Air Quality in Rockville, Maryland — Live
Live readings from PurpleAir sensors across Rockville — with free alerts when summer ozone or drifting wildfire smoke pushes the air into unhealthy territory.
AQI 6 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Rockville, Maryland is AQI 6 — Good and falling — with PM2.5 at 1.0 µg/m³, the median of 5 live PurpleAir sensors reading 0 to 11. 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 Rockville: 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 Rockville and Gaithersburg, Bethesda, North Bethesda, Kensington. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Rockville
The sensors Canairy reads in Rockville agree right now — all 5 sit in the Good band, a 11-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.4 mi WSW | 5 | Good |
| 1.4 mi E | 0 | Good |
| 5.0 mi SE | 10 | Good |
| 5.0 mi ESE | 11 | Good |
| 6.0 mi SE | 6 | Good |
For most of the year, the air around Rockville is unremarkable in the best way. Montgomery County sits entirely within the rolling Piedmont plateau, not a smoke-prone canyon or a valley that traps pollution, and there's no refinery or port anywhere nearby. The real story here is summer: hot, humid afternoons cook exhaust from the I-270 and I-495 corridors into ground-level ozone, and the Metropolitan Washington Council of Governments still calls Code Orange and Code Red Air Quality Action Days across the region most summers. On top of that, smoke drifting down from Canadian wildfires has become a recurring visitor — a Code Purple alert, the region's most severe rating, went out for fine particle pollution on July 17, 2026.
What Canairy does for Rockville
A clear verdict
Not just a number — a plain-English call for Rockville: 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 Rockville or across the country, on one screen.
What the air in Rockville is doing next
| When | AQI | Expected air quality | Main pollutant |
|---|---|---|---|
| Today | 42 | Good | ozone |
| Tomorrow | 44 | Good | ozone |
| Thursday | 45 | Good | ozone |
A steady inflow of clean Canadian air is expected Tuesday as high pressure sits just north of the region. Expect both ozone and fine particulates to be comfortable in the Good AQI range. Winds turn southerly Wednesday, persisting into Thursday as high pressure shifts off the New England coast. An uptick in temperatures and dew points will lead to a slight increase in both ozone and fine particulates. However, given an initially clean residual air mass and late season sunlight duration, expect both to remain in the Good AQI range statewide. For the latest air quality information, please visit our website here. -MDE
Forecast from EPA AirNow for the Suburban DC reporting area. Canairy watches the live sensors against it and tells you when the air actually crosses your threshold, rather than leaving you to check.
Summer heat and highway traffic are what push Rockville's air into unhealthy territory
Rockville doesn't have the geography that traps pollution the way a mountain valley does — Montgomery County lies entirely within the Piedmont plateau, rolling terrain with nothing to bottle up dirty air. What it does have is traffic. Interstate 270, described as the main highway leading northwest out of the Washington metro area, runs straight through the city as the spine of the I-270 Technology Corridor, and the Capital Beltway (I-495) is a few miles south. On hot, sunny, windless summer afternoons, exhaust from that traffic reacts with heat and sunlight to form ground-level ozone, the main reason the region calls Air Quality Action Days.
The Metropolitan Washington Council of Governments forecasts and issues those Code Orange, Code Red, and Code Purple days for the whole metro area, and Rockville — as the Montgomery County seat sitting inside the same air-shed as downtown DC — is covered by the same forecast. In 2015 the EPA tightened the national ozone health standard from 75 to 70 parts per billion, a change Maryland's own environment agency has said would push forecast poor-air days up by roughly 30 percent, meaning summers with more, not fewer, orange and red days ahead.
Canadian wildfire smoke has started showing up as its own summer risk
Rockville isn't a wildfire town, but wildfire smoke still reaches it. In early June 2023, smoke from wildfires burning in Nova Scotia and Quebec settled over Washington, D.C., Maryland, and Virginia, with the region's air quality among the worst in the country by June 8. More recently, MWCOG issued a Code Purple alert — Very Unhealthy, the second-most-severe category on the AQI scale — on July 17, 2026, specifically for fine particle pollution carried down from wildfires burning in Canada.
None of that smoke starts anywhere near Montgomery County. It travels hundreds of miles on the upper-level wind pattern and settles over the whole Mid-Atlantic at once, which means a calm, humid Rockville afternoon can turn hazy with no fire, and often no local warning sign, anywhere close by. That's exactly the kind of shift a citywide forecast can miss for a day or two — it's why checking a live sensor reading near your own house matters more on these particular afternoons than any other time of year.
Outside of ozone season, the numbers back up the calm reputation
Rockville's day-to-day particle pollution is genuinely low by national standards — recent readings from monitors around the city have typically shown PM2.5 in the range of a good, single-digit micrograms-per-cubic-meter day, well under the level that triggers any health concern. There's no heavy industry or shipping traffic anywhere in Montgomery County to keep a baseline of soot in the air the way a refinery town or port city would have.
The one exception worth knowing is winter mornings. Maryland's environment agency notes that temperature inversions — cold air trapped near the ground under a warmer layer above — mean the most polluted part of a winter day is often the early morning commute, before the sun has had a chance to mix the air out. It's a much smaller effect than summer ozone or a smoke event, but it's why a January morning can occasionally read worse than the afternoon that follows it.
Rockville air quality FAQ
What is the air quality in Rockville right now?
As of September 15, 2026 at 8:09 AM EDT, the air quality in Rockville, Maryland is AQI 6 — Good — with PM2.5 at 1.0 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Rockville's air quality get worse in summer?
Heat and sunlight bake vehicle exhaust from the I-270 and I-495 corridors into ground-level ozone, and the Metropolitan Washington Council of Governments calls Code Orange or Code Red Air Quality Action Days across the DC region on the worst of those afternoons. It is a regional, traffic-and-heat problem rather than anything specific to one neighborhood in Rockville.
Does Canadian wildfire smoke reach Rockville?
Yes, periodically. Smoke from Nova Scotia and Quebec wildfires settled over the DC region in early June 2023, and MWCOG issued a Code Purple - Very Unhealthy - alert for the whole metro area on July 17, 2026 because of fine particle pollution from Canadian wildfires. The smoke travels hundreds of miles on upper-level winds, so it can arrive on a clear, calm day with no local warning.
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 Rockville, 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 Rockville
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