He'll use my line of high-end oxygen-producers. I can start him off with some Bambü, which produces a very nice texture, or we can skip directly to Alø, which has some very nice medicinal properties as well.
I have a bamboo floor in my home office, and generally like things made out of bamboo. Not even knowing the actual oxygen-producing properties of bamboo, I can imagine myself trying some bamboo oxygen. And I usually don't like seemingly overpriced stunts like this. I seriously think it could sell big. Oxygen made by your favorite plants! Amazing idea.
There are articles online about the useful effect of certain plants on the atmosphere of offices.
That's for regular punters. Now we need a bit of price discrimination to get the high value customers. No mere "place a bamboo plant in the corner". You need to specify the obscure region of China that the original plant comes from (leave out the fact that you took a million cutting from that plant in an industrial unit somewhere) and describe the quality of the oxygen and other harmonious gases produced by these plants.