9 in 1 Air Quality Detector Smart Air Quality Monitor AQI, PM2.5, PM1.0, PM10, Formaldehyde (HCHO), TVOC, Temperature, Humidity, Time/Date/Alarm Multifunction

This is now a permanent fixture in my 3D printing hobby room. It helps me keep tabs on the air quality so I know when to ventilate the room.Do not confuse this with some of those less capable air quality monitors. I do not know of many that have historical data graphs available for example.At a glance, it gives me the PM1.0, PM2.5, PM10, HCHO, TVOC, and AQI which is an overall indication of air quality. plus it has a colored background around each measurement green=good, yellow=marginal, and red=bad to catch your attention. what is also a plus for 3d printing is it gives the humidity and temperature.A very valuable feature for me is that it has an alarm you can enable/set so when levels are reached. seriously let's face it I am not staring at it all the time so this is invaluable)it has a couple of different ways to display the readings, just numbers, or those larger numbers with colored warning level background, as well as a graph for the readings over time.There is also a setup mode / screen to change the settings of the monitor.i do like the historical graph, lets me look back and see what happened over time. and since the unit knows the time and date, the historical graph has shows time/date info on the graphIt does have rechargeable batteries but I keep it plugged in all the time, so the batteries are more for power outage situations.Speaking of the power, you will need to provide your own USB power adapter. it does come with a usb cable.This is an invaluable tool for me as it keeps me healthy while enjoying my hobby!I hope you found this information valuable.

Overall I like this one the best. How accurate is it? Good question. Owning a manufacturing facility, I added three more around the place...welding, plastics, solvent cleaning...filtered air handling....everything. This has become a tool to measure maintenance of air systems. Our air was reported (at the worst) at 442 per the 2.5 scale. These units were placed out side at that point and measured within 15 points overall. That's pretty accurate. All I can say at this point is is a reliable tool and easy to use.