Date: May 21, 2018

Cloudy. A few showers beginning this evening and ending before morning. Risk of a thunderstorm late this evening. Fog patches developing overnight. Low 11.


Environment Canada
Text Size >   A   A   A

Printer Friendly

Air Quality Health Index

This page was reviewed or revised on Friday, November 17, 2017 10:55 AM

What is the Air Quality Health Index?

The Air Quality Health Index is a scale designed to help you understand what the quality of the air around you means to your health. It is a tool developed by health and environmental professionals to communicate the health risk posed by air pollution.

It is designed to help you make decisions to protect your health and the environment by:

  • Limiting short-term exposure to air pollution
  • Adjusting your activity during episodes of increased air pollution and encouraging physical activity on days when the index is lower
  • Reducing your personal contribution to air pollution

The Index provides specific advice for people who are especially vulnerable to the effects of air pollution as well as the general public.

How is the Air Quality Health Index presented?

The Air Quality Health Index is a scale that lists a number from 1 to 10+ to indicate the level of health risk associated with air quality.

Scientists created the index by estimating the daily change in mortality risk for ten cities from 1998-2000 and plotting it on a 10 point scale; the higher the number, the greater the risk and the need to take precautions.

Check out the Ministry of the Environment's website on more information on the Air Quality Health Index and what the AQHI categories, values and colours mean at

Check the Air Quality Health Index for Sarnia-Lambton at or call 1-800-387-7768.


Ministry of the Environment and Climate Change _ Air Quality Health Index
Health Canada - Frequently Asked Questions on Air Quality
Health Canada - Air Quality