Air quality · Utah
Air quality in Utah
Across the 5 Utah ZIPs with EPA county air-quality data, the median day ranges from Good to Moderate (median AQI 44–57). 4 days across those counties reached Unhealthy or worse in 2025. This is a 2025 county annual summary, not a live reading.
Last verified 2026-09-24 · methodology
Air quality by ZIP code in Utah
EPA's 2025 annual summary for each ZIP's county. Median AQI is the typical day; lower is cleaner.
| ZIP | Median AQI | Good days | Unhealthy or worse |
|---|---|---|---|
| 84101Salt Lake CitySalt Lake County | 57 Moderate | 121 of 365 | 1 |
| 84060Park CitySummit County | No data | ||
| 84111Salt Lake City (Downtown)Salt Lake County | 57 Moderate | 121 of 365 | 1 |
| 84109Salt Lake City (Sugar House)Salt Lake County | 57 Moderate | 121 of 365 | 1 |
| 84770Saint George (UT)Washington County | 44 Good | 274 of 365 | 0 |
| 84102Salt Lake City (Downtown)Salt Lake County | 57 Moderate | 121 of 365 | 1 |
County-level figures from EPA Air Quality System (AQS), annual county summary, joined to each ZIP by county. None of them is a measurement at a specific address.
What lands here
Pages show the 2025 median AQI category (Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, Hazardous) for the ZIP's county, plus the year's max/90th-percentile AQI and day-count breakdown by category.
Source & refresh
EPA Air Quality System (AQS), annual county summary. Refreshed annual (epa aqs publication). Primary source →
Utah top concern
Radon Zone 1, wildfire, water-supply scarcity
Utah is uniformly Zone 1 radon. Wildfire risk concentrates in the Wasatch + southern UT. Great Salt Lake decline + Colorado River allotment uncertainty drive water-supply pressure on Salt Lake metro EPA SDWIS systems.
See Utah state page for the full state-level rollup across all 12 dimensions.
Read more on air quality
Editorial deep-dives explaining the source data, its limits, and how to read it.
EPA AQI categories explained — what 0–50 Good through 301–500 Hazardous mean
Plain-English guide to the six EPA Air Quality Index categories: 0–50 Good, 51–100 Moderate, 101–150 Unhealthy for Sensitive Groups, 151–200 Unhealthy, 201–300 Very Unhealthy, 301–500 Hazardous — what each level means and who is at risk.
AQI explained — what 50, 100, 150 actually mean for your lungs
Plain-English guide to the EPA Air Quality Index (AQI) and the 6 categories from Good to Hazardous. When to take precautions and which pollutants matter.
Wildfire Hazard Potential — what the USFS scale means and how to defend your home
Plain-English guide to the USDA Forest Service's Wildfire Hazard Potential 1–5 scale, how to read your community's risk, and concrete home-defense measures.
AirNow + wildfire smoke — when AQI is a real-time tool
How EPA AirNow handles real-time wildfire smoke, what the colors mean during fire season, and where AirNow leaves gaps you should know about.