In dry winter, a humidifier with wet mist has become a must-have for many families. However, on February 10, a piece of news in CCTV-4’s “China News” column, “humidifier is easy to become a” health killer “if not used properly”, caused many people who often use humidifiers to panic. In the report, CCTV reporters tested the PM2.5 of the room before and after humidification. Using a portable PM2.5 tester, the experimenter first measured the PM2.5 value in the room before using the humidifier, which was 0.133mg/m3. Then, put mineral water, tap water and distilled water into the humidifier respectively, and measure the indoor PM2.5 value after humidification. The results showed that after humidifying with mineral water, tap water and distilled water, the results were 0.211mg/m3, 0.363mg/m3 and 0.176mg/m3 respectively, which significantly increased compared with the previous background.
Can humidifiers really aggravate indoor PM2.5? This reporter sought confirmation from Peng Yingdeng, a researcher of the national urban environmental pollution control technology research center. He responded that there was no need to refuse to use the humidifier because of fear of PM2.5. Because humidifier will not harm health, but can effectively improve indoor humidity and increase negative oxygen ions.
Regarding the design and results of the experiment, he said that there were certain problems. On the one hand, the portable PM2.5 detector used in the experiment is not particularly professional, and the data detected may not be accurate. On the other hand, even if professional testing instruments are used, people will misunderstand the testing results due to the congenital defects in the testing technology. This is because the working principle of humidifier is to cut water into water vapor aerosol particles, and PM2.5 is also an aerosol particle in essence. The current detection technology can not effectively distinguish water vapor aerosol particles from harmful aerosol particles (PM2.5). In addition, the automatic PM2.5 detection instrument can not completely dehumidify, which naturally can not avoid the interference of water vapor, and the water mist emitted by the humidifier will be mistaken for PM2.5. However, water vapor particles are different from harmful PM2.5. They are beneficial aerosol particles. Therefore, although the PM2.5 detection value in the room rises after the humidifier is used, it does not harm the body. Therefore, if you don’t feel stuffy and uncomfortable, the suddenly rising PM2.5 value at home is likely to be just the interference of water vapor, so don’t worry too much.
As for the different test results of the three kinds of water used in the experiment, Peng Yingdeng said that no matter what kind of water was added to the humidifier, the mist like aerosol particles would be detected. However, the PM2.5 value detected by using different water quality does have differences, especially tap water, which has increased the PM2.5 value in the air by nearly three times. This is because tap water contains calcium and magnesium ions and some impurities, and the generated aerosol particles can significantly improve the mass concentration of PM2.5. It should also be noted that, unlike distilled water, these impurities do have a certain negative impact on health after being ejected with the mist. Therefore, Peng Yingdeng suggested that distilled water or purified water with less impurities and safety should be used, and tap water should be used as little as possible. In addition, the use of humidifiers should be limited. The larger and longer the humidifier is, the better the effect will be. According to the most suitable standard for human body, the indoor humidity is best controlled at 45% ~ 55%.
Finally, with regard to the indoor pollution problem that people have been worried about, Peng Yingdeng reminded that indoor is a closed space, which is more likely to accumulate PM2.5. But the most fundamental protection method is to ensure forced exhaust of kitchens and toilets, and often open windows for ventilation to keep fresh air flowing.
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