Metro area air quality · 2025
Truckee-Grass Valley, CA
Median AQI 44 (Good). 79.6% of monitored days rated Good across this metro's EPA monitoring network.
- 44
- Median AQI
- 79.6%
- Good-air days
- 0
- Unhealthy days
- 62%
- Cleaner than US metros
Aggregated from EPA Air Quality System (2025), 181 monitored days. EPA AQS →
The verdict
The Truckee-Grass Valley, CA metro runs good on the EPA scale, cleaner than the median US metro, a median AQI of 44 with 79.6% of 181 monitored days in the Good band.
- 44
- median AQI · Good
- 79.6%
- days rated Good
- 62%
- cleaner than US metros
- 84
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2025.
Insights: Truckee-Grass Valley, CA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 44 over 181 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 144 Good days (80%), 37 Moderate (20%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 61 while the highest single-day reading hit 84 (Moderate). Metro residents averaged roughly 23.9 clean-air days per 30-day window across the reporting year.
Across the 2020–2025 trend window, good days shifted by -79 and the median AQI moved -2 points, which classifies the multi-year trajectory as improving. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Athens-Clarke County, GA (66.7% good, AQI 44); Bartlesville, OK (65.6% good, AQI 44); Bloomington, IL (64.1% good, AQI 44).
Air Quality Summary
Median AQI
44
Good
Good Days
79.6%
144 of 181 days
Max AQI
84
Moderate
Health Grade
Good
90th pct: 61
AQI Day Breakdown (2025)
Distribution of 181 monitored days across EPA AQI categories.
Good
144
80%
Moderate
37
20%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Truckee-Grass Valley, CA metro area's air quality is rated Good based on 79.6% 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 Truckee-Grass Valley, CA metro compare?
How Truckee-Grass Valley, CA compares
5-Year Air Quality Trend
Air quality is improving in the Truckee-Grass Valley, CA metro. Best year: 2024 (313 good days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 223 | 111 | 11 | 46 | 277 |
| 2021 | 183 | 129 | 13 | 50 | 326 |
| 2022 | 185 | 161 | 3 | 50 | 293 |
| 2023 | 282 | 81 | 0 | 42 | 97 |
| 2024 | 313 | 50 | 0 | 36 | 132 |
| 2025 | 144 | 37 | 0 | 44 | 84 |
Metros with Similar Air Quality
Metro areas across the US with a similar median AQI to Truckee-Grass Valley, CA.
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Worst Air Quality
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All Metro Areas
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Best and Worst City Air
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Air Quality Guides
Frequently Asked Questions
What is the air quality in the Truckee-Grass Valley, CA metro area? ▼
How many unhealthy air days does Truckee-Grass Valley, CA have? ▼
Is air quality in Truckee-Grass Valley, CA getting better or worse? ▼
What does AQI 44 mean for health? ▼
What is the 90th percentile AQI for Truckee-Grass Valley, CA? ▼
How does Truckee-Grass Valley, CA compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. 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 files (metro-level) · 2020–2025
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.