Best to ignore all that FDA FUD, but there are a couple of things to remember when you start with an ozone air generator.
It the unit is NOT oxygen tank driven you will have Nitrogen Oxides (NO) produced depending on the amount of moisture in the air. Some units are better others are worse at this.
It is possible the NO is bothering you but more likely is that ozone breathing can cause some lung issues for a few days. Good ozone air machines can be setup to start out slow, I mean very slow like on trickle timers.