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Public Health wildfire smoke response


Wildfires are becoming more frequent and severe across the western United States and Canada. While wildfires may occur in remote locations, the smoke plumes they generate can be carried by atmospheric currents and impact air quality in communities across King County. These plumes can result in poor air quality conditions that last anywhere from a few days to weeks on end, placing large populations at risk to the health effects of wildfire smoke exposure.

Public Health – Seattle & King County developed its Wildfire Smoke Response Plan (378 Kb) to describe actions the department may take before and during a wildfire smoke event to protect community health and limit health disparities. This page provides an overview of the risks facing our community, Public Health response actions, and recommendations for preparedness and response professionals to support regional coordination across King County during a wildfire smoke event.

Health impacts and community risk factors

Wildfire smoke is a complex mixture of organic and inorganic material which can impact human health when inhaled. Pets and other animals may also be at risk from wildfire smoke. Of principal public health concern are the risks associated with fine particulate matter, otherwise referred to as PM2.5.

PM2.5 consists of particles smaller than 2.5 microns in size (about 20 times smaller than the width of a human hair) that can be drawn deep into the body through breathing, resulting in impacts to respiratory and cardiovascular systems. These particles are of the greatest health concern.
Air quality and the health risks associated with air pollution are measured using the Air Quality Index (AQI), which shows the amount of PM2.5 µg/m3 in the air at a given location and the associated health risks.

Responding to wildfire smoke

Guidance for response partners

Puget Sound Clean Air Agency (PSCAA) produces air quality alerts when AQI levels reach 101 and above. The National Weather Service may also produce an alert if the smoke in the high atmosphere is forecasted to impact the population.

Public Health recommends that response partners take key actions in line with identified AQI levels to prevent or reduce the risk of adverse health impacts from wildfire smoke in their communities. The Public Health Recommended Wildfire Smoke Measures (265 Kb) are established to protect those most vulnerable to the health impacts of wildfire smoke, and include recommendations and considerations relating to messaging, reducing outdoor activities, and opening cleaner air sites.

  • What does wildfire smoke do to our bodies?

    • Wildfire smoke has been found to be more toxic than other sources of particulate matter that people are more commonly exposed to. Breathing in smoke can affect you right away, causing trouble breathing, irritated sinuses, headaches, stinging eyes, chest pain, and fatigue. The impacts of inhaling wildfire smoke often compound throughout the event and symptoms often linger several days after the smoke may have cleared. People often experience the most severe health impacts from wildfire smoke the day after exposure.
    • Wildfire smoke exposure may exacerbate respiratory, metabolic, and cardiovascular chronic conditions like asthma, chronic obstructive pulmonary disease (COPD), and congestive heart failure. It can also impact mental health and increase stress.
  • What increases risk of wildfire smoke related health issues?

    • Wildfire smoke affects the health of everyone, even those who perceive themselves to be young and healthy. Some people may experience health impacts at lower levels of wildfire smoke exposure than others.
    • Underlying health conditions and individual factors and determinants such as age, employment, housing status and type, and outdoor activity levels may increase an individual's risk of health issues during a wildfire smoke event.
    • People at higher risk of health complications include: those unable to reduce their exposure to wildfire smoke, especially people living unsheltered or working outdoors for prolonged periods of time; people with chronic health conditions, especially asthma, COPD, and heart disease; older adults and children; and pregnant people.
  • How do I find my local air quality level?

    • Puget Sound Clean Air Agency (PSCAA) is the region's local air quality authority. To find current AQI levels, go to Sensor Maps on Instant setting.
    • Forecasted AQI can be found through the WA Wildfire Smoke Blog, a joint effort between state and local governments to track wildfires and their impacts across the state.
    • The U.S. EPA AirNow Fire and Smoke map can also be used as a source to obtain real time air quality information and to identify how wildfire smoke plumes are impacting air quality across the region.
  • What steps should be taken when there is an air quality alert for wildfire smoke?

    • People should move indoors and use an air filtration system to stay protected from wildfire smoke. See Public Health's Wildfire Smoke Preparedness page for steps and resources.

AQI Values

Public Health Recommendations

Unhealthy for
Sensitive Groups
(AQI 101 – 150)


  • Recommend sharing public health messaging regarding health effects of wildfire smoke exposure and public mitigation measures to reduce wildfire smoke exposure, particularly for sensitive groups (e.g., how to create cleaner air rooms at home or locations that might be made available to the public to access cleaner air during a wildfire smoke event, such as libraries, shopping centers, and other locations).
  • Consider cancelling children’s outdoor recess, physical education, athletic practices, and games, or moving them indoors or to an area with good air quality.
  • Consider resource mobilization for locations to serve as cleaner air sites for individuals experiencing homelessness.1
  • Consider activation and opening of cleaner air sites for individuals experiencing homelessness.

Unhealthy for All
(AQI 151 – 200)


  • Recommend activation and opening of cleaner air sites for individuals experiencing homelessness.
  • Consider activation and opening of cleaner air sites for general population or directing people to locations where they can access cleaner air during a wildfire smoke event.2
  • Recommend cancelation and/or rescheduling of outdoor children’s activities, athletic practices and games, or moving them indoors or to an area with better air quality.
  • Recommend amplifying public health messaging and sharing information on available locations where individuals and families can go to seek cleaner air within your jurisdiction.
  • Recommend reduction of strenuous outdoor activities for all populations.
  • Consider canceling outdoor public events and activities.

Very Unhealthy for All
(AQI 201 – 300)


  • Recommend activation and opening of cleaner air sites for general population or directing people to locations where they can access cleaner air during a wildfire smoke event.2
  • Recommend expanding hours of operation for cleaner air sites for people experiencing homelessness to accommodate overnight-use.
  • Recommend event organizers cancel of outdoor public events and activities.
  • If school is in session, recommend school closure if indoor air PM 2.5 levels cannot be kept lower than 125.5 μg/m3 (AQI value of 201).

Public Health response

Public Health takes action based on the forecasted AQI levels and air quality alerts that are issued, including:

  • Public Information, Messaging, and Community Outreach: Public Health produces health messaging on how to stay safe during periods of poor air quality. Outreach strategies prioritize reaching populations who are at highest risk from wildfire smoke-related illnesses due to exposure levels, age, or other risk factors. Information may go out through social media, partner channels, the Public Health Insider blog, and the media. Through the work of Public Health’s Healthcare for the Homeless Network, and in partnership with King County Regional Homelessness Authority, outreach is conducted to connect individuals experiencing homelessness with information and available resources.
  • Data and Surveillance: Public Health collects data on wildfire smoke-related impacts to the community, including: visits to emergency departments; emergency calls and impacts to the Emergency Medical System (EMS); and deaths. This data is often preliminary during the wildfire smoke event and is compiled in the following days as more individuals feel the health effects from prolonged exposure to unhealthy air quality. Once the data is compiled, it is used to inform future response efforts.
  • Health and Safety Guidance: During wildfire smoke events, Public Health shares Public Health Recommended Wildfire Smoke Measures with response partners to better align efforts at messaging, opening cleaner air sites, and reducing outdoor activities. Public Health may also share additional existing guidance to support key partners in their decision-making, such as employers with outdoor workers and King County school systems.

Keeping plans relevant

The Wildfire Smoke Response Plan is reviewed prior to each fire season to ensure Public Health’s guidance remains accurate and response activities continue to protect community health and limit health disparities, as King County and the broader region experience increasing numbers of extreme weather events. The revision process includes engagement and feedback from across Public Health programs, response partners, and impacted communities.

Additional wildfire smoke resources

Forecast resources

Cleaner air site resources

Public information and messaging