Superior hydroxyls are provided which have effects on organic and inorganic compounds and/or pollutants over substantial periods of time and/or at substantial distances from where the superior hydroxyls are generated. Also provided is a hydroxyl generator, in which UV lamps are positioned such that the coronas which they produce when emitting UV radiation fill substantially all the interior space of the hydroxyl generator. The coronas overlap each other by a maximum amount of between 5% and 25% of the radius of each corona.