Environment Canada issued a special air quality statement Monday morning, saying it was in place “due to the possibility of deteriorating air quality as a result of fireworks for Diwali.”
The statement received some backlash on social media, with some questioning why the South Asian festival was singled out and similar warnings are not issued for Victoria Day or Canada Day.
Others accused the national agency of racism and cherry picking when fireworks may affect air quality.
An Environment Canada Meteorologist tells CityNews the statement has nothing to do with Diwali specifically.
Geoff Coulson, Warning Preparedness Meteorologist at Environment Canada, tells CityNews that forecasters at the agency’s Weather Centre noticed a spike in the Air Quality Health Index (AQHI) at some monitoring stations in the GTA in the late evening on Nov. 4, 2021, the day Diwali was celebrated, and continued into the early morning hours of Nov. 5. They issued the statement because they noticed a similar weather pattern setting up this year.
“This weather pattern is called an inversion and acts to keep the air in the lowest levels of the atmosphere from easily mixing with air from above. In these stagnant air situations, smoke from fireworks can build up near the ground and cause locally higher readings of the AQHI,” he says.
Coulson added that the time of year can play a role in making such inversions occur more frequently.
“In late spring and summer (i.e. Victoria Day, Canada Day), the days are longer and if inversions were to form they would usually do so later into the overnight hours. All this to say, that the type of stagnant weather conditions expected this evening would occur less frequently in the late spring and summer. Whereas, by late October, the days are becoming noticeably shorter, and therefore, inversions can occur earlier in the evening/overnight period,” he says.
Historical readings for the AQHI values around the GTA during Diwali 2021 can be found here.
Coulson says he believes this is the first time such a statement has been issued for fireworks smoke.
Around 2:30 p.m. Monday, the agency edited the air quality statement on its website to read “as air quality is expected to deteriorate this evening due to meteorological conditions common at this time of year,” removing any mention of Diwali or fireworks.