Wildfire smoke: How to use AQI for worker safety

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.