Overview: This year began with nearly five months of Kingston average PM2.5 airborne particulate levels having been unusually healthy. Then the intense western wildfires from June through August turned it into the second-worst of the past six years. The end of most of those fires and the more northeasterly airflows brought by Atlantic hurricanes made October a relatively healthy month. To date in 2025, Kingstonians who did not take measures such as those recommended in our Self-Protection page were exposed to an average of 6.6 µg/m3 fine particulate concentrations from the air we breath. That dangerously exceeds both the 5.0 µg/m3 WHO-recommended limit and the 5.8 µg/m3 threshold beyond which, as you can see on our Health Impacts page, excess mortality begins to soar. It will come as an unwelcome surprise to most Kingstonians that PM2.5 levels have exceeded the WHO limit in 51 of the past 70 months! Do you know others who might benefit from more awareness of the reality of our air quality and how they can better protect their health? If so, please share this link: https://kingstonairquality.ca.
by Ron Hartling
The purpose of this site is to raise awareness of the uncomfortable reality that, with respect to fine particulate matter (PM2.5), Kingston air quality is consistently worse than the World Health Organization (WHO) standard. The site gives practical advice on managing household exposure to health-damaging particulates. Updates are posted daily around 7 am but the satellite view below shows the current Kingston reading at any time of day. If you live elsewhere, just click at your location on the map. For ease of personal decision-making, overall daily risk levels are categorized by severity in the table to the right.
Note that, while most Canadian and US sources define Risk Level 1 as airborne fine-particulate-matter (PM2.5) concentrations less than 12 micrograms per cubic meter (µg/m3), I employ “Level 0” to differentiate readings within the far more evidence-based, less politically-influenced WHO healthy zone. Click on the Health impacts page for clarification on the differences between short- and long-term exposure risks.
Commentary as of Sunday November 16 at 6:45 am
Yesterday’s readings: Kingston’s PM2.5 readings yesterday were significantly healthier than expected, varying between 3 and 4 µg/m3 over the past 24 hours for a daily average of 3.4 µg/m3. That was identical to Friday’s average. The 6:30 am satellite view indicates a further drop to a rare, perfect 0 µg/m3.
Forecast for today: Kingston PM2.5 readings are likely to remain within the healthy Level-0 range for the next several days.
Detailed forecast: Environment Canada’s 24-hour forecast for Kingston calls for the strong northeasterly airflow to continue for most of that period, but for a brief full westerly interval overnight. That is consistent with the nearby Jetstream, which is also strongly northwesterly. The timing of yesterday’s change in wind directions was fortuitous as it spared Eastern Ontario from a looming polluted US airmass.
Personal protective measures: No such measures should be needed over the next several days.
This 6 am satellite view of PM2.5 fine particulate flows over North America shows a much-improved picture from an air quality perspective over most of the eastern half of the continent. A strong northwesterly airflow has essentially pushed nearly all of the polluted air which dominated the view yesterday morning out over the Atlantic.
Summary of recent readings
This table summarizes and provides context for the most recent three weeks of Kingston PM2.5 airborne fine particulate readings. The key numbers are, of course, the daily averages because that’s what informs us how our recent exposures have contributed to or ameliorated whatever annual exposure to toxic particulates we are comfortable with or accepting of. For those who choose to lower their at-home exposure in order to better protect their and their households’ long-term health, the numbers provide important information on how much effort may be required to stay within their comfort levels.
To facilitate that analysis, the table also computes each day’s risk category (usually a mix of 0’s, 1’s and 2’s), as well as 7- and 28-day running averages and medians. It also reports on the minimum and maximum readings for each day, as well as on the number of hours that day during which Kingston PM2.5 readings may have exceeded either or both the World Health Organization’s recommended maximum and the seriously outdated and therefore misleading US/Canadian equivalent.