Is the Air Quality Good in Washington, Utah?
Mostly — air quality in Washington, Utah is fair, not pristine. The city earns a Grade of C (fair) on a 5-year median AQI of 44 (Good), with 6 unhealthy-air days over five years (about 1 per year). Healthy adults are fine most of the time, but sensitive groups should watch the daily forecast.
Who Can Safely Breathe the Air in Washington, Utah?
Healthy adults can continue normal outdoor activity in most weather, but should pay attention to AQI alerts during the worst pollution windows. People with asthma, heart disease, or pregnancy should reduce prolonged or intense outdoor exertion on flagged days, and consider running an indoor HEPA air cleaner during peak season. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.
Across the past five years, this area has logged just 6 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 1 days per year, or roughly one every other month. That is a low count by national standards.
Washington, Utah Air Quality Snapshot
| Air Quality Grade | C63/100 |
| 5-Year Median AQI | 44 (Good) |
| Most Recent Median AQI (2023) | 43 (Good) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Stable (+0.04 AQI/yr) |
| Unhealthy Days (last 5 yr) | 6 |
| National Rank (cleanest = #1) | #726 of 1,020 (71th most polluted percentile) |
| Utah Rank | #8 of 15 |
What Does the C Grade Mean?
Washington, Utah earns a C — air quality is fair, but not great. With a 5-year median AQI of 44, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.
Washington, Utah's 5-year median AQI of 44 is 3 points above the national average of 41 — meaningfully more polluted than the typical U.S. metro tracked here. Within Utah, Washington, Utah's air quality is roughly typical for the state, where the average city posts a 5-year median AQI of 43.
For context within Utah: Wayne, Utah currently holds the state's cleanest grade (B, AQI 11), while Salt Lake, Utah sits at the bottom (D, AQI 57).
What's in Washington, Utah's Air?
The dominant pollutant in Washington, Utah is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle exhaust and industrial emissions. It is worst on hot, sunny, stagnant summer days. Ozone irritates the lungs, triggers asthma attacks, and reduces lung function — even healthy adults can feel chest tightness and shortness of breath after exercising in elevated ozone.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Ground-Level Ozone | 345 | 95% |
| Fine Particulate Matter (PM2.5) | 20 | 5% |
Is the Air Getting Better or Worse?
Air quality in Washington, Utah has held roughly steady over the past decade, with year-to-year shifts in median AQI of less than half a point. That stability makes the city's long-run grade a reliable signal of what residents can expect day-to-day.
In 2014, Washington, Utah posted a median AQI of 44. By 2023 that figure was 43 — a drop of 1 AQI points cleaner across 10 years of EPA records.
Year-by-Year AQI in Washington, Utah
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 44 | 284 | 1 | Ozone |
| 2015 | 43 | 276 | 3 | Ozone |
| 2016 | 43 | 281 | 0 | Ozone |
| 2017 | 45 | 256 | 1 | Ozone |
| 2018 | 44 | 223 | 1 | Ozone |
| 2019 | 45 | 283 | 0 | Ozone |
| 2020 | 44 | 276 | 3 | Ozone |
| 2021 | 45 | 256 | 3 | Ozone |
| 2022 | 44 | 288 | 0 | Ozone |
| 2023 | 43 | 291 | 0 | Ozone |
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
More about Washington, Utah
Washington, Utah has an Air Quality Grade of C (fair) with a 5-year median AQI of 44. The dominant pollutant is Ground-Level Ozone, and air quality has been stable over the past decade.
The data source behind this answer is the EPA Air Quality System (AQS). Every figure on the page traces back to that source; the methodology page describes the inputs and the refresh cadence in full detail.
A practical caveat: the headline answer above reflects the most recent the EPA Air Quality System (AQS) vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: EPA Outdoor Air Quality Data, 2026.