Air Quality in Renton, Washington — Live
Live readings from PurpleAir sensors across Renton — with free alerts the moment the air turns.
AQI 32 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Renton, Washington is AQI 32 — Good and falling — with PM2.5 at 5.7 µg/m³, the median of 5 live PurpleAir sensors reading 25 to 39. Canairy's verdict: Breathe easy.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Renton: weeds pollen is the strongest of the three at a high level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Renton and Tukwila, Kent, Newcastle, Maple Valley. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Renton
The sensors Canairy reads in Renton agree right now — all 5 sit in the Good band, a 14-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 5.8 mi E | 37 | Good |
| 6.4 mi NE | 25 | Good |
| 6.9 mi NNW | 28 | Good |
| 7.1 mi WNW | 39 | Good |
| 8.9 mi NW | 32 | Good |
Renton sits at 85 feet above sea level where the Cedar River empties into the south end of Lake Washington, with the flank of Cougar Mountain rising to the north and the East Renton Plateau climbing behind it. Unlike most of its neighbors, the things that shape Renton's air are almost all local and almost all built: two freeways that cross in the middle of town, two factories large enough to need federal air operating permits, and a regional landfill nine miles up the Cedar River valley. On an ordinary day none of them push the numbers far, which is worth saying plainly. But they are the reason a reading taken next to Rainier Avenue and a reading taken on the plateau are not the same reading.
What Canairy does for Renton
A clear verdict
Not just a number — a plain-English call for Renton: open the windows, or keep them shut.
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A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
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Two freeways cross in the middle of town
Interstate 405 runs north-south through Renton, and State Route 167 crosses it here on its way up the Green River Valley from Tacoma. SR 167 does not end at the interchange either. It carries on north through Renton as a six-lane stretch of Rainier Avenue before finishing at SR 900. WSDOT's own description of the I-405 corridor is blunt: travelers on Interstate 405 between Renton and Bellevue experience one of the state's worst commutes, and the agency has been widening and rebuilding it, including a redesigned NE 44th Street interchange, since 2015.
The traffic on SR 167 is not just commuters. About 8 percent of it is freight serving the industrial areas of the Green River Valley, and peak daily volumes on the highway reach around 129,000 vehicles. Diesel exhaust is a fine-particle and nitrogen dioxide source that falls off sharply with distance from the road, so the practical effect in Renton is that the closer a home, school or park is to the 405/167 knot, the more the local sensor is worth checking rather than a citywide average.
Boeing and Kenworth both hold air operating permits here
Only a couple of dozen facilities in the whole four-county Puget Sound region are large enough to need a Title V air operating permit, which is the federal permit reserved for major sources of air pollution. Two of them are in Renton. The Puget Sound Clean Air Agency lists Boeing (Renton), whose permit was renewed on December 11, 2017 and administratively amended several times since, most recently in March 2024, and Kenworth Truck Company, the truck plant on the valley floor.
The Boeing site is the 737 line. It is about 1,100,000 square feet of floor space next to Renton Municipal Airport, built in 1941 on ground that only exists because the level of Lake Washington was lowered in 1916, and it turns out 737 MAX airliners and P-8 Poseidon military derivatives. A Title V permit is not an accusation; it is a reporting and limits regime, and it means the emissions from these two sites are counted and capped rather than guessed at. It also means Renton's industrial air story is concentrated in a fairly small part of the city, down near the lake and the airport.
Up the Cedar River valley, and the winter burn bans
Nine miles southeast of Renton, out past Maple Valley, is the Cedar Hills Regional Landfill: 920 acres taking roughly 2,500 short tons of waste a day delivered by about 130 trucks. It has a bioenergy plant that captures landfill methane and burns it to make electricity for the Puget Sound Energy grid, and it holds a Title V permit of its own. It sits upvalley of Renton, which matters on nights when cold air drains down the Cedar River valley toward the lake.
The other winter factor is much closer to home. Wood stoves and fireplaces are the main reason the Puget Sound Clean Air Agency calls cold-season burn bans, and Renton is in King County, where a Stage 1 ban is issued when the 24-hour average of fine particles is expected to exceed 35 micrograms per cubic meter within 48 hours. That is a later trigger than Snohomish and Pierce counties get, where the agency acts at 30 micrograms within 72 hours. If a ban is called, uncertified stoves and fireplaces stop, and all outdoor burning stops with them.
Renton air quality FAQ
What is the air quality in Renton right now?
As of September 10, 2026 at 5:10 AM PDT, the air quality in Renton, Washington is AQI 32 — Good — with PM2.5 at 5.7 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why is there smoke in Renton today?
It depends on the time of year. In July, August and September it is usually wildfire smoke that has traveled in from fires well outside King County, and it arrives across the whole region at once rather than in one neighborhood. From late autumn through winter, smoke you can actually smell in Renton is far more likely to be wood smoke from stoves and fireplaces nearby, held down by a cold, still night. If it is neither season and the haze is local to the valley floor, traffic on I-405 and SR 167 is the more likely source, and it clears when the wind picks up.
Does the Boeing plant affect Renton's air?
The Boeing Renton factory is a major source under the federal Title V program, which is why the Puget Sound Clean Air Agency issues it an air operating permit and tracks what it emits. Kenworth Truck Company in Renton holds one too. That regime sets limits and requires reporting rather than leaving emissions unmeasured. For day-to-day air on the ground, most Renton residents will see more variation from traffic and from winter wood smoke than from the plant itself, and the sensor nearest you is the honest way to tell.
When does Renton get a wood-burning burn ban?
Renton is in King County, so the Puget Sound Clean Air Agency issues a Stage 1 burn ban when it expects the 24-hour average of fine particles to exceed 35 micrograms per cubic meter within 48 hours. Stage 1 stops burning in fireplaces, uncertified wood stoves and uncertified inserts, and stops all outdoor burning including recreational fires. Stage 2 goes further and stops any wood burning at all, certified stoves and pellet stoves included, unless you have an approved sole-heat-source exemption. Under both stages, visible smoke is prohibited even from an exempt device.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 5 curated PurpleAir sensors Canairy tracks in and around Renton, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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Air quality near Renton
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