Median AQI
27
Good
Colorado · County air quality · 2025
Prowers County, Colorado
Median AQI 27 (Good). 92.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 27
- Median AQI
- 92.6%
- Good-air days
- 2
- Unhealthy days
- 86%
- Cleaner than US counties
Prowers County's 2025 annual median AQI is 27 (Good), with 92.6% Good days
According to the U.S. EPA Air Quality System, Prowers County, Colorado posted a 2025 median AQI of 27 (Good) across 365 monitored days, with 92.6% rated Good and 2 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Prowers County's 92.6% Good-day share places it cleaner than 86% of US counties in 2025.
- Closest median-AQI peer
- Brown County (83.6% Good, median AQI 27) is the closest nationwide median-AQI peer to Prowers County.
- 2020–2025 trend
- Prowers County's floor-qualifying Good-day share is worsening from 2020 to 2025 (93.7% → 93.1%).
- Median AQI
- Median AQI: 27
The verdict
According to EPA Air Quality System monitoring data, Prowers County's air is good on balance, cleaner than most US counties, a median AQI of 27 with 92.6% of 365 monitored days in the Good band, driven mainly by PM2.5.
- 27
- median AQI · Good
- 92.6%
- days rated Good
- PM2.5
- main pollutant
- 86%
- cleaner than US counties
2 days reached Unhealthy or worse; the worst single reading hit AQI 652 - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly.
Annual release change
What changed in the 2025 EPA annual release
- Prowers County's peak single-day AQI rose from 98 to 652 between the 2024 and 2025 EPA annual releases, a change of +554 points.
- Prowers County's Good-day share rose from 87.7% to 92.6% between the 2024 and 2025 EPA annual releases, a change of +4.9 percentage points.
Data updated August 2026
- Good · 338 d · 92.6%
- Moderate · 25 d · 6.8%
- Very Unhealthy · 1 d · 0.3%
- Hazardous · 1 d · 0.3%
How did Prowers County's air break down in 2025?
Across 365 monitored days, 338 fell in the Good band (AQI 0–50) and 2 reached Unhealthy or worse. The worst single day peaked at AQI 652 (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). 365 days monitored. Median AQI: 27 (Good).
Insights: Prowers County, Colorado. EPA monitors recorded a median Air Quality Index of 27 across 365 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 338 (93%) fell in the Good band (AQI 0–50), 25 (7%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 45, while the worst single-day peak hit 652 (Hazardous). Residents averaged about 27.8 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (294 days), PM10 (71 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -0.8 points and the median AQI moved +10 points, placing the multi-year trajectory at worsening. The annual record contains 2 days at Unhealthy or worse. On those days, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Adams (55.1% good, AQI 49); Alamosa (91.5% good, AQI 25); Arapahoe (58.1% good, AQI 48); Archuleta (83.0% good, AQI 34); Boulder (58.4% good, AQI 48); Chaffee (66.0% good, AQI 48).
Air Quality Summary
Good Days
92.6%
338 of 365 monitored days
17.6pp vs 75% target
Max AQI Recorded
652
Hazardous
Health Grade
Excellent
90th-pct AQI 45
Prowers County, Good days share 92.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Prowers County, Unhealthy-or-worse share 5.5%
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 365 monitored days across EPA AQI categories.
Good
338
93%
Moderate
25
7%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
1
0%
Hazardous
1
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Prowers County.
- PM2.5 · 294 days · 80.5%
- PM10 · 71 days · 19.5%
Health Impact Assessment
Excellent
Prowers County's air quality is rated Excellent based on 92.6% 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 652, 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 652 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 PM2.5, driving AQI on 294 of 365 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Prowers County. Highest Good-day share: 2023 (96.0%, 336 of 350 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 327 | 19 | 1 | 2 | 17 | 238 |
| 2021 | 345 | 14 | 1 | 0 | 19 | 584 |
| 2022 | 330 | 22 | 0 | 1 | 18 | 330 |
| 2023 | 336 | 13 | 1 | 0 | 19 | 103 |
| 2024 | 321 | 45 | 0 | 0 | 25 | 98 |
| 2025 | 338 | 25 | 0 | 0 | 27 | 652 |
How does Prowers County compare?
How Prowers County compares
Good-day share better than US avg
Prowers County 92.6%
Brown County, South Dakota 83.6%
US average 76.0%
Median AQI better than US avg
Prowers County 27
Brown County, South Dakota 27
US average 39
Unhealthy days / yr worse than US avg
Prowers County 2
Brown County, South Dakota 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Prowers County (27), not geographic neighbors.
Brown County, South Dakota
Median AQI 27 · 83.6% Good-day share
Columbia County, Oregon
Median AQI 27 · 92.9% Good-day share
Linn County, Oregon
Median AQI 27 · 80.0% Good-day share
Oneida County, New York
Median AQI 27 · 84.4% Good-day share
Orange County, New York
Median AQI 27 · 86.9% Good-day share
Sheridan County, Wyoming
Median AQI 27 · 89.1% Good-day share
Same primary pollutant: PM2.5
PM2.5 led the AQI on the most monitored days here. These peers share that driver and the closest Good-day share (a second relationship type beyond median-AQI neighbors).
Garfield County, Washington
92.5% Good-day share · median AQI 19
Pitkin County, Colorado
92.3% Good-day share · median AQI 19
Twin Falls County, Idaho
92.9% Good-day share · median AQI 26
Lubbock County, Texas
92.9% Good-day share · median AQI 24
Caguas County, Puerto Rico
93.0% Good-day share · median AQI 5
Hughes County, South Dakota
93.0% Good-day share · median AQI 18
Colorado counties on the map
Geographic containment only, other monitored counties in Colorado, independent of AQI or pollutant match.
What Prowers County's air means for you
On most days the air here is fine, but PM2.5 drives 2 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-PM2.5 days, the guide explains what a median of 27 means for exposure. Health guidance
- See how Prowers County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Prowers County with its Colorado neighbours before drawing a conclusion about the region. All of Colorado
Based on 365 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
Keep exploring the annual AQI record
Air-quality reading list
Frequently Asked Questions
What is the air quality in Prowers County, Colorado? ▼
Prowers County has a median Air Quality Index (AQI) of 27, rated "Good." 92.6% of monitored days (338 out of 365) had good air quality in 2025.
What is the main pollutant in Prowers County? ▼
The primary pollutant in Prowers County is Fine Particles (PM2.5), which was the main AQI driver on 294 days (81% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Prowers County have? ▼
In 2025, Prowers County recorded 2 unhealthy air days (0 Unhealthy, 1 Very Unhealthy, 1 Hazardous). The maximum AQI reached 652 - 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 Prowers County getting better or worse? ▼
Air quality in Prowers County 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: 2023 at 96.0% (336 of 350 days). Lowest qualifying Good-day share: 2024 at 87.7% (321 of 366 days).
What does AQI 27 mean for health? ▼
Prowers County's median AQI of 27 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Prowers County compare to other counties in Colorado? ▼
Prowers County has 92.6% good air days. Nearby counties in Colorado: Adams (55.1% good), Alamosa (91.5% good), Arapahoe (58.1% good), Archuleta (83.0% good), Boulder (58.4% good), Chaffee (66.0% good).
What is the 90th percentile AQI in Prowers County? ▼
The 90th percentile AQI for Prowers County is 45, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 652 - 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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Prowers County, Colorado · 2020–2025
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Every figure on PlainAirData 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.