How the California wildfires can impact the health of people hundreds of miles from Los Angeles

Multiple wildfires in Southern California have destroyed homes, caused at least 10 deaths and forced tens of thousands of people to evacuate. California Gov. Gavin Newsom declared a state of emergency on Tuesday.

Currently, air quality in the immediate areas surrounding the fire is poor, while surrounding areas seem to be largely OK, according to data from the U.S. Environmental Protection Agency (EPA). But doctors expect that will change as the fire continues to burn and winds shift.

While wildfires create unhealthy air conditions for people who live in nearby areas, that smoke and particulate matter can drift and affect those who live thousands of miles away — with a recent study shedding further light on the quantifiable dangers of even faraway wildfires. Researchers at the University of Maryland found that medical visits for heart and lung problems in Baltimore spiked almost 20% in June 2023, when smoke from severe wildfires in Western Canada drifted 2,000 across North America, affecting people along the U.S. East Coast.

Here's what experts expect from the current situation in California — and how it might impact the health of people both near and far.

Why is wildfire smoke dangerous?

Wildfire smoke is a mixture of gases and fine particulate matter created from burning vegetation and structures, according to the Centers for Disease Control and Prevention (CDC). Different potentially hazardous compounds are released in the smoke, including carbon monoxide, carbon dioxide, hydrocarbons, particulate matter (PM), benzene, acrolein and aldehydes, according to the CDC.

“Wildfires emit very high levels of particulate matter, which can have significant effects on human health, particularly [for] those that have pre-existing disease, including diabetes, hypertension and obesity,” Loren Wold tells Yahoo Life. Wold is a particulate matter researcher and associate dean for research operations and compliance in the Ohio State University’s College of Medicine.

This smoke can also have a big impact on your lungs, Dr. Simon Meredith, a pulmonologist at Northwell Lenox Hill Hospital, tells Yahoo Life. “For people with any kind of chronic lung disease, such as [chronic obstructive pulmonary disease] COPD or asthma, this can lead to irritation of the airways, causing them to feel shorter of breath.”

But even people without chronic lung disease can end up with airway irritation from wildfire smoke, leading to symptoms like a cough and shortness of breath, Meredith says.

High levels of particulate matter can even affect your heart, increasing blood pressure and causing sudden cardiac events like a heart attack, Wold says. “Exposure to elevated particulate matter levels long term can cause changes in heart function similar to patients with heart disease,” Wold says.

“The biggest concern is for children,” Dr. Brian W. Christman, professor in the division of allergy, pulmonology and critical care medicine at Vanderbilt Medicine, tells Yahoo Life. “They have smaller caliber airways so irritation and swelling manifest with problems earlier.” (Adults with asthma, chronic obstructive pulmonary disease and heart disease are also at risk of serious health complications, he adds.)

How does wildfire smoke affect people who aren’t near the fire?

Wildfire smoke can drift, creating issues for people who live far away from the source of the fire. “The particulates travel hundreds of miles and can cause sinus and upper airway irritation,” Dr. Reynold A. Panettieri tells Yahoo Life. Panettieri is a researcher and vice chancellor for translational medicine at the Rutgers Institute for Translational Medicine and Science.

Panettieri says that even people not near the fire can have serious health effects from wildfire smoke if it’s concentrated enough. You can experience a range of potential health issues if you’re exposed to wildfire smoke over several days, according to the EPA:

• Respiratory symptoms, such as coughing, phlegm, wheezing and trouble breathing

• Respiratory illness, including bronchitis, lower lung function and an increased risk of asthma exacerbation

• Cardiovascular issues, including heart failure, heart attack and stroke

Again, air quality in the areas outside of Los Angeles largely seems unaffected by the fires right now. But that will likely change, Dr. Fady Youssef, a pulmonologist and critical care specialist at MemorialCare Long Beach Medical Center in Long Beach, Calif., tells Yahoo Life. He lives in Orange County, which borders Los Angeles County, and says that the air quality is currently “adequate.”

“Whether it will travel will depend on how the winds shift and carry the smoke,” he says. Youssef points out that his area saw poor air quality for a few weeks until recently due to fires in Visalia, Calif., which is more centrally located in the state and hundreds of miles away. “We haven’t seen the impact in Orange County yet from the Los Angeles fires, but we likely will,” he says.

A lot depends on the direction of the wind. “If the winds blow the smoke offshore, it will help,” Christman says. Still, he anticipates some impact on air quality, even in areas outside of California. “Large pollution wildfire smoke can have very distant effects,” Christman says.

Panettieri says there’s “no doubt” the smoke will travel. “The particulate matter, which is the unburned materials from combustibles, are going to travel quite a distance,” he says. However, he stresses that “the likelihood of it going over the Rocky Mountains is pretty low.” Still, “in the near region, these people are going to be exposed to significant amounts of particulate matter,” Panettieri adds.

That doesn’t mean you’re doomed if you have a few bad air-quality days from wildfire smoke, though — it’s just that it could be an issue. “Those who do not live close to the wildfires are less likely to experience major issues,” Meredith says. “However, those who have a chronic lung condition are likely to experience more symptoms from the poor air quality that may be present because of the wildfires.”

Wold agrees. “The distance from the wildfire smoke is important, as levels will lessen according to distance,” he says. “However, the particulate matter contained within wildfire smoke can travel significant distances.”

How to protect yourself from wildfire smoke, no matter where you live

At baseline, doctors say it’s important to pay close attention to air quality alerts in your area, particularly if you have an underlying health condition that may be affected by wildfire smoke or pollution. The National Weather Service offers an air quality index, and AirNow allows you to look up air quality by your ZIP code. “I check the air quality where I am almost daily,” Youssef says. “I have it programmed on my watch.”

If the air quality in your area isn’t great, Panettieri recommends doing your best to stay indoors to avoid exposure to smoke. That includes shutting your windows and turning on your home’s central air, if you have it, to recirculate air inside instead of pulling it in from outside.

Wold also suggests limiting strenuous outdoor activities like exercise and wearing a high-quality mask like an N95 when you need to be outside. “This is particularly important for individuals with preexisting health conditions,” he says. If you’re able, using a portable air purifier with a HEPA filter in one or more rooms in your house should also help, according to the CDC.

Finally, it’s a good idea to keep an eye on your health when the air quality is poor. “Any changes in breathing patterns, including shortness of breath or difficulty breathing, as well as changes in heart rate and blood pressure should be checked by a medical professional,” Wold says.