LOS ANGELES (AP) — Extreme heat and wildfire smoke are independently harmful to the human body, but their impact on the cardiovascular and respiratory systems is more dangerous, affecting some communities more than others.
A study published Friday in the journal Science Advances said climate change is increasing the frequency of both hazards, especially in California. The authors found that the combined harm of extreme heat and wildfire smoke inhalation increased hospitalizations and disproportionately affected low-income communities and Latino, Black, Asian and other racially marginalized residents.
The reasons for this are diverse and complex, according to authors from the University of California, San Diego’s Scripps Institution of Oceanography and the UCLA Fielding School of Public Health. Structural racism, discriminatory practices, lack of health insurance, less understanding of health harms, and the greater prevalence of multiple co-occurring conditions are among the reasons.
Infrastructure, environment and available resources are also factors. Air-conditioned homes and businesses and tree-shaded neighborhoods are better protected from extreme heat, and some buildings filter smoke from wildfires and insulate heat more efficiently. Areas with access to cooling centers, such as libraries, also provide greater protection.
“Even if you’re very susceptible — if you have a lot of comorbidities — you may have a lot of opportunities to not be affected, not to be hospitalized, not to have to go to the emergency room, but if you live somewhere quite far from here,” said study author and climate change epidemiologist Tarik Benmarhnia, a climate change epidemiologist at UC San Diego. “They don’t have access to a lot of social services or amenities, … that could create more problems,” he said.
Experts warn that climate change, which worsens extreme weather events such as droughts, heat waves and wildfires, will increase the frequency and intensity of these events occurring simultaneously.
Although the study focused on California, similar patterns can be found in other regions of the western United States such as Oregon and Washington state, parts of Canada including British Columbia, and areas with Mediterranean climates, Benmarhnia said.
Researchers analyzed California health records broken down by 995 ZIP codes that cover most of the state’s population during extreme heat and toxic air events resulting from wildfires. They found that between 2006 and 2019, hospitalizations for cardiorespiratory problems increased by 7% on days when both conditions were present, and that rates were higher than rates in ZIP codes where people were poor, nonwhite, lived in densely populated areas, and did not have health problems. care.
Both hot weather and wildfire incidences were higher in California’s Central Valley and the state’s northern mountains; This was probably due to more forest fires in the surrounding mountains.
Those who live in the Central Valley’s agricultural heartland are particularly vulnerable to adverse health effects, both because they are more likely to work outdoors and are exposed to pesticides and other environmental hazards, Benmarhnia said.
Beyond health risks, hospitalization has other significant consequences, such as losing work or school hours or facing hefty medical bills.
Christopher T. Minson, a professor of human physiology at the University of Oregon who was not part of the research, said that on extremely hot days, the human body has a harder time cooling itself down through sweating. The body can become dehydrated, forcing the heart to beat faster, which increases blood pressure.
“If you’re dehydrated or have any type of cardiovascular disease, … you’re going to be less tolerant of that heat stress, and that heat stress can become very, very dangerous,” he said.
According to the Environmental Protection Agency, some particles found in wildfire smoke can easily enter the nose and throat and eventually reach the lungs. Even the smallest particles can enter the bloodstream.
The combination of heat and smoke can cause inflammation in the body, which “will further worsen all of your cardiovascular regulations and put you at greater risk of heart attack and other problems like weakness in the long run,” Minson said. health consequences of this. So it’s definitely a snowball effect.”
A study conducted by the University of Southern California in 2022 revealed that the risk of death increases on days when extreme temperatures and air pollution coincide. The likelihood of death increased by 6.1% during heat waves; increased by 5% when air pollution was extreme; and on days when both were combined, the threat jumped to 21%.
Dr. While working at a hospital in Los Angeles, Catharina Giudice noticed an increase in emergency room visits by patients with various health problems on extremely hot days. When fires flare, she has seen asthma and other respiratory diseases worsen.
As climate change increases the intensity and frequency of heat waves and wildfires, Giudice worries about low-income and minority communities that are less adapted to them.
“For a variety of reasons, they tend to feel climate change much worse than other underserved communities, and I think it’s really important to highlight that social injustice aspect of climate change,” said emergency room physician and researcher at Harvard T.H. Chan. School of Public Health, which was not part of the study.
Agencies such as the National Weather Service and local air quality districts issue separate advisories and warnings on days of extremely hot and toxic air, the authors noted. However, they argue that “it would be beneficial to issue a common warning earlier, taking into account compound exposure.”
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