Smoke Gets In Your Eyes -- Your Lungs and Your Brain

"It's not just a few days in these extreme events that you need to protect  yourself."

"It is also the days when the sky looks OK [while air quality indexes or weather reports warn of the presence of smoke]."

Dr. Kai Chen, associate professor, Yale School of Public Health 

 

The health effects of short-term PM_2.5 exposure, and subsequently smoke, can range from relatively minor (e.g., eye and respiratory tract irritation) to more serious health effects (e.g., exacerbation of asthma and heart failure and premature death). In addition, there is initial evidence that short-term smoke exposure may lead to preterm birth (Picciotto et al. 2024) and impact brain function (i.e., cognitive performance as measured through a brain-training game) (Cleland et al. 2022). Fine particles are respiratory irritants, and exposures to high concentrations can lead to persistent coughing, phlegm, wheezing and difficulty breathing. Exposure to PM_2.5 may affect the body’s ability to remove inhaled foreign materials, such as viruses and bacteria, from the lungs. For example, some studies have reported an increase in the risk of COVID-19 cases and deaths in response to wildfire smoke exposure (Zhou et al. 2021; Meo et al. 2021; Schwarz et al. 2022). Although most healthy people will recover quickly from smoke exposure, some may experience health effects such as pulmonary inflammation and transient reductions in lung function (U.S. EPA 2019).

United States Environment Protection Agency  

Vancouver skyline   Wildfires and smoke have always occurred in British Columbia, but they are becoming more frequent and severe as the climate changes. Wildfire smoke is a form of air pollution that can affect your health.  BC Centre for Disease Control 

 

Evaluation of air pollution from wildfires presents unique challenges, compared to air pollution from other sources, such as traffic or industrial point sources, as smoke exposure is seasonal and episodic in nature (Gould et al., 2023). Also, as the number and size of wildfires impacting an area are variable and as smoke production from wildfires is not constant or steady, the concentration of smoke experienced by populations can vary considerably, and can include high levels of exposure for short time periods or moderate exposure levels lasting for several days or longer. Additionally, to evaluate the health effects of wildfire smoke, it is necessary to distinguish the contribution of wildfire smoke from that of other sources of air pollution within the mixture that people are exposed to. To address this, researchers have employed a variety of methods to assess exposure to wildfire smoke for use in health studies including use of land-based PM monitors, satellite imagery, air quality modelling, comparison of fire versus non-fire periods, proximity to wildfire burn area, and self-reports. In these studies, the most commonly used surrogates for wildfire smoke exposure are PM_2.5 (particles with a diameter of 2.5 micrometres or less) and PM₁₀ (particles with a diameter of 10 micrometres or less). For the primary investigations included in the systematic reviews considered here, the health outcome data were based on administrative sources (for example, mortality registries, health care utilization data), surveys, or self-reports. In addition, most of the primary studies focused on short-term or episodic exposure to wildfire smoke (that is, daily exposure), while some of the studies assessing mental health impacts considered health effects in years following the wildfires, and studies of reproductive or developmental impacts considered wildfire smoke exposure during the gestational period. It is noted that the health effects of PM_2.5, a key pollutant in wildfire smoke, have been extensively studied and Health Canada has evaluated the health risks of ambient PM_2.5 (that is, PM_2.5 from all sources combined) (Health Canada 2022). 

Government of Canada 

People who are exposed to smoke from wildfires, according to more recent scientific investigations, are increasingly assailed by lung-damaging toxins, but new discoveries identify that hearts, brains and other body organs are also being damaged by wildfire smoke. Smoke exposure could sound the death knell of up to 1.9 million people in the United States alone, over three decades, according to one 2025 study. Lungs can be penetrated deeply by the concentration of airborne particles known as PM2.5, from wildfires.

 

PM2.5 is a primary pollutant that air quality indexes measure, but fails to reflect other substances that can be contained in wildfire smoke that include lead, mercury and formaldehyde, cautions Karl Nadeau, dean of the University of California, Los Angeles Fielding School of Public Health. Preliminary research suggests that wildfire smoke may be of greater harm than air pollution from more common sources such as car exhaust. Fire in proximity to urban areas, moreover, may be of particular toxicity, through consuming buildings vehicles and electronics.

 

Smoke and flames from the Palisades Fire fill the sky as seen from the Pacific Palisades neighborhood of Los Angeles. | Getty Images

 

Associations between wildfire smoke and cardiovascular hospitalization, diabetes complications, preterm birth, cancer, impaired cognition and other problems, as well as respiratory effects including  attacks of asthma have been associated through scientific analytical studies. Wildfire smoke was linked in a 2024 study to deaths from cardiovascular, digestive, endocrine and kidney diseases. Asthma attacks and heart attacks can increase within an hour, in the presence of the severity of ambient smoke, pointed out professor Michael Brauer with the University of British Columbia.

 

Cognitive effect research has seen a significant expansion, explains Stephanie Cleland, associate professor at Simon Fraser University in British Columbia. Dr. Cleland was lead author of a 2022 study finding smoke exposure to be associated with lower scores on a 'brain training' game. A link between cumulative exposure throughout a school year and lower standardized test scores was also found through research, while other studies indicate a possible association with dementia. 

 

Less dramatic, lower-level exposures over time have an add-on impact, according to Professor Chen, who suggests the wearing of masks to be avoidance-helpful to exposure to ambient smoke during such events, not necessarily only when the surrounding air is redolent of burning, charred wood, and the atmosphere turns grey in reduced visibility with wildfire smoke. One study published in 2025 linked the risk of death from all causes with three-year exposure to wildfire smoke. Yet another 2025 study concluded that as average wildfire exposure increased, North Americans over age 65 suffered a higher risk of dying from chronic obstructive pulmonary disease.  

