Air Quality in Houston: What Residents Should Know

By The Change Lab -- via manual_seed -- Apr 18, 2026

Overview

Houston has some of the worst air quality of any major U.S. city. The combination of petrochemical refineries along the Ship Channel, vehicle emissions from 7 million people, and Gulf Coast weather patterns that trap pollutants creates persistent ozone and particulate matter problems — especially from April through October.

Bad air days affect everyone, but hit hardest in communities near the Ship Channel, in northeast Houston, and anywhere near major highways. If you have asthma, heart disease, or young children, monitoring air quality is not optional.

Source: EPA AirNow; Texas Commission on Environmental Quality (TCEQ); Houston Health Department

The Framework

Key Ideas

What pollutes Houston's air:

Ground-level ozone — formed when vehicle exhaust and industrial emissions cook in sunlight. Worst on hot, sunny, windless days. Houston frequently exceeds EPA ozone standards.
Particulate matter (PM2.5) — tiny particles from refineries, construction, diesel trucks, and fires. Can penetrate deep into lungs.
Industrial emissions — the Houston Ship Channel corridor has one of the highest concentrations of petrochemical facilities in the world. Upsets, flaring events, and leaks release benzene, sulfur dioxide, and other pollutants.

Air Quality Index (AQI):

0-50 (Green) — Good. Safe for everyone.
51-100 (Yellow) — Moderate. Unusually sensitive people should limit prolonged outdoor exertion.
101-150 (Orange) — Unhealthy for sensitive groups. People with asthma, children, and older adults should reduce outdoor activity.
151-200 (Red) — Unhealthy for everyone. Limit outdoor exertion.
201+ (Purple/Maroon) — Very unhealthy to hazardous. Stay indoors.

Source: EPA; TCEQ; American Lung Association

Put It Into Practice

Practice

Check today's air quality:

airnow.gov — enter your ZIP code for current AQI and forecast
TCEQ Houston monitoring: tceq.texas.gov/airquality

Protect yourself on bad air days:

Check AQI before exercising outdoors. Run or bike in the morning — ozone peaks in the afternoon.
Keep windows closed on Orange or Red days. Run A/C on recirculate.
If you have asthma, keep your rescue inhaler with you and follow your action plan.
N95 masks filter PM2.5 if you must be outdoors during a smoke or industrial event.

Report a pollution event:

Smell something chemical, see unusual smoke, or notice plant flaring? Report it to TCEQ at 1-888-777-3186 (24/7 environmental complaint hotline).
You can also file online at tceq.texas.gov/complaints.
Air Alliance Houston tracks industrial pollution and advocates for communities: airalliancehouston.org.

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