Air Quality Monitor, GEARDON Accurate Testing Formaldehyde(HCHO) Detector with TVOC/AQI/Temp/HUM Test Data Monitor, Air Quality PM2.5/PM10 Meter Multi Testers

Update 10\17\20.Two years later and sadly, each summer and fall I pull this piece of kit out and monitor the air quality. It still works well. It is accurate within +/- 5 PM 2.5 ug/m3 (measured against the nearest purple air sensor). Would buy again.Original review:Live about 100 miles from the Camp Fire in California. Used the meter to gauge outside air quality vs. indoor. Outside was measuring at 240 PM 2.5 ug/m3. Then i measured inside the house. I thought the house would insulate on its own. I was wrong. Though not as high as the outside measurements, the house still needed air purifiers. After a few hours with the air purifiers running, indoor measurements were down to 19 (very good).This meter helped us to make an important decision to invest in air filters for our home.It was a very worthwhile investment.The white stuff on the meter in the photo is the ash from the forest fire. Everyone stay safe. Support our brave Fire Fighters!

I have done some simple testing of PM 2.5 with visibility and other PM measurements. Also by turning my HEPA filter on and off in my rooms, and the meter seems accurate. I have discovered that to turn the monitor off it is really necessary to hold the on/off button down for 3-4 seconds. If this is not done, the monitor will go into a standby mode and continue to drain the battery even though the screen is off.

This arrived in a scuffed box with mild abrasions on the device itself that made me wonder if it had been previously returned. The temperature gauge is wildly inaccurate (by up to 20 F), and inconsistently so. Moreover, the screen has several manufacturing defects, and the battery rapidly drains. It’s going back.

Sir; It works just great. we have ck. every room in our house We have 4 Air purifiers going in the house. now we know they are working. And here in so, Cal you don't know the days air gets bad some days. We can check when we want, I would say every house in So. Calif should have one.

It works very well. I'm afrad of the smell of the new furniture is harmful to my kids so I bought this unit. The number shows on the screen is very close to the test kit I used. It's reusable and can be kept on all the time to monitor the level of harmful air. A must have to know about your indoor air quality.

Portable, fast start up. Excellent display. It helped me confirm the air quality where I work. I had concerns about dusts in the air and this helped me measure the levels. I think it has a lot of value for the money. Especially when it comes to safety and health.

What exactly does Milddle mean?The battery doesn’t last long when unplugged.

Great little device about 85% accurate but good enough for the price. Great for testing HVAC