During a wildfire, smoke can make the outdoor air unhealthy to breathe. The biggest health threat from smoke is from fine particles. These microscopic particles can get into your eyes and respiratory system – whether you are outdoors or indoors, where they can cause health problems such as burning eyes, runny nose and illnesses such as bronchitis. Fine particles also can aggravate chronic heart and lung diseases - and even are linked to premature deaths in people with these conditions.
Heavy smoke and ash can pose serious, immediate risks to your safety and health if you are close to a wildfire. Being miles from a wildfire may also expose you to unhealthy air quality. Local officials may advise residents to stay indoors during times of poor air quality. Smoke from the outdoors can enter your home and make it unhealthy to breathe indoor air.
If you are healthy, you're usually not at a major risk from short-term exposure to smoke. Still, it's a good idea to avoid breathing smoke outdoors and indoors if possible.
Outdoor air, including fine particles from wildfire smoke, can enter your home through:
Open windows and doors, which is known as natural ventilation.
Mechanical ventilation devices such as a bathroom or kitchen fan that vents to the outdoors, or heating, ventilation and air conditioning (HVAC) systems with a fresh air intake.
Small openings, joints, cracks and around closed windows and doors.
Those at greatest risk from wildfire smoke include:
People who have lung diseases like COPD or asthma or heart disease
Older adults, especially those with increased risk of heart and lung diseases
Children (their airways are still developing, and they breathe more air per pound of body weight than adults)
Expectant mothers affected by smoke may also be at risk for problems such as preterm birth and babies born with low birth weight.
Reduce your risk
If an active fire in your area is very close to your house, evacuating may be best. Fires can spread quickly, and the smoke plume can make it difficult to see during an evacuation. In addition, it can be nearly impossible to keep dense smoke from building up in the indoor air. Pay close attention to local emergency alerts to know when to evacuate.
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) and pay attention to public health messages about safety measures.
Keep indoor air as clean as possible if you are advised to stay indoors. Keep windows and doors closed. Run an air conditioner 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, go to a designated shelter away from the affected area.
Follow the advice of your doctor or other health care provider about medicines and about your respiratory management plan if you have asthma or another lung disease. Consider evacuating if you are having trouble breathing. Call your doctor for advice if your symptoms worsen.
Consider purchasing a portable air cleaner or high-efficiency HVAC filter as part of your preparation in order to help improve your indoor air quality during a wildfire smoke event. Choose one that is sized for the room in which you will use it. You may need to consult a professional HVAC technician to determine the highest efficiency filter that will work best for your system.
Avoid strenuous activity during smoky times to reduce how much smoke you inhale. Avoid activities that create more fine particles indoors, such as smoking cigarettes, frying or broiling food, burning incense or spraying aerosol products. Do not vacuum because vacuuming stirs up particles already inside your home.
Wear a mask. N95 mask filters out 95% of particles in wildfire smoke. Make sure it is worn correctly and is tightly fitting. If the N95 mask has a valve, put something on top of the valve to seal it off. N95 masks are not meant to be reused because they become less effective with each use. Cloth masks aren’t able to efficiently filter out these hazardous particles due to the type of fabric and overall structure, which is not typically tight fitting. However, they can be more effective than wearing no mask. N100 or P100 filters keep out 99.97% of these same particles but can make breathing difficult.
Source: U.S. Environmental Protection Agency and Center for Disease Control and Protection
