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From VOA Learning English, this is the Education Report.
Students at Saint Louis University are launching weather balloons into the sky above St. Louis, Missouri. The United States space agency NASA is paying for this activity. It's a part of a study to improve our understanding of air pollution and climate.
A group of students surround a laptop computer and a radio receiver outside the Saint Louis Science Center. They're getting ready to take part in a NASA project to measure ozone. The students hear the sound of information.
Inside container made of Styrofoam material are small instruments, they measure direction, temperature, humidity, air pressure and ozone. The students tested all the instruments. When they are certain everything is operating correctly, they attach the container to a weather ballon.
The ballon will carry it into the atmosphere three times higher than jets airplane. But first, the students need to fill the ballon with helium gas, so it can rise. They need a lot of helium, fully blown up, the ballon will be 2 to 3 meters in diameter.
A voice announces the launch time.
"This is Gary Morris with the Saint Louis University weather balloon launch team at the St. Louis planetarium. We're five minutes from a weather balloon launch."
Gary Morris is a professor at Valparaiso University in Indiana. He is the lead trainer for the nationwide study. The professor says NASA wants more information on ozone because how it affects our atmosphere ― both good and bad.
High up in what is called the stratosphere, the ozone layer keeps harmful ultraviolet radiation from reaching the earth. But near the ground, emissions from cars and petrochemical plants form ozone pollution and smog, the unhealthy air condition that affects breathing.
Jack Fishman leds the ozone study at Saint Louis University. He says new requirements that decrease pollution have lowered ozone levels in American cities, but he notes that pollution in remote areas continues to increase. He blames industrial activity in eastern Asia for that pollution.
Mr Fishman says polluted air is being blown across the Pacific by currents in the upper atmosphere. He says ozone pollution has slown the growth of farm crops and forests.
And now, at the Saint Louis Science Center, is time for the balloon launch. OK, comes a voice, ready...
"Five, four, three, two, one, lift-off! Alright!"
And that's the VOA Education Report. I'm Jerilyn Watson.
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