Geosciences Related
Geosciences students Renee Boudreaux and Ryan Perna, along with Wenging Yao, launch a balloon from the UH campus to measure ozone and meteorological conditions.  The balloon’s instrumentation box is monitored by computer for two hours as it makes a 90-minute ascent into the upper atmosphere and a 45-minute descent by a small orange parachute.
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by Noelle Heinze
One month a year, it is not healthy to be outside in Houston. 

Ozone. It can harm lung function and irritate the respiratory system, convert cholesterol in the bloodstream into artery hardening plaque, damage car tires, and stunt the growth of some plant species. It’s pale blue, and for as many as 35 days a year, high levels of ozone can be found for several hours in the air Houstonians breathe.

In the upper atmosphere, naturally occurring ozone protects the earth from the sun’s damaging ultraviolet light.  In the lowest part of the atmosphere—the boundary layer—ozone is a destructive air pollutant, formed by a reaction among hydrocarbons, nitrogen oxides, and sunlight.

“Houston has as many as 35 days of high ozone a year, compared with the EPA’s recommendation of three days over a three-year period,” says UH Assistant Professor of Atmospheric Sciences Barry Lefer. “One month a year, for several hours a day, it is not healthy to be outside in certain areas of Houston.”

In an effort to learn how ozone is being formed in Houston and how to reduce it, a large multi-agency project titled Texas Air Quality Study II (TexAQS II) has brought hundreds of scientists to Houston for the months of August and September.

Scientists from the National Oceanic and Atmospheric Administration (NOAA), Environmental Protection Agency (EPA), Texas Commission on Environmental Quality (TCEQ), The University of Texas (UT), and numerous other agencies and universities are working with experts from the UH Institute for Multi-dimensional Air Quality Studies (IMAQS) to examine Houston’s air quality.

Meteorological conditions, ozone, and many other photochemical smog-related measurements are being taken from the ground, by aircraft and ship, and with balloon-borne instruments.

Lefer and Associate Professor of Atmospheric Sciences Bernhard Rappenglueck, along with more than 40 visiting scientists from different universities and national labs, are working at the UH Moody Tower “Supersite,” an 18-stories-high rooftop lab, where measurement towers and sophisticated instrumentation trailers have been set up.

In addition, measurements are being taken at the UH Coastal Center in La Marque and other surface sites around Houston, while weather balloons are launched two to six times a day from the UH campus.

Among some of Rappenglueck’s studies are measurements of organic nitrates to tell what kind of hydrocarbons are making ozone and measurements of toxics in the air, which are produced by gasses emitted from a variety of sources, including industries and traffic.

Two of Lefer’s studies involve calculating the rate at which sunlight is creating reactions that make ozone and determining how clouds and particles in the atmosphere reduce or produce ozone.

Using all of these measurements, IMAQS Director and Professor of Atmospheric Sciences Daewon Byun will test air quality models he has developed to predict where ozone pollution is headed and which neighborhoods are getting the most impact. Byun is also providing daily weather and air quality forecasting results from advanced computer models for the EPA and the State of Texas to help determine if an air quality alert should be issued.

“These measurements will be used to improve our ozone forecasting and to help target culprit emissions that exacerbate Houston air quality,” says Byun.

Visit the IMAQS Web site at for daily ozone forecasts.

© University of Houston 2006