Air Quality in San Antonio, Texas — Live
Live readings from PurpleAir sensors across San Antonio — with free alerts the moment the air turns.
AQI 44 from 5 PurpleAir sensors · Trending up · data from PurpleAir
As of , the air quality in San Antonio, Texas is AQI 44 — Good and rising — with PM2.5 at 8.0 µg/m³, the median of 5 live PurpleAir sensors reading 43 to 52. 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 San Antonio: 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 San Antonio and New Braunfels, Schertz, Helotes, Converse. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in San Antonio
The sensors Canairy reads in San Antonio are 9 AQI points apart right now, from Good to Moderate, which is the whole reason one city-wide number can mislead you: the median describes air you may not be standing in.
| From city center | AQI | Category |
|---|---|---|
| 1.6 mi WSW | 52 | Moderate |
| 2.9 mi WSW | 45 | Good |
| 2.9 mi SW | 43 | Good |
| 2.9 mi E | 47 | Good |
| 4.9 mi S | 43 | Good |
San Antonio's air problem is ozone, and on paper it has been getting worse rather than better. Bexar County was first designated nonattainment for the 2015 federal ozone standard in September 2018 at the mildest classification, Marginal. It moved to Moderate effective November 2022, and on 22 July 2024 it was reclassified again, to Serious. The county now has until 24 September 2027 to meet the standard, with the 2026 ozone season as the attainment year, and the tier after Serious is Severe. None of this is visible from a window. Ozone is a colourless gas that builds on hot, still afternoons, so the worst days here usually look like nice days.
What Canairy does for San Antonio
A clear verdict
Not just a number — a plain-English call for San Antonio: 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 San Antonio or across the country, on one screen.
What the air in San Antonio is doing next
| When | Expected air quality | Main pollutant |
|---|---|---|
| Today | Good | ozone |
| Tomorrow | Good | ozone |
| Sunday | Good | ozone |
https://www.tceq.texas.gov/airquality/monops/forecast_today.html
Forecast from EPA AirNow for the San Antonio 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.
Bexar County is the nonattainment area, and only Bexar County
The 2015 ozone nonattainment area for San Antonio is Bexar County on its own. Atascosa, Bandera, Comal, Guadalupe, Kendall, Medina and Wilson are all designated attainment or unclassifiable, so someone in New Braunfels or Boerne lives outside the regulated area while breathing much the same air on a bad day. The line is a regulatory boundary drawn around monitors, not a wall. Ozone forms downwind of where its ingredients are emitted, which is why the highest readings in a metro are often taken well away from the traffic that helped make them.
The ladder Bexar County has climbed explains why local rules keep tightening. Marginal in 2018 brought almost no new obligations. Moderate in 2022 required an attainment demonstration. Serious, effective 22 July 2024, lowers the threshold at which a business counts as a major source and adds tougher permitting and offset requirements. It followed the county missing its moderate deadline, and the State of Texas asked the EPA for the reclassification rather than waiting to be pushed into it.
The quarries and kilns along the north side
The Balcones Escarpment that gives north San Antonio its hills is limestone, and limestone is what cement is made from. Alamo Cement runs a kiln and quarry at 6055 W. Green Mountain Road on the far north side under TCEQ air permit 6758, and Vulcan Materials operates the 1604 Quarry at 4303 N Loop 1604 East, out near Stone Oak. These are permitted industrial neighbours to a great deal of housing that was built long after they opened.
Day to day this shows up as dust rather than a citywide AQI swing. Crushing, hauling and blasting throw coarse particles that mostly settle within a mile or two, so the effect registers on the sensor nearest you far more than on a city average. If you live within sight of a quarry face, a single sensor on your own block will tell you more than any regional number ever will.
The Eagle Ford gas fields sit upwind on a south wind
The Eagle Ford Shale runs in an arc across South Texas below San Antonio, close enough to matter. Modelling work by the Alamo Area Council of Governments with the TCEQ estimated the play could add as much as 7 parts per billion to San Antonio's ozone. Against a standard of 70 ppb, that is not a rounding error for a county that has spent years sitting a whisker over the line.
The prevailing summer wind here is from the south and southeast, which is the direction the fields lie in. It is the same flow that brings Gulf moisture up. So the setup for a bad ozone day in San Antonio is usually a warm, humid, light southerly afternoon rather than anything dramatic.
San Antonio air quality FAQ
What is the air quality in San Antonio right now?
As of September 11, 2026 at 7:11 AM CDT, the air quality in San Antonio, Texas is AQI 44 — Good — with PM2.5 at 8.0 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why is there smoke in San Antonio today?
Most bad-air days in San Antonio involve no smoke at all. The pollutant that keeps the county in nonattainment is ozone, which is invisible and odourless, so the worst afternoons look perfectly clear. When there is genuine smoke it is usually a grass or brush fire during a drought summer, or land-clearing burning in the surrounding counties. A quick check: if the sky looks hazy but the sensors near you read low PM2.5, you are probably looking at humidity rather than particles.
Why did San Antonio's ozone classification get worse?
Because the county missed its deadlines. Bexar County was designated Marginal nonattainment for the 2015 ozone standard in September 2018, reclassified to Moderate effective November 2022, and reclassified again to Serious effective 22 July 2024 after failing the moderate attainment deadline. Serious carries a 24 September 2027 deadline based on the 2026 ozone season, plus tighter permitting thresholds for industry in the meantime.
Does the Eagle Ford Shale affect San Antonio's air?
It appears to. Work by the Alamo Area Council of Governments with the TCEQ estimated that emissions from the Eagle Ford play, which lies south of the city, could raise San Antonio's ozone by up to 7 parts per billion. The fields sit in the direction of the prevailing summer wind, so their contribution is largest on exactly the warm southerly days when ozone is already forming fastest.
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 San Antonio, 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 San Antonio
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