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AirHistory

What Is the Air Quality in Stevens, Washington?

Stevens, Washington has an Air Quality Grade of C (fair) with a 5-year median AQI of 42. The dominant pollutant is Fine Particulate Matter (PM2.5), and air quality has been worsening over the past decade.

Stevens, Washington Air Quality Snapshot

Air Quality GradeC54/100
5-Year Median AQI42 (Good)
Most Recent Median AQI (2023)46 (Good)
Dominant PollutantFine Particulate Matter (PM2.5)
10-Year TrendWorsening (+0.83 AQI/yr)
Unhealthy Days (last 5 yr)42
National Rank (cleanest = #1)#623 of 1,020 (61th most polluted percentile)
Washington Rank#25 of 30

What Does the C Grade Mean?

Stevens, Washington earns a C — air quality is fair, but not great. With a 5-year median AQI of 42, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.

Stevens, Washington's 5-year median AQI of 42 is right around the national average of 41 across the 1,020 monitored U.S. cities tracked here. Within Washington, Stevens, Washington runs more polluted than the state average of 31 — local sources or geography are concentrating pollution above the state's typical reading.

For context within Washington: Garfield, Washington currently holds the state's cleanest grade (A, AQI 20), while Asotin, Washington sits at the bottom (D, AQI 43).

What's in Stevens, Washington's Air?

The dominant pollutant in Stevens, Washington is Fine Particulate Matter (PM2.5). Fine particulate matter — particles less than 2.5 micrometers across — comes mostly from combustion: vehicle exhaust, wildfire smoke, residential wood burning, and industrial emissions. Because these particles are small enough to enter the bloodstream, PM2.5 is the pollutant most strongly linked to cardiovascular disease, respiratory illness, and premature death.

Days by Dominant Pollutant (2023)

PollutantDays as DominantShare of Year
Fine Particulate Matter (PM2.5)35397%
Coarse Particulate Matter (PM10)123%

Is the Air Getting Better or Worse?

Air quality in Stevens, Washington has been getting worse over the past decade, with median AQI climbing by roughly 0.8 points per year. That bucks the national trend of broad improvement, and most often reflects either growing wildfire smoke exposure (particularly across the West) or rising local emissions from population and freight growth.

In 2014, Stevens, Washington posted a median AQI of 39. By 2023 that figure was 46 — a rise of 7 AQI points dirtier across 10 years of EPA records.

Year-by-Year AQI in Stevens, Washington

YearMedian AQIGood DaysUnhealthy DaysDominant Pollutant
2014392234PM2.5
20153622412PM2.5
2016342542PM2.5
20174719517PM2.5
20184620017PM2.5
2019362231PM2.5
2020422199PM2.5
20214420316PM2.5
2022432088PM2.5
2023462048PM2.5

Health Context for Stevens, Washington

Across the past five years, this area has logged 42 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 8 days per year. That is roughly typical for a U.S. metro, with most caution days clustered in summer (ozone) or wildfire season.

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 PM2.5 penetrates deep into the lungs and bloodstream, an N95 or KN95 mask provides meaningful protection on smoky or high-particulate days — surgical masks do not.

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.

Stevens, Washington has an Air Quality Grade of C (fair) with a 5-year median AQI of 42. The dominant pollutant is Fine Particulate Matter (PM2.5), and air quality has been worsening 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.