Worst air pollution St. Johnsbury, today and tomorrow
Today (9 August): Air quality in St. Johnsbury is fair. NO2 is fair; AQI and O3 are medium; PM2.5, PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 9:00 AM (O3: 40.9/100).
Tomorrow (10 August 2026): Air quality in St. Johnsbury is fair. AQI worsens to fair; O3 increases to fair; all other pollutants stay as today. Pollution peaks around 11:00 AM (O3: 34.0/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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The dominant factor behind St. Johnsbury's air quality is cold, clean northern air masses; this is some of the cleanest air in New England. That mix of factors is fairly representative of towns in this part of the country. Longer-term residents of St. Johnsbury tend to plan outdoor activity around these predictable shifts.
Today - 9 August | Pollution peaks at 09:00
AQI:
Medium
40.9/100
PM2.5 (fine particles):
Good
15.5/100
PM10 (coarse particles):
Good
10.7/100
NO2 (nitrogen dioxide):
Fair
32.4/100
O3 (ozone):
Medium
40.9/100
SO2 (sulfur dioxide):
Good
2.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
10.2/100
PM1 (ultrafine particles):
Good
10.8/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 11:00
AQI:
Fair
34.0/100
PM2.5 (fine particles):
Good
11.2/100
PM10 (coarse particles):
Good
7.5/100
NO2 (nitrogen dioxide):
Fair
25.2/100
O3 (ozone):
Fair
34.0/100
SO2 (sulfur dioxide):
Good
2.0/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
7.3/100
PM1 (ultrafine particles):
Good
7.8/100
Pollen forecast in St. Johnsbury
View pollen forecastFrequently Asked Questions
Is air quality bad in St. Johnsbury right now?
On 9 August 2026, overall air quality in St. Johnsbury is fair. NO2 is the main pollutant at 32.4/100. Pollution peaks around 9:00 AM (O3: 40.9/100).
Will air quality be worse tomorrow in St. Johnsbury?
On 10 August 2026, air quality conditions in St. Johnsbury will be similar to today, with AQI forecast at fair at 34.0/100. Pollution peaks around 11:00 AM (O3: 34.0/100).
When is air pollution at its worst in St. Johnsbury?
Air quality across St. Johnsbury rises and falls with the seasons. In short, a brief window in early autumn tends to be the cleanest stretch, once summer haze clears out, whereas hot, humid summer days bring the highest ozone risk, often worsened by pollution transported in from other regions. Coastal sea breezes can offer some relief from inland summer ozone buildup.
Are air quality levels in St. Johnsbury based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
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Data provided by Airmine — Last update: 9 August 2026 at 20:27 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
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