Totally correct there, concrete also has a large impact aswell as peat, people panic too much with regards to 'greenhouse gasses', we have scientific proof that the air was more dense with it millions of years ago yet nature flourished with rain forests covering only a quarter of what we have now. CO2 and carbon monoxide is not something we should worry about, we should be worrying about the carcinogenics that are put into the atmosphere, carbon monoxide is a way of life for us and the plants that depend in it......