Strategies to Reduce Exposure Outdoors

Go indoors when appropriate: Particle levels and activity levels are generally lower indoors.

Go outdoors when air quality is better: Smoke levels can change a lot during the day, so wait until air quality is better before being active outdoors.

Reduce activity levels and time outdoors:  If it is necessary to go out when particle pollution from wildfire smoke is high, spend as little time outside as possible and reduce activity levels.

Reduce smoke in a vehicle: Close the windows and run the car’s air conditioner in recirculate mode to reduce air intake from outside.

Reduce exposure to heat: Keep an eye on air quality and temperature conditions and schedule outdoor activities for cooler and less smoky times of day, if possible.

•     Stay hydrated (choose water or drinks with electrolytes over sugary beverages).
•     Limit strenuous activity and exercise. Rest often in shady areas.
•     Wear lightweight, loose-fitting clothing (absorbent or wicking clothing is also appropriate).

Pay attention for early signs of heat-related illness: Take the precautions above for early symptoms including feeling unwell, headache, sweating and thirst, nausea, lightheadedness, fatigue, heat rash and muscle cramps. More serious symptoms require immediate medical attention, including fainting or loss of consciousness, weakness, extreme fatigue, severe nausea and difficulty speaking.

Over the course of a work shift, outdoor workers may face greater or more prolonged exposure to both smoke and heat and have less ability to spend time indoors than the general public. Because of this, outdoor workers should be especially careful when both smoke and heat are present and take what measures they can to reduce exposure to both.

Use a respirator: If outdoor levels of PM_2.5 (particulate matter) are in the unhealthy ranges, or your patients have symptoms, advise them to consider wearing a filtering NIOSH Approved® N95® respirator having the words “NIOSH” and the filter series (e.g. “N95” or “P100”) printed on it. Paint masks, dust masks or surgical masks do not prevent smoke inhalation. Use the respirator correctly to get the most protection possible.

During periods of shortages of N95® filtering facepiece respirators, use of respirators conforming to standards used in other countries that are similar to NIOSH Approved® respirators (e.g., KN95 respirators certified under the People's Republic of China standards) are expected to provide greater protection than surgical masks (i.e., facemasks), homemade masks or improvised mouth and nose covers like bandanas and scarves.

For selecting and donning a respirator, advise your patients to choose a respirator that is sized to fit tightly over their nose and under their chin (Figure 13). Most respirators have two straps to go around the head.

•  Supervised fit testing is the best way to determine if a respirator fits, but even without fit testing a respirator will provide some protection to most people.
•  Since fit testing is usually not available to the public, your patients can assess how well the device fits by performing a user seal check every time they put on the respirator following the instructions on the package. Some manufacturers’ donning procedures are also available from the NIOSH Approved Filtering Facepiece Respirators Listing. For additional instructions, see the Donning and Doffing and User Seal Checks  if they cannot get a good face seal, they should try a different model or size.

Inform your patients:

• That any leakage around the edge of the respirator causes unfiltered air to enter and be inhaled, and it increases a person’s exposure to wildfire smoke particles by 10% or more. Exposure while wearing a poorly fitting respirator can be the same as that from not wearing it.
• To follow CDC’s recommendations for Community Respirators and Masks.
  • Children ages 2 years and older can wear respirators; however, NIOSH Approved® respirators do NOT come in sizes suitable for very young children. If a child needs to wear a respirator, choose one that is comfortable, and that the child can wear correctly. If a respirator does not fit properly or is uncomfortable, a child might take it off when it is needed or wear it incorrectly.
  • People with certain disabilities or their caregivers may assess whether they are able to tolerate a respirator by considering if they are able to obtain a proper fit, avoid touching the respirator frequently, limit excess saliva on the respirator, remove the respirator without assistance and communicate while wearing it.

Figure 13. Two types of N95® disposable filtering facepiece respirators. Note the presence and placement of the two straps above and below the ears. Photos courtesy of the California Department of Public Health

Figure 14. A one-strap paper mask is not a respirator and provides little or no protection from smoke particles. Photo courtesy of the California Department of Public Health.

Effects of Respirator Use

• Your patients with heart or lung disease will need your guidance in using respirators since they may be particularly sensitive to the effects of respirator use (e.g., making it harder to breathe, facial discomfort, headaches, etc.). If you determine wearing a respirator is appropriate, provide your patient with instructions on proper use and precautions.
• Wearing a respirator, especially if it’s hot or the patient is physically active, can increase your patient’s risk of heat-related illness. Inform your patient:
  • to take breaks often and drink water and
  • if they have difficulty breathing, get dizzy or have other symptoms while wearing a respirator, to remove it as soon as possible, preferably in a place with cleaner air.
•  Because wearing a respirator during pregnancy can make it harder for a woman to breathe (particularly late in pregnancy), it is important for you and your patient to work together to ensure that the patient can safely and comfortably use the appropriate respirator at all stages of pregnancy. If your patient follows the recommended weight gain limits for pregnancy, how well a filtering facepiece respirator fits and the level of protection it provides should not change during the pregnancy.

Efficiency of NIOSH Approved® N95® respirators against wildfire smoke

• NIOSH Approved® N95® respirators will be more than 95% efficient at removing wildfire smoke particles in the PM_2.5 size fraction since they have filter efficiencies against particles that are smaller (≥96%) and larger (≥99.5%) than 0.3 µm.
• Studies have shown that when correctly put on according to the manufacturer’s instructions (including minimizing any gaps between the face and respirator) and used properly, N95® respirators will significantly reduce the wearer’s exposure to smoke particles. (Brousseau et al. 2010; Coffey et al. 2004; Duling et al. 2007)

For more information about respirator selection and use, see:

• Protect Your Lungs from Wildfire Smoke or Ash (pdf) (424 kb)
• How to tell if your N95 Respirator is NIOSH Approved
• Use of NIOSH Approved Respirators.
• Protecting Workers and the Public from Wildfire Smoke.
• Roberge RJ, Kim JH, Powell JB. N95 respirator use during advanced pregnancy. American Journal of Infection Control 2014; 42(10): 1097–1100.
• Roeckner JT, Krstić N, Sipe BH, Običan SG. N95 filtering facepiece respirator use during pregnancy: A systematic review. American Journal of Perinatology 2020; 37(10): 995–1001.
• About Personal Protective Equipment
• Kim JH, Roberge RJ, Powell JB. Effect of external airflow resistive load on postural and exercise-associated cardiovascular and pulmonary responses in pregnancy: a case control study. BMC Pregnancy and Childbirth 2015; 15: 45.
• Roberge RJ, Kim JH, Palmiero A, Powell JB. Effect of pregnancy upon facial anthropometrics and respirator fit testing. J Occup Environ Hygiene 2015; 1(4): 262–271.

Attribution
N95® and NIOSH Approved® are certification marks of the U.S. Department of Health and Human Services (HHS) registered in the United States and several international jurisdictions.
P100® is a certification mark of the U.S. Department of Health and Human Services.

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