Cabin filters with active carbon are a special group of filters. The filtration medium consists of two outer layers made of synthetics fabric, capable of trapping solid particles and aerosols with efficiency equal to standard Cabin filters. Additional, third layer of filtering medium placed inside fabric layers is an active carbon granulate, which filters the air from harmful gases. The active carbon has a porous structure similar to graphite. It attracts harmful gases to its surface due to the effect of absorption. The specific surface of one gram of active carbon comes to even 900 m² and therefore the amount of gases stopped may be significant. Practically, the amount of active carbon in filters allows eliminating about 90% of harmful gases such as ozone, hydrocarbons, sulphur and nitrogen compounds during the whole filter exploitation period.