Wildfires are currently wreaking havoc globally, exacerbated by an unprecedented heat wave. The smoke, which contains harmful gases and particulate matter, is enveloping millions, posing significant health risks.
Here’s a brief overview of the dangers associated with wildfire smoke.
What is in wildfire smoke?
Wildfire smoke is far more toxic than typical air pollution; it can linger for weeks and travel thousands of miles. The fires consume not only vegetation but also buildings, vehicles, and their contents. Consequently, wildfire smoke often contains soil particles and biological materials, alongside small quantities of chemicals, metals, plastics, and other synthetic debris.
What are the known health effects?
Kent Pinkerton, co-director at UC Davis’s Center for Health and Environment, pointed out that laboratory studies have shown wildfire smoke leads to greater inflammation and tissue damage compared to ordinary air pollution.
Research indicates a correlation between wildfire smoke exposure and increased incidents of heart attacks, strokes, and cardiac arrests, along with a rise in emergency room visits for asthma cases. Moreover, there have been noted decreases in immune response and survival rates post-surgery. For instance, a study conducted in Maryland identified a surge in heart and lung conditions linked to smoke traveling from over 3,000 miles away.
Other health issues tied to wildfires include problems with the eyes and skin. Pregnant individuals exposed to wildfire smoke have been associated with higher risks of miscarriage, low birth weight, and preterm labor. A particular California study found connections between wildfire exposure and cellular damage in the placenta during early pregnancy stages, while another suggested that late-term exposure might elevate the risk of autism diagnoses.
The lingering impacts of smoke exposure can be long-lasting. Following the 2014 Hazelwood Coal Mine Fire in Australia, elevated heart disease rates persisted for over two years, with respiratory ailments remaining problematic for up to five years.
A 2026 US survey linked wildfire smoke to heightened risks for various cancers, including lung and breast cancer, where the danger grows with the intensity of smoke exposure. Notably, individuals who experienced the 2018 California wildfires showed cognitive changes within months following their exposure. Long-term effects may even extend to an increased risk of dementia.
Moreover, data from California indicated a spike in fungal infections occurring months post-exposure, likely due to spores contained in the smoke.
Is there a safe level of inhaled particles?
“Unfortunately, there are no safe levels of inhalable particles from wildfire smoke,” Doug Bruge, chair at the University of Connecticut’s School of Public Health Sciences, noted. “The more one is exposed, the greater the risk—yet, even below national safety standards, these particles can lead to health issues.”
An inflammatory response is triggered in everyone exposed, but children, the elderly, and those with chronic conditions are the most susceptible.
Keith Bain, director of the Center for Air Quality Research at UC Davis, emphasized that even healthy adults can quickly feel the effects, such as sore throats, coughing, and brain fog, which may linger long after the smoke clears.
What can help reduce risk?
Experts recommend wearing N95 masks and minimizing outdoor activities when wildfire smoke is present. The longer one is outside, especially engaging in heavy exertion, the more pollutants are inhaled, according to Dr. Jasvinder Singh, a pulmonary specialist in Baltimore.
Using an indoor air purifier capable of filtering particles smaller than 2.5 microns is also advised. “Air purifiers can lower exposure, and our studies have indicated a reduction in the cognitive impacts of air pollution,” Bruge mentioned.
If purchasing a purifier isn’t feasible, there are simple instructions available from UC Davis for creating one using inexpensive materials.
Additionally, the EPA provides guidance on products and strategies to lessen exposure to wildfire smoke.
Are people safe indoors?
Experts indicate that particles from wildfire smoke can infiltrate buildings in significant amounts. It’s suggested that the concentration of wildfire pollutants indoors can be around half of what’s found outside. However, if buildings aren’t well-sealed, indoor levels might reach 70% of outdoor concentrations, especially in older structures where drafts allow pollutants to enter easily.
During wildfire events, the EPA recommends avoiding indoor activities that might release more particulates into the atmosphere, such as frying food, using candles, or vacuuming without a HEPA filter.
Exposure to indoor wildfire smoke has been compared to secondhand cigarette smoke. “These particles tend to permeate everything—from your clothes to surfaces—and can release harmful gases long after the smoke has settled,” experts stated.
What is unknown?
The increasing frequency of wildfires, likely tied to climate change, raises concerns about more frequent exposure. Yet, the health impacts over multiple seasons remain ambiguous.
“It’s challenging to forecast because it’s tough to ascertain the extent of exposure or the duration and contents of the smoke,” Bain remarked.
Research is ongoing concerning the long-term effects of smoke particles on water supplies, crops, and livestock, as well as the impacts of urban wildfire smoke. Additionally, there are investigations into the potential amplification of extreme heat effects due to wildfire smoke exposure.
Lastly, nutrients found in wildfire smoke could contribute to harmful algae blooms downriver, thus affecting drinking water supplies and local ecosystems, some researchers have warned.
