Region in California, United States
Air quality in Napa Valley
Fairly clean
The annual average PM2.5 in Napa Valley was 8 µg/m³ in 2021, about 1.6 times the WHO guideline of 5 µg/m³. Wildfire smoke can cause unhealthy air for days, mainly in late summer and fall.
Key facts
- PM2.5: 8 µg/m³ yearly average (2021). Measured at Vallejo-Fairfield, CA, 29 km away.
- PM10: 14 µg/m³ (2021).
- Nitrogen dioxide: 11 µg/m³ (2021), mostly from traffic.
- Worst months: Sep–Oct.
- Recent average: 10.8 µg/m³ over the last five years of measurements.
PM2.5 by year
| Year | Annual average |
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| 2021 | |
| 2021 | |
| 2020 | |
| 2020 | |
| 2019 | |
| 2019 | |
| 2018 | |
| 2018 | |
| 2017 | |
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| 2016 | |
| 2015 | |
| 2015 |
Air quality across United States
| Place | PM2.5 | Level |
|---|---|---|
| Maui | 2 µg/m³ | Meets the WHO guideline |
| Honolulu | 3 µg/m³ | Meets the WHO guideline |
| Kauai | 3 µg/m³ | Meets the WHO guideline |
| Big Island | 3 µg/m³ | Meets the WHO guideline |
| Lake Tahoe | 5.2 µg/m³ | Fairly clean |
| Portland | 5.8 µg/m³ | Fairly clean |
| Denver | 6 µg/m³ | Fairly clean |
| Seattle | 6.1 µg/m³ | Fairly clean |
| Miami | 6.2 µg/m³ | Fairly clean |
| Miami Beach | 6.2 µg/m³ | Fairly clean |
| Washington, D.C. | 6.3 µg/m³ | Fairly clean |
| Boston | 6.4 µg/m³ | Fairly clean |
| Orlando | 6.7 µg/m³ | Fairly clean |
| New York City | 7.1 µg/m³ | Fairly clean |
| Philadelphia | 7.2 µg/m³ | Fairly clean |
| Charleston | 7.3 µg/m³ | Fairly clean |
| Nashville | 7.7 µg/m³ | Fairly clean |
| Phoenix | 7.9 µg/m³ | Fairly clean |
| Scottsdale | 8 µg/m³ | Fairly clean |
| Napa Valley | 8 µg/m³ | Fairly clean |
| New Orleans | 8.2 µg/m³ | Fairly clean |
| San Diego | 8.2 µg/m³ | Fairly clean |
| Atlanta | 8.5 µg/m³ | Fairly clean |
| Dallas | 8.5 µg/m³ | Fairly clean |
| Chicago | 8.7 µg/m³ | Fairly clean |
| Austin | 9 µg/m³ | Fairly clean |
| San Antonio | 9 µg/m³ | Fairly clean |
| Las Vegas | 9.7 µg/m³ | Fairly clean |
| Los Angeles | 10.5 µg/m³ | Moderate |
| Houston | 11.1 µg/m³ | Moderate |
Quick answers
Is the air in Napa Valley bad?
Fairly clean: 8 µg/m³ of PM2.5 on average, 1.6× the WHO guideline. It's usually worst in Sep–Oct.
When is the air worst in Napa Valley?
Wildfire smoke can cause unhealthy air for days, mainly in late summer and fall.
How does Napa Valley compare with the rest of United States?
People in United States breathe 7 µg/m³ of PM2.5 on average (2023, World Bank/WHO), against 8 µg/m³ measured here.
More about Napa Valley
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Sources
- WHO Ambient Air Quality Database
- WHO air quality guidelines (2021)
- Live air quality map (WAQI)
- Visit Napa Valley
- Napa County
Annual averages are measured values reported to the WHO; check a live map for today's air. Compiled and reviewed by SoloSquare. How we compile and score this. Spotted something out of date? Tell us.