Houston Air Quality
Houston, Texas · 7.3M metro population
Moderate
2024 avg
72
Annual AQI
2024 average
9.8 μg/m³
PM2.5
2.0× WHO limit
90
Summer Ozone AQI
Summer peak
62
Unhealthy Days/yr
AQI > 100
Monthly AQI Pattern
Houston peaks in July–August when heat + petrochemical VOCs cook into ozone
Houston's Air Quality Challenges
The World's Largest Petrochemical Complex
The Houston Ship Channel hosts the largest concentration of petrochemical facilities in the Western Hemisphere — 500+ industrial plants including refineries, chemical plants, and plastics manufacturers. These facilities emit massive volumes of VOCs (volatile organic compounds) and NOx that react in Texas heat to form ground-level ozone. Houston has been in ozone non-attainment for decades despite significant improvements.
Texas Heat Amplifies Ozone
Houston's subtropical climate — hot, humid summers with intense UV — is ideal for ozone formation. The VOC and NOx emissions from refineries and 4+ million vehicles cook into ozone on hot summer afternoons. AQI regularly exceeds 100 from June through September. On the worst summer days, east Houston near the Ship Channel can hit AQI 150–170.
Hurricane Harvey: A Chemical Disaster
Hurricane Harvey (August 2017) caused catastrophic flooding of the Houston Ship Channel, triggering chemical spills, fires, and uncontrolled releases from dozens of industrial facilities. The resulting air and water pollution was a direct consequence of building critical industrial infrastructure in a flood-prone area. Harvey's environmental aftermath highlighted the intersection of climate change, industrial risk, and community health in Houston.
Environmental Justice: Ship Channel Communities
Communities adjacent to the Houston Ship Channel — including Manchester, Harrisburg, and Pasadena — are predominantly Latino and low-income neighborhoods that face the heaviest industrial pollution burden. Cancer rates in some Ship Channel communities are among the highest in Texas. Environmental justice advocates have fought for decades against fence-line pollution and for cumulative impact assessments.