Air Quality in Baltimore, Maryland — Live
Live readings from PurpleAir sensors across Baltimore — with free alerts the moment smoke drifts in.
AQI 14 from 4 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Baltimore, Maryland is AQI 14 — Good and holding steady — with PM2.5 at 2.5 µg/m³, the median of 4 live PurpleAir sensors reading 11 to 16. 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 Baltimore: weeds pollen is the strongest of the three at a low 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 Baltimore and Towson, Dundalk, Catonsville, Glen Burnie. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Baltimore
The sensors Canairy reads in Baltimore agree right now — all 4 sit in the Good band, a 5-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.9 mi SE | 16 | Good |
| 2.5 mi E | 15 | Good |
| 2.8 mi WNW | 11 | Good |
| 3.5 mi NNE | 13 | Good |
Baltimore's air carries the weight of its geography and its industry. Summer heat off the Chesapeake cooks up some of the worst ground-level ozone on the East Coast, Canadian wildfire smoke has twice pushed the whole region into emergency alerts, and along the harbor in neighborhoods like Curtis Bay, coal dust and port traffic have been part of daily life for generations.
What Canairy does for Baltimore
A clear verdict
Not just a number — a plain-English call for Baltimore: 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 Baltimore or across the country, on one screen.
Wildfire smoke turned the sky orange twice in three years
In June 2023, smoke from wildfires in Quebec funneled south into the Mid-Atlantic and put most of Maryland, Baltimore included, under a Code Red air quality alert. It was among the worst air the city had recorded in years, with the sun dimmed to a hazy orange and health officials urging everyone to stay inside. For a place used to thinking of wildfires as a western problem, it was a hard lesson that smoke travels.
It happened again on July 17, 2026, when Canadian smoke pushed Baltimore and most of the state to Code Purple, the very unhealthy level, upgraded from Code Red earlier that morning. On days like these the smoke can arrive fast and the AQI can climb through the afternoon, which is exactly the kind of change worth catching early rather than finding out about after your eyes start stinging.
The Chesapeake heat and the bay breeze make ozone worse
Baltimore sits at the head of the Chesapeake, and that location is a big reason the metro area earns failing grades for ozone. On hot, sunny summer days the bay breeze pushes cooler air inland and stalls pollution over the region, concentrating ozone right along the water and into the city. The American Lung Association's 2026 State of the Air report, which covers 2022 through 2024, gave both Baltimore City and Baltimore County an F for ozone. Baltimore County averaged 5.8 unhealthy ozone days a year, the worst count of any county in Maryland. That set the Washington-Baltimore-Arlington metro's ozone rank at 49th worst in the nation, an improvement on the 36th-worst spot and 7.5 days a year in the previous report.
A lot of it isn't even homegrown. Maryland regulators estimate that roughly 70 percent of the state's ozone problem blows in from power plants and traffic in upwind states, which means Baltimore can have a bad-air day even when its own emissions are low. Ozone is the pollutant that tends to peak on the hottest, stillest afternoons, so a hazy hot day near the harbor is worth a second look before a long run or a kid's outdoor practice.
Curtis Bay and the harbor's industrial legacy
South Baltimore's Curtis Bay neighborhood lives alongside the Port of Baltimore's heavy industry, including CSX's open-air coal export terminal. A year-long study led by Johns Hopkins researchers and Curtis Bay residents, monitoring the air from July 2022 to July 2023 at ten sites, found that particulate matter and black carbon spiked when bulldozers were moving coal and the wind was blowing from the terminal toward homes. Residents had complained about coal dust settling on cars and windowsills for years before the research put numbers to it.
It's a textbook environmental-justice story: a working community carrying the pollution burden of trucks, trains, ships, and coal all at once, which is why residents petitioned Maryland's environmental agency in late 2024 to reject the terminal's permit renewal. Neighborhood-scale sources like this don't always show up on a regional forecast, which is where a nearby sensor reading matters more than a citywide average.
Baltimore air quality FAQ
What is the air quality in Baltimore right now?
As of October 20, 2026 at 8:09 AM EDT, the air quality in Baltimore, Maryland is AQI 14 — Good — with PM2.5 at 2.5 µg/m³, the median of 4 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Baltimore have so many bad ozone days in summer?
Baltimore sits at the head of the Chesapeake Bay, and on hot, sunny days the bay breeze stalls polluted air over the region and concentrates ground-level ozone near the water and in the city. Maryland regulators also estimate that about 70 percent of the state's ozone blows in from upwind states, so Baltimore can have a smoggy afternoon even when local emissions are low. Ozone tends to peak on the hottest, stillest days, which is when the readings on this page are most worth checking.
Is the air in Curtis Bay and South Baltimore worse than the rest of the city?
It can be. A year-long study led by Johns Hopkins researchers and Curtis Bay residents found that particulate matter and black carbon rose in the neighborhood when a nearby coal terminal was moving coal and the wind blew toward homes. Pollution from port traffic and heavy industry is often very local, so a sensor a few blocks away can read quite differently from a citywide average, which is exactly why checking the nearest sensor matters here.
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 Baltimore, 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 Baltimore
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