Major Quebec smog episodes

Smog can occur at any time of year and its causes, intensity and duration may vary. Here are a few major episodes that occurred in Quebec over the last 15 years.

July 4 to 9, 2010

A hot and humid air mass from the Great Lakes moved over southern Quebec and persisted throughout the week. The heat wave was accompanied by particulate smog affecting many parts of Quebec.

May 27 to June 1, 2010

Smoke from forest fires north of the La Tuque area was responsible for poor air quality in many parts of Quebec.

August 15 to 18, 2009

A four-day smog episode was primarily due to high concentrations of fine particulate matter in southwestern Quebec.

Winter 2008-2009

A record 47 days with smog warnings for the Montreal area.

September 6 to 8, 2007

A late smog episode occurred while a warning of high heat and humidity was in effect due to the presence of a mass of hot and humid air covering all of southwestern Quebec.

June 8 to 13, 2005

Southwestern Quebec experienced six consecutive days with a high concentration of fine particulate matter caused by smoke from numerous wildfires raging further north. Some 60 fires destroyed 153,000 hectares of forest.

January 31 to February 8, 2005

A stagnant air mass, seldom seen at this time of year, moved over Quebec. A temperature inversion trapped fine particulate matter at ground level and several southern areas were affected by smog, including Montreal, which experienced a nine-day episode, the longest ever recorded in Quebec.

October 9 to 12, 2003

Aided by airflow from the southwest, a high concentration of fine particulate matter was recorded over southern Quebec, as the temperature reached 20°C over the Thanksgiving weekend.

February 26 to March 2, 2003

Montreal and the surrounding area experienced five consecutive days with a high concentration of fine particulate matter.

August 11 to 14, 2002

Several parts of Quebec, from Montreal to the Beauce and the Mauricie, experienced a four-day heat wave with high concentrations of ozone and fine particulate matter.

July 2 to 9, 2002

Smoke caused by forest fires in the James Bay area was responsible for the high concentration of fine particulate matter observed in areas further south. The smoke plume extended to southern New York and affected all parts of southern Quebec.

June 12 and 13, 1999

A smog episode was caused by a high concentration of ozone in the Montreal area. Ironically, smog warnings were issued while the Canada Formula One Grand Prix was being held.

Summer 1998

Many smog episodes affected Greater Montreal during the summer as a result of high ozone concentrations.

February 10 and 11, 1998

Due to numerous power outages caused by the January ice storm, many people heated their homes with wood stoves, which increased concentrations of fine particulate matter to the point where they formed smog in Montreal and the surrounding areas.

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