Extreme Heat Adds to Wildfire Air Pollution, Disproportionately Affecting Poor U.S. Communities: Study

Individuals residing in areas of the U.S. that experience extreme heat and wildfire smoke at the same time are more likely to be hospitalized with serious health concerns, according to the findings of a new study, which warns that the effects are even worse among poor and minority communities.

Extreme heat and wildfire smoke events are increasing because of climate change across the country, especially in California. Extreme heat is considered temperatures above 90 degrees for two to three consecutive days, and many areas of California experience temperatures above 100 degrees for days or weeks on end during the summer months.

In a report published last week in the medical journal Science Advances, researchers from the Scripps Institution of Oceanography at the University of California, San Diego, conducted a study using high-resolution satellite imaging, temperature readings, and air quality monitoring data, and compared that to data for unscheduled hospitalizations in California from 2006 to 2019.

The findings indicate that exposure to both extreme heat and wildfire smoke increased hospitalizations due to cardiac probles and worsening lung conditions, especially in low-income areas, and the combined effects were greater than either factor alone.

Researchers found there were more unscheduled hospital visits for respiratory conditions linked to severe asthma, bronchitis, difficulty breathing, and cardiac effects like stroke and heart attack when California experienced both high temperatures and heavy smoke from wildfires on the same day.

The number of days where both extreme heat and wildfire smoke occurred, leading to increased hospitalizations, was high during the study period.

U.S. Poor Disproportionately Affected

The data also indicated that the air pollution effects were worse in low-income communities, minority communities, and communities with lower educational levels, lower health insurance coverage, lower proportion of car ownership, and less tree cover, with residents in those areas experiencing greater rates of hospitalizations.

Researchers warn many people can’t avoid the heat or wildfire smoke if they don’t have air conditioners or air purifiers, like many homes in low-income communities. Some communities can’t cool homes down with increased tree canopy or must walk to work or other places in extreme heat.

The reality is that climate change makes these types of events occur more frequently, the researchers concluded.

Wildfire Health Risks

Two-thirds of California experienced record days of extreme heat and heavy wildfire smoke on the same days, according to the data. Experiencing both is harmful to human health. It can worsen lung conditions like asthma and strain the heart.

Pervasive wildfire smoke also increases the risk of death among lung cancer patients who are recovering from surgery, previous studies have found. Particulate matter released in the air pollution of wildfire smoke can increase a person’s risk of cardiac arrest and lead to early death, but the risks are even higher for patients with existing health problems.

Other research has determined that pregnant women exposed to smoke from wildfires face an increased risk of preterm birth, which puts the infant at risk of many health side effects like breathing problems, feeding difficulties, and developmental delays.

Firefighters also face a number of respiratory threats from exposure to smoke while fighting wildfires, including the risk of asthma, chronic obstructive pulmonary disease (COPD), and other respiratory consequences.

“This study highlights the need to incorporate compound hazards and environmental justice considerations into evidence-based policy development to protect populations from increasingly prevalent compound hazards,” the researchers concluded.

California’s Air Resources Board said they plan to launch new educational resources this year to help residents protect themselves from heat and smoke. But researchers recommend health agencies consider issuing joint heat and smoke warnings to help prevent many of the health effects.