Air Quality Index
An Air Quality Index (AQI) is a way of transforming complex air quality measurements into a single number and descriptive term. The British Columbia AQI is directly comparable to AQI’s issued in all major Canadian cities as we follow the same Federal guidelines.
The AQI numbers are interpreted thus: 0 to 25 is GOOD, 26 to 50 is FAIR, 51 to 100 is POOR, and 100+ is VERY POOR. An AQI in excess of 50 represents the point at which BC Environment normally becomes concerned about the level of human health impact.
|
Air Quality |
General Health Effects |
Cautionary Statements |
|
0-25 |
No measured effects are associated
with air quality in this range. |
No precautions are necessary for the general population. |
|
26-50 |
When Index values are in this
range, there is adequate protection
against effects on the general
population. |
No precautions are necessary for the general population. |
|
51-100 |
Short-term exposure may result in
irritation or mild aggravation of
symptoms in sensitive persons. |
Persons with existing heart or
respiratory ailments should reduce
physical exertion and outdoor activity. |
|
101- |
Significant aggravation of persons
with heart and lung disease.
Many people in the general
population may notice symptoms. |
Persons with respiratory and
cardiovascular diseases should stay
indoors and minimize physical activity. |
Common air pollutants, such as fine particulates (PM10 & PM2.5), ozone, nitrogen oxides, sulphur dioxide, and carbon monoxide are measured continuously at a state-of-the-art monitoring station at Okanagan College on KLO Road in Kelowna. A central computer in Victoria gathers this information and an hourly AQI value is calculated.
The AQI is not an amalgamation of all measured pollutants, but rather the value of the pollutant with the highest AQI number. Every hour, Environment Canada and the Provincial Environment Ministries convert each pollutant concentration into an AQI number according to a methodology developed. The highest AQI number becomes that hours overall AQI value. When issuing the AQI it is common practice to note which pollutant is “driving” the AQI.
Why is it Important?
The main purpose of the Air Quality Index is to inform the public about the present state of air quality. Having a daily Air Quality Index available via the media builds awareness in the public. For asthmatics and other concerned residents it may even influence their behavior. For example, in a situation where the AQI is high (above 50) those with respiratory problems may choose to refrain from strenuous exercise or temporarily avoid the polluted region
Todays Air Quality Index
See Today's Index at this site