Bellevue Real-Time AQI Tracker
Get Alerts For Unhealthy AQI In Your Area
When air quality in your area reaches unhealthy levels, we'll send you a quick alert, along with expert tips on how to reduce your exposure.
What's Actually In Bellevue Air Today?
What High AQI Means for Your Lungs in Bellevue
How to Read AQI
The Air Quality Index (AQI) measures how polluted the air is and how it may affect your health.
0–50 (Good): Air quality is satisfactory.
51–100 (Moderate): Acceptable, but some pollutants may pose minor concerns.
101–150 (Unhealthy for Sensitive Groups)
151–200 (Unhealthy)
201–300 (Very Unhealthy)
301+ (Hazardous)
Moderate
Still okay for most, but if you have asthma or allergies, take it easy and avoid long outdoor workouts.
Shop MERV 11 filters→What's the Right Filter for Your AQI Level?
Check Today's Live Real Time Air Quality Index AQI Map in Bellevue, WA Now
TL;DR
Bellevue, Washington's air quality is bad today if the real-time map above shows an Air Quality Index (AQI) of 101 or higher. Most King County days rate Good. Bad days usually mean late-summer wildfire smoke or winter wood smoke. Filterbuy acts at AQI 100: a MERV 13 in your HVAC, the fan on On, a portable HEPA air cleaner in each occupied room, and the house closed up.
Key Takeaways
Most unhealthy readings come from fine particles (PM2.5) in wildfire smoke and winter wood smoke.
About 8,531 residents and 40,000 workers sit inside Bellevue's freeway Air Pollution Exposure Zones.
EPA recommends a MERV 13 or higher HVAC filter during smoke, and most systems can take one.
How to Read the Live Bellevue Air Quality Map
The live map shows Bellevue's current AQI on a 0 to 500 scale, from green (Good) to maroon (Hazardous). Once it passes 100, the air is unhealthy for at least some people. Filterbuy's 60-second check:
Read the number, then the timestamp.
Note the pollutant: PM2.5 usually means smoke or soot, ozone a hot afternoon.
Smoky sky but a low number? Check the smoke map.
November through February, check burn ban status too.
Bellevue's neighborhood monitor is a PM2.5 station on SE 12th Street, active since 2016 and listed in the Washington State Department of Ecology's 2026 network plan. A single monitor can't see every block, so homes beside freeway ramps may run higher on still mornings.
Bellevue AQI Levels and the Right Move at Each One
On Good or Moderate days, most people need no changes; late Moderate is the time to stock a MERV 13 and spares. At AQI 100, Filterbuy's action line, check AirNow and county guidance first, then take four steps:
Put a MERV 13 filter in your HVAC system.
Set the thermostat fan from Auto to On so it filters continuously.
Run a portable HEPA air cleaner in each occupied room, bedrooms first.
Close the house up, and skip candles, frying, smoking and unsealed vacuums.
EPA sets the categories. Filterbuy acts at 100, the top of Moderate; Unhealthy for Sensitive Groups starts at 101.
Since May 6, 2024, the EPA counts PM2.5 above 9.0 µg/m³ as Moderate rather than Good, so some once-green days now show yellow.
When the Map Doesn't Match the Sky Over Bellevue
The number can trail the sky. NowCast averaging delays a fast surge by an hour or two, and smoke riding high can turn the sky orange while street-level air reads Moderate.
Ecology saw this in 2020, when cooler temperatures on the night of September 10 pulled the plume down to ground level. If you see or smell smoke, close up before the number catches up.
Is It Safe to Be Outside in Bellevue Today?
Under EPA's AirNow guidance, at 101 to 150, children, older adults and people with heart or lung disease should cut back on strenuous activity; at 151 and above, everyone should. If you have asthma, COPD or heart disease, follow your doctor's plan. Public Health – Seattle & King County recommends a tight-fitting N95 for anyone who must be out in smoke. Above 100, skip trails beside I-405, such as parts of Mercer Slough Nature Park.
Where Bellevue Gets Air Quality Forecasts and Burn Ban Warnings
The Puget Sound Clean Air Agency (PSCAA) runs a fine particle sensor map covering King County and its neighbors. During fire season, the Washington Smoke Blog posts smoke forecasts.
PSCAA also calls burn bans. Stage 1 stops wood fireplaces, uncertified stoves and outdoor burning; Stage 2 covers all wood and pellet devices except approved sole heat sources. Bans come 48 to 72 hours ahead of stagnant air, so Filterbuy treats a Stage 1 call as a reminder to check your filter. See current burn ban status or call 800-595-4341.
How Air Quality Shifts Across Bellevue Neighborhoods
With no heavy industry, Bellevue's neighborhood differences come mostly from freeway traffic. A 2023 City of Bellevue report notes that I-405, I-90 and SR 520 each carry over 100,000 trips a day and links health risks to homes up to 1,500 feet away. About 13 percent of the city's land, where 8,531 people live and 40,000 work, sits inside its Air Pollution Exposure Zones.
Source: City of Bellevue (2023). ZIP codes are approximate.
What Drives Bellevue Air Pollution: PM2.5, Ozone and More
PM2.5 drives most of Bellevue's high readings. These fine particles come from wildfire smoke, wood burning and vehicle exhaust, and reach deep into the lungs.
In summer, ground-level ozone joins in. It forms when exhaust reacts in sunlight and peaks on hot afternoons, and King County got an ozone F in the 2026 State of the Air report. Ozone is a gas, so pleated filters don't capture it; on hot afternoons, keep windows shut and move workouts to the morning.
