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

According to the 2025 EPA AQS county release on PlainAirData, Prowers County, Colorado ranks #70 of 951 by median AQI (27) and #134 by good-day share (92.6%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • 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.

Compared against 366 monitored days in 2024 and 365 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

Data updated August 2026

Prowers County AQI category distribution Stacked-segment bar showing the share of monitored days that fell in each EPA AQI category, Good, Moderate, USG, Unhealthy, Very Unhealthy, Hazardous, with median AQI marker. AQI category distribution 365 monitored days G Median AQI 27 0 50 100 150 200 300 500 Prowers County
  • 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 →
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).

Where Prowers County sits nationally

COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Prowers County's Good-day share is 92.6% - cleaner than 86% of that comparison set.

Prowers County Good-day share vs. every US county

Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release

92.6% Cleaner than 86% higher than 86% of 951 US counties

0.0%–5.0%: 0 US counties (0%). Below this entry. 5.0%–10.0%: 1 US counties (0%). Below this entry. 10.0%–15.0%: 4 US counties (0%). Below this entry. 15.0%–20.0%: 4 US counties (0%). Below this entry. 20.0%–25.0%: 1 US counties (0%). Below this entry. 25.0%–30.0%: 5 US counties (1%). Below this entry. 30.0%–35.0%: 9 US counties (1%). Below this entry. 35.0%–40.0%: 4 US counties (0%). Below this entry. 40.0%–45.0%: 16 US counties (2%). Below this entry. 45.0%–50.0%: 16 US counties (2%). Below this entry. 50.0%–55.0%: 32 US counties (3%). Below this entry. 55.0%–60.0%: 50 US counties (5%). Below this entry. 60.0%–65.0%: 77 US counties (8%). Below this entry. 65.0%–70.0%: 93 US counties (10%). Below this entry. 70.0%–75.0%: 109 US counties (11%). Below this entry. 75.0%–80.0%: 114 US counties (12%). Below this entry. 80.0%–85.0%: 123 US counties (13%). Below this entry. 85.0%–90.0%: 99 US counties (10%). Below this entry. 90.0%–95.0%: 117 US counties (12%). This entry sits in this band. 95.0%–100.0%: 70 US counties (7%). Above this entry. 100.0%–105.0%: 7 US counties (1%). Above this entry. This county 0.0% 100% every floor-qualified US county, bucketed by value

Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025

Pollutant Breakdown

Days where each pollutant was the primary driver of AQI readings in Prowers County.

Prowers County, Colorado criteria pollutant distribution Stratified-band visualization showing the share of monitored days each criteria pollutant (PM2.5, PM10, O3, NO2, CO) was the primary AQI driver. PM2.5 · 80.5% PM10 · 19.5% 0% 25% 50% 75% 100% Prowers County, Colorado · 365 monitored days Criteria pollutant column
  • PM2.5 · 294 days · 80.5%
  • PM10 · 71 days · 19.5%

2024 daily-monitor rhythm in Prowers County

Month-by-month median AQI from EPA day-level county monitors (366 reported days in 2024). Oct posted the highest typical readings (median AQI 48, peak 74); Nov was cleanest at median 19. Summer months (Jun–Aug) averaged median AQI 34 vs 22 in Dec–Feb.

0 10 20 30 40 50 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 23 20 25 23 23 26 38 38 36 48 19 23
Prowers County median daily AQI by calendar month (2024, EPA daily county file)

Five-year seasonal record

EPA day-level county files · 2020–2024

1,781 daily readings show a recurring local pattern: Oct has the highest matched-month median AQI (32), while Feb is lowest (13). Each cell is that month’s median daily AQI, not a current-air forecast.

JanFebMarAprMayJunJulAugSepOctNovDec
2020 12810152028182533371910
2021 151213191319252433202424
2022 111112312319141818241720
2023 81616191512192223313219
2024 232025232326383836481923

Lower AQI is better. The colors summarize EPA AQI bands; gaps mean the county had no day-level record for that month.

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
2020 327 19 1 2 17
2021 345 14 1 0 19
2022 330 22 0 1 18
2023 336 13 1 0 19
2024 321 45 0 0 25
2025 338 25 0 0 27

How does Prowers County compare?

How Prowers County compares

Good-day share better than typical
Prowers County 92.6%
Brown County, South Dakota 83.6%
Typical US county 76.0%
Median AQI better than typical
Prowers County 27
Brown County, South Dakota 27
Typical US county 39
Unhealthy days / yr worse than typical
Prowers County 2
Brown County, South Dakota 0
Typical US county 1

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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Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.

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.