Median AQI
12
Good
Arizona · County air quality · 2025
Navajo County, Arizona
Median AQI 12 (Good). 99.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 12
- Median AQI
- 99.6%
- Good-air days
- 0
- Unhealthy days
- 96%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Navajo County's air is good on balance, among the cleanest 5% of US counties, a median AQI of 12 with 99.6% of 273 monitored days in the Good band, driven mainly by PM10.
- 12
- median AQI · Good
- 99.6%
- days rated Good
- PM10
- main pollutant
- 96%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 53.
Data updated July 2026
- Good · 272 d · 99.6%
- Moderate · 1 d · 0.4%
How did Navajo County's air break down in 2025?
Across 273 monitored days, 272 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 53 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 273 days monitored. Median AQI: 12 (Good).
Insights: Navajo County, Arizona. EPA monitors recorded a median Air Quality Index of 12 across 273 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 272 (100%) fell in the Good band (AQI 0–50), 1 (0%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 24, while the worst single-day peak hit 53 (Moderate). Residents averaged about 29.9 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM10 (265 days), PM2.5 (8 days). Across the 2020–2025 trend window, good days shifted by -42 and the median AQI moved -31 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 53, moderate but never Unhealthy. 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
99.6%
272 of 273 monitored days
24.6pp vs 75% target
Max AQI Recorded
53
Moderate
Health Grade
Excellent
90th-pct AQI 24
Navajo County, Good days share 99.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Navajo 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 273 monitored days across EPA AQI categories.
Good
272
100%
Moderate
1
0%
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 Navajo County.
- PM10 · 265 days · 97.1%
- PM2.5 · 8 days · 2.9%
Health Impact Assessment
Excellent
Navajo County's air quality is rated Excellent based on 99.6% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 99.6% of monitored days in 2025, with a median AQI of 12. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM10, driving AQI on 265 of 273 monitored days.
5-Year Air Quality Trend
Air quality is improving in Navajo County. Best year: 2024 (359 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 314 | 50 | 2 | 0 | 43 | 136 |
| 2021 | 292 | 72 | 1 | 0 | 44 | 101 |
| 2022 | 307 | 57 | 0 | 0 | 44 | 93 |
| 2023 | 290 | 74 | 0 | 0 | 43 | 84 |
| 2024 | 359 | 2 | 0 | 0 | 13 | 53 |
| 2025 | 272 | 1 | 0 | 0 | 12 | 53 |
How does Navajo County compare?
How Navajo County compares
Good-day share better than US avg
Navajo County 99.6%
Apache County, Arizona 99.6%
US average 76.5%
Median AQI better than US avg
Navajo County 12
Apache County, Arizona 14
US average 38
Unhealthy days / yr about average
Navajo County 0
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 Navajo County.
Beaverhead County, Montana
AQI 12 · 100.0% good
Columbiana County, Ohio
AQI 12 · 100.0% good
Cook County, Minnesota
AQI 12 · 100.0% good
Mayagnez County, Puerto Rico
AQI 12 · 96.9% good
Socorro County, New Mexico
AQI 12 · 100.0% good
Windham County, Vermont
AQI 12 · 100.0% good
What Navajo County's air means for you
The air here stays in the breathable range year-round, with PM10 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM10 days, the guide explains what a median of 12 means for exposure. Health guidance
- See how Navajo County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Navajo 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 Navajo County, Arizona? ▼
Navajo County has a median Air Quality Index (AQI) of 12, rated "Good." 99.6% of monitored days (272 out of 273) had good air quality in 2025.
What is the main pollutant in Navajo County? ▼
The primary pollutant in Navajo County is Coarse Particles (PM10), which was the main AQI driver on 265 days (97% of monitored days). Irritates airways and can aggravate asthma and bronchitis.
How many unhealthy air days does Navajo County have? ▼
In 2025, Navajo County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 53.
Is the air quality in Navajo County getting better or worse? ▼
Air quality in Navajo County is improving based on 5-year trends (2020-2025). Best year: 2024 with 359 good days. Worst year: 2025 with 272 good days.
What does AQI 12 mean for health? ▼
Navajo County's median AQI of 12 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 Navajo County compare to other counties in Arizona? ▼
Navajo County has 99.6% 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 Navajo County? ▼
The 90th percentile AQI for Navajo County is 24, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 53 (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.