Median AQI
34
Good
Washington · County air quality · 2025
Yakima County, Washington
Median AQI 34 (Good). 81.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 34
- Median AQI
- 81.1%
- Good-air days
- 0
- Unhealthy days
- 55%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Yakima County's air is good on balance, cleaner than the median US county, a median AQI of 34 with 81.1% of 243 monitored days in the Good band, driven mainly by PM2.5.
- 34
- median AQI · Good
- 81.1%
- days rated Good
- PM2.5
- main pollutant
- 55%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 87.
Data updated July 2026
- Good · 197 d · 81.1%
- Moderate · 46 d · 18.9%
How did Yakima County's air break down in 2025?
Across 243 monitored days, 197 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 87 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 243 days monitored. Median AQI: 34 (Good).
Insights: Yakima County, Washington. EPA monitors recorded a median Air Quality Index of 34 across 243 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 197 (81%) fell in the Good band (AQI 0–50), 46 (19%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 58, while the worst single-day peak hit 87 (Moderate). Residents averaged about 24.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (211 days), PM10 (32 days). Across the 2020–2025 trend window, good days shifted by -1 and the median AQI moved -12 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 87, moderate but never Unhealthy. Nearby counties show comparable readings: Adams (94.7% good, AQI 19); Asotin (73.8% good, AQI 35); Benton (88.9% good, AQI 35); Chelan (87.2% good, AQI 27); Clallam (88.5% good, AQI 26); Clark (89.3% good, AQI 31).
Air Quality Summary
Good Days
81.1%
197 of 243 monitored days
6.1pp vs 75% target
Max AQI Recorded
87
Moderate
Health Grade
Good
90th-pct AQI 58
Yakima County, Good days share 81.1%
National avg
Share of monitored days at AQI 0-50 (Good band).
Yakima County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 243 monitored days across EPA AQI categories.
Good
197
81%
Moderate
46
19%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Yakima County.
- PM2.5 · 211 days · 86.8%
- PM10 · 32 days · 13.2%
Health Impact Assessment
Good
Yakima County's air quality is rated Good based on 81.1% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 81.1% of monitored days in 2025, with a median AQI of 34. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 211 of 243 monitored days.
5-Year Air Quality Trend
Air quality is improving in Yakima County. Best year: 2024 (248 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 198 | 153 | 6 | 2 | 46 | 743 |
| 2021 | 175 | 163 | 12 | 14 | 52 | 210 |
| 2022 | 178 | 181 | 5 | 1 | 51 | 158 |
| 2023 | 203 | 158 | 1 | 1 | 46 | 233 |
| 2024 | 248 | 111 | 6 | 1 | 37 | 153 |
| 2025 | 197 | 46 | 0 | 0 | 34 | 87 |
How does Yakima County compare?
How Yakima County compares
Good-day share better than US avg
Yakima County 81.1%
Adams County, Washington 94.7%
US average 76.5%
Median AQI better than US avg
Yakima County 34
Adams County, Washington 19
US average 38
Unhealthy days / yr about average
Yakima County 0
Adams County, Washington 0
US average 0
Other Counties in Washington
Air quality comparison for nearby counties in Washington.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Yakima County.
Belknap County, New Hampshire
AQI 34 · 87.9% good
Dyer County, Tennessee
AQI 34 · 79.4% good
Flagler County, Florida
AQI 34 · 97.4% good
Grant County, Oregon
AQI 34 · 66.7% good
Highlands County, Florida
AQI 34 · 93.2% good
Johnson County, Texas
AQI 34 · 91.6% good
What Yakima County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 34 means for exposure. Health guidance
- See how Yakima County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Yakima County with its Washington neighbours before drawing a conclusion about the region. All of Washington
Based on 243 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Yakima County, Washington? ▼
Yakima County has a median Air Quality Index (AQI) of 34, rated "Good." 81.1% of monitored days (197 out of 243) had good air quality in 2025.
What is the main pollutant in Yakima County? ▼
The primary pollutant in Yakima County is Fine Particles (PM2.5), which was the main AQI driver on 211 days (87% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Yakima County have? ▼
In 2025, Yakima County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 87.
Is the air quality in Yakima County getting better or worse? ▼
Air quality in Yakima County is improving based on 5-year trends (2020-2025). Best year: 2024 with 248 good days. Worst year: 2021 with 175 good days.
What does AQI 34 mean for health? ▼
Yakima County's median AQI of 34 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Yakima County compare to other counties in Washington? ▼
Yakima County has 81.1% good air days. Nearby counties in Washington: Adams (94.7% good), Asotin (73.8% good), Benton (88.9% good), Chelan (87.2% good), Clallam (88.5% good), Clark (89.3% good).
What is the 90th percentile AQI in Yakima County? ▼
The 90th percentile AQI for Yakima County is 58, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 87 (Moderate).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
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.