[ClaireSolt]

Some health nuts note that there is less oxygen and more COS than there used to be. We need the oxygen. Burning uses oxygen and releases co2. To restore the balance, you must plant trees (or corn to make ethanol :)

[dirtbiker]

Some health nuts note that there is less oxygen and more COS than there used to be.

Last time I checked, it was still at 21%, same as it has been for the 47 years of my life.

I would ask for them to cite their sources, but they would just link to some loony leftist pseudo scientific chatroom/blog/report....