wildfires increased hospitalizations and disproportionately affected low-income communities and Latino, Black, Asian, and other racially racialized residents. marginalized.

The reasons are varied and complex, according to authors from the Scripps Institution of Oceanography at the University of California San Diego and the UCLA Fielding School of Public Health. Structural racism, discriminatory practices, lack of medical insurance, less understanding of health harms, and a higher prevalence of multiple coexisting conditions are among the reasons.

Infrastructure, the surrounding environment and available resources are also factors. Homes and workplaces with air conditioning and neighborhoods with tree canopy are better protected from extreme heat, and some buildings filter smoke from wildfires and insulate heat more effectively. Areas with access to cooling centers, such as libraries, also provide more protection.

“Even if you’re very susceptible – you have a lot of comorbidities – you may have many opportunities to not be affected, not to be hospitalized, not to have to go to the emergency room, but if you live in a place that’s fairly “Remote, it doesn’t have access to a lot of social services or amenities, … that can be more problematic,” said Tarik Benmarhnia, study author and climate change epidemiologist at UC San Diego.

Experts warn that climate change – which makes extreme weather events such as droughts, heatwaves and wildfires worse – will increase the frequency and intensity of their simultaneous occurrence.

Although the study focused on California, similar trends can be found in other parts of the western United States, such as Oregon and Washington state, in parts of Canada, including in British Columbia, and in areas with a Mediterranean climate, Benmarhnia said.

Researchers analyzed California health records (broken down by 995 ZIP codes covering most of the state’s population) during episodes of extreme heat and toxic air from wildfires. They found that between 2006 and 2019, hospitalizations for cardiorespiratory problems increased by 7% on days when both conditions existed, and they were higher than in ZIP codes where people were more likely to be poor, not white, living in dense areas and without health. care.

California’s Central Valley and the northern mountains of the state experienced higher incidences of hot temperatures and wildfires, likely due to more wildfires in the surrounding mountains.

Residents of the agricultural heartland of the Central Valley are particularly vulnerable to the adverse health effects of both phenomena, as they are more likely to work outdoors and be exposed to pesticides and other environmental hazards, a Benmarhnia said.

Beyond the health risks, being hospitalized has other significant consequences, such as loss of work or school hours, or high medical bills.

On extremely hot days, the human body has a harder time cooling itself by sweating, said Christopher T. Minson, a professor of human physiology at the University of Oregon who was not involved in the study. The body can become dehydrated, causing the heart to beat faster, which raises blood pressure.

“If you’re dehydrated or you have cardiovascular disease, you’re going to be less able to tolerate that heat stress, and that heat stress can become very, very dangerous,” he said.

Some particles found in wildfire smoke can easily enter through the nose and throat, eventually reaching the lungs, according to the Environmental Protection Agency. Even the smallest particles can enter the bloodstream.

The combination of heat and smoke can cause inflammation in the body, Minson said, which “is going to make your whole cardiovascular regulation worse, and you’ll be even more at risk for heart attacks and other problems like poor health.” long-term “. health outcomes arise from this. So it’s definitely a snowball effect.

A 2022 study by the University of Southern California found that the risk of death increased on days when extreme heat and air pollution coincided. During heat waves, the probability of death increased by 6.1%; when air pollution was extreme, it increased by 5%; and on days when the two were combined, the threat skyrocketed to 21%.

When Dr. Catharina Giudice worked at a Los Angeles hospital, she noticed an increase in emergency room visits from patients with various health conditions on extremely hot days. When the wildfires broke out, she saw more people with exacerbated asthma and other respiratory illnesses.

As climate change fuels the intensity and frequency of heat waves and wildfires, Giudice worries about low-income and minority communities who are less adapted to them.

“For a variety of reasons, they tend to experience climate change much worse than other, non-underserved communities, and I think it’s really important to highlight this social injustice aspect of climate change,” the doctor said. emergency physician and researcher at Harvard TH Chan. School of Public Health, which was not part of the study.

The authors noted that agencies such as the National Weather Service and local air quality districts issue separate advisories and warnings on days of extreme heat and toxic air. But they say “issuing a common warning earlier, given the compound exposure, would be beneficial.”

© 2024 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.