TemtopAir Quality Monitor PM2.5 AQI Detector Professional Indoor AQI Monitor, P10

It's a handy device. Gives me an indication of PM2.5 levels in the house and outside if need be. Having an air purifier is a good idea with all the smoke from Australian fires of late, but monitoring the air also gives one a good idea whether using an air purifier is needed or not (except when smoke levels are high and the need is obvious). I am happy to recommend this one to others. After use with 2020 bushfires, now in 2023 monitoring wood smoke particulates from new neighbour who installed a wood heater. Wood heaters should be banned, but meanwhile this monitor is most useful for monitoring indoor PM2.5 levels.

You cannot calibrate P10 though it has pin hole. As per support email, you leave it on for 1-2 hrs outside for calibration. May be calibration not needed at all. Looks reasonably accurate.

I like the easy to understand interface, although the instructions didn't really make clear the calibration process. It could also explain how it measures the particulate matter it claims to measure, as there is no way of knowing if it is accurate.

It will not work after some time. And you will not get any support from temtopus support. Don't buy

I live in California, where unfortunately our summer air quality has deteriorated significantly the past 3 years due to wild fires. Understanding the current air quality is important for managing my family's health. I bought an industrial strength air purifier that has an AQI reading on its dashboard, but unfortunately when it runs the AQI is always under 10 because the sensor is right next to the newly cleaned air. I needed a way to measure the AQI 30 feet away from it and also in other rooms that aren't near the air purifier. This product seemed perfect for my needs. But, can it be trusted? I decided to order 3 and laid them out side by side. One would expect all 3 to measure roughly the same AQI, right? I've attached photos with the results. By way of reference, according to purpleair.com today's air quality outside is somewhere between 110 and 120. There are a half dozen purple air sensors near me all in that range, so that is a trustable baseline.The first photo shows all 3 set up in my bedroom. I'm not sure which to believe, but I am inclined to believe the 63 is false. It is disturbing that the range of measurement is so large.The second photo shows all 3 set up outside my front door. The 63 one from indoors appears to be the most accurate (at 112), but the others seem reasonably close.The third photo is the "63" one set up directly on top of my air purifier. The air purifier's reading says 4 but the 63 one stays at 56. Almost certainly way off.The fourth photo is all 3 set up on top of the air purifer. The 4 unit matches the air purifier's sensor, but the 12 unit seems pretty close as well.In each of the four photos, after I moved the units I let them sit for a few minutes before taking the photos. I only took the photos after they settled on their number.Conclusions: 1) There is a huge discrepancy between the units, even though they are the exact same product. This is unacceptable. There is a big difference between my bedroom being 8 vs 63. I am inclined to believe the 8 number much more than the 63. But when you put the same units outside, the 63 becomes the more believable of the two. 2) The units successfully measure when they move from good air to bad air. So they are not completely worthless.The entire purpose of the product is to accurately measure air quality, and if the accuracy can't be trusted that makes it a 1 star product. It seems reasonable to bump it to 2 stars because the unit does track when air quality gets worse, in a general sense. My wife accidentally threw away the box to one of the 3, so I plan to return the two higher ones and keep the low one. The low one was accurate when placed on top of the air purifier, might have been accurate in my bedroom, and only under reported AQI by ~20 when placed outside.