Mining, Steel mill workers (galvanising), scientists testing the capabilities of zinc (eg. zinc-air batteries), businessmen in corporations working with zinc (eg, ReVolt Technology), and engineers designing practical applications of zinc usage. I'm sure that there are more that I just can't think of at the moment.

oxygen and hydrogen

No. Some amount of zinc may be present in fuel used in motor vehicle and as such zinc oxide may be present in air in traces. ( You have a lead free fuel available. )

Zinc chloride- in deodorants Zinc pyrithione- anti-dandruff shampoos Zinc sulfide- in luminescent paints Zinc ditheye or zinc methyl- in the organic laboratory

zinc is very reactive, if you leave zinc out in air, it will oxidize, that's how reactivie it is.