 Randomization is achieved with blocks of six 6, with four 4 patients receiving Albuterol-HFA for every one 1 patient receiving Proventil-HFA and every one 1 receiving the Placebo-HFA. At each Clinical Visit that takes place every 3 weeks, the double-blinded T, P or evaluator-blinded R study drugs will be distributed in resealable masking pouches to the subjects of each arm. 