Activated charcoal is usually used to remove substances that are odorous, from the air. The substances are removed by the mechanism called adsorption. Activated charcoal is manufactured by treating normal charcoal with oxygen which creates lots of pores in the charcoal. As a result, the surface area of the charcoal will increase and it becomes highly capable of adsorbing substances. But, the activated charcoal adsorbs only the impurities that are attracted to carbon.