What is the main source of formaldehyde

People will have more or less contact with some toxic gases in their daily life and work, and the most common exposure to toxic gases is when decorating a house. The gas that poses the greatest threat to the human body after a house is renovated is formaldehyde, but most people are not clear about the factors that cause formaldehyde. So, what are the main sources of formaldehyde?

First, what is the main source of formaldehyde? In addition to being used directly as a disinfectant, sterilizer, and preservative, 35% to 40% formaldehyde aqueous solution is commonly known as formalin, which is widely used to soak biological specimens, disinfect seeds, etc. In the food industry, it is also used to preserve foods that are difficult to store, such as aquatic products. The main natural emission sources of formaldehyde include forest fires, release from animal excrement, release from microbial activities and plant volatilization, while man-made emission sources include building materials, decorations, tobacco leaves and incomplete combustion of fuel, industrial production, food, clothing, etc. In addition to being used directly as a disinfectant, sterilizer, and preservative, 35% to 40% formaldehyde aqueous solution, commonly known as formalin, is widely used to soak biological specimens, disinfect seeds, etc. In the food industry, it is also used to preserve foods that are difficult to store, such as aquatic products. Formaldehyde is widely used in organic synthesis, synthetic materials, surfactants, plastics, rubber, leather, papermaking, dyes, pharmaceuticals, pesticides, coatings, photographic films, explosives and other industries. Its derivative products mainly include paraformaldehyde, polyoxymethylene, phenolic resin, urea-formaldehyde resin, amino resin, urotropine and polyols. Resins produced with formaldehyde as raw material are mainly used as adhesives and are used in large quantities in various artificial boards. Urea-formaldehyde foam resin made from urea-formaldehyde resin is a thermal insulation material used to make prefabricated panels as building envelopes. It can also be used as a filling material for thermal insulation. Movable houses use urea-formaldehyde foam resin insulation material (UFFI) as a building material. In the textile industry, formaldehyde is used for resin finishing of clothing fabrics to achieve anti-wrinkle, anti-shrinkage, flame retardant and other effects, or to maintain the durability of printing and dyeing, or to improve the feel. Currently, pure cotton textiles are mostly treated with formaldehyde printing and dyeing auxiliaries to increase the stiffness of cotton fabrics.

Second, the natural emission sources of formaldehyde mainly include forest fires, release from animal excrement, release from microbial activities and plant volatilization. The man-made emission sources are as follows: building materials, decorations, interior decoration and other building materials commonly used in floor leather, plastic veneer, plywood, latex paint, synthetic fiber, adhesives, etc. release formaldehyde. Newly renovated hotels, guest rooms, and family rooms have more sources of formaldehyde pollution due to the use of the above-mentioned decoration materials. Studies have reported that the formaldehyde concentration in the air of decorated rooms is significantly higher than that in undecorated rooms, and the indoor formaldehyde concentration in newly renovated rooms increases significantly within half a month. In addition, there are potential hazards of formaldehyde in newly renovated public places. In addition to coming from building materials, indoor formaldehyde also comes from decorative materials such as paints, plastic panels, thermal insulation and sound insulation. The average formaldehyde concentration in mainstream smoke from incomplete combustion of tobacco leaves and fuel is 212 mg/m3, and in sidestream smoke it is 18-58 mg/m3. Smoking two cigarettes in a 30m3 room can cause the formaldehyde concentration in the indoor air to reach more than 0.1 mg/m3. Fuel combustion in the kitchen is another major source of indoor formaldehyde, with values ​​reaching 0.40 mg/m3.

What are the main sources of formaldehyde? Formaldehyde is widely used as raw material in industrial production. Formaldehyde volatilization, leakage and other incidents during production, transportation, storage, use and waste disposal, as well as wastewater discharge can lead to formaldehyde pollution. In addition, alcohol production also releases formaldehyde into the air. Food itself contains formaldehyde. In recent years, some food producers have added sodium formaldehyde sulfoxylate during the production and processing of bread products to improve the appearance of inferior flour products, resulting in excessive formaldehyde. Some of the cosmetics, detergents, pesticides, printing inks, textile fibers, and disinfectants and preservatives used in hospitals and medical schools may contain formaldehyde. In particular, formalin, which is often used directly as a preservative in pathology and anatomy laboratories, causes more serious air pollution. Surveys show that the concentration of formaldehyde in the air of local analysis rooms and specimen storage rooms is higher than that in offices, classrooms, and specimen preparation rooms. In addition, although formaldehyde has a killing effect on various microorganisms, its disinfection speed is slow, and strong irritating gases often remain in the space after disinfection, which irritate the eyes and nasal mucosa. Textiles containing formaldehyde in clothing will gradually release free formaldehyde during the process of people wearing and using them, which can cause respiratory and skin inflammation through contact with the human respiratory tract and skin, and can also irritate the eyes. Industrial waste gas, automobile exhaust, photochemical smog power plants, refineries, waste incineration plants, wood and fuel combustion, etc. directly release formaldehyde into the atmosphere, and also release formaldehyde precursors, hydrocarbons, which are oxidized in the air to indirectly produce formaldehyde. When photochemical smog pollution occurs, the indirectly generated formaldehyde may exceed the direct emissions. In places far away from urban areas, methane oxidation is the main source of formaldehyde. The formaldehyde produced by the above process can pollute the atmosphere, mix with rainwater, and enter the soil and water bodies, increasing the formaldehyde content of the water bodies.