If you are only interested in HCHO levels this should do the trick for you. I have used it in different environments and in different conditions it has worked well for me. At the moment it is worth 5 stars. If you want to check temperature and humidity, it is not accurate with more than 5% errors. His TVOC scale never changed under different conditions - guessing it won't work. But since I only looked at HCHO, which shows well, the errors in the other tests are negligible. That's why I give 4 stars. Compare measurements from two different devices. The current temperature is 79F and the humidity is 53%.
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