I find it a little tough to take anyone seriously that says they are in favor of clean air, but they drive an RV. Your RV is still gulping huge amounts of fossil fuel and what is coming out of the tailpipe is not breathable oxygen.
Don't get me wrong, I will never give up my RV but I'm not going to brag about being willing to pay extra for clean air when, in reality, if I really wanted to make an improvement in air quality I would give up my fuel guzzling RV completely and drive a Prius.
Face the truth, if you have made the decision to own an RV, you are really saying that you are willing to pay to consume more fuel and pollute the atmosphere more than most people.