How the Seattle-Bellevue Area Compares with Other U.S. Metros
The American Lung Association's 2026 State of the Air report ranks the Seattle-Tacoma metro 8th worst for short-term particle pollution, a weighted 11.3 unhealthy days a year from 2022 to 2024, yet passing for year-round particles.
We read that as good news with a catch: bad days come in short bursts. Compare Filterbuy's Seattle AQI map, Tacoma AQI map and Washington air quality map.
Wildfire Smoke Season on the Eastside
Of those bursts, wildfire smoke is the biggest. In September 2020, it pushed the Puget Sound Clean Air Agency's fine particle readings to their highest level since monitoring began in 1999, with 12 harmful days.
When smoke is forecast, check our Bellevue wildfire and smoke map and the AirNow Fire and Smoke Map for plume direction. Filterbuy's founder puts it plainly:
After years of manufacturing air filters, the lesson I would pass on to Bellevue families is simple: prepare before the smoke arrives. Check your filter size and keep a MERV 13 in that size on the shelf before the September east winds.
No Ducts? Cleaner Air in Bellevue Apartments and Condos
No ducts, no filter slot. If your apartment heats with baseboard or wall units, portable HEPA air cleaners are your main defense, not a backup, and they'll do more here than any HVAC filter Filterbuy sells. Size each one to the room: EPA calls for a smoke CADR of at least two-thirds of the floor area, so a 300-square-foot bedroom needs about 200. Skip ionizers and ozone generators, which EPA advises against.
Filterbuy's Take: What Bellevue's Freeway Map Tells a Filter Maker
At Filterbuy, we've built HVAC filters in the U.S. for more than a decade and shipped millions to homes. The city's 2023 planning report reaches our conclusion: MERV 13 or better near busy roads.
I hear the same assumption from homeowners near highways and industrial parks: they think changing their filter more often will fix a high pollution problem. The rating matters far more than the schedule. A fresh MERV 8 filter still lets most fine particles through, while a MERV 13 filter catches far more of them.
Michelle Wan, Brand Manager and Air Quality Writer, Filterbuy
Beyond the freeways, we plan around Bellevue's two-peak air year:
Matching Your Filter to Bellevue's AQI
For wildfire and wood smoke, use MERV 13; outside those seasons, MERV 8 or 11 is enough. EPA notes most furnaces and HVAC systems take a MERV 13 without equipment problems when it's replaced often, so the only check is fit. During smoke, replace it when it looks dark brown or black, often well before the usual interval.
The question I get most is which MERV to buy. The one to ask first is whether the filter you are holding actually fills the slot. A rating describes the media, not the gap around it.
Michelle Wan, Brand Manager and Air Quality Writer, Filterbuy
That's why Filterbuy stocks 600+ sizes and will cut custom filters to the eighth of an inch.
Shop Filterbuy MERV 8, MERV 11 or MERV 13 in your size, or set up an air filter subscription so spares are on hand before smoke season.
Supporting Statistics
216 Good days in King County (2023)
Only 5 days reached the unhealthy range.
Causes: August wildfire smoke and winter wood smoke.
Why it matters: Bad air comes in short bursts. Check the live map.
Source: Puget Sound Clean Air Agency
Americans spend 90 percent of their time indoors
Some pollutants run 2 to 5 times higher indoors.
Why it matters: Your HVAC filter works on the air you breathe most.
Source: U.S. EPA
35,000 new Bellevue homes planned by 2044
About 18 percent of its freeway exposure-zone land allows apartments or mixed use.
Why it matters: More households will live near freeway exhaust.
Source: City of Bellevue
Frequently Asked Questions
What Is the Air Quality in Bellevue Today?
Check the live map above: under 51 is Good, 51 to 100 Moderate, and 101 or higher unhealthy for some people.
Is the Air Quality Bad in Bellevue Today?
Once the live map shows 101 or higher, yes. Follow AirNow guidance, and start Filterbuy's four steps at 100.
What Is a Bad Bellevue PM2.5 Level Today?
On EPA's 2024 scale, PM2.5 up to 9.0 µg/m³ is Good, 35.5 to 55.4 µg/m³ is Unhealthy for Sensitive Groups, and 55.5 µg/m³ or more is Unhealthy for everyone.
What MERV Filter Do I Need for Wildfire Smoke in Bellevue?
MERV 13. Install it before smoke season, set the fan to On, and replace it when it turns dark.
Does a Burn Ban Mean Bellevue's Air Is Unhealthy?
Not necessarily. Bans come before forecast stagnant air, so the AQI may still read Good.
Glossary
Air Quality Index (AQI): EPA's 0 to 500 health scale with six color categories.
PM2.5: Fine particles 2.5 micrometers or smaller, from smoke and exhaust.
Ground-level ozone: A gas formed when emissions react in sunlight.
NowCast: EPA's recent-hours weighting for a near-real-time AQI.
Puget Sound Clean Air Agency (PSCAA): Air authority for King, Kitsap, Pierce and Snohomish counties.
Burn ban: A PSCAA wood-burning limit, Stage 1 or Stage 2.
Air Pollution Exposure Zone: Bellevue's term for high-traffic freeway land.
MERV: Minimum Efficiency Reporting Value, a 1 to 16 HVAC filter rating.
HEPA: High-efficiency filtration for portable air cleaners, not HVAC systems.
Smoke CADR: A portable cleaner's filtered-air output for smoke.