Going to be lazy and do it via photos. The titles of the photos tells what was going on:

So one thing to look at is the later photos where side by side I have showed the counts reistered by the particle counter Jeff has been using (white casing Met one particle counter) compared to the syle of particle counters avaialiable to on-site personnel (grey casing Met one particle counter). These readings were taken at the same time, in the same place, for the same duration. Gary was the first to point out to me that to first order the White casing Met one counter is a factor of 10 lower than the grey casing met one particle counter. Is there perhaps a setting that is wrong on one of them, as this isnt the case for just one reading but al lthe readings taken side by side with the two counters.