BC Government photo
By Dorothy Li B.Sc.(Pharm), CSPI, BC Drug and Poison Information Centre
Reviewed by Sarah Henderson, PhD Senior Scientist, Environmental Health Services, BC Centre for Disease Control
Although wildfires are a normal and natural part of summers in British Columbia, the 2017 and 2018 seasons were two of the most devastating on record. Approximately 65,000 people were evacuated in 2017 and more than 1.2 million hectares burned in both summers, releasing at least 200 million tonnes of smoke into the atmosphere each year.
Hot and dry conditions, thunderstorms, and damage caused by the mountain pine beetle all played a role. Climate change scientists forecast worsening wildfires and smoke across North America over the coming decades. Exposure to wildfire smoke has been associated with a wide range of health outcomes, from increased respiratory symptoms through to premature mortality. The following discusses these health effects in more detail, the public health response in B.C., and opportunities for pharmacists and pharmacy technicians to make a positive contribution.
Health effects of wildfire smoke
The composition of wildfire smoke is complex, depending on vegetation type, moisture content, weather and combustion temperature. Wildfires can generate a huge amount of air pollution with plumes that travel hundreds or thousands of kilometers. The most health-relevant components include: particulate matter less than 2.5 micrometers in diameter (PM2.5), volatile organic compounds (VOC), carbon monoxide, other gases and trace heavy metals. Of these, PM2.5 concentrations are considered the best indicator of wildfire smoke health risks. The PM2.5 can deposit deep in the respiratory tract causing oxidative stress and inflammation that can affect other areas, particularly the cardiovascular system. Exposure to the larger particles, VOCs, and other gases can cause irritation to mucous membranes. The most common symptoms of wildfire smoke exposure are irritation, rhinitis, cough, phlegm, wheezing, and headaches. Most healthy people recover from these acute effects when the smoke clears, but some people may develop dyspnea, severe cough, dizziness, chest pain, or heart palpitations.
Most research has been limited to epidemiological designs requiring large sample sizes. The frequency of certain health outcomes during periods of exposure is generally compared with periods of non-exposure. Health outcomes studied include mortality, hospital admissions, emergency room visits, primary health-care visits, and medication dispensations for specified diseases. These studies have most consistently linked wildfire smoke to asthma and chronic obstructive pulmonary disease (COPD) exacerbations, acute bronchitis, pneumonia, and otitis media. While strong evidence shows that PM2.5 from other sources (traffic, industry, domestic fuel) has cardiovascular effects including death, population-based studies on wildfire smoke have been inconsistent. These studies may have been limited by exposure misclassification or small study populations. Toxicological studies in animal models, however, do support the potential for cardiovascular effects.
Certain populations are identified at higher risk: people with chronic conditions (asthma, COPD, heart disease, and diabetes), pregnant women and the developing fetus, infants and children, and the elderly. Children may be at particular risk because they spend more active time outdoors, inhale more air per body mass and have immature lungs. Elderly may have decreased lung function and pre-existing lung, heart, or other conditions that put them at increased risk.
The mental health impacts of wildfire smoke are not well understood, but people exposed to wildfire events have increased rates of post-traumatic stress, depression and anxiety. Risk factors include evacuation, physical injury and property damage. During the Northwest Territories wildfires in 2017, prolonged time indoors and evacuation lead to isolation and feelings of fear, stress and uncertainty. Disruption of traditional activities for First Nations communities also affected livelihood and food security. Much more research on wildfire smoke is needed to elucidate these outcomes, as well as to assess the long-term risks, specific effects on the developing fetus, and the efficacy of recommended interventions.
Responding to wildfires
Following the severe wildfire season of 2010, B.C. introduced a provincial coordination group and guideline document to assist future response to smoke events. To provide guidance to the coordination group and the public, the BC Centre for Disease Control (BCCDC) systematically reviewed wildfire smoke health effects, populations at risk, tools for surveillance and interventions. The reviews concluded that staying indoors reduced asthma symptoms and use of portable air cleaners improved health outcomes, and the BCCDC therefore recommended these as intervention strategies. Other recommendations include: staying well hydrated, avoiding strenuous work or exercise outdoors, cancelling outdoor events, and spending time in cleaner air spaces, such as libraries and community centres. Key messages for the public are being distilled into a series of fact sheets available online.
The BCCDC also developed the B.C. Asthma Prediction System (BCAPS), which tracks PM2.5 concentrations and salbutamol dispensations to predict the health impacts of smoke exposures 24 to 48 hours before they occur. This validated tool assists medical health officers with making public health recommendations, such as contacting pharmacies to ensure adequate salbutamol supply, intimating the provision of clean air shelters, or making informed decisions about community evacuations in the worst case scenario.
There are practical ways pharmacists and pharmacy technicians can respond to wildfire events (see Table 1).
Before wildfire season starts
Prompt patients with asthma or COPD to visit their physician for written action plans to recognize and respond to worsening symptoms; assist them in establishing an adequate supply of their rescue medications. Such action plans decrease emergency visits and hospital admissions.
During wildfire season
Stay tuned to the Air Quality Health Index (AQHI), local air quality reports and advisories; maintain an adequate supply of bronchodilator and corticosteroid inhalers; recommend patients carry their bronchodilator (reliever) inhaler with them at all times.
During times of poor air quality
Offer delivery services to at-risk populations; emphasize minimizing exposure to wildfire smoke while clarifying the role of N95 respirators. Limiting time spent outdoors offers more practical protection than wearing a N95 respirator for most people, especially those at higher risk. People who must work outdoors during smoky conditions may benefit from wearing a properly fitted and fit-tested N95 respirator. Refer these clients to WorkSafeBC.
During evacuations and declared provincial states of emergency
Dispense an emergency supply of medications to displaced persons (prescription not required).
Wildfire smoke exposure is an increasingly important public health issue. Being informed and prepared for wildfire season can help pharmacists and pharmacy technicians care for people affected by wildfire smoke events.
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