Yes, entirely safe when used correctly and in line with our operating instructions. Ozofresh generators are designed and built to specifically avoid any health risks that might be present in other machines.
The noise you may notice is the fan(s), the only moving parts in an ozone generator. Their job is to suck oxygen in to create the ozone, and to help propel the ozone as high as possible. Because ozone is heavier than air, it needs to reach a decent height in order for it to be effective at removing pollutants in the air.
In order to maintain a constant level of clean air, it is important to run an ozone generator on a regular basis. Simply implement it into your existing cleaning procedures to cause as little disturbance to your day as possible.