Review on Temtop PMD 351 Handheld Professional by Will Schimmel

What's Inside: The PMD 331 comes very nicely packaged in a very expensive custom Pelican case. Firm foam holds gauge and accessory pouch. The device has a charger and a DB9 serial port, as well as a USB port for transferring files to flash drives. A flash drive is included and a calibration filter. Build Quality: Rock solid, this is rated for use in a lab or clean room so everything is made with A+ quality materials. Operation: As simple as it may be, simply turn the unit on and after it has gone through the 10 second boot-up process, you can press the start button and the internal pump will turn on and draw in air. During the adjustable sampling time, the numbers will change slightly depending on how many particles you get. At the end of the normal 60 second cycle, the instrument records and stores the average and starts a new test. This will continue as long as the device is powered on and set to poll. The menu is very intuitive, you can view the records for each sample and export them for plotting or analysis. Accuracy: I have visited several clean rooms in my electronics engineering years, but I no longer have access to these rooms to make comparisons. I can say that the device works on the same principles as we do and the numbers it puts out are very much in line with what I would expect outside of a clean room. Tests done: I have attached some screenshots, as you can see I was reading outside my home in a wooded area where the air smells like the freshness of a forest but as you can see pollen and other particles in the air form a pretty thick mix. The concentration of 0.3 µm particles is very high. In the second picture, I took a sample in my bedroom and there are a lot less particles in the air, but it's not big. I then ran my giant Inofia HEPA filter in my room for 50 minutes based on factory RPM at high speed which will circulate the air around 3-5 times and as you can see the results are quite dramatic and accurate . with an approximately three-fold reduction in the number of particles of any size in space. I'll come back to this test and try 24 hour HEPA filtration to see how clean I get the air.