2019 Annual Regional Air Quality Index Statistics

Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs

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2019 Annual Regional Air Quality Index Statistics

The Air Quality Index (AQI) was calculated in 2019 for 24 weather regions, the Island of Montréal being divided into four sub-regions.

The percentage of days in which the AQI was deemed “good” or “acceptable” varied from 89% for Montréal (324/365) to 100% for the Témiscouata, Rivière-du-Loup, Lac-Saint-Jean, Montmagny, Laurentides, Vaudreuil-Huntingdon and Lachute regions.

Montréal was where air quality was most often “poor*,” with a proportion of 11% (41/365 days). This result varied little compared with the 2018 figure of 9%.

In overall terms, the respective AQI “good,” “acceptable” and “poor” proportions were 62%, 37% and 2%. Compared to 2018, the “good” proportion of results increased by 9%, with the gain coming from a decrease in the “acceptable” category.

*Occurs when the concentration of at least one of the contaminants used to calculate the AQI exceeds its hourly reference value at one or more of the region’s measuring stations.