The main harmful substances of internal pollution are formaldehyde, benzene and radioactive substances. Formaldehyde: mainly contained in glue, many glued boards contain formaldehyde, such as large core boards, which have irritating smell and spicy eyes. Benzene: radioactive substance with pungent smell mainly contained in paint: mainly contained in stone materials such as tiles and marble, colorless and tasteless. Ammonia gas: found in concrete additives, antifreeze, brighteners, etc. Radon gas: exists in concrete additives, antifreeze, whitening agents, marble and granite; TDI: Toluene Dicyanate, which is very toxic, is produced in plates, paints, coatings, sealants, insulating materials and so on. Among them, formaldehyde is the most harmful to human body, which can cause respiratory and nervous system diseases, such as cough, sore throat, chest tightness, dizziness, nausea, limb weakness, dyspnea, drowsiness and other symptoms. More serious induction of cancer such as nasal cancer, laryngeal cancer, skin cancer and leukemia. Generally, the cycle of toxic gas activity is 1- 10 years, especially in the first year. During this period, toxic gases volatilize quickly and release a large amount, which is more harmful to human body. Excessive indoor formaldehyde is harmful to people's health, so corresponding measures must be taken to reduce the content of formaldehyde. The best way to ventilate is ventilation. 2, plant absorption method Plants have a strong ability to absorb formaldehyde, such as cactus, chlorophytum, reed, ivy, cycad, chrysanthemum and so on. . Generally speaking, plants and herbs with large leaves absorb formaldehyde better, such as chlorophytum, Huwei orchid and so on. 3. Put tea residue, grapefruit peel, onion slices, pineapple pieces, etc. by folk soil spreading method. In a newly renovated room or fumigate the whole room with white vinegar. 4. Activated carbon adsorption solid activated carbon has the characteristics of many pores and has strong adsorption and decomposition effects on harmful substances such as formaldehyde. The smaller the activated carbon particles, the better the adsorption effect. 5. Photocatalyst decomposition method Under the stimulation of light, the catalyst in photocatalyst generates negative ions and hydroxyl radicals with oxygen and moisture in the air, which can oxidize and decompose various organic pollutants and inorganic pollutants, and finally degrade into harmless substances such as carbon dioxide, water and corresponding acids, thus achieving the functions of decomposing pollutants and purifying the air. 6. Chemical purification method There are two kinds of formaldehyde scavengers on the market at present. One is to purify the air by neutralizing formaldehyde and generating harmless substances. You can try the above method.