2023 Annual Air Quality Summary

by Ron Hartling

Kingstonians’ exposure to damaging PM2.5 airborne particulates in 2023 has been by far the worst in more than a decade.  Fine airborne particulate matter is like lead in that there is no safe exposure level, but countless studies show that the health risks soar dramatically when the average PM2.5 content in the air we breathe exceeds 5.8 micrograms per cubic meter (µg/m3). As explained in this site’s Health Impacts page, the World Health Organization’s strongly evidence-based 2015 recommendation holds that average exposure should be kept down to 5 µg/m3, with no more than 3 or 4 days averaging more than 15 µg/m3.  Kingston’s 2023 average was 8.7 µg/m3, which was 173% of the WHO maximum, and we experienced 32 days during which the average exceeded 15 µg/m3.

Kingston’s very worst hourly PM2.5 reading, likely ever, was a highly toxic (Risk Level 6) 463 µg at 6 am on June 7, 2023, with a record-breaking daily average of 211 µg/m3. During the course of 2023, we also experienced 11 separate days with Level-3 PM2.5 daily averages, our first since 2021.


Excluding Kingston’s 2023 wildfire season, our average reading for January through March and October through December was 6.0 µg/m3.  Analysis shows the primary cause to have been US heavy-industry emissions which, as discussed in more detail on our Evidence page, enter our airspace whenever winds are blowing from southerly directions.

Canada’s 2023’s summer of disastrous wildfires and consequent clouds of toxic air from coast to coast was the eminently predictable result of accelerating global heating and the failure of our federal and provincial governments to maintain the fire-fighting capacity to snuff out new wildfires very soon after their appearance, before they have to opportunity to grow out of control.  The extra energy imparted by ever-rising temperatures into continent-scale weather systems enables those systems to stall in place, forcing the jet stream to divert around them rather than pushing such systems out over the Atlantic as before. As has happened in June of that year, near-stationary weather systems with limited or no precipitation have lots of time to dry out forest floors, turning them into tinder boxes for voracious wildfires.  Such conditions have long been predicted in the climate models, and they have now manifested. Meanwhile, science-deaf provincial governments have downsized back-country firefighting to the point that we have far too little capacity to attack more than a small number of simultaneous wildfires, which spread rapidly and pump ever more smoke into the near-stationary but circulating air masses, hitting areas like Kingston which had long remained mostly unscathed during the usual April through September wildfire season.  Canada’s federal government can and should to much more to better manage the resulting wildfires, as outlined in our solution page.

It would be easy to dismiss 2023’s high readings as having been due to that unprecedented wildfire season. What’s important to realize, however, is that Kingston PM2.5 readings have been exceeding the WHO maximum even during the months when wildfires are not an issue.  Four of those 32 days in which our daily average readings exceeded 15 µg/m3 occurred outside of wildfire season, and many within that season were days in which wildfires smoke was not a factor in Kingston’s air quality.