2.1.1. Diffusers and evaporators
‘Diffuser type’ odorizers usually consist of a fragrance liquid/gel, a storage container and some means to control evaporation or diffusion to an evaporation surface. Typical examples are stick diffusers, where several (typically 6e12)wood sticks are placed in a bottle and slowly evaporate the rising fragrance liquid over a time frame of days to weeks. Other constructions with similar function, e.g. with a wooden lid, a membrane or perforated plastic part can be found as well. For small rooms or cars gel-/liquid-filled evaporators are available. Items of each group were tested.