Industrial Hygienist Assitance During Wildfire Season

AQI Versus AQHI

Air pollution is a serious public health issue that affects millions of people around the world. In Canada, the Air Quality Health Index (AQHI) is a tool that is helping to raise awareness about the risks associated with air pollution and to provide the public with accurate and timely information about air quality.

​Compared to other air quality indices, such as the Air Quality Index (AQI) used in the United States, the AQHI takes into account the effects of multiple pollutants on human health. While the AQI focuses on individual pollutants and their associated health risks, the AQHI provides a single measure of air quality that reflects the overall impact of the air pollution mix.
 
The AQHI is calculated using data from air quality monitoring stations across Canada, and it is updated hourly to provide the most up-to-date information about air quality. The AQHI is also designed to be easy to understand, with a scale ranging from 1 to 10+ and associated health messages that provide advice on how to reduce exposure to air pollution.
 
Compared to the AQI, which uses a scale ranging from 0 to 500, the AQHI is more sensitive to moderate levels of multiple pollutants, which is one of the objectives of this new formulation. The AQHI is also more accurate in reflecting the overall impacts of the air pollution mix and the occurrence of effects at low levels of exposure.

AQHI

​Overall, the AQHI is an important tool for protecting public health and promoting awareness of the risks associated with air pollution. By providing accurate and timely information about air quality, the AQHI empowers individuals to make informed decisions about their exposure to air pollution and take steps to protect themselves and their families.
 
One of the key strengths of the AQHI is its ability to communicate air quality information in a way that is easy to understand and act upon. The AQHI scale ranges from 1 to 10+ and is accompanied by health messages that provide advice on how to reduce exposure to air pollution. This makes it easier for individuals to understand the risks associated with air pollution and take appropriate action to protect their health.  

What is PM2.5

Relative Particle Size - source EPA

PM stands for particulate matter (also called particle pollution): the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope.
Particle pollution includes:

• PM10 : inhalable particles, with diameters that are generally 10 micrometers and smaller; and
• PM2.5 : fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller.
  • How small is 2.5 micrometers? Think about a single hair from your head. The average human hair is about 70 micrometers in diameter – making it 30 times larger than the largest fine particle.

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AQI

AQI uses a scale ranging from 0 to 500,  and is easier to use by Industrial Hygienist since it can be calculated with one parameter such as PM2.5. If you're interested in learning more about air quality and the AQI, the website airnow.gov is a great resource. The website provides information about the AQI and how it is calculated, as well as real-time air quality data for cities across the United States.
 

How to Access Air Quality using AQI and AQHI

Direct reading instruments such as particulate monitors can be used by industrial hygienists to determine the AQHI and AQI at a job site. These instruments measure the concentration of specific pollutants in the air in real-time, allowing for immediate assessment of air quality.
 
To determine the AQHI, the industrial hygienist would need to measure the concentrations of nitrogen dioxide (NO2), ozone (O3), and particulate matter (PM2.5) using direct reading instruments. The readings would then be used to calculate the AQHI using the formula provided by the Canadian government.  The formula for the AQHI based on PM2.5 is:

AQHI Calculation for PM2.5

The formula below is the AQHI is available on line https://www.airnow.gov/aqi/aqi-calculator-concentration/ and interprets the results and provides recommendations without having to look them up manually.

Screenshot AQI Calculator

What's the Air Quality In My Neighborhood

Click the link below to see the AQI levels in Western Canada.  The map is interactive and can be used to look up the AQI around the world.

Current Air Quality - Western Canada

Interpreting PM2.5 Readings

AQHI Tables

AQHI Risk Rankings - Source Environment Canada

AQI Tables

AQI Risk Rankings - Source Airnow.gov

How to Protect Workers

​In Canada the Occupational Health and Safety Regulations do not specifically address how to protect worker with respect to wildfire smoke.  However other parts of the regulations do apply such as:

• Controlling Worker Exposure – hazard assessments and implementing controls
• Personal Protective Equipment
• Emergency Preparedness and Response

 
WHS Occupational Hygienist can assist employers in conducting a risk assessment and implementing an exposure control plan to minimize worker exposure to wildfire smoke.  Also check out the services WHS can provide following a wildfire in your area or fire in your home or business.

Check Out WHS Disaster Response Services

Contact WHS Occupational Hygienist