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Air Quality Health Index

What is the Air Quality Health Index (AQHI)?

The AQHI is a national health-based index to help individuals protect their health and the health of people in their care. The AQHI uses a simple 10-point scale to indicate the level of health risk associated with local air quality – the higher the reading, the greater the health risk and the greater the need to take precautions. On rare occasions, the Air Quality Health Index may be 10+, which means that there is a very high health risk.

The chart below contains the AQHI scale, the level of health risk and associated health messages.

Health Risk Air Quality
Health
Index
Health Messages
At Risk Population * General Population
Low Risk 1-3 Enjoy your usual outdoor activities. Ideal air quality for outdoor activities.
Moderate Risk 4-6 Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptons. No need to modify your usual outdoor activites unless you experience symptons such as coughing and throat irritation.
High Risk 7-10 Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy. Consider reducing or rescheduling strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation
Very High Risk Above 10 Avoid strenuous activities outdoors. Children and the elderly shoudl also avoid outdoor physical exertion. Reduce or reschedule strenuous activities outdoors, especially if you experience symptons such as coughing and throat irritation.

Why is the AQHI important?

The AQHI is an important tool that helps you plan a healthy day.

Since strenuous activities increase the amount of air you breathe, the AQHI can help you decide when to enjoy the benefits of physical activity and when to reduce or reschedule your activity.

The AQHI helps you understand your response to different pollution levels to help plan and enjoy outdoor physical activities at times when health risks are low.

Who is considered an at-risk population?

At-risk populations include children, the elderly, people with pre-existing heart and breathing problems and people who work outdoors. The AQHI provides different health messages for the at-risk and general population.

How is the AQHI calculated?

The AQHI is calculated based on the risk from three pollutants - ozone, particulate matter 2.5 and nitrogen dioxide - which reflect the cumulative health impacts.

How often should I check the AQHI and how?

Check the AQHI every day at the national AQHI website. Information is updated hourly and a forecast is also provided for the next day.

In the Region of Peel, the AQHI readings for City of Mississauga and Brampton will be taken at the Ministry of Environment's Air Quality monitoring stations. The AQHI reading for Caledon will be taken from the monitoring station in Newmarket.

What is the Air Quality Index (AQI)?

The Ministry of Environment measures the air quality in Ontario using a rating scale called the Air Quality Index (AQI). The AQI scale ranges from 0 to over 100 - the lower the AQI number, the better the air quality.

What is the difference between the AQI and the AQHI?

The AQHI is a simple 10 point-scale which indicates the level of health risk associated with local air quality. The AQHI is based on human health outcomes - the higher the number, the greater the health risk.

The AQI is based on six key air pollutants: sulphur dioxide, ozone, nitrogen dioxide, carbon monoxide, total reduced sulphur and particulate matter (PM2.5).

Each hour, the concentration of the six pollutants is measured at particular stations across Ontario. The pollutant with the highest number at the given hour becomes the AQI. The AQI triggers smog watch and smog advisories.

Which Index is more important - the AQI or the AQHI?

Both Indices are important, but the AQHI is very important because it communicates air pollution levels that are predicted to pose a health risk to individuals.

Where can I find today's AQHI level?

AQHI levels can be found at the national AQHI website. (Please note that for the AQHI rating for Caledon, check under Newmarket).

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