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.
Ozone has a number of benefits which can enhance your day-to-day life. There are some things in life that you become accustomed to and it is only once you break the cycle and try the alternative that you realise what you have been missing out on.