The main weather factors affecting air quality indices the next several days include:
- a low pressure trough is centered over New York State and is causing mainly cloudy skies across the forecast regions along with showers or thundershowers and northwesterly winds
-the low is forecast to track to the northeast during Monday and partly to mainly cloudy skies with a northwesterly flow are forecast to continue with scattered showers expected mainly for eastern Ontario
-below seasonal temperatures and less humid conditions are forecast
Tuesday and Wednesday:
-an upper trough is forecast to remain over the region and is forecast to cause continuing partly to mainly cloudy skies with scattered showers or thundershowers
- a mainly northwesterly flow and below seasonal temperatures are expected to persist
Air quality forecast:
A clean northwesterly flow is the main weather factor forecast to cause air quality indices to generally be in the good category for the next several days.
Smog, comprised of Ozone (O3) and/or Fine Particulate Matter (PM2.5), is primarily a summer phenomenon, occurring mostly in southern Ontario; however, PM2.5 can elevate smog levels during all months of the year. For this reason, the ministry reports the AQI hourly, seven days a week; and continues to provide air quality forecasts daily.