I monitored the dust counts during the installation of the HAM4 North & South doors. In general the particle counts under the cleanroom area were 0. Occasionally there were 0.3µ counts of 1 to 3 particles per 20 second sample time. I saw very few counts for larger particles.
 
   During the actual door installation dust counts were in the 1 to 5 particles per 20 second sample time. Many times during the operation the counts were 0. The highest counts on the North side were in the 75-80 0.3µ particles per 20 seconds sample time, during the removal of the two soft covers. The highest particle counts on the South side were in the 70-77 0.3µ particles per 20 second sample time, while the flange was being wiped down with alcohol. In both of these cases the counts returned to the 0 to 3 count range, in a few minutes.