Worst air pollution Napa, today and tomorrow
Today (9 August): Air quality in Napa is fair. AQI, PM2.5, NO2, and O3 are fair; PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (O3: 34.9/100).
Tomorrow (10 August 2026): Air quality in Napa is fair. All pollutants stay as today. Pollution peaks around 8:00 AM (O3: 37.6/100). Airmine updates local air quality forecasts four times daily.
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Napa's air quality reflects the Napa Valley's partial topographic enclosure between the Mayacamas and Vaca mountains, with vehicle emissions from CA-29 and the surrounding Napa Valley wine country operations contributing local sources. Summer wildfire smoke from the surrounding Wine Country ranges is a severe and recurring seasonal concern, while the Petaluma Gap Delta breeze provides afternoon ventilation and the valley's enclosed character creates periodic temperature inversion episodes.
Today - 9 August | Pollution peaks at 08:00
AQI:
Fair
34.9/100
PM2.5 (fine particles):
Fair
24.1/100
PM10 (coarse particles):
Good
9.1/100
NO2 (nitrogen dioxide):
Fair
31.2/100
O3 (ozone):
Fair
34.9/100
SO2 (sulfur dioxide):
Good
12.3/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.3/100
PM1 (ultrafine particles):
Good
17.8/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 08:00
AQI:
Fair
37.6/100
PM2.5 (fine particles):
Fair
21.1/100
PM10 (coarse particles):
Good
9.4/100
NO2 (nitrogen dioxide):
Fair
23.0/100
O3 (ozone):
Fair
37.6/100
SO2 (sulfur dioxide):
Good
11.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.4/100
PM1 (ultrafine particles):
Good
14.3/100
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Frequently Asked Questions
Is air quality bad in Napa right now?
On 9 August 2026, overall air quality in Napa is fair. AQI is the main air quality indicator at 34.9/100. Pollution peaks around 8:00 AM (O3: 34.9/100).
Will air quality be worse tomorrow in Napa?
On 10 August 2026, air quality conditions in Napa will be similar to today, with AQI forecast at fair at 37.6/100. Pollution peaks around 8:00 AM (O3: 37.6/100).
When is air pollution at its worst in Napa?
Air quality across Napa rises and falls with the seasons. In short, the rainy winter months generally bring the cleanest air, as storms clear traffic and woodsmoke pollution, whereas summer and early autumn bring the highest risk, with heat-driven ozone and wildfire smoke both peaking from July through October. Wine country and inland valley locations tend to see more smoke buildup than the immediate coast.
Are air quality levels in Napa 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: 10 August 2026 at 02:34 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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