A spokeswoman for the mayor's office, Joanna Dovan,says the Pittsburgh area has been working to improve its air quality.

VOA: special.2009.07.13

The group's recent "State of the Air" report said Pittsburgh has the worst short-term fine particle pollution in the country.

VOA: special.2009.07.13

Mars Day at the Smithsonian Air and Space Museum in Washington is a celebration of our solar system's most famous planet.

VOA: special.2010.07.28

It says the aim is to bring air guitarists out of the house where they secretly perform and onto the world's stage.

VOA: special.2009.08.14

We attended this year's United States Air Guitar Championships in Washington,D.C.to learn more about this unusual activity.

VOA: special.2009.08.14

In nineteen eighty-five, the group's members expressed their displeasure in the song,"MTV C Get off the Air."

VOA: special.2011.08.05

Senator Nelson knew there was growing public concern about the country's polluted air, rivers and land.

VOA: special.2010.04.21

And now the pitcher holds the ball, and now he lets it go, And now the air is shattered by the force of Casey's blow.

VOA: special.2011.04.04

Arrows whistled through the air. A spear went through the body of Stockard's wife.

VOA: special.2010.11.06

An observatory opened recently at the Smithsonian Institution's National Air and Space Museum.

VOA: special.2009.10.27

Some travel guides have described Luxor as the world's largest "open-air museum."

VOA: special.2011.03.08

His S-38 amphibian flew through the air and then landed on water.

VOA: special.2010.09.10

And Virgil Grissom,of the Air Force, worked on Mercury's electrical systems.

VOA: special.2009.06.10

The Smithsonian's National Air and Space Museum in Washington,D.C.owns the plane.

VOA: special.2009.03.18