We exhale CO2. The complainant has incorrectly attacked a "greenhouse gas" as toxic. The intended gas would be CO (carbon monoxide) which actually is pretty bad for you. The firestations here have vacuum collection systems that attach directly to the exhaust pipes of the trucks and ambulances since apparently Diesel exhaust has been associated with certain, shall we say, bad things. Other press recently identified Diesel exhaust as causing decreased circulation during exercise.
Sorry, but your ill-advised author actually has a point. Good luck with the real issue troubling humankind - how to get along with other people whose viewpoints differ from our own.
http://circ.ahajournals.org/cgi/content/abstract/112/25/3930