8-in-1 Indoor Air Quality Monitor, Formaldehyde Detector, Temperature & Humidity Meter, Sensor, Tester Detect PM2.5, CO, CO2, HCHO,TVOC,AQI Micron Dust, Home Air Test Kits

There are SO MANY choices for these air sensors, it's mind boggling and hard to decide.The last brand I tried was useless, ... the display was a fixed number, might as well have been a table decoration paper weight. Had to send it back.But THIS brand is Phenomenal!It checks for 5 types of substances, and has worked perfectly in my tests. The only one I haven't checked yet is formaldehyde, but considering how well it has performed in the other 4 tests, I suspect it will be satisfactory on that one also. UPDATED: I was able to check this 5th test factor and as expected it worked!The overall air quality gauge is a nice bonus as well!It should be noted that there is another review that has done extensive piecemeal tests on the 5 measurements this takes, and that some of them may be approximated due to the way this device is designed. This is good information, indicating that other sensors are available that are more accurate for specific testing, although in many cases this one should be useful for amateur purposes, and other sensors will likely be needed if used for professional purposes.For instance, I was able to to make it go out of range momentarily by exposing the device to fragrance infused hand sanitizer. I must say though, that I'd rather have a device like this which is sensitive and detects substances, than one which does not alert the user at all, and from what I've seen, it is very good with most specific substances as well. It even detected a large increase in particulate matter from smokey air that drifted though the neighborhood from forest fires several dozen miles away.I really love this unit! Here are the range of readings it gives me rather consistently when the air is normal:InsidePM2.5 = 7HCHO = .03TVOC = .06CO = 1CO2 = 600OutdoorsPM2.5 = 9HCHO = .02TVOC = ZEROCO = ZEROCO2 = 400

I use several meters in inspection field, and this item gives 7 different readings.Some days wonder if temp and humidity are correct, but have no other device to compare to other than data from weather appsI've checked with other devices for CO2, HCHO, CO, and VOC and all are close to what my previous meters show.Is actually handy to have just 1 device to carry, instead of 7.Screen shows well for temp, humidity, and CO2, but all others have green color that is tougher to read in sunlight (see included photos)For most part, works great.4 stars only because varied readings for temp/humidity

Works great, makes me feel guilty, about smoking. When I smoke it shows me the pollution level in my room.

The PM 2.5 always reading as 7 ug, when you look at the pictures of the other reviewers, everybody's PM2.5 is 7, which means the PM2.5 doesn't work at all. On my unit, it always showing 7, and never change no matter what, even you blow the smoke to it, it still shows as 7.

Works okay for basic monitoring, but accuracy and build quality could be better.

I bought this unit to check CO and CO2 levels indoors. Several days after it arrived the air health crisis of June 2023 from Canada came to Indiana. It was interesting to see how the PM2.5 particulate matter showed up in my home. Before the air problem I had a reading of zero or 1 and after the smoke arrived it was as high as 9 indoors with closed windows and the air conditioner running. When I took the unit outside, the display quickly began to rise until it was reading 31 for PM2.5. That was today 6/9/23 with 80F 26% RH and it is pretty hazy outside...dry, hazy and a dull white not blue sky. Normally, in Indiana's countryside, the air does not become hazy until the fall when the harvesting of the farm fields cause massive amounts of dust in the outdoor air. Good purchase at a time when needed.

I will not speak to or rate the accuracy of this device as I do not have a laboratory setup where I can compare the results to high-grade equipment.However, I will discuss the user interface and usability of the device. Some points:- The device will turn itself ON when a charging cable is connected to it, regardless of the position of the hardware "clicky" switch marked for On/Off operation. This tells me that the On/Off switch is more of a notion than an actual switch for power, kinda like the "power" button on your cell phone is not really a power on/off button.- There is a 199 second countdown when the unit is turned on where it states "Preheating" on the screen, and if any button is pushed during this time the internal voice announces "Warming up, please wait". This countdown/warm up sequence occurs at every start of the unit - regardless if you turn it off for 1 millisecond and turn it right back on, which tells me there is no "extra sensor" for telling the unit that it is "warmed up" and ready to run. It just assumes that the 199 seconds is what it takes to prepare its sensors for operation. This could have consequences that a failed sensor may give an errant reading without the unit doing any diagnostic to tell if the sensor is failed.- There is a - I guess you call it "mute" button on the device, except it doesn't mute much of anything. Even the directions say that it is a "Mute" button, and you should "Cycle to switch the sound on/off". If you press it, the speaker icon on the display goes dark, but the buttons still register a loud "BEEP!" when pressed. Also, when the "mute" button is pressed during the above mentioned "warm up" period, the speaker icon will dim, but any other button push will still have the voice state "Warming up, please wait". So much for the "mute" function, as I said it doesn't mute much of anything.- There is a setting in the "Settings" that allows you to turn off the mercilessly loud "BEEP!" with every button press. This setting does survive multiple sessions. Why the "mute" button above does not do the same thing is beyond me.- There is a setting that states "Display:" and has the choice of "Style 1" and "Style 2". Style 1 has "smoothed" numbers that look like they come from a standard, modern font. Style 2 has the numbers represented in an old 8-segment LED style, like old hand-held calculators in the 70's and 80's. Was this trip really necessary?- The user interface uses different colors to tell you if the reading value is - I guess - "safe", or more harmful. The documentation appears to reference the Chinese government values for each of the sensed values, so whatever the CCP had as its "safe" level at the time this thing was programmed is shown in green, then anything supposedly harmful will be shown in (progressively) yellow, then red, and finally purple. EXCEPT for CO and CO2 levels. Those are white all the time, no color changes in either "Style" or any value that I can get them to read, high or low.- There is a "Corrections" item in the settings that allows you to correct the readings (add more, or subtract some value from a reading) for HCHO, PM2.5, TVOC, Temperature, and Humidity. But not for CO or CO2. This may be due to what another review said that this unit does not really read CO or CO2, and simply infers these values from other sensor data like the PM and TVOC readings. The manual also does not state anything about "safe levels" or sensor ranges for either of these two carbon-based displayed values, but it does have that information for all the other sensors. Why would they display something they don't have a sensor for? If there are actually CO and CO2 sensors in the unit, why can we not A) calibrate them, or B) have them change colors for "safeness" like the other values do? I do believe that the CCP Ministry of Environmental Protection are busy-body enough one-upping the rest of the world to show they are "better than everyone else", that there are probably multiple places you can find their recommendations for "safe" and "dangerous" level specifications for these gasses.All in all, this appears to be the cheapest working-at-first-glance sensor of this type on AMZ at the time of this review. I know that companies engineer these devices to a price point, but some of the cost-cutting may affect performance, and in the long run maybe someones health. If you depend on this unit for your health, IMHO consult a doctor first.