Metro area air quality · 2025

Sierra Vista-Douglas, AZ

Median AQI 45 (Good). 69.9% of monitored days rated Good across this metro's EPA monitoring network.

45
Median AQI
69.9%
Good-air days
2
Unhealthy days
45%
Cleaner than US metros

Sierra Vista-Douglas, AZ posted a 2025 median AQI of 45 (Good) with 69.9% Good days

According to the U.S. EPA Air Quality System, the Sierra Vista-Douglas, AZ CBSA recorded a median AQI of 45 across 365 monitored days in 2025, with 69.9% rated Good and 2 unhealthy or worse. This is an annual metro comparison, not a live advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US metros
The Sierra Vista-Douglas, AZ CBSA's 69.9% Good-day share places it cleaner than 45% of US metros in 2025.
Closest median-AQI peer
Akron, OH (61.6% Good, median AQI 45) is the closest nationwide median-AQI peer to Sierra Vista-Douglas, AZ.
2020–2025 Good-day shift
Sierra Vista-Douglas, AZ's Good-day share moved -4.0 points from 2020 to 2025 (median AQI +0).
Median AQI
Median AQI: 45

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

Sierra Vista-Douglas, AZ's median AQI 45 is in the upper (dirtier) CBSA tercile on this site. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 45 and 69.9% of 365 monitored days in the Good band.

45
median AQI · Good
69.9%
days rated Good
45%
cleaner than US metros
328
worst single reading

2 days reached Unhealthy or worse across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Sierra Vista-Douglas, AZ metro's Good-day share rose from 63.6% to 70.4% between the 2024 and 2025 EPA annual releases, a change of +6.9 percentage points.
  • Sierra Vista-Douglas, AZ metro's peak single-day AQI rose from 307 to 328 between the 2024 and 2025 EPA annual releases, a change of +21 points.
  • Sierra Vista-Douglas, AZ metro's median AQI fell from 48 to 45 between the 2024 and 2025 EPA annual releases, a change of -3 points.

Compared against 354 monitored days in 2024 and 362 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Sierra Vista-Douglas, AZ's median AQI 45 is in the upper (dirtier) CBSA tercile on this site. Signature read: median AQI 45 (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 45 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 255 Good (70%), 106 Moderate (29%), and 2 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 71; the highest single-day reading hit 328 (Hazardous).

Across 2020–2025, Good-day share shifted -4.0 points and median AQI moved +0 (worsening). The annual record contains 2 days at Unhealthy or worse. Metros with comparable AQI profiles include Akron, OH (61.6% good, AQI 45); Ardmore, OK (67.9% good, AQI 45); Asheville, NC (69.9% good, AQI 45).

Health effects of air pollution →

Air Quality Summary

Median AQI

45

Good

Good Days

69.9%

255 of 365 days

Max AQI

328

Hazardous

Health Grade

Moderate

90th pct: 71

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

255

70%

Moderate

106

29%

USG

2

1%

Unhealthy

1

0%

Very Unhealthy

0

0%

Hazardous

1

0%

Health Impact Assessment

Moderate

The Sierra Vista-Douglas, AZ metro area's air quality is rated Moderate based on 69.9% good air days. There were 2 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 328, well into the Hazardous range.

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.

How does the Sierra Vista-Douglas, AZ metro compare?

How Sierra Vista-Douglas, AZ compares

Good-day share worse than typical
Sierra Vista-Douglas, AZ 69.9%
Akron, OH 61.6%
Typical US metro 70.6%
Median AQI worse than typical
Sierra Vista-Douglas, AZ 45
Akron, OH 45
Typical US metro 41
Unhealthy days / yr worse than typical
Sierra Vista-Douglas, AZ 2
Akron, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Sierra Vista-Douglas, AZ metro. Highest Good-day share: 2022 (79.9%, 291 of 364 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 271 93 0 45
2021 259 104 0 45
2022 291 73 0 44
2023 272 90 0 44
2024 225 128 1 48
2025 255 106 1 45

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Sierra Vista-Douglas, AZ (45).

Akron, OH

Median AQI 45 · 61.6% Good-day share

45

Ardmore, OK

Median AQI 45 · 67.9% Good-day share

45

Asheville, NC

Median AQI 45 · 69.9% Good-day share

45

Cheyenne, WY

Median AQI 45 · 75.1% Good-day share

45

Clinton, IA

Median AQI 45 · 59.5% Good-day share

45

Fort Dodge, IA

Median AQI 45 · 59.2% Good-day share

45

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Sierra Vista-Douglas, AZ's 2 (independent of median AQI).

Bridgeport-Stamford-Norwalk, CT

2 unhealthy-or-worse days · median AQI 44

44

Chattanooga, TN-GA

2 unhealthy-or-worse days · median AQI 49

49

Cincinnati, OH-KY-IN

2 unhealthy-or-worse days · median AQI 56

56

Columbus, GA-AL

2 unhealthy-or-worse days · median AQI 48

48

Davenport-Moline-Rock Island, IA-IL

2 unhealthy-or-worse days · median AQI 46

46

Grand Rapids-Wyoming, MI

2 unhealthy-or-worse days · median AQI 52

52

Frequently Asked Questions

What does AQI 45 mean for health? ▼
An AQI of 45 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
How many unhealthy air days does Sierra Vista-Douglas, AZ have? ▼
In 2025, the Sierra Vista-Douglas, AZ metro area recorded 2 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 1 Hazardous). The maximum AQI reached 328.
What is the air quality in the Sierra Vista-Douglas, AZ metro area? ▼
The Sierra Vista-Douglas, AZ metro area has a median Air Quality Index (AQI) of 45, rated "Good." 69.9% of monitored days (255 out of 365) had good air quality in 2025.
Is air quality in Sierra Vista-Douglas, AZ getting better or worse? ▼
Air quality in the Sierra Vista-Douglas, AZ metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2022 at 79.9% (291 of 364 days). Lowest qualifying Good-day share: 2024 at 63.6% (225 of 354 days).
How does Sierra Vista-Douglas, AZ compare to other metro areas? ▼
The Sierra Vista-Douglas, AZ metro has 69.9% good air days. Similar metros: Akron, OH (61.6% good), Ardmore, OK (67.9% good), Asheville, NC (69.9% good).
What is the 90th percentile AQI for Sierra Vista-Douglas, AZ? ▼
The 90th percentile AQI for the Sierra Vista-Douglas, AZ metro area is 71, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 328 (Hazardous).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Sierra Vista-Douglas, AZ, 2025. See our methodology for how AQI, median, and coverage figures are computed.

Read our methodology , how this data is sourced, computed, and verified.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Sierra Vista-Douglas, AZ · 2020–2025