The writer William McFee once said, “There is nothing like an odor to stir memories.” What he neglected mentioning is that sometimes those odors are foul and they’re linked to bad memories like fires and floods. You want those odors gone for good.

After removing the source of the smell and a thorough cleaning, there are two types of units that most restoration contractors use today to purge a room or a building of bad smells. Ozone generators, which have been around for awhile, and its younger cousin the hydroxyl radical generator.

What’s the difference?

Ozone generators – (Xactimate code: CLN DODROZ) delivers ozone to the area being deodorized which will effectively oxidize and remove odor molecules in the air through the oxidation process. These should only be used in unoccupied areas that should be thoroughly ventilated before reentering. Ozone can also break down rubber components when exposed for too long.

Hydroxyl radical generators – (Xactimate code: CLN DODHY) without getting too technical, they don’t deliver hydroxyl radicals to the area being deodorized because the oxidation of the odor molecules goes on as they pass through the unit. Hydroxyl radicals are not exiting the unit as is the case with ozone generators that deliver ozone from the unit to the surrounding atmosphere. So it’s important that the unit is placed in the middle of the room and not against walls to maximize air flow through the unit. But they are completely safe for humans and animals to be around.


Both of these machines achieve the same results, but the big difference is the time factor. If an ozone generator can do the job in a day, a hydroxyl radical generator may take up to five days. But if you have a situation where people or animals cannot be moved, or you want to be able to continue working in an area without stopping, then you’ll want to use a hydroxyl generator.