Air Quality in Houston, Texas — Live

Live readings from PurpleAir sensors across Houston — with free alerts the moment the air turns.

Live Houston AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Houston and Pasadena, Deer Park, Galena Park, Channelview.

The Houston Ship Channel runs 52 miles from the turning basin east of downtown out toward Galveston Bay, and the petrochemical plants along it sit next door to neighbourhoods where people have lived for generations. Monitors at Galena Park and Manchester have historically recorded elevated benzene and 1,3-butadiene, two chemicals that come out of refining and out of the plants that make synthetic rubber and plastics. On top of that, the EPA moved the Houston-Galveston-Brazoria area from Moderate to Serious nonattainment for the 2015 ozone standard effective 22 July 2024 — a change the State of Texas asked for, because the region was not going to meet the deadline it had.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

Fifty-two miles of chemistry, with people living along all of it

The state does monitor the Ship Channel corridor — the TCEQ runs 228 monitoring stations across Texas, roughly 47 of them in the Houston area — but four of those, including the one nearest Cloverleaf, are owned by Houston Regional Monitoring, a network of 30 petrochemical companies. The gaps are real and specific. The Cloverleaf monitor does not measure particulate matter, sulfur dioxide or formaldehyde, and a 2019–2020 study found formaldehyde in Cloverleaf at more than 13 times the EPA's chronic health screening level. Community monitors installed by Air Alliance Houston recorded nitrogen dioxide above the EPA threshold more than 3,000 times and ozone violations more than 850 times between April and December 2022. Since 2020 that group has put in nearly 30 stations of its own to fill in what the state network misses.

The city has started closing some of those gaps too. Houston's enhanced air quality monitoring project covers Allendale/Meadowbrook, Pecan Park and Park Place, in ZIP codes 77012 and 77017, and tracks four pollutants: 1,3-butadiene, benzene, formaldehyde and ethylene oxide. It uses the existing Milby and Chavez fixed-site monitors, plus passive samplers at nine community-chosen locations for a full year, and a 30-day mobile route for ethylene oxide designed by residents. The reason for the focus is straightforward — the TPC and Goodyear plants in that stretch are the largest emission sources of 1,3-butadiene in Houston.

The week the ITC tanks burned in Deer Park

The fire at the Intercontinental Terminals Company site in Deer Park started on 17 March 2019 and burned for 64 hours straight, destroying ten storage tanks that each held more than three million gallons — naphtha, xylene, and pygas, a benzene-rich blend. Deer Park issued two shelter-in-place advisories: 18 hours right after the tanks caught, then about eight more on 21 and 22 March. Then the warnings stopped, and the benzene did not.

On 31 March, two weeks after the fire, EPA monitors picked up benzene spikes above 1,000 parts per billion near San Jacinto Elementary School in residential Deer Park. Before the fire, benzene there typically ran around 5 ppb. Officials had set 1,000 ppb as the threshold for warning the public, a number adapted from workplace standards — Texas's own health guideline is 180 ppb per hour, and scientists involved argued the right number was 27. Levels stayed dangerously elevated for more than two weeks, with documented spikes on seven separate days after the public warnings had ended, and no further advisories were issued.

The Gulf gives the air back to you

Houston's summer air problem is partly a wind problem. On days with a recirculating sea breeze — emissions pushed offshore in the morning, then carried back over the city in the afternoon — PM2.5 runs about 30 percent higher than under other wind patterns, averaging 11.18 micrograms per cubic metre against 8.04 on plain southerly days. Ozone on those same days averaged 52.47 ppb, roughly 70 percent higher. Nothing new is being emitted; yesterday's pollution simply comes back, aged, with today's on top of it. That is why a still, humid, sunny afternoon in July can read worse than a windy weekday with the same traffic.

Then there is the dust. Every summer, plumes lifted off the Sahara ride the Saharan Air Layer across the Atlantic, through the Caribbean and the Gulf, and reach the Texas coast after a trip of roughly a week. When the outbreaks are thick, Houston notices them as hazy skies and worse air quality, and the fine particles can irritate eyes, nose and throat. The same dry layer that hazes the sky pulls moisture out of the atmosphere and makes it harder for storms to organise, so a dusty week is often also a quiet week in the tropics.

Houston air quality FAQ

Why is there smoke in Houston today?

In Houston it is worth checking whether it is smoke at all. In June, July and August, hazy brown skies here are often Saharan dust that has crossed the Atlantic and the Gulf over about a week, and it hazes the whole sky rather than coming from one direction. Real smoke is usually industrial and usually east of downtown — the 2019 ITC tank fire in Deer Park burned for 64 hours and put ten tanks' worth of naphtha, xylene and benzene-rich pygas into the air. If you can smell it and it has a direction, look toward the Ship Channel. If the whole sky is milky and the sun is orange, look at the dust forecast.

What is the air quality in Houston right now?

This page shows the live AQI for Houston, calculated from PurpleAir sensors around the city and updated continuously. Houston is big enough that one number rarely covers it — the air in Pecan Park on an east wind is not the air in the Heights — so it is worth saving the specific places you care about rather than watching a citywide figure.

Why does Houston's air get worse on hot, still summer afternoons?

Because of the sea breeze. On days when the breeze recirculates, morning emissions get pushed out over the water and then carried back inland in the afternoon, so the city breathes its own exhaust twice. Measured across Houston summers, PM2.5 on those days averaged 11.18 micrograms per cubic metre against 8.04 on ordinary southerly days, and ozone averaged 52.47 ppb — about 70 percent higher. Heat and sunlight then cook the leftovers into more ozone.

Should I worry about benzene if I live near the Ship Channel?

Benzene is a known human carcinogen, and monitors at Galena Park and Manchester have historically recorded elevated levels of it and of 1,3-butadiene. It is worth knowing that a PurpleAir sensor does not measure benzene — it measures fine particles, PM2.5. The two often move together during an industrial fire or a flaring event, so a sudden PM2.5 spike near the channel is a reasonable signal to close the windows, but for benzene specifically the relevant data comes from the TCEQ network, the city's Milby and Chavez monitors, and the community stations Air Alliance Houston has been adding since 2020.

What AQI level is unhealthy?

Under the US EPA scale, AQI 0–50 is Good and 51–100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups — kids, older adults, and people with asthma or heart conditions — and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Get Canairy free on Google Play.