Metro area air quality · 2025
Vallejo-Fairfield, CA
Median AQI 33 (Good). 99.2% of monitored days rated Good across this metro's EPA monitoring network.
- 33
- Median AQI
- 99.2%
- Good-air days
- 0
- Unhealthy days
- 99%
- Cleaner than US metros
Vallejo-Fairfield, CA posted a 2025 median AQI of 33 (Good) with 99.2% Good days
According to the U.S. EPA Air Quality System, the Vallejo-Fairfield, CA CBSA recorded a median AQI of 33 across 356 monitored days in 2025, with 99.2% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The Vallejo-Fairfield, CA CBSA's 99.2% Good-day share places it cleaner than 99% of US metros in 2025.
- Closest median-AQI peer
- Bangor, ME (84.2% Good, median AQI 33) is the closest nationwide median-AQI peer to Vallejo-Fairfield, CA.
- 2020–2025 Good-day shift
- Vallejo-Fairfield, CA's Good-day share moved +47.8 points from 2020 to 2025 (median AQI -18).
- Median AQI
- Median AQI: 33
Aggregated from EPA Air Quality System (2025), 356 monitored days. EPA AQS →
The verdict
Vallejo-Fairfield, CA sits in the upper Good-day tercile among EPA CBSA metros on this site (99.2% of 356 monitored days). On the EPA scale the metro runs good, among the cleanest 10% of US metros, with a median AQI of 33 and 99.2% of 356 monitored days in the Good band.
- 33
- median AQI · Good
- 99.2%
- days rated Good
- 99%
- cleaner than US metros
- 61
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Vallejo-Fairfield, CA metro's Good-day share rose from 94.0% to 99.2% between the 2024 and 2025 EPA annual releases, a change of +5.2 percentage points.
- Vallejo-Fairfield, CA metro's peak single-day AQI fell from 80 to 61 between the 2024 and 2025 EPA annual releases, a change of -19 points.
- Vallejo-Fairfield, CA metro's median AQI fell from 36 to 33 between the 2024 and 2025 EPA annual releases, a change of -3 points.
Vallejo-Fairfield, CA sits in the upper Good-day tercile among EPA CBSA metros on this site (99.2% of 356 monitored days). Signature read: 99.2% Good-day share (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 33 over 356 measured days in 2025 (Good / Excellent). The monitored-day split lands at 353 Good (99%), 3 Moderate (1%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 42; the highest single-day reading hit 61 (Moderate).
Across 2020–2025, Good-day share shifted +47.8 points and median AQI moved -18 (improving). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Bangor, ME (84.2% good, AQI 33); Clarksburg, WV (72.4% good, AQI 33); Grants Pass, OR (68.2% good, AQI 33).
Air Quality Summary
Median AQI
33
Good
Good Days
99.2%
353 of 356 days
Max AQI
61
Moderate
Health Grade
Excellent
90th pct: 42
AQI Day Breakdown (2025)
Distribution of 356 monitored days across EPA AQI categories.
Good
353
99%
Moderate
3
1%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Vallejo-Fairfield, CA metro area's air quality is rated Excellent based on 99.2% good air days. No unhealthy air days were recorded in 2025.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the Vallejo-Fairfield, CA metro compare?
How Vallejo-Fairfield, CA compares
5-Year Air Quality Trend
Air quality is improving in the Vallejo-Fairfield, CA metro. Highest Good-day share: 2025 (99.2%, 353 of 356 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 183 | 167 | 6 | 51 | 228 |
| 2021 | 215 | 147 | 0 | 44 | 126 |
| 2022 | 235 | 130 | 0 | 43 | 93 |
| 2023 | 269 | 95 | 0 | 40 | 105 |
| 2024 | 343 | 22 | 0 | 36 | 80 |
| 2025 | 353 | 3 | 0 | 33 | 61 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Vallejo-Fairfield, CA (33).
Bangor, ME
Median AQI 33 · 84.2% Good-day share
Clarksburg, WV
Median AQI 33 · 72.4% Good-day share
Grants Pass, OR
Median AQI 33 · 68.2% Good-day share
Lawrenceburg, TN
Median AQI 33 · 81.5% Good-day share
Roanoke Rapids, NC
Median AQI 33 · 78.1% Good-day share
Rockland, ME
Median AQI 33 · 97.8% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Vallejo-Fairfield, CA's 0 (independent of median AQI).
Aberdeen, SD
0 unhealthy-or-worse days · median AQI 27
Aberdeen, WA
0 unhealthy-or-worse days · median AQI 22
Adrian, MI
0 unhealthy-or-worse days · median AQI 41
Akron, OH
0 unhealthy-or-worse days · median AQI 45
Albany, GA
0 unhealthy-or-worse days · median AQI 46
Albany, OR
0 unhealthy-or-worse days · median AQI 27
Frequently Asked Questions
How many unhealthy air days does Vallejo-Fairfield, CA have? ▼
What is the air quality in the Vallejo-Fairfield, CA metro area? ▼
Is air quality in Vallejo-Fairfield, CA getting better or worse? ▼
What does AQI 33 mean for health? ▼
How does Vallejo-Fairfield, CA compare to other metro areas? ▼
What is the 90th percentile AQI for Vallejo-Fairfield, CA? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Vallejo-Fairfield, CA, 2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Vallejo-Fairfield, CA · 2020–2025