Wildfires and wildfire smoke

The frequency and intensity of Canadian wildfires is increasing due to the changing global climate, as well as long-standing forest management practices. Ever-worsening fire seasons impact communities in a variety of ways, including through smoke exposure and the threat of property damage, evacuation, and loss of life. The resources assembled here are intended to assist public health practitioners, decision-makers, and the public by providing guidance regarding public health impacts, community preparedness, risk communication and response to wildfires and wildfire smoke.

You can also find additional emergency preparedness resources on our other subject guides:

• Indigenous disaster response
• Oil spills and health
• Floods: Prevention, preparedness, response and recovery
• Psychosocial impacts: Resources for mitigation, response and recovery
• Extreme heat
• Preventing indoor overheating

Review of the 2023 wildfire season in Canada

The 2023 wildfire season in Canada was unprecedented with respect to its length, intensity, geographic scope, area burned, and smoke pollution. This section highlights some of the most recent information on the impacts of the extradentary 2023 season, some of which has not yet been published in the peer-reviewed literature.

• Drivers and impacts of the record-breaking 2023 wildfire season in Canada (Jain et al., Aug 2024)
  This journal article results from collaboration between the top wildfire scientists in Canada. It describes in detail how the 2023 wildfire season was different from any previous season. It also highlights the role of the climate change in wildfire risks, and the implications for future wildfire seasons.
   
• The 2023 wildfire season in Québec: an overview of extreme conditions, impacts, lessons learned and considerations for the future (Boulanger et al., Feb 2024)
  This preprint article provides insight into the record-setting wildfire season in Quebec, and the unusual environmental conditions that contributed to the extreme fire behaviour. It also thoughtfully discusses the disproportionate impacts of the fires on Indigenous people and communities.
   
• Severe global environmental issues caused by Canada’s record-breaking wildfires in 2023 (Wang et al., Nov 2023)
  This peer-reviewed article is primarily focussed on emissions from the 2023 wildfires in Canada, their global air quality impacts, and their contributions to the greenhouse gases (GHGs) that drive climate change. The authors estimate that the GHGs released by the fires were more than double the GHG emissions reductions planned in Canada over the next 10 years.

Mitigating wildfire and smoke risks

• FireSmart Canada (Canadian Interagency Forest Fire Centre, May 2024)
  This webpage is an essential resource for individuals and neighbourhoods wishing to make their communities FireSmart. Resources include manuals, articles, online courses, in-person workshops, and case studies across Canada. Many resources are available in both official languages, and new resources are added regularly. 
   
• Mapping wildfire hazard, vulnerability, and risk to Canadian communities (Erni et al., Feb 2024)
  This peer-reviewed article maps wildfire risk across Canada and examines intersections with the built environment. It estimates that more than 300,000 people live in areas with high or very high risk. The authors also highlight the risk disparities for Indigenous communities, where 18.9% of the population are at high risk compared with 2.4% of the non-Indigenous population. 
   
• The right to burn: Barriers and opportunities for Indigenous-led fire stewardship in Canada (Hoffman, Mar 2022)
  This peer-reviewed article describes how Indigenous people in Canada and worldwide have used fire for millennia to shape the landscape and reduce wildfire risk. These practices were not permitted post-colonization, but there is now renewed interest in cultural burning for the long-term health of forests in Canada. 
   
• Wildfire management in Canada: Review, challenges, and opportunities (Tymstra et al., Jan 2020)
  This peer-reviewed article takes a broad view of wildfire management in Canada, providing important perspectives regarding the need to protect public health and safety while recognizing that current strategies are insufficient. However, it does not address the role of Indigenous-led stewardship in forest management.

Resources for public health practitioners

• Wildfires in Canada: Toolkit for public health authorities (PHAC, Aug 2023)
  This toolkit summarizes information and collates resources to support public health authorities preparing for and responding to the physical and mental health impacts of wildfires and smoke. It provides useful information and helpful links to support public health practitioners.
   
• Wildfire smoke factsheets (BCCDC, Jul 2023)
  This webpage hosts several short, printable fact sheets that public health practitioners can use to communicate with the public about wildfire smoke. They include fact sheets on health risks, preparedness, portable air cleaners, pregnancy outdoor exercise, understanding the Air Quality Health Index, and the use of face masks. New fact sheets are added every year, and some are available in multiple languages.
   
