Air Quality in Marysville, Washington — Live
Live readings from PurpleAir sensors across Marysville — with free alerts the moment the air turns.
AQI 79 from 5 PurpleAir sensors · Trending up · data from PurpleAir
As of , the air quality in Marysville, Washington is AQI 79 — Moderate and rising — with PM2.5 at 23.9 µg/m³, the median of 5 live PurpleAir sensors reading 65 to 85. Canairy's verdict: Mostly clear.
For scale, that PM2.5 reading is about 1.6 times 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 Marysville: weeds pollen is the strongest of the three at a moderate 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 Marysville and Everett, Arlington, Lake Stevens, Tulalip. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Marysville
The sensors Canairy reads in Marysville agree right now — all 5 sit in the Moderate band, a 20-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.8 mi ENE | 85 | Moderate |
| 5.5 mi W | 71 | Moderate |
| 5.6 mi SSW | 81 | Moderate |
| 6.7 mi E | 65 | Moderate |
| 9.7 mi SW | 79 | Moderate |
Marysville's air problem is not a fire season. It is a time of day. Community PurpleAir sensors around the city show that heavy wood stove use produces consistent spikes in fine particle pollution in the evening, night after night through the cold months, and Snohomish County's own Climate Vulnerability Tool puts Marysville alongside Darrington and Monroe as the places in the county with some of the worst air quality. The American Lung Association has graded Snohomish County an F. None of that describes a city under permanent haze; it describes a city where the number at 8 PM in January can be several times the number at 2 PM the same day.
What Canairy does for Marysville
A clear verdict
Not just a number — a plain-English call for Marysville: open the windows, or keep them shut.
Smoke alerts
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.
Every place you care about
Home, work, the kids' school — across Marysville or across the country, on one screen.
Downtown sits five feet above the slough
The shape of the ground here works against still winter nights. Downtown Marysville sits on the bank of Ebey Slough about five feet above sea level, on the north edge of the Snohomish River delta, and the land climbs from there to around 160 feet near Smokey Point and over 465 feet in the eastern highlands. Interstate 5 and the Tulalip Reservation form the western edge, Ebey Slough the southern one. On a cold, clear evening, cool air slides off the higher ground and settles on the delta floor, and whatever was released down there settles with it.
That is why an evening reading in one part of Marysville can be so different from another. Smoke from a neighbor's stove does not spread evenly across a city with 450 feet of relief across it and a river delta at the bottom. It pools where the cold air pools. If you live low, near the slough or the flats, the sensor closest to your street is telling you something a city-wide average cannot.
The county keeps putting Marysville on the list
Marysville is one of the places Snohomish County's Climate Vulnerability Tool identifies as having some of the worst air quality in the county, and the pattern behind it is old stoves. Graeme Carvlin of the Puget Sound Clean Air Agency put it plainly: there are still a lot of older stoves out there. The agency pays residents $500 to swap a wood stove for gas, electric, or a modern unit that meets federal standards, and it has recycled more than 8,000 stoves across Snohomish, King and Pierce counties over the past sixteen years.
There is a longer-term effort as well. The Snohomish Conservation District has partnered with Marysville, Everett and the Tulalip Tribes on a five-year push to grow the tree canopy, and has already planted thousands of trees. Canopy will not clear a January inversion, but the direction of travel is the point: the wood smoke here is a stock of old appliances being worked through slowly, not a single source anyone can switch off.
What a Stage 2 burn ban actually stops
Marysville is in Snohomish County, and the Puget Sound Clean Air Agency uses a tighter trigger here than it does around Seattle. A Stage 1 ban is called when the 24-hour average of fine particles is expected to exceed 30 micrograms per cubic meter within 72 hours, against 35 micrograms within 48 hours for King and Kitsap counties. Stage 1 stops fireplaces, uncertified stoves and uncertified inserts, and stops all outdoor burning including recreational fires.
Stage 2 is the one worth knowing about, because it catches the appliances people assume are exempt. Under Stage 2 no wood-burning fireplace, wood stove, insert or pellet stove may be used at all, certified or not, unless it is your only source of heat and you hold an approved exemption. Under both stages it is illegal to produce visible smoke even from a device you are allowed to run. If your home heat is a wood stove, the practical move is knowing a ban is coming before it lands rather than after.
Marysville air quality FAQ
What is the air quality in Marysville right now?
As of September 10, 2026 at 6:44 AM PDT, the air quality in Marysville, Washington is AQI 79 — Moderate — with PM2.5 at 23.9 µg/m³, the median of 5 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
Why is there smoke in Marysville today?
Check the season and the hour. Between roughly November and February the answer is usually wood smoke from stoves and fireplaces close by. PurpleAir sensors around Marysville show a consistent evening spike driven by heavy wood stove use, and it is worst on cold, still nights when the air over the delta stops moving. In July, August and September the more likely answer is wildfire smoke that has drifted in from fires well outside Snohomish County, which arrives across the whole region at once rather than in one neighborhood.
Why is Marysville worse than the rest of Snohomish County?
It is mostly residential wood burning meeting unhelpful geography. Snohomish County's Climate Vulnerability Tool names Marysville, along with Darrington and Monroe, among the places in the county with the worst air quality, and community sensor data attributes the recurring evening pollution spikes here to high wood stove use. Downtown sits about five feet above sea level on the edge of the Snohomish River delta, which is exactly the kind of low, flat ground where cold air and smoke settle overnight instead of blowing through.
Can I get help replacing an old wood stove in Marysville?
Yes. The Puget Sound Clean Air Agency runs a change-out program that pays $500 to residents who replace a wood stove with gas, electric, or a newer wood stove that meets federal standards. More than 8,000 stoves have been recycled through it across Snohomish, King and Pierce counties over the past sixteen years. The agency's own view is that plenty of older stoves are still in service, which is a large part of why evening readings in Marysville behave the way they do.
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 Marysville, 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 Marysville
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