Median AQI
45
Good
Arizona · County air quality · 2025
Santa Cruz County, Arizona
Median AQI 45 (Good). 63.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 45
- Median AQI
- 63.6%
- Good-air days
- 1
- Unhealthy days
- 20%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Santa Cruz County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 45 with 63.6% of 272 monitored days in the Good band, driven mainly by PM2.5.
- 45
- median AQI · Good
- 63.6%
- days rated Good
- PM2.5
- main pollutant
- 20%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 187.
Data updated July 2026
- Good · 173 d · 63.6%
- Moderate · 97 d · 35.7%
- USG · 1 d · 0.4%
- Unhealthy · 1 d · 0.4%
How did Santa Cruz County's air break down in 2025?
Across 272 monitored days, 173 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 187 (Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 272 days monitored. Median AQI: 45 (Good).
Insights: Santa Cruz County, Arizona. EPA monitors recorded a median Air Quality Index of 45 across 272 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 173 (64%) fell in the Good band (AQI 0–50), 97 (36%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 64, while the worst single-day peak hit 187 (Unhealthy). Residents averaged about 19.1 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (225 days), PM10 (47 days). Across the 2020–2025 trend window, good days shifted by -35 and the median AQI moved +1 points, placing the multi-year trajectory at improving. 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
63.6%
173 of 272 monitored days
-11.4pp vs 75% target
Max AQI Recorded
187
Unhealthy
Health Grade
Moderate
90th-pct AQI 64
Santa Cruz County, Good days share 63.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Santa Cruz 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 272 monitored days across EPA AQI categories.
Good
173
64%
Moderate
97
36%
USG
1
0%
Unhealthy
1
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Santa Cruz County.
- PM2.5 · 225 days · 82.7%
- PM10 · 47 days · 17.3%
Health Impact Assessment
Moderate
Santa Cruz County's air quality is rated Moderate based on 63.6% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 1 days reached "Unhealthy for Sensitive Groups" (AQI 101-150) and peak AQI reached 187. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 225 of 272 monitored days.
5-Year Air Quality Trend
Air quality is improving in Santa Cruz County. Best year: 2023 (265 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 208 | 147 | 4 | 1 | 44 | 170 |
| 2021 | 169 | 189 | 1 | 1 | 52 | 171 |
| 2022 | 220 | 136 | 1 | 0 | 43 | 138 |
| 2023 | 265 | 92 | 1 | 0 | 37 | 145 |
| 2024 | 213 | 139 | 8 | 0 | 43 | 494 |
| 2025 | 173 | 97 | 1 | 1 | 45 | 187 |
How does Santa Cruz County compare?
How Santa Cruz County compares
Good-day share worse than US avg
Santa Cruz County 63.6%
Apache County, Arizona 99.6%
US average 76.5%
Median AQI worse than US avg
Santa Cruz County 45
Apache County, Arizona 14
US average 38
Unhealthy days / yr worse than US avg
Santa Cruz 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 Santa Cruz County.
Adair County, Oklahoma
AQI 45 · 59.2% good
Allen County, Indiana
AQI 45 · 58.2% good
Atascosa County, Texas
AQI 45 · 58.0% good
Baker County, Florida
AQI 45 · 69.1% good
Carson City County, Nevada
AQI 45 · 79.3% good
Clinton County, Iowa
AQI 45 · 59.9% good
What Santa Cruz County's air means for you
On most days the air here is fine, but PM2.5 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-PM2.5 days, the guide explains what a median of 45 means for exposure. Health guidance
- See how Santa Cruz County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Santa Cruz County with its Arizona neighbours before drawing a conclusion about the region. All of Arizona
Based on 272 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 Santa Cruz County, Arizona? ▼
Santa Cruz County has a median Air Quality Index (AQI) of 45, rated "Good." 63.6% of monitored days (173 out of 272) had good air quality in 2025.
What is the main pollutant in Santa Cruz County? ▼
The primary pollutant in Santa Cruz County is Fine Particles (PM2.5), which was the main AQI driver on 225 days (83% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Santa Cruz County have? ▼
In 2025, Santa Cruz County recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 187.
Is the air quality in Santa Cruz County getting better or worse? ▼
Air quality in Santa Cruz County is improving based on 5-year trends (2020-2025). Best year: 2023 with 265 good days. Worst year: 2021 with 169 good days.
What does AQI 45 mean for health? ▼
Santa Cruz County's median AQI of 45 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 Santa Cruz County compare to other counties in Arizona? ▼
Santa Cruz County has 63.6% 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 Santa Cruz County? ▼
The 90th percentile AQI for Santa Cruz County is 64, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 187 (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.