Worst air pollution Grand Junction, today and tomorrow
Today (20 September): Air quality in Grand Junction is fair. AQI, PM2.5, NO2, O3, and PM1 are fair; PM10, SO2, CO, and HCHO are good. Pollution peaks around 10:00 AM (O3: 39.8/100).
Tomorrow (21 September 2026): Air quality in Grand Junction is moderate. AQI worsens to moderate; NO2 increases to moderate; O3 increases to moderate; PM1 decreases to good; all other pollutants stay as today. Pollution peaks around 8:00 AM (O3: 50.2/100). Airmine updates local air quality forecasts four times daily.
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Grand Junction's air quality reflects the Colorado River valley's partial topographic enclosure between the Book Cliffs to the north and the Uncompahgre Plateau to the south, with vehicle emissions from I-70 and the surrounding Piceance Basin oil and gas extraction operations generating elevated VOCs and NOₓ. Winter temperature inversions in the valley can trap emissions for extended periods, while summer ozone from the concentrated oil and gas extraction in the surrounding Grand Valley adds the primary warm-season air quality concern.
Today - 20 September | Pollution peaks at 10:00
AQI:
Fair
39.8/100
PM2.5 (fine particles):
Fair
26.4/100
PM10 (coarse particles):
Good
16.8/100
NO2 (nitrogen dioxide):
Fair
24.8/100
O3 (ozone):
Fair
39.8/100
SO2 (sulfur dioxide):
Good
1.1/100
CO (carbon monoxide):
Good
0.6/100
HCHO (formaldehyde):
Good
3.0/100
PM1 (ultrafine particles):
Fair
20.9/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 08:00
AQI:
Moderate
50.2/100
PM2.5 (fine particles):
Fair
25.4/100
PM10 (coarse particles):
Good
16.2/100
NO2 (nitrogen dioxide):
Moderate
44.2/100
O3 (ozone):
Moderate
50.2/100
SO2 (sulfur dioxide):
Good
1.3/100
CO (carbon monoxide):
Good
0.6/100
HCHO (formaldehyde):
Good
3.4/100
PM1 (ultrafine particles):
Good
17.8/100
Pollen forecast in Grand Junction
View pollen forecastAir quality forecasts for neighbourhoods and landmarks in Grand Junction
Frequently Asked Questions
Is air quality bad in Grand Junction right now?
On 20 September 2026, overall air quality in Grand Junction is fair. AQI is the main air quality indicator at 39.8/100. Pollution peaks around 10:00 AM (O3: 39.8/100).
Will air quality be worse tomorrow in Grand Junction?
On 21 September 2026, air quality conditions in Grand Junction will be worse than today, with AQI forecast at moderate at 50.2/100. Pollution peaks around 8:00 AM (O3: 50.2/100).
When is air pollution at its worst in Grand Junction?
Like most US cities, Grand Junction sees air quality shift from season to season. Typically, spring and autumn generally bring the cleanest, most stable air, while wildfire smoke drifting in from across the region is the main summer concern, while winter inversions can trap pollution locally. Higher-elevation, more exposed locations generally avoid the worst of the valley inversion episodes.
Are air quality levels in Grand Junction 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: 20 September 2026 at 14:33 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.
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.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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