• BC Health and Smoke Exposure (HASE) coordination committee guideline (BCCDC, May 2023)
  This guideline outlines how public health and other partners respond to wildfire smoke, including pre-season preparedness, seasonal response, and post-season review. Although it is specific to BC, it may provide a useful example for policy and practice in other jurisdictions.
   
• Wildfire smoke: a guide for public health officials (Multiple US Agencies, Sep 2021)
  This guide is designed to help public health practitioners prepare for smoke events, take measures to protect the public, and communicate with the public about wildfire smoke and health. The guide is updated regularly, and the appendices include links to several useful resources and fact sheets.  
   
• Preparation for forest fires and the assessment of health effects from forest fire smoke:  Guidelines for health staff in Northern Saskatchewan communities (Population Health Unit, 2016)
  This guideline is designed to help public health officials in northern communities prepare for smoke events, take measures to protect the public, and communicate with the public about wildfire smoke and health, including useful fact sheets. Although it is specific to Saskatchewan, it may provide a useful example for other jurisdictions.

Indigenous and remote perspectives

• Wildfire smoke and protective actions in Canadian Indigenous communities (Batdorf and McGee, Jun 2023)
  This narrative review summarizes 51 articles about decision making during wildfire smoke events in Indigenous communities across Canada. It describes how Indigenous populations are more exposed to wildfires and smoke, and advocates for culturally safe and appropriate public health responses to smoke exposures.
   
• Exploring Indigenous ways of coping after a wildfire disaster in Northern Alberta, Canada (Montesanti et al., May 2021)
  This peer-reviewed article describes how Indigenous communities coped with the aftermath of the 2016 wildfire season in Alberta, which was the most destructive in Canadian history. It emphasizes disparities between Indigenous and non-Indigenous people in Canada related to wildfires and highlights the benefits of strong social cohesion in many Indigenous communities.
   
• Evacuating First Nations during wildfires in Canada (McGee, Mar 2020)
  This peer-reviewed article explores the wildfire evacuation experiences of seven First Nations in three provinces. It finds that many of the Nations do not have current and culturally safe emergency plans for their communities, leading to distress during and after evacuations. This research motivated the development of guidance for communities and external agencies.
   
• The summer of smoke: Ecosocial and health impacts of a record wildfire season in the Northwest Territories, Canada (Dodd, Mar 2018)
  This peer-reviewed article describes how wildfire and smoke affected the lives of people in northern Canada during the summer of 2014. Data gathered through interviews highlights the physical, emotional, mental, and social harms of severe wildfires, including disruptions to traditional ways of living for Indigenous people.

Health effects of wildfire smoke

• The public health paradox of wildfire smoke (Henderson et al., Apr 2024
  In this opinion piece, the BC Centre for Disease Control describes how the relationship between wildfire smoke concentrations and acute respiratory outcomes is non-linear, and how the effects of smoke plateau at higher concentrations. It urges public health practitioners and the public to take actions to reduce smoke exposure whenever wildfires are affecting air quality, not just under extreme conditions.
   
• The firestorm within: A narrative review of extreme heat and wildfire smoke effects on brain health (White, Apr 2024)
  This narrative review describes how extreme heat, wildfire smoke, and both exposures together can affect brain health in humans. There is emerging evidence that exposures related to climate change are negatively affecting our brains, and this is a very informative and comprehensive and review of biological mechanisms and epidemiologic observations.
   
• Health effects of wildfire smoke exposure (Gould et al., Jan 2024)
  This systematic review appears in the Annual Review of Medicine, which is a widely respected source of scientific information that is published once annually. Evidence on the health effects of wildfire smoke is expanding quickly, and this review provides the most recent comprehensive synthesis.
   
• Long-term exposure to wildfires and cancer incidence in Canada: a population-based observational cohort study (Korsiak et al., May 2022)
  This peer-reviewed article examines the relationship between proximity to wildfires in Canada and increased risk of lung and brain cancers over a 20-year period. This is some of the first epidemiologic evidence suggesting that long-term exposure to wildfires and smoke may be associated with increased cancer risk.
   
• Health impact analysis of PM_2.5 from wildfire smoke in Canada (Matz et al., Jul 2020)
  This peer-reviewed article uses data from multiple sources to estimate the health impacts of wildfire smoke in Canada for the 2013-2015 and 2017-2018 wildfire seasons. It concludes that wildfire smoke contributes to increased deaths, hospital admissions, emergency room visits, and symptoms of illness every year. These increases result in billions of dollars of economic impacts for Canada.

