Air Quality in Olathe, Kansas — Live
Live readings from PurpleAir sensors across Olathe — with free alerts when spring burn smoke or summer ozone push the air into unhealthy territory.
AQI 19 from 4 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Olathe, Kansas is AQI 19 — Good and falling — with PM2.5 at 3.5 µg/m³, the median of 4 live PurpleAir sensors reading 15 to 23. 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 Olathe: weeds pollen is the strongest of the three at a very 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 Olathe and Lenexa, Overland Park, Gardner, De Soto. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Olathe
The sensors Canairy reads in Olathe agree right now — all 4 sit in the Good band, a 8-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 3.0 mi NW | 23 | Good |
| 7.1 mi ESE | 19 | Good |
| 12.0 mi NE | 15 | Good |
| 14.2 mi NNE | 20 | Good |
Most of the year, the air in Olathe is unremarkable in the best way — this stretch of Johnson County has no wildfire season, no refinery, and no port. What it does have is two predictable rough patches: a run of hazy days each spring when ranchers and land managers burn the Flint Hills tallgrass prairie a county or two southwest, and a stretch of hot, still summer afternoons when the whole Kansas City metro's ground-level ozone climbs into unhealthy territory.
What Canairy does for Olathe
A clear verdict
Not just a number — a plain-English call for Olathe: 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 Olathe or across the country, on one screen.
Every spring, the Flint Hills send smoke this way
Each spring, ranchers and conservationists deliberately burn an average of about 2.1 million acres of Flint Hills tallgrass prairie — mostly in April — to knock back invasive trees and renew the grazing land that supports more than a million head of cattle a year, according to EPA Region 7. The Flint Hills sit well southwest of Olathe, but the smoke plume doesn't stay put: it rides the wind northeast into the shared Kansas City airshed, and Johnson County is squarely in that path.
This isn't a once-a-decade event. On March 26, 2025, Kansas recorded three separate exceedances of the federal 24-hour PM2.5 standard as a large smoke plume from Flint Hills burning stretched into southeast Kansas, and the state issued a health advisory over hazy metro-area skies. A year later, the Kansas Department of Health and Environment issued another advisory on March 25, 2026, covering burning from March 24 through the following Thursday, forecasting AQI from Moderate up to locally Unhealthy across central and eastern Kansas. Olathe residents don't need to see a fire to breathe its smoke.
Summer swaps smoke for ozone
Once burn season passes, Johnson County's air-quality story shifts entirely. The county forecasts ground-level ozone from March 1 through October 31 as part of the Mid-America Regional Council's regional SkyCast program, which covers the whole bi-state Kansas City airshed — Johnson and Wyandotte counties in Kansas, and Jackson, Clay, and Platte counties in Missouri. June through August produce the most Ozone Alert Days, when heat and sunlight cook vehicle exhaust and evaporating gasoline into unhealthy ozone concentrations.
Because the airshed spans a state line, the fixes Johnson County publicizes are regional too: refuel after dusk, skip topping off the tank, and put off mowing with gas-powered equipment on Alert days, since lawn and garden equipment alone is estimated to cause about 9% of the metro's ozone-forming emissions. None of that makes Olathe unusual for a car-dependent Midwestern metro, but it does mean a clean morning can slide to Moderate or worse by a hot July afternoon — exactly the kind of shift a once-a-day forecast misses.
A shared airshed with a real history
This is not a new problem for the area. Johnson County was folded into the Kansas City, MO-KS nonattainment area for the federal 1-hour ozone standard back in 1992 — one of the earlier tests of how a metro split across a state line coordinates pollution control. That specific standard was revoked in 2005 once EPA moved to a tighter 8-hour ozone limit, but the underlying geography never changed, which is why MARC's SkyCast still treats Johnson County as one piece of a shared metro problem rather than testing Olathe's air in isolation.
In practice, that means the reading that matters here is rarely one countywide monitor. Ozone and fine particulates drift in from Wyandotte County, from Kansas City, Missouri's highway network, and from the Flint Hills, depending on the season and the wind. That's part of why Canairy reads sensors placed around Olathe itself, rather than leaning on a single regional station, so the number tied to your neighborhood reflects what's actually settling there.
Olathe air quality FAQ
What is the air quality in Olathe right now?
As of September 14, 2026 at 7:09 AM CDT, the air quality in Olathe, Kansas is AQI 19 — Good — with PM2.5 at 3.5 µg/m³, the median of 4 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Olathe get hazy in early spring?
Each spring, ranchers and land managers burn roughly 2.1 million acres of Flint Hills tallgrass prairie, mostly in April, to control invasive trees and renew grazing land. The smoke plume drifts northeast into the Kansas City airshed, and on March 26, 2025, and again in late March 2026, the Kansas Department of Health and Environment issued air quality health advisories after burning pushed PM2.5 past federal limits and hazed over the metro, Olathe included.
Why does Olathe's air quality get worse in summer?
From roughly June through August, heat and sunlight react with vehicle exhaust and gasoline vapor to form ground-level ozone. Johnson County forecasts ozone as part of the Mid-America Regional Council's SkyCast program for the whole Kansas City airshed, and Ozone Alert Days are most common on hot, still summer afternoons.
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 4 curated PurpleAir sensors Canairy tracks in and around Olathe, 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
Go deeper
Air quality near Olathe
We watch Olathe's air. You live your life.
Set your threshold once and get a heads-up only when the air actually changes for you. Free on the App Store & Google Play.