EnviroNearby

Whitman County, Washington air quality history

Daily Air Quality Index summaries from EPA monitors in Whitman, Washington, 2000–2025.

87%
Good days in 2025
23
Median daily AQI, 2025
0
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Whitman, Washington on 365 days. 317 of those days (87%) were in the Good range, and the median daily AQI was 23. That median is lower than the typical monitored county in Washington (median 28 across 30 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 365 days. Across the years with fuller monitoring, the share of Good days rose: an average of 80% in 2002–2004 versus 87% in 2023–2025.

Years with fewer than 120 monitored days (2000, 2001) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%2000: Good 47 of 60 days2000: Moderate 13 of 60 days20002001: Good 57 of 60 days2001: Moderate 3 of 60 days2002: Good 89 of 122 days2002: Moderate 33 of 122 days20022003: Good 309 of 365 days2003: Moderate 56 of 365 days2004: Good 307 of 366 days2004: Moderate 59 of 366 days20042005: Good 332 of 365 days2005: Moderate 33 of 365 days2006: Good 305 of 365 days2006: Moderate 58 of 365 days2006: Unhealthy for Sensitive Groups 2 of 365 days20062007: Good 309 of 365 days2007: Moderate 56 of 365 days2008: Good 320 of 366 days2008: Moderate 46 of 366 days20082009: Good 330 of 365 days2009: Moderate 35 of 365 days2010: Good 335 of 365 days2010: Moderate 30 of 365 days20102011: Good 315 of 363 days2011: Moderate 48 of 363 days2012: Good 308 of 366 days2012: Moderate 54 of 366 days2012: Unhealthy for Sensitive Groups 2 of 366 days2012: Unhealthy 2 of 366 days20122013: Good 291 of 365 days2013: Moderate 74 of 365 days2014: Good 320 of 363 days2014: Moderate 43 of 363 days20142015: Good 297 of 362 days2015: Moderate 57 of 362 days2015: Unhealthy for Sensitive Groups 7 of 362 days2015: Unhealthy 1 of 362 days2016: Good 344 of 366 days2016: Moderate 22 of 366 days20162017: Good 299 of 365 days2017: Moderate 56 of 365 days2017: Unhealthy for Sensitive Groups 5 of 365 days2017: Unhealthy 4 of 365 days2017: Very Unhealthy 1 of 365 days2018: Good 303 of 365 days2018: Moderate 55 of 365 days2018: Unhealthy for Sensitive Groups 5 of 365 days2018: Unhealthy 2 of 365 days20182019: Good 324 of 365 days2019: Moderate 41 of 365 days2020: Good 335 of 366 days2020: Moderate 23 of 366 days2020: Unhealthy for Sensitive Groups 1 of 366 days2020: Unhealthy 5 of 366 days2020: Very Unhealthy 2 of 366 days20202021: Good 310 of 365 days2021: Moderate 45 of 365 days2021: Unhealthy for Sensitive Groups 5 of 365 days2021: Unhealthy 4 of 365 days2021: Very Unhealthy 1 of 365 days2022: Good 306 of 365 days2022: Moderate 55 of 365 days2022: Unhealthy 4 of 365 days20222023: Good 323 of 365 days2023: Moderate 40 of 365 days2023: Very Unhealthy 1 of 365 days2023: Hazardous 1 of 365 days2024: Good 310 of 366 days2024: Moderate 56 of 366 days20242025: Good 317 of 365 days2025: Moderate 48 of 365 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501002000: 90th percentile AQI 582001: 90th percentile AQI 462002: 90th percentile AQI 562003: 90th percentile AQI 542004: 90th percentile AQI 532005: 90th percentile AQI 482006: 90th percentile AQI 552007: 90th percentile AQI 542008: 90th percentile AQI 522009: 90th percentile AQI 502010: 90th percentile AQI 472011: 90th percentile AQI 522012: 90th percentile AQI 562013: 90th percentile AQI 562014: 90th percentile AQI 522015: 90th percentile AQI 562016: 90th percentile AQI 442017: 90th percentile AQI 582018: 90th percentile AQI 582019: 90th percentile AQI 512020: 90th percentile AQI 472021: 90th percentile AQI 582022: 90th percentile AQI 562023: 90th percentile AQI 532024: 90th percentile AQI 542025: 90th percentile AQI 542000: Median AQI 342001: Median AQI 292002: Median AQI 362003: Median AQI 292004: Median AQI 322005: Median AQI 282006: Median AQI 282007: Median AQI 282008: Median AQI 282009: Median AQI 312010: Median AQI 242011: Median AQI 242012: Median AQI 252013: Median AQI 302014: Median AQI 262015: Median AQI 262016: Median AQI 232017: Median AQI 242018: Median AQI 222019: Median AQI 242020: Median AQI 192021: Median AQI 222022: Median AQI 242023: Median AQI 262024: Median AQI 202025: Median AQI 2320002002200420062008201020122014201620182020202220242025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Fine particles (PM2.5)365100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025365317480000235499PM2.5
2024366310560000205497PM2.5
20233653234000112653326PM2.5
20223653065504002456190PM2.5
20213653104554102258218PM2.5
20203663352315201947237PM2.5
2019365324410000245171PM2.5
20183653035552002258187PM2.5
20173652995654102458210PM2.5
2016366344220000234486PM2.5
20153622975771002656185PM2.5
2014363320430000265295PM2.5
2013365291740000305676PM2.5
20123663085422002556157PM2.5
2011363315480000245273PM2.5
2010365335300000244767PM2.5
2009365330350000315071PM2.5
2008366320460000285267PM2.5
2007365309560000285477PM2.5
20063653055820002855116PM2.5
2005365332330000284865PM2.5
2004366307590000325378PM2.5
2003365309560000295498PM2.5
200212289330000365669PM2.5
2001605730000294659PM2.5
20006047130000345880PM2.5

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Washington with a similar median AQI in 2025

All monitored counties in Washington

Source: U.S. EPA AirData, “Annual AQI by County” files for 2000–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem