There are all kinds of rumors about formaldehyde circulating on the Internet, some selling anxiety and some promoting formaldehyde-free products. In the process of home inspection, we often encounter owners who are misled by the Internet, resulting in unnecessary anxiety and using the wrong method.

Here, I will share it with the video of CCTV's "One Question to the End" column for your reference.

Formaldehyde, also known as antaldehyde, with the chemical formula HCHO, is one of the most common chemicals in nature and is a colorless and irritating gas.

The specific gravity to air is 1:1.06, soluble in water, and volatile at room temperature. Its 35-40% aqueous solution is formalin, which can be used as antiseptic and adhesive, and is very versatile.

In October 2017, the World Health Organization's International Agency for Research on Cancer classified formaldehyde as a Class I carcinogen.

The harm of formaldehyde is mainly manifested in irritation, sensitization, toxicity and potential carcinogenic risk.

Long-term exposure to high concentrations of formaldehyde may induce or aggravate symptoms such as dizziness, headache, drowsiness, insomnia, decreased immunity, and allergic rhinitis. Long-term inhalation of high concentrations of formaldehyde will have adverse effects on the respiratory system, nervous system and immune system, and in severe cases, it will also increase the risk of lymphoma, leukemia and other diseases.

The "Indoor Air Quality Standard" GB/T18883-2022 stipulates that the one-hour average value of indoor free formaldehyde content shall not be greater than 0.08mg/m³.

The World Health Organization stipulates that the 30-minute average value is no more than 0.1 mg/m³, and the United States and Canada stipulate that the 1-hour average limit is 0.123/mg/m³ and 0.09 mg/m³ respectively.

Formaldehyde is widely used in various aspects, and it is contained in our daily skin care products, textiles, clothing and decoration materials used in decoration.

The main source is all kinds of boards used in decoration, because formaldehyde is often used to produce various resins with strong adhesion, and also to strengthen the hardness of the boards. Therefore, at present, uronic acid resin with formaldehyde as the main component is used as an adhesive in the hugging board, medium-density fiberboard and plywood on the market. In addition, some new furniture, walls and floors should also use adhesives in the decoration auxiliary materials.

Formaldehyde is particularly volatile. When you first enter a room, if you feel a pungent gas, your eyes become uncomfortable, red, your nose sneezes, and your upper respiratory tract is uncomfortable. It shows that the concentration of indoor formaldehyde is already at a high level.

Studies have shown that when the concentration of formaldehyde reaches about 0.13 mg/m³ (the standard limit is 0.08 mg/m³), about 50% of people can feel the presence of irritating gases. At a formaldehyde level of 0.08 mg/m³ (the standard limit), most people do not feel the irritating gas.

The formaldehyde content of 0.08mg/m³ (standard limit) refers to the test result of about 1 hour after the sample is collected for about 1 hour after closing the doors, windows, and fresh air system for 12 hours.

If a person lives at a formaldehyde concentration of 0.08mg/m³ (the standard limit) for a long time, or even for the rest of their lives, there is no risk of causing cancer.

If you have symptoms such as sore throat, dry eyes, red eyes, dizziness and headache in your newly renovated house, you need to pay attention to whether there is excessive formaldehyde, and you can ask a professional formaldehyde testing agency to test the indoor air.

Formaldehyde is widely used in various aspects, and it is contained in our daily skin care products, textiles, clothing and decoration materials used in decoration.

The main source is all kinds of boards used in decoration, because formaldehyde is often used to produce various resins with strong adhesion, and also to strengthen the hardness of the boards. Therefore, at present, uronic acid resin with formaldehyde as the main component is used as an adhesive in the hugging board, medium-density fiberboard and plywood on the market. In addition, some new furniture, walls and floors should also use adhesives in the decoration auxiliary materials.

Formaldehyde is particularly volatile. When you first enter a room, if you feel a pungent gas, your eyes become uncomfortable, red, your nose sneezes, and your upper respiratory tract is uncomfortable. It shows that the concentration of indoor formaldehyde is already at a high level.

Studies have shown that when the concentration of formaldehyde reaches about 0.13 mg/m³ (the standard limit is 0.08 mg/m³), about 50% of people can feel the presence of irritating gases. At a formaldehyde level of 0.08 mg/m³ (the standard limit), most people do not feel the irritating gas.

The formaldehyde content of 0.08mg/m³ (standard limit) refers to the test result of about 1 hour after the sample is collected for about 1 hour after closing the doors, windows, and fresh air system for 12 hours.

If a person lives at a formaldehyde concentration of 0.08mg/m³ (the standard limit) for a long time, or even for the rest of their lives, there is no risk of causing cancer.

If you have symptoms such as sore throat, dry eyes, red eyes, dizziness and headache in your newly renovated house, you need to pay attention to whether there is excessive formaldehyde, and you can ask a professional formaldehyde testing agency to test the indoor air.

Many people may have doubts that although environmentally friendly materials are used, formaldehyde will still exceed the standard. What causes this?

First of all, we must understand that environmentally friendly materials are not equal to formaldehyde-free, as long as it is a plate, there is more or less formaldehyde. In the "Formaldehyde Emission Classification of Wood-based Panels and Their Products" GB/T36900-2021, the wood-based panels and their products are divided into three environmental protection grades, namely E0, E1 and ENF. The formaldehyde limit released by each grade of 1㎡ board in a space of 1m³ is specified. See the figure below for details:

Secondly, formaldehyde has a superposition effect, and the indoor formaldehyde concentration is related to the size of the room, the number of boards used and the number of furniture. Usually there are wooden floors, wooden doors, windows, mattresses, wallpapers, upholstered homes, etc., which will release a certain amount of formaldehyde. The formaldehyde released by these homes may lead to excessive indoor formaldehyde when superimposed.

Is the online treatment of formaldehyde home remedies effective?

There are many home remedies for formaldehyde treatment on the Internet, some put a basin of water at home, some stack tea leaves, and some place green plants. Are these methods effective?

1. Can putting a basin of water in the house reduce formaldehyde?

Indoor water discharge is conducive to formaldehyde soluble in water, but the height of free formaldehyde in the room is mainly between 0.7-1.5 meters, and will not actively dissolve in water, and the effect is minimal.

2. The effect of formaldehyde adsorption by green plants

The placement of green plants is to use the photosynthesis of plants to adsorb a certain amount of formaldehyde, but the adsorption amount of green plants is very small, and the effect is also not obvious.

3. Can tea remove aldehydes?

Placing tea indoors can only use the taste of tea to cover up other tastes, and it will not have any effect on formaldehyde.

4. Effect of activated carbon adsorption

Indoor placement of activated carbon can have a certain adsorption effect, but it is related to the amount of activated carbon, and the activated carbon will be saturated, which may cause secondary pollution.

1. Open windows for ventilation

Open window ventilation is the best way to deal with indoor free formaldehyde, and it is enough to use open window ventilation in summer. If the ventilation conditions are not good, you can use the ventilation function of the air purifier or air conditioner, and the effect will be a little worse than opening the window for ventilation.

If it is winter, you can use the simmering method, first turn on the indoor air conditioning or heating, raise the indoor temperature to more than 20 °C, last for 8-12 hours, and then open the window for 4-8 hours, and the cycle repeats.

2. Spraying of chemicals

For those with high indoor formaldehyde concentration or anxious move-in, there is no way to reduce formaldehyde by ventilation. You can seek professional institutions to use chemical spraying for treatment, and the formaldehyde that will be released will be harmlessly decomposed.

3. Good air release package