How was the AQI Developed?

The Index was originally developed in 1978 by a federal-provincial committee, and was named Index of the Quality of the Air (IQUA). In 1995 the dust and smoke component of the index was modified to better represent the effects of small particles on air quality. With the development of more sophisticated and sensitive instrumentation, and to better represent the effects of small particles on air quality, Alberta Environment replaced the dust and smoke component of the index in 2003 with fine particulate matter (PM2.5) and the index was renamed the Air Quality Index (AQI).

It is expected that the introduction of fine particulate matter into the AQI will lead to increases in hours of Fair, Poor and Very Poor air quality. Recalculation of the AQI using PM2.5 data from the year 2002 from selected monitoring stations showed that the time periods associated with very poor air quality were during forest fire events and are therefore an accurate and credible description of the air quality at that time.

Good, Fair, Poor and Very Poor air quality categories are related directly to Objectives under Alberta's Environmental Protection and Enhancement Act (EPEA). These Objectives reflect the maximum desirable, acceptable and tolerable levels specified by the National Air Quality Objectives.

An AQI rating of 25 for a specific air pollutant corresponds to the federal maximum desirable level; a rating of 50 corresponds to the federal maximum acceptable level; and a rating of 100 corresponds to the federal maximum tolerable level.

	How was the AQI Developed? The Index was originally developed in 1978 by a federal-provincial committee, and was named Index of the Quality of the Air (IQUA). In 1995 the dust and smoke component of the index was modified to better represent the effects of small particles on air quality. With the development of more sophisticated and sensitive instrumentation, and to better represent the effects of small particles on air quality, Alberta Environment replaced the dust and smoke component of the index in 2003 with fine particulate matter (PM2.5) and the index was renamed the Air Quality Index (AQI). It is expected that the introduction of fine particulate matter into the AQI will lead to increases in hours of *Fair, Poor* and *Very Poor* air quality. Recalculation of the AQI using PM2.5 data from the year 2002 from selected monitoring stations showed that the time periods associated with very poor air quality were during forest fire events and are therefore an accurate and credible description of the air quality at that time. *Good, Fair, Poor* and *Very Poor* air quality categories are related directly to Objectives under Alberta's Environmental Protection and Enhancement Act (EPEA). These Objectives reflect the maximum desirable, acceptable and tolerable levels specified by the National Air Quality Objectives. An AQI rating of 25 for a specific air pollutant corresponds to the federal maximum desirable level; a rating of 50 corresponds to the federal maximum acceptable level; and a rating of 100 corresponds to the federal maximum tolerable level.