 The purpose of this study is to examine biological pathways of altered blood vessel function resulting from breathing airborne particulate. Blood artery function in healthy men will be measured after particulate exposure either on placebo or on an asthma medication that stops production of an inflammatory biological agent. Lung and blood profiles will be obtained before and after exposure to exhaust fumes. We believe that the inflammatory agent produced by the lungs from breathing these particles causes abnormal artery function. 