Outdoor air quality impacts

• AQ Map hourly PM_2.5 observations across Canada (Nilson, May 2024)
  This interactive map collates all publicly available measurements of fine particulate matter (PM_2.5) across Canada and displays calibrated concentrations in a way that is consistent with Air Quality Health Index (AQHI) values. Other layers can be used to show information such as the locations of current fires, or the Environment Canada smoke forecasts.
   
• FireWork: Canada’s wildfire smoke prediction system (ECCC, 2024)
  This daily forecast uses real-time information about wildfires and weather conditions to predict smoke emissions and their dispersion across Canada up to 72 hours in advance. FireWork provides the official government forecast that is integrated into other national systems, but it is not the only smoke forecast available in Canada.
   
• FireSmoke Canada (BlueSky Canada, 2024)
  This daily forecast also uses real-time information about wildfires and weather conditions to predict smoke emissions and their dispersion across Canada. The BlueSky forecast is generated by academic partners and is often used in media communications about smoke. It also powers tools that managers can use when planning prescribed burns to reduce wildfire risk.

Cleaner indoor air

• Do-it-yourself (DIY) air cleaners: Evidence on effectiveness and considerations for safe operation (Eykelbosh, Jan 2023)
  This evidence review compares home-made and commercially manufactured air cleaners to assess whether DIY options are equally effective. It concludes that both DIY and commercial air cleaners can reduce smoke indoors if they are kept running during wildfires, but that both options can be noisy, and people may not use them consistently as a result.
   
• Wildfire smoke clean air centers: Identifying barriers and opportunities for improvement from California practitioner and community perspectives (Treves et al., Aug 2022)
  This peer-reviewed article explores the management and use of clean air centers in California, where wildfires have had marked impacts on air quality over the past 20 years. By interviewing both managers and users, the authors were able to identify barriers and gaps that can be addressed to improve uptake and public health in future years.
   
• Planning framework for protecting commercial building occupants from smoke during wildfire events (ASHRAE, June 2021)
  This guidance document provides detailed information on heating, ventilation, and air conditioning (HVAC) and other building measures to protect occupants against smoke exposure. The document outlines how to develop, implement and evaluate a smoke readiness plan, with numerous additional linked resources. Full guidance from ASHRAE is expected in late 2024.
   
• Guidance for cleaner air spaces during wildfire smoke events (Health Canada, Sept 2020)
  This guidance document outlines how to create protected “cleaner air” spaces, for public or private use, during smoke events. It describes the health effects of fine particulate matter, carbon monoxide, and carbon dioxide, and provides information about how to manage all three pollutants indoors.

Other interventions for wildfire smoke

• Climate change and health: Rethinking public health messaging for wildfire smoke and extreme heat co-exposures (Coker et al., Mar 2024)
  This peer-reviewed article describes how government agencies in Canada and the US communicate about the risks of co-exposure to wildfire smoke and extreme heat. There is growing evidence of an interaction between these exposures, meaning that heat increases the risks associated with wildfire smoke, and wildfire smoke increases the risks associated with heat.
   
• A scoping review of wildfire smoke risk communications: Issues, gaps, and recommendations (Vien et al., Jan 2024)
  This scoping review included 21 peer-reviewed articles about wildfire smoke risk communications with the objective of identifying research gaps. It reports that very few studies include information about behavioral change related to wildfire smoke messaging, which makes it challenging to evaluate the effectiveness of communications programs.
   
• N95 respirators for cardiovascular protection during wildfire smoke events (Brook et al., Jan 2024)
  This rapid communication estimates how many people need to wear N95 respirators to reduce the number of heart attacks caused by wildfire smoke. It suggests that respirators can play a useful role in public health protection, but also highlights the challenges and limitations such as mask fit and user compliance. 
   
• What is the effectiveness of public health interventions on reducing the direct and indirect health impacts of wildfires? (NCCMT and NCCEH, Oct 2023)
  This rapid evidence review addresses the public health effectiveness of interventions such as evacuations, staying indoors, and using air cleaners. It reports that air cleaners can significantly reduce indoor wildfire smoke exposures. It also highlights that evacuations are very stressful and may cause long-term mental health harms for affected populations.
   
• Public health messaging for wildfire smoke: Cast a wide net (Shellington, Apr 2022)
  This peer-reviewed article reports on a survey conducted in British Columbia, to assess how people accessed information on wildfire smoke, health, and protective measures. The authors conclude that public health practitioners should use multiple communications strategies, and that local radio is important for reaching Indigenous, rural, and remote communities.

