Activated carbon filters used in hydroponic green houses and grow rooms are the most effective means of cleansing the extracted air to remove any odors. These filters work by a method called adsorption (as opposed to absorption). Simply put, adsorption means that odor-causing molecules stick to the inside of the activated carbon without the carbon itself increasing in size. Premium carbon filters such as the Mountain Air® range not only have a useful life much longer than competing brands, they also retain odor-causing molecules more effectively, which leads to a later breakthrough point. Users of these filters can rest assured knowing that their extraction air will be odorless right up until it’s time for a new filter.