At present, there are two types of filter materials used in the treatment process of waste gas biofilters/pools: inorganic filter materials and organic filter materials Inorganic filter materials are mainly composed of aerated concrete, porous ceramic particles, lava particles, or slag. Organic filter materials include humic bark, wood chips, plant roots, branches, sawdust, peat, and their mixtures. Due to its low cost and easy availability, organic filter media has been widely used. In developed countries, bark has been widely used as a biological filter material in the process of exhaust gas treatment. In China, it has been applied in the treatment of harmful pollutants in industries such as chemical, pharmaceutical, electroplating, painting, printing, as well as in the treatment of odors generated by wastewater treatment plants, composting plants, and landfill sites