Date: December 4, 2016

Cloudy. 60 percent chance of rain showers or flurries early this evening. Snow mixed with rain beginning early this evening then changing to 60 percent chance of flurries after midnight. Local snowfall amount 2 to 4 cm. Wind southeast 20 km/h becoming southwest 20 near midnight. Low plus 1.


Environment Canada
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Outdoor Air Quality

This page was reviewed or revised on Monday, December 21, 2015 1:51 PM

Poor air quality is largely a product of burning fossil fuels. We use them to power our vehicles, to produce energy and to manufacture consumer products. The increasing consumption of carbon based fuels has a direct impact on air quality – it harms the earth’s ecosystems and negatively affects our health.

This section defines smog – its sources and health effects. It also describes how you can minimize your risk to harmful air pollutants and provides tips about what you can do to reduce your own emissions."

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.

The Air Quality Health Index is measured on a scale ranging from 1 to 10+:

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

Special Air Quality Statements and
Smog and Air Health Advisories

The purpose of these alerts is to inform people with breathing difficulties to avoid unnecessary exposure to smog, to inform major pollution sources that they should consider, if possible, reducing their emissions, and to solicit everyone's help in lessening the problem by curtailing activities that produce smog.

If a high risk Air Quality Health Index value is forecast to last for 1 to 2 hours, then a Special Air Quality Statement (SAQS) will be issued. The purpose of a Special Air Quality Statement is to be precautionary and to be vigilant of your health as it relates to the Air Quality Health Index.

If the high risk Air Quality Health Index is forecast to be persistent, a duration of at least 3 hours, then a Smog and Air Health Advisory (SAHA) will be issued.

Both Special Air Quality Statements and Smog and Air Health Advisories are issued jointly by Environment Canada and the Ontario Ministry of the Environment and Climate Change.

To sign up to receive an email when an air quality alert (Special Air Quality Statement or Smog and Air Health Advisory) is issued, please visit:

Source: Ministry of the Environment and Climate Change

Related Links:

How You Can Improve Outdoor Air Quality

Smog and Your Health

Winter Air Quality