Occupational health

• Air pollution, wildfire smoke, and worker health (Cabral and Dillender, Mar 2024)
  This working paper from the US National Bureau of Economic Research (NBER) uses data from Texas to examine the relationship between wildfire smoke and occupational injuries. It finds that, on average, injuries are increased by 2.8% on smoky days, which has significant economic impacts.
   
• Wildfire smoke: Frequently asked questions (WorkSafe BC, Aug 2023)
  This factsheet provides employees and employers with information on the health hazards of wildfire smoke and measures that can be taken to minimize the effects on workers.
   
• Face-to-face with scorching wildfire: Potential toxicant exposure and the health risks of smoke for wildland firefighters at the wildland-urban interface (Hwang et al., Mar 2023)
  This viewpoint provides a comprehensive review of air pollutant exposures for wildland firefighters, with a focus on the risks of interface fires where anthropogenic fuels contribute to the complex wildfire smoke mixture. It calls for more use of prescribed burning to reduce wildfire risks, and more research into respiratory protection options for wildland firefighters. 
   
• Key requirements: Oregon’s permanent rules for protection from wildfire smoke (Oregon Occupational Safety and Health, Jun 2022)
  This fact sheet describes employer actions necessary to meet the key requirements of new state legislation related to occupational wildfire smoke exposure. The information is specific to Oregon and there are no Canadian jurisdictions with similar regulations, but the general approach is useful for employers trying to understand how to address smoke exposures.
   
• Working in smoke: Wildfire impacts on the health of firefighters and outdoor workers and mitigation strategies (Navarro, Dec 2020)
  This peer-reviewed article describes the conditions to which wildland firefighters are exposed and their potential health impacts, given that they generally do not wear respiratory protection on the job. It also highlights some risk-mitigating and risk-enhancing situations of which clinicians may need to be aware when working with wildland firefighters.
   
• A systematic review of the health impacts of occupational exposure to wildland fires (Groot et al., 2019)
  This systematic review provides an excellent overview of multiple risks associated with occupational exposure to wildfires and smoke. It includes information on outcomes such as musculoskeletal injuries and post-traumatic stress disorder (PTSD), in addition to smoke-related outcomes.

After the wildfire

• Wildfire resources (Alberta Health Services, 2024)
  This comprehensive webpage provides resources to the public on mental health supports, health care services, and information about restoring and preparing homes for reoccupation. There is also a guide for reopening businesses after a wildfire. While these resources are specific to Alberta, much of the information will be useful in other jurisdictions.
   
• Polycyclic aromatic hydrocarbons (PAHs) in wildfire smoke accumulate on indoor materials and create postsmoke event exposure pathways (Laguerre and Gall, Apr 2024)
  This peer-reviewed article describes a laboratory study in which glass, cotton and air filter media were exposed to smoke and then tested over several months for PAHs. The PAHs persisted on the materials for several weeks, but cleaning glass with a commercial cleaner or ethanol, and laundering cotton in a washing machine followed by heat drying reduced PAH concentrations by 62-71% and 48%, respectively.
   
• The persistence of smoke VOCs indoors: Partitioning, surface cleaning, and air cleaning in a smoke-contaminated house (Li et al., Oct 2023)
  This peer-reviewed article describes a laboratory study in which a test home was exposed to smoke and the effectiveness of different cleaning approaches was evaluated. Portable air cleaners reduced concentrations of fine particulate matter, but vacuuming, mopping, and dusting were more effective for reducing volatile organic compounds (VOCs).
   
• Returning home safely after a wildfire (Government of Northwest Territories, May 2023)
  This guidance document provides information and useful checklists for people who have been evacuated due to wildfire activity. The sections on Fire Retardants and Residue, Cleaning Your Home, and Taking Care of Yourself and Others are applicable in all communities affected by wildfires and smoke pollution. 
   
• Human risks associated with aerially applied fire retardants (Alberta Health Services, May 2022)
  This screening risk assessment considers the potential health effects of fire retardant exposure for people returning home after a wildfire. It recommends avoiding ingestion of food and water that has been in direct contact with fire retardants, as well as cleaning areas where children play.
   
• Prevalence rates and predictors of generalized anxiety disorder symptoms in residents of Fort McMurray six months after a wildfire (Agyapong et al., July 2018)
  This peer-reviewed article examines the prevalence and risk factors of generalized anxiety disorder symptoms in residents of Fort McMurray six months after the wildfire. Significant predictors included witnessing of homes being destroyed by the wildfire, living in a different home after the wildfire, and receiving limited governmental support.