More than 6.5 million people worldwide die, in part, because of air pollution, according to the National Institutes of Health (NIH).
Studies show that the particulate matter associated with wildfires—which are increasingly prevalent and destructive—may have a harsher impact on respiratory health than particulate matter from other sources.
To reduce the risk of poor health outcomes, doctors can advise patients to consider purchasing portable air cleaners, closing doors and windows, and wearing N95 respirators during wildfire smoke events.
In June 2023, raging wildfires in Quebec, Canada, created unhealthy air quality for more than 100 million people in North America. Orange-tinted haze blanketed countless cities that don’t usually deal with the fallout of wildfires. Suddenly many people faced questions about the ill effects of polluted air on human health.
As wildfires increase and more people confront the effects of air pollution, physicians can recommend that patients use portable air cleaners, wear N95 respirators, and implement other tactics to help prevent poor health outcomes.
How particulate matter affects patients
Air pollution is a byproduct of both natural and human-made resources.
Wildfires, for example, release hazardous smoke that can lead to irritation of the eyes. What’s more, says sources, they transport other dangerous particulate matter (PM) over long distances—particulates that can seriously damage various organs and bodily systems.
According to a 2020 review published in Frontiers in Cell and Developmental Biology, PM is “is a complex mixture of solids and liquids suspended in the air,” originating from natural sources, such as dust and wildfires, as well as from anthropogenic sources, including emissions from coal burning and the operation of power plants.
PM is complex, as it may contain inorganic matter (eg, heavy and transition metals and elemental carbon) plus organic matter (eg, polycyclic aromatic hydrocarbons). It may also have biological components, such as spores and viruses.
PM is classified by its aerodynamic diameter, which defines it as inhalable, fine particulate, or ultrafine particulate. Researchers consider PM2.5—fine particulate matter measuring <2.5 μm—to be one of the most dangerous. With a large surface area, it can adsorb various toxic substances.
"Because of its small particle size, it can penetrate deep into the lungs and deposit in the terminal bronchioles and alveoli with breath, and even enter the circulatory system through the gas-blood barrier."
— Authors, Frontiers journal
Exposure to PM2.5, they go on to say, most commonly endangers the respiratory and cardiovascular systems.
Some researchers argue that PM2.5 originating from wildfires is more harmful to respiratory health than PM2.5 from other sources.
A 2021 study published by Nature Communications used hospital admission and location data and a series of statistical approaches and exposure definitions to assess the respiratory health effects of wildfire-specific PM2.5 in Southern CA.
The researchers identified upticks in respiratory hospitalizations as the concentration of PM2.5 increased. However, with a 10 μg per cubic meter increase in wildfire-specific PM2.5, the increase in hospitalizations ranged from 1.3%-10%, compared to the rate of 0.67%-1.3% with increased PM2.5 originating from other sources.
These findings point to the potential need for air quality policies to consider how the source of PM2.5 may influence its impacts on human health—especially the respiratory system.
Knowing that wildfires have become more prevalent as the climate changes, how can physicians prepare patients to protect themselves from the resulting air pollution?
A 2023 article published by the EPA recommends that patients do the following:
Check HVAC systems. To effectively keep smoke out of their homes, patients can learn how their heating, ventilation, and air conditioning systems truly work.
“Important features to understand include using appropriate high-efficiency air filters and closing the fresh-air intake if the central air system or room air conditioner has one,” the EPA says. “Your patients may consider having a professional check the HVAC system and walk them through these features.”
Patients can also significantly improve the air quality in their homes by replacing low-efficiency fiberglass filters with medium or high-efficiency filters, which can remove up to 95% of particles that would normally pass through.
Purchase portable air cleaners. Patients can use a self-contained air filtration appliance alone or with central air filtration to keep PM at bay.
At-risk patients should use an appliance with a high-efficiency HEPA filter and ensure that the machine is sized appropriately for the space it will occupy. It’s crucial for these patients to secure an appliance before a smoke event occurs. Once it starts, air cleaners may be in short supply, and leaving the house to buy one can be hazardous.
One thing patients may want to consider when purchasing an air cleaner is the level of noise that these machines can produce, as this can affect how often they are willing to use it.
Wear N95 respirators. Many home improvement stores and online shops sell NIOSH-approved respirators, which the EPA states patients can use to protect themselves against poor air quality—and researchers agree.
One 2021 study published by GeoHealth looked at how effectively a range of face coverings and respirators can protect patients against the harmful effects of severe air pollution.
They found that N95 respirators offer “robust protection” against various forms of PM. When worn with a leak rate of 5%, the masks can reduce exposure by more than a factor of 14.
“Our models suggest that although natural-fiber masks offer minor reductions in respiratory hospitalizations attributable to smoke (2%–11%) due to limited filtration efficiency, N95 respirators and to a lesser extent, surgical and synthetic-fiber masks may lead to notable reductions in smoke-attributable hospitalizations (22%–39%, 9%–24%, and 7%–18%, respectively),” the authors wrote.
In addition, the EPA encourages at-risk patients to develop an evacuation/relocation plan and a disease management plan if smoke levels are expected to remain high.
Overall, the more prepared your patients are to navigate a bad air quality event, the better their chances are of steering clear of air quality–related health issues.
What this means for you
Wildfires are increasingly common in our changing climate. As patients confront the effects of air pollution, you can advise them to take charge of their health by wearing N95 respirators when necessary. You may also recommend that patients purchase portable air purifiers and check their HVAC systems. Finally, you may encourage patients with heart or lung issues to develop a disease management plan prior to fire season.