Hydroxyls are molecules consisting of one oxygen atom and one hydrogen atom and are the neutral form of the hydroxide ion (OH−). Hydroxyl radicals are created naturally in the atmosphere when the sun's ultraviolet rays react with water vapor (H2O) and oxygen (O2). They rapidly decompose chemicals in the air and are often referred to as "nature's broom" or the "detergent" of the atmosphere because of the crucial role they play in helping to keep the Earth's atmosphere clear of harmful organic and inorganic compounds.
Within milliseconds, hydroxyls recombine with other compounds to form peroxy-free radicals which quickly react with VOCs and inorganic gases. These cascading reactions continue to occur as contaminants are broken down into carbon dioxide and water. In other words, the hydroxyl radical will destabilize other organic compounds by taking away a hydrogen molecule to become water. The lifetime of OH radicals in the Earth atmosphere is very brief, thus, OH radical molecule does not adversely affect humans, animals or plants.
Because the lifespan of a hydroxyl radical is relatively short, it is hard for them to reach indoor spaces. Hydroxyl generators help to recreate this natural process in places where UV light from the sun cannot reach (such as indoors), working as an air filter that continuously cleans the air from viruses, bacteria, and allergens.