EPA Method 201A of 40 CFR 51, Appendix M is the standard method for measuring PM10.
This method uses an in-stack cyclone that separates the PM10 from the total PM. There are three significant limitations to this method:
1. It normally requires a stack diameter of at least 18 inches (approximately).
2. It normally requires a sampling port diameter of 6 inches.
3. The gas cannot contain entrained water droplets.
for PM2.5 measurements. One approach is to use an adaptation of Method 201A and incorporate a second cyclone to differentiate between PM10 and PM2.5.
selects out particles larger than 10micrometers then uses GF filter to trap all particles bigger than 0.3 micron.

1 cmol(+)/kg equals 1 meq/100g