The air quality health index (AQHI) is a scale that has been created to provide citizens of Canada with a complete picture of how their health would be affected by the quality of air in any region. The index is updated regularly and takes into consideration the levels of ozone, particulate matter and nitrogen dioxide in the air. These are the substances primarily responsible for the ill-effects of the constituents of air on human health. The AQHI can take values from 1 - 10+. People can enjoy outdoor activities freely when the level is below 4, a level between 4 - 6 poses a moderate health risk, when the level goes between 7 - 10 the health risks are high and for levels more than 10 citizens should avoid outdoor activities as far as possible and if possible use means to protect them from the harmful constituents of the air. The AQHI does not take into consideration many unwanted gases present in the atmosphere as their effect is insignificant compared to those included in the index.
The air quality index AQI on the other hand takes into consideration only one air pollutant and how its level affects the environment as well as human health. Compared to the AQHI, the AQI is more difficult to use as a measure of how exposure to air affects human health.
While air quality has been reported for many years, this new Air Quality Health Index (AQHI) has been created with a different goal - to report on the health risk posed by a specific level of air quality. The Air Quality Index (AQI) reports current air quality based on a specific level of an individual air pollutant. Two-day air quality forecasts are also provided. The new Air Quality Health Index (AQHI) reports on the health risk posed by a mixture of pollutants including ground-level ozone, particulate matter and nitrogen dioxide . The Air Quality Index (AQI) communicates the air quality of the single worst pollutant. The index rating for the new Air Quality Health Index (AQHI) is the sum of the health risks from each of the pollutants in the index.