NASA planes research Houston pollution
Two NASA aircraft will fly over the Houston area to study air pollution throughout the month of September. The project studies air quality between pollution at the surface, where people are exposed, and pollution overhead.
“We are measuring air pollutants and weather variables to develop a better understanding of the chemical and meteorological processes that contribute to Houston’s poor air quality,” said Barry Lefer, associate department chair of the Department of Earth and Atmospheric Sciences.
Measurements are taken from multiple locations in Houston, including UH, UH System at Sugar Land, Conroe, Liberty County, UH Coastal Center and Galveston.
NASA scientists have been working with the Texas Commission on Environmental Quality, UH, the University of Texas, Rice University and Baylor University on the project.
The larger aircraft, the NASA P-3B, flies as low as 1,000 feet over Houston, taking in air directly to analyze it for various pollutants. This aircraft can fly up to 15,000 feet above the atmosphere.
The NASA P-3B flies over eight different locations in the Houston area including Galveston, Smith Point, UH, West Houston, Conroe, Channelview, Deer Park and Manvel Croix.
“The P-3B flies for eight hours. The King Air flies for four hours; lands to refuel, and flies again for four hours on each flight day,” said NASA research scientist James Crawford.
NASA King Air, the smaller aircraft, flies at approximately 27,000 feet, overlooking Houston with a laser ranging instrument to examine the pollution. A spectrometer looks at the light reflected from the ground to assess gaseous pollution.
“The NASA King Air has two remote sensing instruments: a special camera that measures air pollutants that form photochemical smog; and the other shoots multiple eye-safe lasers downward to measure the optical properties and layering of particles below the aircraft,” Lefer said.
The P-3B holds two pilots, a flight engineer, a mechanic and 19 scientists while the NASA King Air holds two pilots and two scientists.
The principles behind the pollution sensors are taken in measurements that are either charge- or light-based.
“These sensors use some physical or chemical property of the molecule or particle to allow for its detection. Could be that it absorbs specific wavelengths of light, scatters light, reacts with another compound, dissolves in water and conducts electricity … All of these physical characteristics are measured and quantified with calibrated sensors,” Lefer said.
The photochemical smog that impacts all of Houston is highest during the day.
“Pollution is quite different at night; however, during this project, we will not have any nighttime flights simply because the current air quality satellites use reflected sunlight to measure pollution, so they do not collect data at night,” Lefer said.
Results will be analyzed and presented at the end of 2014.