Utah · County air quality · 2025

Wasatch County, Utah

Median AQI 45 (Good). 65.8% of monitored days rated Good, direct from EPA Air Quality System stations.

45
Median AQI
65.8%
Good-air days
0
Unhealthy days
24%
Cleaner than US counties

Wasatch County's 2025 annual median AQI is 45 (Good), with 65.8% Good days

According to the U.S. EPA Air Quality System, Wasatch County, Utah posted a 2025 median AQI of 45 (Good) across 365 monitored days, with 65.8% 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
Wasatch County's 65.8% Good-day share places it cleaner than 24% of US counties in 2025.
Closest median-AQI peer
Baltimore County (64.7% Good, median AQI 45) is the closest nationwide median-AQI peer to Wasatch County.
2024–2025 trend
Wasatch County's floor-qualifying Good-day share is worsening from 2024 to 2025 (90.2% → 65.8%).
Median AQI
Median AQI: 45

According to the 2025 EPA AQS county release on PlainAirData, Wasatch County, Utah ranks #750 of 951 by median AQI (45) and #721 by good-day share (65.8%). 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
  • Wasatch County's Good-day share fell from 90.2% to 65.8% between the 2024 and 2025 EPA annual releases, a change of -24.4 percentage points.
  • Wasatch County's median AQI rose from 37 to 45 between the 2024 and 2025 EPA annual releases, a change of +8 points.

Compared against 153 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

Wasatch 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 M Median AQI 45 0 50 100 150 200 300 500 Wasatch County
  • Good · 240 d · 65.8%
  • Moderate · 124 d · 34.0%
  • USG · 1 d · 0.3%

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

Across 365 monitored days, 240 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 105 (USG).

EPA AQS →
Wasatch County, Good days share 65.8%
National avg

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

Wasatch 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 Wasatch County sits nationally

COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Wasatch County's Good-day share is 65.8% - cleaner than 24% of that comparison set.

Wasatch County Good-day share vs. every US county

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

65.8% 24th percentile higher than 24% 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%). This entry sits in this band. 70.0%–75.0%: 109 US counties (11%). Above this entry. 75.0%–80.0%: 114 US counties (12%). Above this entry. 80.0%–85.0%: 123 US counties (13%). Above this entry. 85.0%–90.0%: 99 US counties (10%). Above this entry. 90.0%–95.0%: 117 US counties (12%). Above this entry. 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 Wasatch County.

Wasatch County, Utah 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 · 87.7% PM2.5 · 12.1% 0% 25% 50% 75% 100% Wasatch County, Utah · 365 monitored days Criteria pollutant column
  • Ozone · 320 days · 87.7%
  • PM2.5 · 44 days · 12.1%
  • NO₂ · 1 days · 0.3%

2024 daily-monitor rhythm in Wasatch County

Month-by-month median AQI from EPA day-level county monitors (153 reported days in 2024). Aug posted the highest typical readings (median AQI 48, peak 108); Dec was cleanest at median 31. Summer months (Jun–Aug) averaged median AQI 48 vs 31 in Dec–Feb.

0 10 20 30 40 50 Aug Sep Oct Nov Dec 48 44 38 31 31
Wasatch County median daily AQI by calendar month (2024, EPA daily county file)

Health Impact Assessment

Moderate

Wasatch County's air quality is rated Moderate based on 65.8% good air days. No unhealthy air days were recorded in 2025.

Air quality was acceptable on 65.8% of monitored days in 2025, with a median AQI of 45. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.

The dominant pollutant is Ozone, driving AQI on 320 of 365 monitored days.

5-Year Air Quality Trend

Air quality is worsening in Wasatch County. Highest Good-day share: 2024 (90.2%, 138 of 153 monitored days).

Year Good Moderate USG Unhealthy Median AQI
2024 138 14 1 0 37
2025 240 124 1 0 45

How does Wasatch County compare?

How Wasatch County compares

Good-day share worse than typical
Wasatch County 65.8%
Baltimore County, Maryland 64.7%
Typical US county 76.0%
Median AQI worse than typical
Wasatch County 45
Baltimore County, Maryland 45
Typical US county 39
Unhealthy days / yr better than typical
Wasatch County 0
Baltimore County, Maryland 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 Wasatch County, Utah · 2020–2025

Embed this widget

Copy this snippet to embed a live-linked card on your own site. Attribution to PlainAirData is baked into the widget.

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.