I took some particle counter measurments in B102, B111, B111A, and B111B. In all the clean rooms, the particle count was 0. These clean rooms were the B102 cleanroom with the optical cavities, the B111B mobile cleanrooms, the Southern most B111A long table, and the Northern most B111B short table.
I also took some 10 second particle counts outside the clean rooms. Data is 0.3 um count/0.5 um count/1.0 um count)
B102: 1268/72/28 (there were lots of people and activity during this measurment)
B111 (entryway): 495/46/28
B111B: 177/51/39
B111A: 95/17/13
These seem like very good measurments.
The particle counter is on the optics tables in B111B.
It should probably read "Northern most B111A short table" considering there is no short table in B111B.
Data extrapolated to a full minute for easy comparisons:
B102: 7608/432/168 (there were lots of people and activity during this measurment)
B111 (entryway): 2970/276/168
B111B: 1062/306/234
B111A: 564/102/78