Median AQI
49
Good
Arizona · County air quality · 2025
Yuma County, Arizona
Median AQI 49 (Good). 53.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 49
- Median AQI
- 53.5%
- Good-air days
- 1
- Unhealthy days
- 9%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Yuma County's air is good on balance, among the most polluted counties nationally, a median AQI of 49 with 53.5% of 273 monitored days in the Good band, driven mainly by Ozone.
- 49
- median AQI · Good
- 53.5%
- days rated Good
- Ozone
- main pollutant
- 9%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 211.
Data updated July 2026
- Good · 146 d · 53.5%
- Moderate · 120 d · 44.0%
- USG · 6 d · 2.2%
- Very Unhealthy · 1 d · 0.4%
How did Yuma County's air break down in 2025?
Across 273 monitored days, 146 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 211 (Very Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 273 days monitored. Median AQI: 49 (Good).
Insights: Yuma County, Arizona. EPA monitors recorded a median Air Quality Index of 49 across 273 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 146 (53%) fell in the Good band (AQI 0–50), 120 (44%) registered Moderate readings, and 6 (2%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 73, while the worst single-day peak hit 211 (Very Unhealthy). Residents averaged about 16.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (161 days), PM10 (68 days), PM2.5 (44 days). Across the 2020–2025 trend window, good days shifted by -60 and the median AQI moved +0 points, placing the multi-year trajectory at stable. Residents and visitors experienced 1 unhealthy-or-worse days combined, periods when the EPA recommends sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Apache (99.6% good, AQI 14); Cochise (65.6% good, AQI 46); Coconino (62.5% good, AQI 48); Gila (52.0% good, AQI 50); La Paz (68.6% good, AQI 47); Maricopa (16.4% good, AQI 71).
Air Quality Summary
Good Days
53.5%
146 of 273 monitored days
-21.5pp vs 75% target
Max AQI Recorded
211
Very Unhealthy
Health Grade
Moderate
90th-pct AQI 73
Yuma County, Good days share 53.5%
National avg
Share of monitored days at AQI 0-50 (Good band).
Yuma County, Unhealthy-or-worse share 0.4%
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 273 monitored days across EPA AQI categories.
Good
146
53%
Moderate
120
44%
USG
6
2%
Unhealthy
0
0%
Very Unhealthy
1
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Yuma County.
- Ozone · 161 days · 59.0%
- PM10 · 68 days · 24.9%
- PM2.5 · 44 days · 16.1%
Health Impact Assessment
Moderate
Yuma County's air quality is rated Moderate based on 53.5% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality reached unhealthy levels on 1 days in 2025 (0 Unhealthy, 1 Very Unhealthy). Sensitive groups, including people with asthma, COPD, cardiovascular conditions, children, and adults over 65, should review the daily breakdown below and follow local air-quality advisories on high-AQI days.
Sensitive group advisory
People with asthma, COPD, heart disease, children, pregnant women, and adults 65+ should follow EPA AQI alerts daily and limit outdoor exertion when AQI exceeds 100. Real-time conditions: airnow.gov.
The dominant pollutant is Ozone, driving AQI on 161 of 273 monitored days.
5-Year Air Quality Trend
Air quality is stable in Yuma County. Best year: 2022 (228 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 206 | 157 | 2 | 0 | 49 | 319 |
| 2021 | 186 | 173 | 5 | 1 | 50 | 170 |
| 2022 | 228 | 128 | 9 | 0 | 46 | 142 |
| 2023 | 204 | 150 | 6 | 4 | 48 | 519 |
| 2024 | 212 | 149 | 3 | 1 | 47 | 179 |
| 2025 | 146 | 120 | 6 | 0 | 49 | 211 |
How does Yuma County compare?
How Yuma County compares
Good-day share worse than US avg
Yuma County 53.5%
Apache County, Arizona 99.6%
US average 76.5%
Median AQI worse than US avg
Yuma County 49
Apache County, Arizona 14
US average 38
Unhealthy days / yr worse than US avg
Yuma County 1
Apache County, Arizona 0
US average 0
Other Counties in Arizona
Air quality comparison for nearby counties in Arizona.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Yuma County.
Allegheny County, Pennsylvania
AQI 49 · 51.6% good
Arkansas County, Arkansas
AQI 49 · 51.6% good
Ashley County, Arkansas
AQI 49 · 53.9% good
Clayton County, Georgia
AQI 49 · 53.1% good
Cleveland County, Oklahoma
AQI 49 · 53.7% good
Dewey County, Oklahoma
AQI 49 · 56.6% good
What Yuma County's air means for you
On most days the air here is fine, but Ozone drives 1 unhealthy-or-worse day a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 49 means for exposure. Health guidance
- See how Yuma County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Yuma County with its Arizona neighbours before drawing a conclusion about the region. All of Arizona
Based on 273 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 Yuma County, Arizona? ▼
Yuma County has a median Air Quality Index (AQI) of 49, rated "Good." 53.5% of monitored days (146 out of 273) had good air quality in 2025.
What is the main pollutant in Yuma County? ▼
The primary pollutant in Yuma County is Ozone (O3), which was the main AQI driver on 161 days (59% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Yuma County have? ▼
In 2025, Yuma County recorded 1 unhealthy air days (0 Unhealthy, 1 Very Unhealthy, 0 Hazardous). The maximum AQI reached 211.
Is the air quality in Yuma County getting better or worse? ▼
Air quality in Yuma County is stable based on 5-year trends (2020-2025). Best year: 2022 with 228 good days. Worst year: 2025 with 146 good days.
What does AQI 49 mean for health? ▼
Yuma County's median AQI of 49 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 Yuma County compare to other counties in Arizona? ▼
Yuma County has 53.5% good air days. Nearby counties in Arizona: Apache (99.6% good), Cochise (65.6% good), Coconino (62.5% good), Gila (52.0% good), La Paz (68.6% good), Maricopa (16.4% good).
What is the 90th percentile AQI in Yuma County? ▼
The 90th percentile AQI for Yuma County is 73, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 211 (Very Unhealthy).
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.