What about NASA? Don't they use a filter that controls CO2 levels? I only saw this on the movie "Apollo 13." I'm not sure if the movie is completely true or not. I'm pretty sure the technology is possible. I'm pretty sure later on down the road, CO2 emissions from exhaust can greatly be reduced. It just boggles my mind that there may be a possibility that there might be better ways of cleaning the exhaust of our lovely, clunky, rinky-tinky, internal combustion engines.