How long does it take to detect formaldehyde?

In daily formaldehyde testing, many homeowners mentioned why some people say they want to close doors and windows for 2 hours, 12 hours, and even 48 hours? Even when they communicated with some of their peers, they also said that they had to shut down for at least 12 hours. There was a lot of disagreement, and it was unclear. How many hours would it take to shut down?
In fact, the regulations regarding the closure of doors and windows, as early as in 2001 and 2002, there were national regulations and standards introduced. They were GB50325-2001 "Civil Construction Project Indoor Environmental Pollution Control Regulations" and GB/T18883-2002 " National Indoor Air Quality Standards. Among the two standards, the former stipulates that the time for closing doors and windows is 1 hour and the latter is 12 hours.
Which standard should be used? Before clarifying this issue, we can compare the two standards to find out the differences. These differences are mainly due to different institutions, different object orientations, and different detection conditions. 50325 was promulgated by the Ministry of Construction. It is a national mandatory standard and is enforced by law. It is a pollutant control standard for the construction engineering environment and only involves five air indicators, namely formaldehyde, benzene series, ammonia, helium, and TVOC. The detection condition is to close the door and window for 1 hour.
18883 is issued by the Ministry of Health. It is a national recommended standard and is not mandatory. It belongs to the minimum standard of living environment health, involving 19 air quality indicators, indoor temperature, humidity, air volume, sulfur dioxide, nitrogen dioxide, carbon monoxide, carbon dioxide, ammonia, ozone, formaldehyde, benzene, toluene, xylene, benzo The detailed regulations are provided for earthworms, respirable particles, TVOCs, biology, total number of bacteria, radioactivity, and earthworms. The detection condition is to close the doors and windows for 12 hours.
18883 It is more scientific to close doors and windows for 12 hours before testing. This time period is close to the daily living status, that is, the occupants can generally guarantee twice the opportunity to open the window for ventilation every day. 50325 detection conditions (formaldehyde, benzene, ammonia, TVOC four items) is carried out after closing doors and windows for one hour. Obviously, the 50325 standard considers more that the builders and decorators meet the most basic environmental protection requirements for decoration.
According to our actual test data, in the comparison of the test results of 12 hours and 1 hour in the house, the value tends to be 2 to 3 times worse, that is to say, if the 50325 test reaches the standard house, the 18883 test is likely to fail to reach the standard. It also does not meet the minimum standards for a healthy living environment.
How long should it be closed as an ordinary resident? In fact, you can choose, because it is directly related to the cost of governance. If you have low requirements on the living environment and economic conditions are limited, you may choose to close the test for one hour. If you are qualified, you will not need to govern. On the contrary, it will be closed for 12 hours, but at this time, more than 90% of the homes will be exceeding the standard, and if it is to be treated, it will cost a fee.
However, it is necessary to remind that if the furniture is complete, ready to stay, then close the doors and windows must be operated in accordance with 12 hours, that is, according to GB/T18883---2002 "national indoor air quality standards" provisions.

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