During the last few days of vent activity in BSC1 late last month for the ITMy alignment, I parked the BSC1 particle counter inside the chamber with us.  Attached is a plot noting the events that the particle counter witness (thx, Justin!).  Things to say about the plot:

1) The particle counter has small spikes to ~15 counts/cub.ft during the quiet nighttime hours while no activity was taking place anywhere in the LVEA.  Note, we'll take a second monitor into the chamber during our next study such that we can confirm counts.

2) The highest counts seem to be during the soft cover activity.  My guess is that the settled particulate in the chamber gets quickly stirred up by the soft cover (or has even collected in the soft cover since that is the direction of "out") and gets re-tossed around in the chamber.

3) There is a longer than expected ringdown of particulate counted for the hours after people have left the chamber and the soft cover had been restored to the door.  It takes many hours for the particulate to settle back to the floor or horizontal surfaces after getting kicked up from traffic.

4) The overall counts of ~100 cnts/cu.ft are in line with what Robert reported in his in-chamber particulate measurement last month:

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=2071

For the record, I wiped the flooring in the chamber as I exited the chamber (not shown on the plot), pulling from the far side towards the door with many IPA saturated wipes.