This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

SAN DIEGO — As California wildfires increase in both intensity and frequency, residents in common burn areas wonder about the impact of repeated exposure to smoky air.

While there’s a wealth of information on the short-term effects of wildfire smoke, long-term exposure is a trickier topic, according to the Environmental Protection Agency.

Multiple officials who answered’s inquiries by email and phone pointed to the agency’s smoke-ready toolbox. It contains all kinds of resources aimed at helping people understand and prepare for poor air quality. But there’s a blank space under the heading “long-term exposures.”

“Studies have not evaluated the health effects attributed to wildfire smoke exposure over multiple seasons,” the footnote reads.

Gayle Hagler, an EPA environmental engineer and air resource advisor, says some of the trouble with understanding long-term impact comes from the variety of factors that influence each instance.

How long a person was exposed to smoke, how concentrated it was and the person’s breathing rate at the time can vary significantly, making no two “smoke events” the same.

Some people are more at risk during any exposure to smoke, and would be the primary concern for repeated or long-term exposure, too: people with heart or lung disease, older adults, people with diabetes, pregnant women, and children and teenagers (because their respiratory systems are still developing).

When nearby wildfires produce hazy skies in your area, that’s largely due to “fine particles” known by experts as PM 2.5, with 2.5 representing the size of the particulate matter (2.5 microns or less in width), Hagler told FOX 5.

Particles so tiny are particularly troubling from a health perspective, because they’re able to travel deep within the lungs. Hagler said most of what experts can theorize about repeatedly breathing wildfire smoke comes from what the science generally says about long-term PM 2.5 exposure.

It’s been linked to premature death, according to the California Air Resources Board, especially in those with chronic heart or lung diseases. Repeated exposure has also been linked in studies to reduced lung function growth in children.

Exposure to PM 2.5 in general has been linked to the following, according to the EPA:

  • nonfatal heart attacks
  • irregular heartbeat
  • aggravated asthma
  • decreased lung function
  • increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing

Outside of what we know about fine particulates, a few epidemiologic studies have looked at the cumulative effect of wildfire smoke exposure on the health of wildland firefighters, according to the EPA. Some showed a progressive decline in lung function.

“However, it is unclear if this decline persists across off-seasons and it is difficult to compare a wildland firefighter’s occupational exposure and resulting health effects to those experienced by the general population,” the agency writes. “But certainly, more caution is warranted during extended exposures.”

Being ‘smoke ready’

While the answer to the question of repeated exposure is less than satisfying, Hagler said the EPA is clear on its mission to protect people in the face of year-round wildland fires.

“Wildfires are increasing in intensity overtime due to a changing climate,” she told FOX 5. “Because of that continued increase in risk, wildfire response and smoke response is certainly a priority.”

Hagler and other EPA smoke specialists work on the ground near fires as air resource advisors, analyzing air quality, making recommendations to residents and making sure they have what they need.

Updates on the agency’s Air Now platform give specialized recommendations based on a person’s risk factors.

Basic details about what kind of mask you need to protect from wildfire particulates, buying home air cleaners and other wildfire prep resources are available on the EPA website.

Just like we prepare to evacuate from wildfires, residents should start preparing to encounter the smoke that fires produce. “Continue living your life, but optimize it for reduced smoke impacts,” Hagler said.

You can learn more here.