noble gas
Air is one. There are many others.
Carbon monoxide
Odorless gasses: Carbon Monoxide (CO), Nitrogen, Oxygen, Carbon Dioxide, Argon, Helium, Hydrogen, Water vapour, Xenon, Neon Malodorous gasses: Hydrogen sulfide, ozone, nitrogen oxide, mercaptans,...
Well, according to Tony Abbott, carbon dioxide is a colourless, odourless and weightless gas. Anyone who paid attention in Science would know otherwise.