Worst air pollution Longmont, today and tomorrow
Today (16 July): Air quality in Longmont is fair. AQI, NO2, and O3 are fair; PM2.5, PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 6:00 AM (O3: 34.1/100).
Tomorrow (17 July 2026): Air quality in Longmont is fair. All pollutants stay as today. Pollution peaks around 6:00 AM (O3: 38.0/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Longmont's air quality reflects the Front Range position north of Denver, with vehicle emissions from US-287 and the surrounding technology and oil and gas extraction operations in the Denver-Julesburg Basin contributing local sources. The Rocky Mountains provide clean westerly airflows on most days, while the Front Range temperature inversion problem periodically affects the northern Boulder County corridor and summer wildfire smoke from Colorado forests is an increasingly frequent seasonal concern.
Today - 16 July | Pollution peaks at 06:00
AQI:
Fair
34.1/100
PM2.5 (fine particles):
Good
14.7/100
PM10 (coarse particles):
Good
13.4/100
NO2 (nitrogen dioxide):
Fair
32.9/100
O3 (ozone):
Fair
34.1/100
SO2 (sulfur dioxide):
Good
5.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.9/100
PM1 (ultrafine particles):
Good
9.4/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 06:00
AQI:
Fair
38.0/100
PM2.5 (fine particles):
Good
16.0/100
PM10 (coarse particles):
Good
9.2/100
NO2 (nitrogen dioxide):
Fair
21.8/100
O3 (ozone):
Fair
38.0/100
SO2 (sulfur dioxide):
Good
3.3/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.6/100
PM1 (ultrafine particles):
Good
10.2/100
Pollen forecast in Longmont
View pollen forecastFrequently Asked Questions
Is air quality bad in Longmont right now?
On 16 July 2026, overall air quality in Longmont is fair. AQI is the main air quality indicator at 34.1/100. Pollution peaks around 6:00 AM (O3: 34.1/100).
Will air quality be worse tomorrow in Longmont?
On 17 July 2026, air quality conditions in Longmont will be similar to today, with AQI forecast at fair at 38.0/100. Pollution peaks around 6:00 AM (O3: 38.0/100).
When is air pollution at its worst in Longmont?
Longmont sees air quality change through the year, as a brief window in autumn tends to bring the year's best air, before winter inversions set in; by contrast, valley and basin locations can see pollution trapped under cold air for days during winter inversions. Higher-elevation, more exposed locations generally avoid the worst of the valley inversion episodes.
Are air quality levels in Longmont 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.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 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.
For long term forecasts and maps, see the Airmine app