Median AQI
66
Moderate
Arizona · County air quality · 2025
Pinal County, Arizona
Median AQI 66 (Moderate). 24.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 66
- Median AQI
- 24.6%
- Good-air days
- 4
- Unhealthy days
- 1%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Pinal County's air is moderate on balance, among the most polluted counties nationally, a median AQI of 66 with 24.6% of 268 monitored days in the Good band, driven mainly by Ozone.
- 66
- median AQI · Moderate
- 24.6%
- days rated Good
- Ozone
- main pollutant
- 1%
- cleaner than US counties
4 days reached Unhealthy or worse; the worst single reading hit AQI 1215 - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly.
Data updated July 2026
- Good · 66 d · 24.6%
- Moderate · 178 d · 66.4%
- USG · 20 d · 7.5%
- Hazardous · 4 d · 1.5%
How did Pinal County's air break down in 2025?
Across 268 monitored days, 66 fell in the Good band (AQI 0–50) and 4 reached Unhealthy or worse. The worst single day peaked at AQI 1215 (Hazardous) - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly.
EPA AQS →Air quality data from EPA Air Quality System (2025). 268 days monitored. Median AQI: 66 (Moderate).
Insights: Pinal County, Arizona. EPA monitors recorded a median Air Quality Index of 66 across 268 measured days in 2025, earning a Moderate classification and a Very Poor health grade. Of those days, 66 (25%) fell in the Good band (AQI 0–50), 178 (66%) registered Moderate readings, and 20 (7%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 100, while the worst single-day peak hit 1215 (Hazardous). Residents averaged about 7.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (161 days), PM10 (93 days), PM2.5 (14 days). Across the 2020–2025 trend window, good days shifted by -20 and the median AQI moved -7 points, placing the multi-year trajectory at improving. Residents and visitors experienced 4 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
24.6%
66 of 268 monitored days
-50.4pp vs 75% target
Max AQI Recorded
1215
Hazardous
Health Grade
Very Poor
90th-pct AQI 100
Pinal County, Good days share 24.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Pinal County, Unhealthy-or-worse share 1.5%
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 268 monitored days across EPA AQI categories.
Good
66
25%
Moderate
178
66%
USG
20
7%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
4
1%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Pinal County.
- Ozone · 161 days · 60.1%
- PM10 · 93 days · 34.7%
- PM2.5 · 14 days · 5.2%
Health Impact Assessment
Very Poor
Pinal County's air quality is rated Very Poor based on 24.6% good air days. There were 4 unhealthy days in 2025 when outdoor activity should be limited.
Air quality posed significant health risk in 2025. Sensitive groups, including people with asthma, COPD, cardiovascular conditions, children, pregnant women, and adults over 65, should monitor AirNow.gov alerts and limit outdoor activity on Unhealthy (AQI 151+) and Very Unhealthy (201+) days. Peak readings reached AQI 1215, beyond EPA's standard 0-500 scale, indicating an extreme event.
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.
Note: EPA's standard AQI scale caps at 500 (Hazardous category 301-500). The 1215 peak reading represents an extreme event, typically wildfire smoke, extrapolated beyond the index's design range. See EPA wildfire smoke guidance.
The dominant pollutant is Ozone, driving AQI on 161 of 268 monitored days.
5-Year Air Quality Trend
Air quality is improving in Pinal County. Best year: 2023 (109 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 86 | 196 | 74 | 8 | 73 | 1194 |
| 2021 | 72 | 240 | 49 | 4 | 70 | 198 |
| 2022 | 91 | 238 | 28 | 3 | 61 | 689 |
| 2023 | 109 | 211 | 38 | 5 | 64 | 709 |
| 2024 | 77 | 219 | 65 | 3 | 77 | 337 |
| 2025 | 66 | 178 | 20 | 0 | 66 | 1215 |
How does Pinal County compare?
How Pinal County compares
Good-day share worse than US avg
Pinal County 24.6%
Apache County, Arizona 99.6%
US average 76.5%
Median AQI worse than US avg
Pinal County 66
Apache County, Arizona 14
US average 38
Unhealthy days / yr worse than US avg
Pinal County 4
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 Pinal County.
Clark County, Nevada
AQI 64 · 25.6% good
Imperial County, California
AQI 64 · 27.4% good
Harris County, Texas
AQI 63 · 8.8% good
Dona Ana County, New Mexico
AQI 70 · 19.4% good
Kern County, California
AQI 61 · 23.8% good
Maricopa County, Arizona
AQI 71 · 16.4% good
What Pinal County's air means for you
On most days the air here is fine, but Ozone drives 4 unhealthy-or-worse days 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 66 means for exposure. Health guidance
- See how Pinal County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Pinal County with its Arizona neighbours before drawing a conclusion about the region. All of Arizona
Based on 268 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 Pinal County, Arizona? ▼
Pinal County has a median Air Quality Index (AQI) of 66, rated "Moderate." 24.6% of monitored days (66 out of 268) had good air quality in 2025.
What is the main pollutant in Pinal County? ▼
The primary pollutant in Pinal County is Ozone (O3), which was the main AQI driver on 161 days (60% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Pinal County have? ▼
In 2025, Pinal County recorded 4 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 4 Hazardous). The maximum AQI reached 1215 - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly.
Is the air quality in Pinal County getting better or worse? ▼
Air quality in Pinal County is improving based on 5-year trends (2020-2025). Best year: 2023 with 109 good days. Worst year: 2025 with 66 good days.
What does AQI 66 mean for health? ▼
Pinal County's median AQI of 66 falls in the "Moderate" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Pinal County compare to other counties in Arizona? ▼
Pinal County has 24.6% 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 Pinal County? ▼
The 90th percentile AQI for Pinal County is 100, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 1215 - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly (Hazardous).
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.