As we all know, furniture, especially new furniture, contains a large amount of formaldehyde, and formaldehyde does great harm to human body, which will affect the upper respiratory tract, stimulate eyes, even lead to leukemia, induce cancer, etc., which is the consensus of academic and medical circles. But at present, the research conclusion that can be confirmed is only qualitative research. How much indoor formaldehyde concentration can affect human health, that is, quantitative research has not formed a scientific conclusion.

四個因素有關：

Four factors are involved

1、室內溫度。由于甲醛的沸點是19℃，當溫度超過19℃后，室內溫度每升高1℃，甲醛揮發速度就上升0.4倍，尤其是在夏季氣溫升高或冬季取暖時釋放更加劇烈，濃度甚會超出平時的4倍。

1. Indoor temperature. Since the boiling point of formaldehyde is 19 ℃, when the temperature exceeds 19 ℃, the volatilization rate of formaldehyde increases by 0.4 times for every 1 ℃ increase of indoor temperature, especially when the temperature rises in summer or heating in winter, the concentration of formaldehyde will even exceed 4 times of normal.

2、室內相對濕度。濕度對甲醛的影響主要是因為家具板材內的脲醛膠是由尿素和甲醛聚合反應生產的，在濕度增大板材受潮情況下，脲醛膠遇水會分解成尿素和甲醛，從而加大板材內游離甲醛的含量，導致揮發空氣中的含量也增加。

2. Indoor relative humidity. The influence of humidity on formaldehyde is mainly because the urea formaldehyde glue in furniture panel is produced by the polymerization reaction of urea and formaldehyde. When the humidity increases, the urea formaldehyde glue will decompose into urea and formaldehyde when the board is wet with water, which will increase the content of free formaldehyde in the board and lead to the increase of the content volatilized into the air.

3、室內空氣流通量。由于室內甲醛的釋放量是一個動態平衡，當室內的甲醛釋放濃度達到一個平衡值時，室內的甲醛就不再釋放了。當我們開窗換氣，打破甲醛的這個平衡值，就會因為室內空氣的流通量的變化，導致家具又會源源不斷的釋放甲醛，所以，通風是加速家具釋放甲醛的方法。

3. Indoor air flow. Because the indoor formaldehyde emission is a dynamic balance, when the indoor formaldehyde emission concentration reaches an equilibrium value, the indoor formaldehyde will not be released. When we open the window for ventilation, breaking the balance value of formaldehyde, the furniture will continue to release formaldehyde due to the change of indoor air circulation. Therefore, ventilation is the best way to accelerate the release of formaldehyde from furniture.

4、室內裝修材料的裝載度。室內甲醛的釋放源不是孤立存在的，根據釋放源不同其揮發時間也不一樣 ，墻壁涂料中的甲醛7-15天即可揮發的差不多了，壁紙膠中的甲醛18個月以上 ，大芯板中的甲醛 15個月5年不等 ，密度板貼面板中的甲醛幾乎都在3年以上甚可超過10年。另外，由于各個甲醛釋放源釋放甲醛的速度相互影響和室內空間裝修承載度的原因，所以，裝修越復雜，甲醛揮發就越慢。

4. Loading degree of interior decoration materials. Indoor formaldehyde emission sources do not exist in isolation. According to different sources, their volatilization time is different. Formaldehyde in wall coating can volatilize almost in 7-15 days. Formaldehyde in wallpaper adhesive lasts for more than 18 months, and formaldehyde in large core board ranges from 15 months to 5 years. Formaldehyde in density board is almost over 3 years or even more than 10 years. In addition, the more complex the decoration, the slower the formaldehyde volatilization.

綜上所述，新家具放置多長時間甲醛可以徹底釋放完，這是一個偽命題，沒有一個統一的標準答案。我們在挑選家具的時候，一定要挑選指數較高的板材家具，從源頭上減少甲醛的含量。

To sum up, how long the new furniture can be completely released formaldehyde is a pseudo proposition, there is no unified standard answer. When we choose furniture, we must choose the board furniture with higher environmental protection index to reduce the formaldehyde content from the source.