I received this particle counter
yesterday but it came with no user guide.
At the moment, I am unsure of the units of measure in the "USA" display. I made a few measurements in my clean chamber and on the desk beside it, and noticed that the values varied considerably over time, so I took measurements every minute for five minutes and got the following results.
Below is the USA Federal Standard 209-E regarding clean room classifications:
If the units of measure of my device are thousands of particles per cubic meter, the chamber is approximately Class 100. Class 100 is defined as having (a maximum?) of 10.6 thousand 0.3μm particles per cubic meter and 3.5 thousand 0.5μm particles per cubic meter. I observed averages of 10.2 and 2.0, respectively but the maximum counts during the five-minute test exceeded those prescribed by the standard for Class 100. Without a calibrated particle counter against which to compare under the same conditions, I have no idea how (in)accurate my counter is.
I’ve asked the seller of my meter to provide the units of measure and when I hear back, I’ll update this post.