Review on 🌬️ YVELINES Air Quality Monitor: CO2, Formaldehyde(HCHO), TVOC, PM2.5/PM10 Detector with Real-Time Data & Mean Value Recording - Ideal for Home and Office by Michael Lucas

I had a previous version of this device for more than 2 years but I wanted to have a second one for a different place in my house. Since the controls on the other were hard to remember, I bought two other competitors before buying the updated version. It's better than the other two I brought, but it's far from perfect. The first should be clear. These are not high precision calibrated devices. You won't get the same readings on every device, although I will say that the readings on my three devices are close together most of the time. Some people expect too much and/or don't understand the measurements (e.g. one reviewer complained about CO2 readings in the 500 range as if that weren't normal). Second disadvantages. When it comes to displaying additional information, the shortcomings in the controls are not as significant, but they are still not intuitive. Previously, you had to switch between showing particles (PM2.5 and PM10) and other quality metrics (e.g. HCHO). But one control seems to be missing - the ability to turn off the backlight. I was planning on leaving this new one in my bedroom and while the backlight isn't very bright it would be nice to turn it off. I also suspect that the CO2 levels are excessive since my house is well ventilated. Finally, I think it's probably impossible to have the highest air quality rating (out of four) because they set very low limits for CO2 (450) and maybe even PM10 (50). Also, this rating was easier to see on the old device because they were four separate LEDs, rather than a small portion of the lower display. You could see it from across the room. In terms of improvements, as already mentioned, you get more information about the display. It also seems to update the data much more frequently, more than once per second, so it probably has a faster processor. Interestingly, although the HCHO value can vary slightly from old to new device, the average of this value seems to be very close in most cases. This means that they are generally very close together. Overall I'm satisfied but it's still not a perfect design, it's just the best design I've ever tried.