BTMETER - Air Particulate Meter PM2.5 PM10 Monitor Meter BT-5800D Pro Particulate Matter Detector, Accuracy +/- 20% Tester for Air Quality Monitoring Indoor Outdoor w/Back Light

I purchased mine in March 2025 to help with TVOC issues related to my furnace, and still use it now for formaldehyde detection and air particulate detection. While I don't have a pro-grade detector to compare this to, it seems to work fine relative to what I'd expect it to detect in specific situations. As I've read in other reviews, it started to crap out after 2 years so I have a while until I reach that point.One thing to note is that if it's been turned off for a while, once you turn it on and TVOC levels finally start showing, it seems to start maxed out at 5.0 mg/m^3 and slowly decrease to where the TVOC level actually is. If you see this, don't be alarmed! Just give it a few minutes, and assuming the TVOC in your air is good, it will slowly fall back to 0.05 mg/m^3 which appears to be its minimum value.

I originally bought a CO2 meter from Amazon (Amprobe CO2-100 very good meter!) and discovered that the CO2 level in my apt was marginally high due to the infrequent running of my HVAC. I am unable to run the fan only as the system is wired (easy fix). but after a lot of research I realized that code in many areas requires a fresh air intake (6" duct seems to be minimal) that pressurizes a dwelling (positive pressure) and prevents unfiltered air from being sucked into the house through cracks and voids. I am in the middle of this project. There is a lot of dust buildup in the house ongoing, so I ordered this meter to check on floating particulate in my condo. The numbers are really high, in the unhealthy 1 and 2 ranges with the AC off. The meter is advertised as +/- 20 %, which is plenty good enough. I checked the meter by measuring various places in the house and also outside. My outside readings are less than 12 and my inside readings are as high as 130. Not good. I also zipped the meter into a gallon zip lock bag while it was outside, and watched the reading as i moved around, to see if it was temperature sensitive. No significant change in readings. All the readings make logical sense, and the reading went down almost in half when I turned on the AC (cool mode). I have a MERV 13 4 inch thick filter replacement (From Amazon's main Air filter vendor, not a great product, too much air bypass), and this filter fits into a 1" filter ceiling mounted intake assembly. I recommend changing out your 1" filter for this filter!!!!! Will help prevent freeze ups!You will love this meter, and the price is very reasonable.BTW, my first meter had a measurement issue and the battery charge function did not work, so it only worked sort of when plugged into the charger. I return it UPS and received the replacement meter in less than 24 hours! WOW!!!

I love this. It is so very helpful during the horrible northwest fire season. After too many years of living with intense smoke during the fire season and after spending some sizeable amount of money on a couple of good air cleaners....I thought I would check to see how well they are working or not with this device.As it turns out when the outside air is showing an aqi in the high 600's which is extremely hazardous to be in for any length of time. When the air cleaners are on the air is safe inside. If I test the air quality in a room that is closed off without access to the air cleaner there is a noticeable difference that the meter accurately measures. I am very confident of this device to a close accuracy. It will show better accuracy of the outside air where I live then what is reported in the farther away cities.7.24.24 updateAfter my initial excitement as written above, sadly this product turned out not so good after all. Last year we luckily didn't have much of a smoke season, so I didn't really use it, but once or twice. It didn't seem accurate at the time. Now with smoke coming in furiously I tried it again. It is clearly no longer accurate.I expected this to work longer than a year. Very disappointing !

This worked well! Easy to charge and read results anytime.

It’s my second air quality assessment device. My first one wasn’t too helpful because all it did was measure humidity/temperature/pressure/and VOCs. It didn’t take into account the particulate matter at all. I have a lot of air purifiers in my house with HEPA filters, and wanted to see how good my air quality really is.As a general summary, particulate matter is very small particles in the air that can, at high levels, adversely influence one’s health and cause irritation of the eyes, nose and throat; asthma, bronchitis, other respiratory problems; heart and lung disease, heart attack, and even stroke. Particulate matter, as opposed to larger particles that are not easily inhaled, is extremely dangerous because the particles are so small that they can bypass the nose and throat and penetrate deep into the lungs and enter the circulatory system.This monitor measures PM2.5 (fine particles with a diameter of less than .5 micrometers, which is about 3% the diameter of a human hair) and PM10 (particulate matter that is 10 micrometers and smaller). Both PM2.5 and PM10 particles originate from motor vehicles, airplanes, power plants, residential wood burning, forest fires, agricultural burning, dust from construction, landfills, dust from open lands, industrial sources, etc. They are either directly emitted into the air, or are produced when gases and particles interact.The meter is very simple in operation. The interface includes just a few basic buttons and displays the levels of PM2.5 and PM10 at the same time. Just a press of a button and it starts measuring. The meter can be used in complete darkness thanks to its lit interface. The back of the meter includes air pollution level reference. There are 6 levels of PM2.5 pollution: Good (0-35 μg/m3), Moderate (36-75 μg/m3), Unhealthy – (76-115 μg/m3), Unhealthy (116-150 μg/m3), Unhealthy + (151-250 μg/m3), and Hazardous (>250 μg/m3). Once it’s done measuring, the bottom of the display will let you know whether your air is good, moderate, unhealthy, or hazardous. One drawback of the interface is that it’s not noiseless and pressing the button keys makes a pretty loud sound.I have used this monitor a couple times and measured particulate matter inside my house and outside. The levels are very low inside where I have several air purifiers running (fluctuating between 1-4 micrometers) and pretty good outside (fluctuating between 10-19 micrometers). I live in a very wooded, low-traffic neighborhood so I would like to believe the measurements are true and the air quality both inside and outside are within normal levels! However, I still expected the numbers to elevate a bit each time a car went by, but they didn’t. In fact, sometimes they went down. I was a bit puzzled at that.The meter comes with a storage case and a charger. I appreciate that I can store it all in our case.