Air quality in Benton County, WA

Includes Kennewick and Richland · EPA monitor readings, 2021 to 2025 · 207,000 people

A few bad days a yearFine particles, ozone and dust
Bad-air days a year
4
days with an AQI over 100

About 1 day in 87. In the early 2000s it was about 3 a year. Benton County has the 9th most bad-air days of the 29 Washington counties with monitors.

1day unhealthy for everyoneAQI over 150, a year
37AQI on a typical dayGood: fine for everyone
Jul to Sepworst monthsFine particles, ozone and dust
954worst day since 2016Sep 7, 2020, dust
How to read the AQIThe EPA's air score runs from 0 to 500. Higher is worse. Over 100 counts as a bad-air day.
Typical day 37 (Good)Worst day 954 (Hazardous)
Good0 to 50Moderate51 to 100Sensitive groups101 to 150Unhealthy151 to 200Very unhealthy201 to 300Hazardous301 to 500

When bad air happens in Benton County

Average bad-air days in each month, from 10 years of daily readings since 2016. Most fall in July, August and September.

Jan0
Feb0.1
Mar0.1
Apr0.1
May0.1
Jun0.1
Jul0.9
Aug2.8
Sep1.7
Oct0.4
Nov0
Dec0
0123JanFebMarAprMayJunJulAugSepOctNovDecOZONESMOKE SEASON0123JFMAMJJASONDOZONESMOKE
Fine particles (smoke, soot)Dust (coarse particles)Ozone (smog)Bars stack in that order, from the bottom.
See the numbers by month
Average bad-air days a year in each month in Benton County, from 10 years of daily readings
MonthOzoneFine particlesDustAll
January0000
February000.10.1
March000.10.1
April000.10.1
May000.10.1
June0.1000.1
July0.9000.9
August0.82.002.8
September01.20.51.7
October000.40.4
November0000
December0000

The worst day since 2016 was September 7, 2020: AQI 954, past the top of the scale at 500, from dust and coarse particles.

What causes it

The pollutant that pushed the AQI over 100 on each of the 63 bad-air days since 2016.

51%particles
29%Ozone: smog that forms in sunlight on hot days
51%Fine particles: smoke and soot
21%Dust: coarse particles blown up by wind

Bad days here come from fine particles such as smoke, ozone on hot afternoons and blowing dust.

CDC estimates by month, 2001 to 2022

The CDC's model counts bad-air days at the county's worst spot, from monitors and satellites. Particles (brown) fill the inside of the ring and ozone (blue) the outside.

January: 0.3 smoky days a yearJFMAMay: 0.0 ozone days a yearMJune: 0.1 ozone days a yearJJuly: 0.0 smoky days a yearJuly: 0.2 ozone days a yearJAugust: 1.1 smoky days a yearAugust: 0.8 ozone days a yearASeptember: 1.0 smoky days a yearSeptember: 0.1 ozone days a yearSOctober: 0.0 smoky days a yearONovember: 0.5 smoky days a yearNDbad daysby month
See the numbers by month
CDC estimated bad-air days a year in each month in Benton County, 2001 to 2022
MonthFine particlesOzone
January0.30
February00
March00
April00
May00
June00.1
July00.2
August1.10.8
September1.00.1
October00
November0.50
December00

What helps in Benton County

Bad days here come from fine particles, ozone and dust, so it takes timing and filtering.

Move workouts to the morning

Ozone peaks on hot, sunny afternoons. Mornings are usually cleaner.

Ozone guide →

Keep one room clean on smoky days

Shut the windows and run an air purifier sized for the room.

Choosing a purifier →

Upgrade the furnace filter

Use MERV 13 if your system can take it, and run the fan on smoky days.

Furnace filters →

For today's reading and tomorrow's forecast, check AirNow by ZIP code. Its fire and smoke map adds smoke plumes.

Purifiers with a verified smoke rating

For a clean room on smoky days. Each has a smoke CADR tested by AHAM's independent program and is certified by California as a mechanical cleaner, so it makes no ozone.

Bedroom or small room

Levoit Vital 100S-P

143 smoke CADR

Everyday
up to 222 sq ft
Heavy smoke
up to 143 sq ft
Filters
about $40 a year

The cheapest unit we found with a verified smoke rating. Enough for a bedroom clean room.

$119.99 at Levoit
Best value for smoke

Levoit Vital 200S-P

250 smoke CADR

Everyday
up to 388 sq ft
Heavy smoke
up to 250 sq ft
Filters
about $50 a year

The most verified smoke cleaning per dollar of any qualifying model: 75% more than the 100S-P for $50 more.

$169.99 at Levoit
Living room or open floor

Levoit Core 600S-P

391 smoke CADR

Everyday
up to 606 sq ft
Heavy smoke
up to 391 sq ft
Filters
$60 to $120 a year

For a big room or a small apartment. Buy the LAP-C601S-WUS version, which CARB lists as mechanical.

$299.99 at Levoit

Why all 3 are Levoit: of the models we checked that pass both tests, these give the most verified smoke cleaning per dollar at each room size. Medify's MA-25 and MA-40 also pass but cost more for the same cleaning.

Ratings from the AHAM Verifide directory and CARB's certified list. Prices from Levoit's site, checked November 7, 2026; they change. We don't earn anything from these links. How to pick a purifier

Every year since 2000

Bad-air days each year. The striped part is days unhealthy for everyone, over AQI 150. The worst recent year was 2021, with 9 bad-air days.

05101520200020052010201514202020252051015202000201014202020252
Unhealthy for sensitive groups (101 to 150)Unhealthy or worse (over 150)
See the numbers by year
Bad-air days each year in Benton County
YearBad-air daysOver 150
200040
200143
200220
200341
200432
200532
200630
200710
200800
200911
201000
201110
201200
201331
201410
2015102
201620
2017145
2018142
201900
2020129
202193
202231
202343
202430
202520

Benton County and its neighbors

Bad-air days a year, 2021 to 2025. Washington counties with monitors averaged about 5 bad-air days a year, weighted by population.

Yakima County9
Benton County4
Umatilla County4
Grant County4
Walla Walla County2
Franklin County2

Nearest county with a full report: King County, WA (7 bad-air days a year).

Questions people ask about air in Benton County

How often is the air bad in Benton County?

From 2021 to 2025, monitors in Benton County recorded about 4 bad-air days a year with an AQI above 100, which is unhealthy for sensitive groups or worse. The worst year in that stretch was 2021, with 9 bad-air days.

What causes bad air in Benton County?

Bad days here come from fine particles such as smoke, ozone on hot afternoons and blowing dust. Bad days cluster in July, August and September.

Where can I see today's air quality in Benton County?

AirNow, run by the EPA and its partners, shows the current AQI and tomorrow's forecast for your ZIP code. Its fire and smoke map adds smoke plumes. On a typical day the AQI in Benton County is about 37, which is good, fine for everyone. Check it most in July, August and September, when bad days here cluster.

About these numbers

Day counts come from the EPA's county air quality summaries, which take the worst reading across a county's monitors each day. Monitors here reported on about 365 days a year from 2021 to 2025. A county is large, and your street can be cleaner or worse. CDC's model, which estimates every county from monitors and satellites, gives the worst spot in Benton County about 7 high-particle days and about 1 high-ozone day a year from 2018 to 2022.

Sources: EPA AirData county AQI summaries (2000 to 2025) and daily county AQI (2016 to 2025); CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone (2001 to 2022). Updated November 8, 2026.