How Info-Smog works

How an air quality forecast is made

Similar to the weather forecast, the Info-Smog program provides air quality forecasts. Using numerical models, Environment and Climate Change Canada meteorologists analyze weather conditions expected for the next few hours to predict the air quality category based on predicted concentrations of ozone and fine particulate matter in the air. The Info-Smog program uses a calculation method based on the one used to calculate the Air Quality Index (AQI), but it uses only the predicted concentrations of ozone and fine particulate matter. The observations of the Air Quality Index are also used in forecasting to check the accuracy of the forecast in real time. There are three categories of air quality forecasts: good, fair and poor. Two air quality forecasts are issued daily at 5 a.m. Eastern Standard Time (EST) (forecast for today, tonight and tomorrow) and at 4 p.m. EST (forecast for tonight and tomorrow). An amendment (forecast change) may be issued at any time if necessary. The forecasts are available to the public and the media through Environment Canada's Official Text Forecasts.

Smog warnings

When the forecast (expected conditions) or actual (measured conditions) air quality is poor, a smog warning for the targeted regions is issued on Environment and Climate Change Canada's Current Conditions and Forecasts page, to the media, our partners as well as a range of platforms including exterior displays. It can also be viewed as a warning bulletin on the Environment and Climate Change Canada site. The smog warnings are accompanied by a message to inform people at risk on measures for reducing the adverse effects of smog. They also seek to educate people about behaviour that can reduce emissions of pollutants that cause smog, depending on the time of year.

Improving our air quality

Everyone can help improve air quality, for example, by not using wood heating. When the use of a car is necessary, it is important to reduce speed and not let the engine idle. These simple actions become more important during a smog warning. Many other measures are posted in the "What you can do to improve air quality" section of the Environment and Climate Change Canada Web site.

More information about smog and its effects on health and the environment is available at Pollution Issues - Smog.