I'm certain that ancient man knew of wind and of our need to breathe, but when did air as a distinct material become obvious? I notice that the four classical elements are water, wind, fire, and earth. As no other gasses were known until the chemists replaced the alchemists, when did air as a medium become known? Did Newton know of air?
Philo of Byzantium, wrote Pneumatica. Which included details of devices operated by air pressure. They knew about it far earlier than newton. He seems to be an early source for knowing about the properties of air with respect to combustion, link.
But if we're talking about classical Greek elements, I thought Empedocles's four elements included air. However it is "wind" in the Babylonian idea from the Enûma Eliš (18th-16th century BCE). I'm not sure what the difference between air and wind is unfortunately, and I don't have access to papers anymore. This is what I would read if I did: http://www.sciencedirect.com/science/article/pii/S0039368102000225