Wildfire smoke is a complex mixture of hazardous particles and pollutants that can lead to a variety of health effects. Depending upon the combustible material, smoke may contain gasses such as carbon monoxide, aldehydes, cyanide vapors, sulfur dioxide, polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM).
Smoke can severely affect air quality and produce significant health effects if the concentration is too high. These effects include conjunctivitis, oropharyngitis, chemical pneumonitis, headaches, gastrointestinal issues, burning of mucosal linings, and exacerbations of preexisting medical conditions such as asthma, chronic obstructive pulmonary disease (COPD), heart disease, etc., and may even lead to death.
The symptoms a person may experience from wildfire smoke range from coughing, wheezing, trouble breathing, shortness of breath, nausea and vomiting, eye irritation and redness, burning of the skin, throat and nose, and potentially lead to pulmonary inflammation and reduced lung function. Physical exertion can exacerbate these health effects. Once the exposure stops, symptoms may last for a couple of days maybe more, but as long as the person is removed from the smoke-saturated environment they should improve.
Under longer periods of exposure, inhalation of the PM in smoke may also reduce the body’s ability to fight off infections such as bacteria, fungi, and viruses. Not to mention, populations exposed to wildfire smoke over long periods of time have a significantly increased risk of cancer, lung disease, cardiovascular disease and mortality. Although in some cases even frequent exposure to smoke even for brief periods can also increase a person’s risk long-term health effects.
When wildland fires are in close proximity to a community, monitoring the air quality index (AQI) is important especially for households with susceptible individuals such as elderly, children, and those with pre-existing medical conditions including those recovering from surgical procedures.
The AQI was developed by the U.S. Environmental Protection Agency (EPA) in order to track concentrations of harmful particulates and other pollutants in the air. It is set on a scale of predictions based on known health effects from air emissions.
An AQI of 0 to 50 is labeled as “Good,” where the likelihood of ill effects from the air at a minimum. Opening windows to bring in fresh air is encouraged.
An AQI of 51 to 100 is considered “Moderate.”
The persons at risk of developing symptoms in this AQI range are those whom have been previously sensitive to pollution. This air quality is considered “acceptable” by the EPA but individuals should consider using respiratory protection when the AQI nears 100.
Households should avoid using whole house fans which draw in outside air without filtering the smoke particles. Also it is advised to change outdoor activities to shorter and less intense durations.
An AQI of 101 to 150 is labeled “Unhealthy for sensitive groups.”
Those at risk are not only those sensitive to pollution, but also persons with heart or lung disease, or who are older adults, children, or pregnant. Those who exercise or work outdoors also are at risk of developing symptoms. Activities outdoors should be reduced as much as possible. Those with medical conditions should keep an extra supply of prescription medications on hand and limit going outside. The EPA begins to caution everyone to stay indoors if possible.
Eye irritation may appear at this AQI even in healthy individuals. Use of antihistamine eye drops is encouraged in acute situations. It is recommended that people contact their healthcare provider to formulate health plans in the case of worsening smoke conditions.
AQI of 151 to 200 is “Unhealthy.”
This means that everyone is at risk. The proper use of respiratory and eye protection is recommended for all exposed populations starting at this level. Smoke particles are 0.7 microns, so regular or cloth face masks do not work to filter out the pollution. Using N95 or KN95 masks will be more effective, or even cartridge masks with chemical filters.
Households are encouraged to consider using HEPA air filters. All outdoor activities should be rescheduled or moved indoors.
AQI 201 to 300 is described as, “Very Unhealthy.”
This is a health Alert for all populations within the area affected. Susceptible groups are instructed to avoid going outside and warned to stay indoors. All long or intense outdoor activities are discouraged for everyone.
Home Filtration is encouraged for all households at this level. Use of air conditioners, air cleaners, and other similar devices is recommended. Setting air conditioning HVAC systems to “on” will help mitigate indoor air quality during these times. Avoid using “auto” settings which are only intermittent filtration. Susceptible individuals should also consider installing a high-efficiency filter (MERV 13 rating or higher) if their HVAC systems are able to tolerate it.
If the AQI is greater than 300, the air is considered “Hazardous.”
Everyone is issued a Health Warning with the recommendation that all outdoor physical activities should be avoided. Indoor physical exertion should be limited and less intense. Susceptible populations should avoid going outside completely if possible AND keep exercise levels very low at home and indoors.
People experiencing symptoms from wildfire smoke should immediately contact their health care provider especially at the first signs of symptoms. This will go a long way in preventing further health complications from exposure to wildfire smoke.
For more information on tracking air quality during wildfires, please go to the following sites:
https://www.airnow.gov
https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5318238.pdf
(Bio: Dr. Zender is an occupational and environmental physician with a background in medical journal writing, industrial accident mitigation, and environmental and chemical exposures.)
Author: Staff
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