The City of Montreal measures air quality in the form of a numerical value called the “Air Quality Index (AQI).” This data set provides access to daily AQI values, updated every hour, approximately 50 minutes after the hour. For example, the 13:00 data is available around 13:50, for all three resources.
*Note: the AQI systems do not change the time: they always use Eastern Standard Time (EST) and not Eastern Daylight Time (EDT). So in the example above, around 13:50 EDT, the most recent data available will be from 12:00 EST. *
Historical values, updated daily, are available [here] (rsqa-iqa-historical).
The [list of stations] (rsqa-liste-des-stations) and [sectors] (rsqa-geographic-sectors) linked to RSQA data is also available.