english: It travels through the bloodstream  to tiny air sacs in the lungs, passing into exhaled air  at a concentration 2,000 times lower, on average, than in the blood.
non_english: Putuje kroz krvotok do malih vazdušnih kesa u plućima, prelazeći u izdahnut vazduh pri koncentraciji 2,000 puta manjoj, u proseku, nego u krvi.