Houston Air Quality in 2019
In 2019, Houston's air quality (Houston-The Woodlands-Sugar Land, TX area) had a median daily AQI of 57 (Moderate) across 365 monitored days. 31 days (8.5%) reached Unhealthy for Sensitive Groups or worse, 82 were Good, and the year's peak AQI was 202 (Very Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 239 of those days. The cleanest month of 2019 was February (median AQI 53, 0 days above 100) and the worst was June (median 71, 9 days above 100, peak 166).
- Good: 22.5%
- Moderate: 69.0%
- Unhealthy for Sensitive Groups: 7.1%
- Unhealthy or worse: 1.4%
Reduce Indoor Ozone in Houston
Today's main pollutant in Houston is ground-level ozone (AQI 24). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
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How was Houston's air quality in 2019?
Moderate on a typical day: median AQI 57, with 31 days above AQI 100 out of 365 monitored — the 3rd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2019: 202 (Very Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 239 days.
- ✓Cleanest month: February; worst: June.
Frequently asked questions
What was the average AQI in Houston in 2019?▾
EPA's Air Quality System puts Houston's (Houston-The Woodlands-Sugar Land, TX) median daily AQI for 2019 at 57, which is Moderate. 31 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 202.
Which month had the worst air quality in Houston in 2019?▾
The cleanest month of 2019 was February (median AQI 53, 0 days above 100) and the worst was June (median 71, 9 days above 100, peak 166).
Was 2019 a good or bad year for Houston's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 3rd cleanest by days above AQI 100. 2019's median of 57 is below the area's typical annual median of 61.
Houston month by month in 2019
Houston air quality month by month, 2019 (Houston-The Woodlands-Sugar Land, TX, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 52 | 1 | 176 | PM2.5 |
| Februarycleanest | 28 | 53 | 0 | 77 | PM2.5 |
| March | 31 | 58 | 3 | 129 | PM2.5 |
| April | 30 | 66 | 5 | 119 | O3 |
| May | 31 | 62 | 2 | 133 | PM2.5 |
| Juneworst | 30 | 71 | 9 | 166 | O3 |
| July | 31 | 58 | 2 | 129 | PM2.5 |
| August | 31 | 58 | 3 | 202 | PM2.5 |
| September | 30 | 55 | 3 | 169 | O3 |
| October | 31 | 53 | 2 | 140 | PM2.5 |
| November | 30 | 59 | 0 | 96 | PM2.5 |
| December | 31 | 56 | 1 | 126 | PM2.5 |
How 2019 compares
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 3rd cleanest by days above AQI 100.
2019's median of 57 is below the area's typical annual median of 61.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Houston
The latest EPA AirNow observation puts Houston's AQI at 24 (O3). The figures above are multi-year annual statistics, not today's reading.
View current Houston air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Houston-The Woodlands-Sugar Land, TX), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.