EnviroNearby

Benton County, Oregon air quality history

Daily Air Quality Index summaries from EPA monitors in Benton, Oregon, 1999–2022.

89%
Good days in 2022
21
Median daily AQI, 2022
0
Days above 100 in 2022
206
Days with an AQI in 2022 (of 365)

In 2022, EPA reported a daily Air Quality Index (AQI) for Benton, Oregon on 206 days. 183 of those days (89%) were in the Good range, and the median daily AQI was 21. That median is lower than the typical monitored county in Oregon (median 33 across 22 counties), and lower than the typical monitored U.S. county (41). The main pollutant was fine particles (PM2.5) on 206 days. Across the years with fuller monitoring, the share of Good days rose: an average of 77% in 2000–2005 versus 90% in 2020–2022.

EPA did not report an AQI for every day of 2022 here (206 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

The most recent year with data for this county is 2022; EPA's files for 2023–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1999, 2001, 2002) 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%1999: Good 88 of 111 days1999: Moderate 22 of 111 days1999: Unhealthy for Sensitive Groups 1 of 111 days19992000: Good 87 of 120 days2000: Moderate 32 of 120 days2000: Unhealthy for Sensitive Groups 1 of 120 days2001: Good 94 of 116 days2001: Moderate 22 of 116 days20012002: Good 88 of 116 days2002: Moderate 28 of 116 days2004: Good 281 of 355 days2004: Moderate 74 of 355 days20042005: Good 291 of 362 days2005: Moderate 70 of 362 days2005: Unhealthy for Sensitive Groups 1 of 362 days2006: Good 303 of 363 days2006: Moderate 60 of 363 days20062007: Good 288 of 359 days2007: Moderate 69 of 359 days2007: Unhealthy for Sensitive Groups 2 of 359 days2008: Good 301 of 366 days2008: Moderate 65 of 366 days20082009: Good 294 of 365 days2009: Moderate 71 of 365 days2010: Good 331 of 364 days2010: Moderate 33 of 364 days20102011: Good 290 of 361 days2011: Moderate 71 of 361 days2012: Good 306 of 355 days2012: Moderate 49 of 355 days20122013: Good 282 of 355 days2013: Moderate 72 of 355 days2013: Unhealthy for Sensitive Groups 1 of 355 days2014: Good 318 of 364 days2014: Moderate 45 of 364 days2014: Unhealthy for Sensitive Groups 1 of 364 days20142015: Good 314 of 365 days2015: Moderate 49 of 365 days2015: Unhealthy for Sensitive Groups 1 of 365 days2015: Unhealthy 1 of 365 days2016: Good 175 of 194 days2016: Moderate 19 of 194 days20162017: Good 294 of 357 days2017: Moderate 61 of 357 days2017: Unhealthy for Sensitive Groups 2 of 357 days2018: Good 313 of 362 days2018: Moderate 47 of 362 days2018: Unhealthy for Sensitive Groups 2 of 362 days20182019: Good 302 of 365 days2019: Moderate 63 of 365 days2020: Good 313 of 366 days2020: Moderate 42 of 366 days2020: Unhealthy 1 of 366 days2020: Very Unhealthy 7 of 366 days2020: Hazardous 3 of 366 days20202021: Good 345 of 365 days2021: Moderate 20 of 365 days2022: Good 183 of 206 days2022: Moderate 23 of 206 days2022
  • 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 year0501001999: 90th percentile AQI 622000: 90th percentile AQI 692001: 90th percentile AQI 612002: 90th percentile AQI 612004: 90th percentile AQI 582005: 90th percentile AQI 572006: 90th percentile AQI 552007: 90th percentile AQI 642008: 90th percentile AQI 582009: 90th percentile AQI 582010: 90th percentile AQI 492011: 90th percentile AQI 572012: 90th percentile AQI 542013: 90th percentile AQI 632014: 90th percentile AQI 522015: 90th percentile AQI 542016: 90th percentile AQI 502017: 90th percentile AQI 582018: 90th percentile AQI 532019: 90th percentile AQI 562020: 90th percentile AQI 562021: 90th percentile AQI 452022: 90th percentile AQI 521999: Median AQI 252000: Median AQI 302001: Median AQI 312002: Median AQI 312004: Median AQI 232005: Median AQI 212006: Median AQI 212007: Median AQI 212008: Median AQI 232009: Median AQI 262010: Median AQI 202011: Median AQI 212012: Median AQI 212013: Median AQI 222014: Median AQI 212015: Median AQI 222016: Median AQI 202017: Median AQI 202018: Median AQI 222019: Median AQI 222020: Median AQI 232021: Median AQI 222022: Median AQI 21199920012004200620082010201220142016201820202022
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2022

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)206100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2022206183230000215268PM2.5
2021365345200000224569PM2.5
20203663134201732356541PM2.5
2019365302630000225687PM2.5
20183623134720002253119PM2.5
20173572946120002058138PM2.5
2016194175190000205068PM2.5
20153653144911002254154PM2.5
20143643184510002152115PM2.5
20133552827210002263109PM2.5
2012355306490000215469PM2.5
2011361290710000215786PM2.5
2010364331330000204972PM2.5
2009365294710000265894PM2.5
2008366301650000235887PM2.5
20073592886920002164106PM2.5
2006363303600000215588PM2.5
20053622917010002157104PM2.5
2004355281740000235898PM2.5
200211688280000316190PM2.5
200111694220000316195PM2.5
2000120873210003069107PM2.5
1999111882210002562114PM2.5

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.

All monitored counties in Oregon

Source: U.S. EPA AirData, “Annual AQI by County” files for 1999–2022 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem