Wyoming · County air quality · 2025

Converse County, Wyoming

Median AQI 40 (Good). 96.2% of monitored days rated Good, direct from EPA Air Quality System stations.

40
Median AQI
96.2%
Good-air days
0
Unhealthy days
94%
Cleaner than US counties

Converse County's 2025 annual median AQI is 40 (Good), with 96.2% Good days

According to the U.S. EPA Air Quality System, Converse County, Wyoming posted a 2025 median AQI of 40 (Good) across 365 monitored days, with 96.2% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US
Converse County's 96.2% Good-day share places it cleaner than 94% of US counties in 2025.
Closest median-AQI peer
Anderson County (91.3% Good, median AQI 40) is the closest nationwide median-AQI peer to Converse County.
2020–2025 trend
Converse County's floor-qualifying Good-day share is improving from 2020 to 2025 (82.5% → 96.2%).
Median AQI
Median AQI: 40

According to the 2025 EPA AQS county release on PlainAirData, Converse County, Wyoming ranks #462 of 951 by median AQI (40) and #55 by good-day share (96.2%). 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
  • Converse County's Good-day share rose from 82.0% to 96.2% between the 2024 and 2025 EPA annual releases, a change of +14.2 percentage points.
  • Converse County's peak single-day AQI fell from 185 to 63 between the 2024 and 2025 EPA annual releases, a change of -122 points.
  • Converse County's Unhealthy-category days fell from 2 to 0 between the 2024 and 2025 EPA annual releases, a change of -2 days.

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

Converse 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 40 0 50 100 150 200 300 500 Converse County
  • Good · 351 d · 96.2%
  • Moderate · 14 d · 3.8%

How did Converse County's air break down in 2025?

Across 365 monitored days, 351 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 63 (Moderate).

EPA AQS →
Converse County, Good days share 96.2%
National avg

Share of monitored days at AQI 0-50 (Good band).

Converse County, Unhealthy-or-worse share 0.0%
National avg

Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).

Where Converse County sits nationally

COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Converse County's Good-day share is 96.2% - cleaner than 94% of that comparison set.

Converse County Good-day share vs. every US county

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

96.2% Cleaner than 94% higher than 94% 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%). Below this entry. 95.0%–100.0%: 70 US counties (7%). This entry sits in this band. 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 Converse County.

Converse County, Wyoming 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. Ozone · 88.5% PM10 · 11.2% 0% 25% 50% 75% 100% Converse County, Wyoming · 365 monitored days Criteria pollutant column
  • Ozone · 323 days · 88.5%
  • PM10 · 41 days · 11.2%
  • NO₂ · 1 days · 0.3%

2024 daily-monitor rhythm in Converse County

Month-by-month median AQI from EPA day-level county monitors (366 reported days in 2024). Jul posted the highest typical readings (median AQI 58, peak 126); Nov was cleanest at median 34. Summer months (Jun–Aug) averaged median AQI 50 vs 36 in Dec–Feb. 2 days crossed Unhealthy (AQI >150) at least once that year.

0 10 20 30 40 50 60 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 36 37 38 44 44 45 58 47 55 40 34 36
Converse County median daily AQI by calendar month (2024, EPA daily county file)

Five-year seasonal record

EPA day-level county files · 2020–2024

1,827 daily readings show a recurring local pattern: Jul has the highest matched-month median AQI (55), while Oct is lowest (33). Each cell is that month’s median daily AQI, not a current-air forecast.

JanFebMarAprMayJunJulAugSepOctNovDec
2020 384239444244476150203638
2021 393941434348746349363238
2022 374042424244505043363436
2023 384443454740464444323936
2024 363738444445584755403436

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

Converse County's air quality is rated Excellent based on 96.2% good air days. No unhealthy air days were recorded in 2025.

Air quality was acceptable on 96.2% of monitored days in 2025, with a median AQI of 40. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.

The dominant pollutant is Ozone, driving AQI on 323 of 365 monitored days.

5-Year Air Quality Trend

Air quality is improving in Converse County. Highest Good-day share: 2025 (96.2%, 351 of 365 monitored days).

Year Good Moderate USG Unhealthy Median AQI
2020 302 60 4 0 42
2021 274 87 4 0 42
2022 314 51 0 0 40
2023 331 34 0 0 42
2024 300 53 11 2 41
2025 351 14 0 0 40

How does Converse County compare?

How Converse County compares

Good-day share better than typical
Converse County 96.2%
Anderson County, South Carolina 91.3%
Typical US county 76.0%
Median AQI worse than typical
Converse County 40
Anderson County, South Carolina 40
Typical US county 39
Unhealthy days / yr better than typical
Converse County 0
Anderson County, South Carolina 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 Converse County, Wyoming · 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.