Overview: Eastern Ontario air quality has been unusually unhealthy for the first two months of 2026, January having been the second-worst of the past seven years and February by far the worst, with an average of 7.5 µg/m3. PM2.5 levels have now exceeded the 5.0 µg/m3 WHO limit in 54 of the past 74 months, more than enough to significantly impair the healthspans of those Eastern Ontario residents who choose not to take the precautions suggested in our Self-protection page. The health risks explained in our Health risks page are an inevitable consequence of living close to the United States, which is the source of virtually all of the toxic fine particulates in the air we breath. 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 critical differences between short- and long-term exposure risks.
Commentary as of Friday March 13 at 6:55 am
Yesterday’s readings: Kingston’s PM2.5 readings yesterday were quite healthy, mostly between 1 and 3 µg/m3 for a daily average of 2.7 µg/m3, our lowest of the past 11 days. Overnight readings climbed slightly to 3 µg/m3.
Forecast for today: Kingston PM2.5 readings are likely to remain within the healthy Level-0 range today and hopefully into tomorrow.
Detailed forecast: Environment Canada’s 24-hour Kingston forecast calls for our current southwesterly winds to shift to southeasterly by mid-morning and to continue from that direction until mid-evening when they will again turn southwesterly before becoming northwesterly overnight. The high-altitude Jetstream will be mostly westerly, but somewhat to our south. As you can see from the satellite view, Eastern Ontario remains in a sweet spot of relatively clean air.
Personal protective measures: No such measures should be required today or tomorrow.
Unsurprisingly, this satellite view of PM2.5 fine particulate flows over North America showed some moderate deterioration of yesterday’s unusually good air quality over most of the populated parts of the continent. Eastern Ontario is well-situated in that respect, with a strong low-pressure system centred on the western tip of Lake Superior pulling the usual incoming US pollutants away from our area.
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.