An estimated 64 million Americans were suffering through high temperatures and also breathing air polluted by wildfire smoke on Thursday, a dangerous combination that¡¯s straining the public¡¯s ability to protect itself and is likely to become increasingly common.
The affected area stretches from Minneapolis to Chicago, Ohio, much of Pennsylvania, the Washington area and up to New York City, according to Bob Oravec, a senior branch forecaster for the U.S. Weather Prediction Center, which is part of the National Weather Service. A smaller population of roughly 13 million people are in areas with both heat advisories and air-quality alerts, mostly in the Mid-Atlantic region, he said.
¡°Extreme heat is expected at this season, but what is new in the context of climate change is really to have simultaneously extreme heat and wildfire smoke,¡± said Tarik Benmarhnia, professor of epidemiology at the University of California at San Diego. ¡°We need to get used to that because it¡¯s not going to be exceptional anymore.¡±
As a warming planet makes extreme weather more intense and frequent, scientists predict such occurrences will increasingly happen at the same time or one after another, a phenomenon known as compound events.
Compound climate events are often driven by the same underlying factors. For instance, the hot, dry conditions that fuel extreme heat can also dry out vegetation and spark wildfires, amplifying damage and creating new risks.
High temperatures alone are dangerous, as is inhaling polluted air. The harm from each individually can be magnified when people experience both together. For someone with a heart condition, whose heart is already working hard to regulate body temperature, breathing fine particles into the lungs can trigger additional health problems such as lung inflammation.
¡°Your body is basically trying to fight two battles at the same time and it can¡¯t,¡± Benmarhnia said. A person with asthma who is experiencing inflammation from wildfire smoke may experience even more inflammation as their body struggles to cool down.
Research has found that the combination of extreme heat and air pollution can increase the risk of hospitalization or premature death from cardiovascular conditions, as well as respiratory illnesses.
Populations that are especially vulnerable include people with preexisting health conditions, people experiencing homelessness, pregnant people, older adults, children and outdoor workers such as farmers and construction workers.
Staying at home and limiting physical activity and time outdoors can help safeguard against both heat and wildfire smoke. Benmarhnia said compound heat and wildfire events can create a difficult dilemma for households without air conditioning and air filtration. While opening windows may help reduce indoor temperatures, doing so during a wildfire can expose residents to hazardous smoke, he said.
Free air-conditioned spaces known as cooling centers are a common way to fight extreme heat. But many cooling centers don¡¯t have strong air-filtration systems in place, according to Benmarhnia. A recent effort in the San Francisco Bay Area to set up so-called clean air centers shows promise, but such centers may not have air conditioning, something he calls a missed opportunity.
In such cases, public health officials may advise people to prioritize staying cool. New York City, for example, said Wednesday amid worsening air quality forecasts that ¡°cool indoor air is the safest place,¡± adding that ¡°heat guidance takes precedence over air quality guidance.¡±
It can also be difficult for officials to respond to overlapping climate hazards because responsibility is often split across agencies. Those overseeing extreme heat and wildfire response, for example, don¡¯t necessarily coordinate, Benmarhnia said.
The divide extends to forecasting. The National Weather Service doesn¡¯t produce air-quality forecasts; those are issued by the Environmental Protection Agency, although the NWS does distribute them to the public.
Ideally, when wildfire smoke and heat overlap, the NWS would issue heat warnings at lower levels, Benmarhnia said.
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