Learn how to incorporate use of the air quality index into your safety efforts.

Smoke from recent wildfires in Canada has created hazardous conditions in many parts of the U.S., highlighting the far-reaching impact of such events and the role that air quality should play in worker safety. Some states, such as California, Oregon and Washington have existing or proposed worker safety regulations specifically related to wildfire smoke due to their familiarity with the hazards of wildfires and their related impact on air quality. However, for many businesses this is a new experience and one that has brought about questions regarding how to understand the safety implications for their employees.

Wildfire smoke is a mix of gases and fine particles from burning vegetation, building materials, and other combustibles. It can make anyone sick. Even someone who is healthy can get sick if there is enough smoke in the air; however, it poses a serious risk for persons with chronic heart or lung diseases. Breathing in wildfire smoke can have immediate health effects, such as: asthma-like symptoms, respiratory tract irritation, discomfort in your eyes, severe headaches, increased heart rate and related fatigue. The impact of these effects can directly impact a worker or increase the risk of related accidents, such as a worker’s uncontrollable cough reaction leading to losing their grip while on a ladder.

For wildfire smoke, the greatest hazard comes from breathing fine particles in the air. The smallest and usually the most harmful particulate matter is called PM2.5 (solid particles and liquid droplets suspended in air with an aerodynamic diameter of 2.5 micrometers or smaller). PM2.5 is one of the five major air pollutants included in the EPA’s Air Quality Index (AQI). The others are ground-level ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, EPA has established national air quality standards to protect public health. Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country.

Understanding AQI

When officials issue air quality warnings, they are based on the AQI. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. Understanding the AQI can help in making safety decisions for your workers, yourself, and your family.

Think of the AQI as a yardstick that runs from 0 to 500. For each pollutant measured in the AQI, a value of 100 generally corresponds to an ambient air concentration that equals the level of the short-term national ambient air quality standard for protection of public health. AQI values at or below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is unhealthy: at first for certain sensitive groups of people, then for everyone as AQI values get higher.

The AQI is divided into six categories. Each category corresponds to a different level of health concern. Each category also has a specific color. The color makes it easy for people to quickly determine whether air quality is reaching unhealthy levels in their communities.

Daily AQI Color

Levels of Concern

Values of Index

Description of Air Quality



0 to 50

Air quality is satisfactory, and air pollution poses little or no risk.



51 to 100

Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.


Unhealthy for Sensitive Groups

101 to 150

Members of sensitive groups may experience health effects. The general public is less likely to be affected.



151 to 200

Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.


Very Unhealthy

201 to 300

Health alert: The risk of health effects is increased for everyone.



301 +

Health warning of emergency conditions: everyone is more likely to be affected.

Source: https://www.airnow.gov/aqi/aqi-basics/


5 Tips for Using AQI and Keeping Workers Safe

So how can you use AQI and your local public health agencies to help keep your employees safe? Consider these five tips:

  1. Incorporate AQI into your workplace safety plan. Because of its impact on worker safety, outdoor air quality should be a part of your workplace safety plan. Outdoor workers have a greater exposure to air quality and environmental hazards and must be protected against the impact of unsafe exposures, but air quality may also impact indoor workers. Generally, an AQI below 150 should not create an exposure for a normally healthy worker; however, as the workforce changes to include a greater number of older workers and more workers have comorbid conditions, it is important to know your workforce and plan accordingly.
  2. Monitor AQI and pay attention to public health messages. The EPA has a site for monitoring your local AQI that is entitled AirNow.gov. Local governments will also issue AQI alerts, and warnings are often included as part of the local weather broadcasts.
  3. Develop action plans for changes in AQI. Just as with outdoor heat, AQI is predictable and action plans can be put in place beforehand to ensure worker safety. When AQI levels will exceed 150, a safety plan should be activated. This may include engineering and administrative controls such as temporary use of shelters or vehicles with air filtering systems, reduced work times, reduced work intensity, increased rest frequency, or use of respiratory protection in accordance with state or federal OSHA regulations. Stop work conditions should also be clearly communicated.
  4. Establish a system to maintain communication. While AQI is predictable, it can change, especially in local wildfire situations where wind direction is a key factor. A means of communication should be in place between office and remote worksites to allow for monitoring and reporting changes in conditions, and for communicating changes in the safety plan.
  5. Heed “stay indoor” warnings and keep your indoor air as clean as possible. If your business is in an area heavily impacted by wildfire smoke or similar particulate matter contaminant that leads local officials to issue “stay indoor” warnings, be sure to limit outdoor exposures and to keep your indoor air as clean as possible. Consult with your HVAC technician or contractor to determine if air intake or filter change adjustments should be made. If you have work-from-home employees, the CDC has recommendations they should follow.

While wildfire smoke is not a new exposure, the continued impact of climate change, growth of wildland-urban interface, and extreme weather patterns only serve to reinforce that some workplace injury and illness exposures are not limited to the four walls or local area of operations. Understanding and planning for how these patterns can impact the safety of your workplace and workers can help you minimize risk and maximize operations and profit.

Additional Resources:

Available at MyLossControlServices.com:

Personal Protective Equipment
The workforce is chAnGING
Manage heat-related risks to minimize work-related injuries

Other sites:

OSHA Wildfires page
NIOSH/CDC Wildfires page
AirNow – Local AQI information, interactive maps, and historical data

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