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Ontario, Canada, L6M 3L1
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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:
The Index provides specific advice for people who are especially vulnerable to the effects of air pollution as well as the general public.
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The AQHI is measured on a scale ranging from 1-10+. The AQHI index values are also grouped into health risk categories as shown below. These categories help you to easily and quickly identify your level of risk.
More information on the scale and the AQHI categories .
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The formula developed to calculate the Air Quality Health Index is based on research conducted by Health Canada using health and air quality data collected in major cities across Canada.
The Air Quality Health Index represents the relative risk of a mixture of common air pollutants which are known to harm human health. Three pollutants were chosen as indicators of the overall outdoor air mixture:
In Ontario, the AQHI number also considers hourly comparisons of individual pollutant concentrations to Ontario’s Ambient Air Quality Criteria (AAQC).
If hourly air pollutant concentrations are higher than Ontario’s AAQC, and the AQHI value is in the low or moderate risk categories, then the Air Quality Health Index value is replaced with the appropriate High or Very High risk value. This adjustment is relevant for:
If the following pollutant thresholds are exceeded when the Air Quality Health Index is Low or Moderate risk (6 or less), then the AQHI is replaced with the appropriate High or Very High risk value (7 or greater):
The Air Quality Health Index is a new approach to communicating about air quality that offers more protective health information. The Air Quality Health Index presents the immediate health risk of the combined effects of the air pollution (smog) mixture.
The Air Quality Health Index is a personal health protection tool for individual Ontarians, especially those most at risk: children, seniors, and people with diabetes, heart and lung disease. The old Air Quality Index had a scale of 0-100+, with values usually in the range of 10-60, and poor air quality designated as values above 50. The Air Quality Health Index is a simplified scale from 1-10+ with three categories “low, moderate and high risk” within this range.
On June 24, 2015, in partnership with Environment Canada, the Ontario Ministry of the Environment and Climate Change adopted the national Air Quality Health Index to report air quality in Ontario.
The Air Quality Health Index provides a number from 1 to 10+ to indicate the level of health risk associated with local air quality. Occasionally, when the amount of air pollution is abnormally-high, the number may exceed 10.
The higher the number, the greater the health risk and our need to take precautions.
The index describes the level of health risk associated with this number as ‘low’, ‘moderate’, ‘high’ or ‘very high’, and suggests steps we can take to reduce our exposure.
It also forecasts local air quality and provides associated health advice.
The index does not measure the effects of odour, pollen, dust, heat or humidity on your health.
You can refer to Today’s Air Quality to check the quality of outdoor air in Halton before heading off to work or play. And you can use the forecasts to plan your activities, whether over the next hour or the next day.
Seniors, children and people suffering from diabetes, heart or lung disease, can use the index to assess the immediate risk air pollution poses to your health and take steps to lessen that risk.
Even if you’re relatively healthy, fit and active, you can consult the index to decide when and how much to exercise or work outdoors.
The purpose of these alerts is to inform people with breathing difficulties
to avoid unnecessary exposure to
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
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
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.
For problems or questions regarding this site, please email Halton
or dial 311 or 905-825-6000
Toll free 1-866-4HALTON (1-866-442-5866) | TTY: 905-827-9833
Halton Region is composed of
the City of Burlington,
the Town of Halton Hills,
the Town of Milton,
and the Town of Oakville .