Air Quality Services

Current Conditions

Sample Current Conditions

Current Air Quality is monitored by the Province of Québec and the City of Montréal, and reported using an Air Quality Index. the Ministère du Développement durable, de l'Environnement et des parcs reports current air quality for certain areas in southern Québec. The City of Montréal reports current air quality conditions on the island of Montréal (in french only). The current air quality is available year round.

Air Quality Forecasts

Sample Air Quality Forecast

Air quality forecasts are produced by Environment Canada, in partnership with the Ministère du Développement durable, de l'Environnement et des parcs, Québec department of Health and Social Services, and the Environment Department of the City of Montréal. The summer Air Quality Forecast is available from May 01 to October 31. The winter Air Quality Forecast is available December 01 to April 15.

Smog Warning

Smog Warnings are jointly issued by Environment Canada, the Ministère du Développement durable, de l'Environnement et des parcs, Québec Department of Health and Social Services, and the Environment Department of the City of Montréal. The summer warnings are available from May 01 to September 30, and winter warnings from December 01 to April 15, when in effect.

Ground Level Ozone versus Stratospheric Ozone

Ground level ozone and stratoshpheric ozone are made up of the same gas, ozone. Their effects on our health are very different. To find out more, click here.

Ground Level Ozone and Particulate Matter – current conditions

From May to September, most Canadian residents can see maps showing the most recent readings of ground level ozone and particulate matter for their area on the AIRNow internet site. AIRNow is a cooperative venture between the Canadian and American federal governments and participating provincial and state governments.

Air Quality Forecast Model (CHRONOS)

The air quality in a given geographical area is strongly influenced by the meteorological conditions and emissions of various pollutants or their precursors, in and around the area of interest. Precursor emissions a significant distance away from a given region can still affect air quality in that region. The MSC uses a chemical transport model called CHRONOS (Canadian Regional and Hemispheric Ozone and NO_x System) to make real-time predictions of air quality over Canada for the next few days. The accompanying animations show the model-simulated fields of ground-level ozone, an important indicator of air quality. Maps of Particulate Matter (PM) showing the levels of PM_2.5 and PM₁₀ are also available.

CHRONOS forecasts the ground level ozone concentration at 10, 50 and 500 metres height.

Air Quality and Weather

Weather conditions play a large part in the amount of air pollution we are exposed to at any given time. Atmospheric stability, along with wind speed and direction play a very important role. The following EC forecast products are used by air quality forecasters as guidance in the production of air quality forecasts.

Ventilation

The ventilation is and indication of the ability of the atmosphere to effectively provide “fresh air” over a given point. It is dependant on the mixing layer depth and the wind speed within the layer.

Areas with poor ventilation (under 2,500 square metres per second) are highlighted on the maps.

Wind Mileage

The wind mileage is an approximation of the distance a parcel of air would travel during the day if moved by the wind. The air quality will suffer in areas with low wind mileage values should these areas become polluted.

Areas with wind mileage below 200 kilometres are highlighted on the maps. Direction and speed of wind are plotted using a “wind barb” pointing in the direction the wind is coming from. The wind speed is shown by the barbs. Each barb represents 10 kilometres per hour, the half barbs 5 kilometres per hour and a filled triangle 50 kilometres per hour.

Mixing Layer Depth

The mixing layer is the atmospheric zone near the earth’s surface where pollutants disperse rapidly. The depth of this layer depends on the temperature and on the stability of the atmosphere at low levels. Lower values of mixing layer depth indicate that the pollutants will be mixed in a smaller volume of air.

Areas with a mixing layer depth of less than 400 metres are highlighted on the maps.