• News
  • News
  • Home > News
    The reporter used a fan filter to make an air purifier to reduce PM2.5.
    Click:1040 Date:2019-01-24 14:59:00 Information Source:

        Recently, a news of a 169 yuan homemade air purifier in Beijing was reported on the Internet. The basic principle is to tie a filter that can filter PM2.5 particles to the front of the electric fan, and let the air pass through the filter through the wind of the fan to achieve the effect of purifying the air. Is this approach feasible? The reporter used a similar method to imitate a simple air purifier and found that it can actually reduce the PM2.5 concentration, but the purification speed is slower than the brand air purifier.
    Experiment preparation 200 yuan online shopping filter
        Recently, a website called "Team Technology Media" published the article "166 yuan DIY an air purifier" written by its special author Thomas Talhelm. Thomas claims to be a Ph.D. student in social psychology at the University of Virginia, and a Fulbright scholar in Beijing from 2012 to 2013.
        The principle of Thomas's self-made air purifier is to tie a HEPA filter that can filter PM2.5 particles to the front of the electric fan, and let the air pass through the filter through the electric fan.
       It is understood that most imported and domestic air purifiers currently on the market rely on HEPA filters. But simply bundling the fan with the HEPA filter can have the effect of purifying the air? The reporter conducted a test.
        The reporter purchased a HEPA filter with a price of more than 200 yuan on the shopping website. Considering that the filter is directly related to the purification effect, Philips AC4144/00 high-performance composite HEPA filter has been selected for many years. This filter is suitable for Philips' main air purifiers such as AC4074/4072, and this filtration The network area is relatively large, and it is suitable for the next step to cover the electric fan.
        The electric fan chose the Gree KYT-2501 rotary fan. The front end of the rotating fan is relatively flat and easy to be affixed to the HEPA filter.
        Subsequently, the front of the page fan was covered with a HEPA filter and fixed with tape to form an air purifier.
    ■ Experiment
    PK brand purifier speed is at least slow
        Note: In order to verify the effectiveness of the homemade air purifier, the reporter chose two other brand air purifiers to compare with. Since the standard value of PM2.5 in China is less than 75 micrograms per 24 hours, the test process is to see how long the three purifiers can reduce the PM2.5 concentration below this standard. Continue testing.
        The experiment was carried out in a room of about 20 square meters. The outlets of the three tested purifiers were more than 1 meter above the ground. A PM2.5 detector was placed two meters away, and the data was recorded every 5 minutes. This way of placing is mainly to detect the position near the air outlet of the purifier.
        Result: The brand A purifier reduced the PM2.5 from 268 to 158 after 5 minutes, and dropped to 75 after 10 minutes, the speed first. The brand B purifier dropped PM2.5 from 266 to 72 after 25 minutes, ranking second. The homemade purifier took 50 minutes to reduce the PM2.5 from 257 to 71.
        The data shows that the homemade air purifier does reduce PM2.5, but it is very slow and can be reduced by up to 30 in 5 minutes, which also results in a total time consumption that is at least double that of the brand purifier tested.
    Filter stickers car outlet effect super purifier
        Note: The PM2.5 value in the car often exceeds the standard due to smoking and other reasons, and it is a confined space. The reporter also tested the homemade air purifier, the car's own air filter purifier, and the brand C car air purifier. effect. When testing the car's own air filter purification effect, it does not use any additional purifiers, but it is filtered by the car's own air circulation equipment. When testing the brand C car air purifier, the air circulation inside the car is turned off.
        RESULTS: Unlike the results of the indoor test, the self-made air purifier reduced the PM2.5 from 1399 to 45 in 15 minutes during the in-vehicle test, ranking first. When only relying on the air filter purifier that comes with the car, the PM2.5 is reduced from 1600 to 74 in 20 minutes, ranking second. When the car air circulation was turned off, it took 25 minutes to reduce the PM2.5 from 1741 to 74, which was the slowest. This is because the car air purifier is connected to the power source through the cigarette lighter, and the power is relatively small, and the power of the car outlet is greater than that of the car purifier. In addition, the filter screen of the self-made air purifier is placed at the air outlet of the air filter device of the automobile, which is equivalent to the air filter device and the HEPA filter to filter the air inside the vehicle.
    Homemade air purifier is more suitable for small spaces
        Dr. He Xiaoxia, director of the Environmental Research Institute of Dahl, said that from the results of this experiment, the way of attaching the HEPA filter in front of the electric fan can actually reduce the effect of PM2.5, but compared to the two of the horizontal evaluation. Purifier, the self-made air purifier PM2.5 slows down, suitable for people with small space and not very high air quality requirements.
        The test in the car shows that the three methods can play the role of purifying the air to a certain extent. Those who drive for a long time need to adopt one of them, otherwise the PM2.5 concentration in the smaller space of the car is compared. High, it will cause some harm to the human body.