How are inert gases used?

Which gases are used in street lamps,and why certain gases are chosen for certain locations?

• Answer:

  Here in Southern California, we use high-pressure sodium lamps that glow yellow, because it cuts down on light pollution. This is done both to cut down light pollution for us people, and also because we have a number of important, large astronomical observatories that were being blinded by the common mostly-white street lights. But instead of rambling on, check out the links below, they have all the information you'll ever need.