HOUSTON — A large dome of high pressure over Texas is expected to worsen air quality across Houston during warm afternoons by trapping ozone close to the earth's surface. Sunny skies combined with the strong high pressure system can degrade air quality in the region during the warmest parts of the day.

High pressure compresses the air and confines pollutants, pollen and gases such as ozone nearer to the surface. Sunshine produces ozone as a normal by-product of solar radiational energy reaching the earth's surface, and the trapped layer concentrates the gas at levels where people breathe.

People with respiratory issues, including severe asthma, could experience worsened symptoms if they spend extended time outdoors under these conditions. The risk is greatest during warm afternoons when sunlight intensifies ozone formation and the high pressure dome prevents the gas from dispersing.

The KPRC2 Weather Team will monitor current air quality over the next few days to inform residents about potential symptom risks. Updates are expected to track how the high pressure system evolves and how ozone concentrations change with afternoon heating.

The combination of abundant sunshine and a strong high pressure dome is a recurring weather pattern in the Houston area, where stagnant air can allow ozone to accumulate through the afternoon hours. Residents sensitive to air quality changes may need to adjust outdoor activity during the warmest portions of the day while the high pressure dome remains in place over Texas.