When I explain to someone that there are several lines of vehicle air filters available that are environmentally sound I usually receive a quizzical look back from that person. For some motorists the idea of environmentally compatible automotive parts is a foreign concept to them. Yet, when you think about it many parts that come standard on just about any vehicle qualifies for that title. A catalytic converter is one part that everyone knows about, even if they don't understand exactly how one works. So, exactly what is an environmentally sound air filter? Let