 

A woman wears an N95 mask to protect herself from high levels of smoke pollution. Daniiielc, Getty Images

 

"The data pretty clearly say that there is no safe level of exposure to wildfire smoke: the more exposure we get, the worse a range of health outcomes. The data also pretty clearly show that our notion of sensitive groups should probably be greatly expanded. In addition to kids, elderly populations, or anyone else with preexisting conditions, like asthma, we need to think about populations like pregnant people whose birth outcomes can be substantially affected by exposure. Portable indoor filtration is often the best option for many households, and well-fitting N95 masks can help when outside. "

"Climate change, and in particular increasing fuel aridity brought about by hotter temperatures and variable rainfall, is playing a central role in the recent rapid increase in wildfire activity and smoke exposure throughout the US. It is certainly not the only factor, but is substantially amplifying the risk brought about by other factors, which include a century of fire suppression that has left abundant fuels in our wildlands, as well as increased human construction and activity in the wildland-urban interface. We can say with strong confidence that climate change has made these events much more likely and much more severe."

Marshall Burke,  associate professor, Stanford Doerr School of Sustainability 

Smoking Cessation

"Some people have suggested the idea of putting a warning on individual cigarettes and using what we call sliding shell."
"I have to tell you these ideas are being studied and I also have to tell you I really like them. They are quite bold."
"When I look at the rates of tobacco use, we have certainly come a long ways[sic], but I personally believe a lot of work needs to be done in this area [persuading smokers to cease imperilling their health]."
"We want to make sure that programs are developed for Indigenous communities by Indigenous communities [with typically high rates of tobacco consumption]."
Federal Health Minister Ginette Petitpas Taylor, Ottawa

"The tobacco companies place the brand name and logos on the cigarette themselves, it's a very good way to communicate with consumers."
"Under plain packaging, they will no longer be able to have that [straight-up advertising] so it is a great idea to have a health warning."
"[It could be as simple as a word like] 'cancer' [or] 'emphysema' [on a cigarette]."
"There are 27 billion cigarettes sold [every year] in Canada. If we can have a health warning on each of those, it's going to inform consumers, it's going to create public discussion, it's going to make the product less appealing and it'll help fight contraband because it will have a unique marking on cigarettes, legitimately sold in Canada."
Rob Cunningham, spokesman, Canadian Cancer Society

AP Photo/Nati Harnik,

"How a committee can pass a tobacco bill without hearing from a tobacco company that has close to 50-per-cent market share is beyond us."
"Plain packaging is perhaps the greatest gift the government can give to the illegal operators."
"Plain packaging forces the legal industry to make our products look like illegal ones."
Eric Gagon, spokesman, Imperial Tobacco 

Cancer, and particularly lung cancer, directly linked to tobacco use, can be reduced by influencing people who smoke to realize that their habit is self-destructive. While tobacco use is not the only determinate for cancer onset, it is the most obviously responsible one. Treatment of patients with emphysema  and cancer related to smoking takes up a large part of the Canadian universal health system, a costly exercise in fear and frustration for those afflicted and a use of medicine that could be reduced because it is environmentally caused through a harmful substance and habitual use.

In heart clinics where patients with such issues are treated, posters urging people not to smoke, for a healthier lifestyle, longevity and enjoyment of life make the case for smoking cessation. Hospitals run programs for smokers attempting to quit their habit. Tobacco use deleteriously affects the heart as well as other organs of the body. Four million Canadians out of a population of 36 million remain smokers, the result of which, an estimated 45,000 people die each year as a direct cause of smoking.
Cancer, lung disease, heart disease, the most dread medical conditions arise through tobacco addiction.

"The Quit Smoking Program (QSP) is a nurse-led clinic that provides you with one-on-one support during your attempt to quit. The program provides a non-judgmental and supportive environment where a “quit plan” is tailored to meet your individual needs. Anyone may self-refer to the program, or be referred by a healthcare provider. The cost is covered by OHIP."
University of Ottawa Heart Institute

Health Canada is currently examining a proposed measure to dis-enhance the packaging of tobacco products. Not an entirely new idea by any means, but one that builds on past packaging warnings of the outcome of tobacco use on human health. On the agenda is a stark move to have tobacco manufacturers who pall at the very idea, entomb their product in absolutely plain packaging. Once Bill S-5 designed to make it a legal reality is given royal assent, new packaging regulations for tobacco products will prohibit promotional information, branding and logos.

Tobacco, apart from posing as a health threat to those who smoke, along with other non-smokers who are in close proximity constantly to smokers, causes other kinds of accidents that impact on people's lives. Cigarettes improperly snuffed out, left to smoulder, can flare up and cause house fires. Fires that can themselves be lethal, and at the very least, lead to loss of property and possessions. Because smoking is more prevalent among the least educated and the poor, cigarette-caused fires have the potential to burn up multiple dwellings at a time, leaving large numbers of people homeless.

Study finds link between vaping now and smoking later in life; still from video

The strategy the Health Department is now pursuing is meant to reduce the current rate of smoking in the public from its 15 percent status to five percent or less with the help of the new legislation. Funding is to be provided for investments to protect youth, increase scientific research, fund non-governmental organizations and to make inroads in curbing smoking in Indigenous communities where smoking rates are known to be much higher than among the general population.

"Smoking cessation is a health priority for the University of Ottawa Health Services Family Health Team.  In 2009, our providers adopted the Ottawa Model for Smoking Cessation (OMSC) in Primary Care. It focuses on helping patients quit smoking long term by providing counselling and cessation medications. The program helps patients identify their smoking status, provides advice on strategies to quit smoking; and provides assistance with quitting. The program includes collaboration with the Heart Institute to provide follow-up counselling to help patients remain smoke-free."
University of Ottawa, Smoking Cessation Program