Wildfire season has returned to the northern hemisphere, and with large fires burning in 10 U.S. western states — and tens of thousands called to evacuate over this past weekend — we thought we’d remind our readers of the health hazards that accompany exposure to smoke, and how to protect against them.
Smoke from wildfires is a mixture of gases and fine particles from burning trees and other plant materials that can hurt your eyes, irritate your respiratory system, and worsen chronic heart and lung diseases. Even when a fire is far away, changing weather conditions can still expose you to ambient smoke.
Who is at Greatest Risk from Wildfire Smoke?
- People who have heart or lung diseases, like congestive heart failure, angina, chronic obstructive pulmonary disease (including emphysema), or asthma, are at higher risk from wildfire smoke. In general, people with these conditions are at higher risk of having health problems than healthy people.
- Older adults are more likely to be affected by smoke. This may be due to their increased risk of heart and lung diseases.
- Children are more likely to be affected by health threats from smoke. Children’s airways are still developing and they breathe more air per pound of body weight than adults. In addition, children often spend more time outdoors engaged in activity and play.
Steps You Can Take to Decrease Your Risk from Wildfire Smoke
- Check local air quality reports. Listen and watch for news or health warnings about smoke. Find out if your community provides reports about the U.S. Environmental Protection Agency’s Air Quality Index (AQI). In addition, pay attention to public health messages about taking safety measures.
- Consult local visibility guides if they are available. Some communities have monitors that measure the amount of particles that are in the air. In the western part of the United States, some states and communities provide guidelines to help people determine if there are high levels of particulates in the air by how far they can see (see table below).
- Use common sense. If it looks smoky outside, it is probably not a good time for outdoor activities or for children to play outdoors.
- The same particles that cause problems for people can cause problems for animals. Don’t force your animals or pets to run or work in smoky conditions. If your pet has heart or lung disease, follow the same guidelines as for sensitive people.
- Keep indoor air as clean as possible. Keep windows and doors closed. Run an air conditioner if you have one, but keep the fresh-air intake closed and the filter clean to prevent outdoor smoke from getting inside. If you do not have an air conditioner and it is too warm to stay inside with the windows closed, seek shelter in a designated evacuation center or away from the affected area.
- Air filtration devices that use HEPA filters can reduce the level of particles indoors, but do not use an air cleaner that works by generating ozone.
- Avoid activities that increase indoor pollution. Burning candles, fireplaces, or gas stoves can increase indoor pollution. Vacuuming stirs up particles already inside your home, contributing to indoor pollution. Smoking puts even more pollution into the air.
- Prevent wildfires from starting. Prepare, build, maintain and extinguish campfires safely. Comply with local regulations if you plan to burn trash or debris. Check with your local fire department to be sure the weather is safe enough for burning.
- Follow the advice of your doctor or other healthcare provider about medicines and about your respiratory management plan if you have asthma or another lung disease. Consider evacuating the area if you are having trouble breathing. Call for further advice if your symptoms worsen.
- Do not rely on dust masks for protection. Paper “dust” masks such as those commonly found at hardware stores are designed to trap large particles, such as sawdust. These masks will not protect your lungs from the small particles found in wildfire smoke.
- Evacuate from the path of wildfires. Listen to the news to stay current with the latest evacuation orders. Follow the instructions of local officials about when and where to evacuate. Take only essential items with you — including any medications you take on a regular or emergency basis — and make plans ahead of time for dealing with pets and other animals. Follow designated evacuation routes—others may be blocked—and expect heavy traffic.
Generally speaking, lower visibility is the result of more smoke in the air, which corresponds to increased health risks.
Many times, you’ll be able to get information regarding visibility, air quality and risks from local news outlets. But, since wildfires tend to occur in remote areas, and smoke shifts with wind currents, media reports may not be available or accurate. In such cases, you can use the following table, developed by the Arizona Department of Health Services. To use the guidelines:
- Face away from the sun.
- Determine the limit of your visibility range by looking for targets at known distances (miles). Visibility range is the point where even high contrast objects totally disappear. It is not the point at which you can see the smoke.
- Use the visibility range values below to determine the health risk.
|Visibility in Miles||Air Quality Index||Health Category||Health Effects|
|10 or more||0 – 50||Good||None|
|5 – 10||51 – 100||Moderate||Unusually sensitive people should consider reducing prolonged or heavy exertion.|
|3 – 5||101 – 150||Unhealthy
for Sensitive Groups
|People with heart or lung disease, older adults, and children should reduce prolonged or heavy exertion.|
|1.5 – 3||151 – 200||Unhealthy||People with heart or lung disease, older adults, and children should avoid prolonged or heavy exertion. Everyone else should reduce prolonged or heavy exertion.|
|1 – 1.5||201 – 300||Very Unhealthy||People with heart or lung disease, older adults, and children should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.|
|1 or less||301 – 500||Hazardous||Everyone should avoid all physical activity outdoors; people with heart or lung disease, older adults, and children should remain indoors and keep activity levels low|
Adapted from materials provided by the Centers for Disease Control (CDC) and the Arizona Department of Health Services.