How smoke, poor air quality can affect the health of people hundreds of miles from Los Angeles

Multiple wildfires in Southern California have destroyed homes, caused at least five deaths and forced about 180,000 people to evacuate. California Governor Gavin Newsom declared a state of emergency on Tuesday.

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

While wildfires create unhealthy air conditions for people who live nearby, 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 from even distant forest fires. University of Maryland researchers found medical visits for heart and lung problems in Baltimore increased by nearly 20% in June 2023, when smoke from severe wildfires in western Canada swept 2,000 people across North America, affecting people along the east coast of the United States.

Here’s what experts expect from California’s current situation — and how it could affect the health of people near and far.

Why is forest fire smoke dangerous?

Wildfire smoke is a mixture of gases and fine particulate matter created by burning vegetation and structures, according to the Centers for Disease Control and Prevention (CDC). A variety of 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.

“Forest fires emit very high levels of particulate matter, which can have a significant impact, particularly on human health [for] those who have a pre-existing condition, including diabetes, hypertension and obesity,” Lauren Wald tells Yahoo Life. Wald is a particulate matter researcher and associate dean for research operations and compliance at The Ohio State University College of Medicine.

That 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 type of chronic lung disease, such as [chronic obstructive pulmonary disease] COPD or asthma, this can lead to irritation of the airways, making them feel more breathless.”

But even people without chronic lung disease can find themselves with airway irritation from wildfire smoke, leading to symptoms like coughing and shortness of breath, Meredith says.

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

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

How does wildfire smoke affect people not near the fire?

Smoke from a forest fire can drift, creating problems for people who live far from the source of the fire. “The particles travel hundreds of miles and can cause irritation to the sinuses and upper respiratory tract,” says Dr. Reynold A. Panettieri to Yahoo Life. Panettieri is a researcher and vice chancellor for translational medicine at the Rutgers Institute for Translational Medicine and Science.

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

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

• Respiratory disease, including bronchitis, reduced lung function and increased risk of asthma exacerbations

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

Again, air quality in areas outside Los Angeles appears largely unaffected by the fires at this time. But that’s likely to change, Dr. Fadi Youssef, a pulmonologist and critical care specialist at MemorialCare Long Beach Medical Center in Long Beach, California, told Yahoo Life. He lives in Orange County, which borders Los Angeles County, and says air quality is currently “adequate.”

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

Much depends on the direction of the wind. “If the winds blow the smoke out to sea, that will help,” says Christman. Still, he expects some impact on air quality, even in areas outside of California. “Wildfire smoke with high pollution can have very far-reaching effects,” says Christman.

Panettieri says there’s “no doubt” the smoke will spread. “Particulate matter, which is unburned material from combustibles, will travel quite a distance,” he says. However, he stresses that “the likelihood of it passing through the Rockies is pretty low.” Still, “in the nearby region, these people will be exposed to significant amounts of particulate matter,” Panettieri adds.

However, that doesn’t mean you’re doomed if you have a few days of poor air quality from wildfire smoke—it’s just that it can be a problem. “Those who don’t live near wildfires are less likely to experience major problems,” says Meredith. “However, those who have chronic lung disease are likely to experience more symptoms from the poor air quality that may be present due to wildfires.”

Wald agrees. “The distance to wildfire smoke is important, as levels will decrease with distance,” he says. “However, particulate matter contained in wildfire smoke can travel significant distances.”

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

For starters, doctors say it’s important to pay close attention to air quality warnings in your area, especially if you have an underlying health condition that could be affected by wildfire smoke or pollution. The National Weather Service offers an Air Quality Index, and AirNow lets you search for air quality by your zip code. “I check the air quality where I am almost every day,” says Youssef. “I programmed it into my watch.”

If the air quality in your area isn’t good, Panettieri recommends doing your best to stay indoors to avoid exposure to smoke. This includes closing the windows and turning on the central air in your home, if you have one, to recirculate the air inside instead of drawing it outside.

Wald also suggests limiting strenuous outdoor activities like exercise and wearing a high-quality mask like an N95 when you must be outside. “This is especially important for people with pre-existing health conditions,” he says. If you can, 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 monitor 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 healthcare professional,” Wald says.