Interim Baseline Radiological Investigation Report in
Support of the Upton Rare Earth Processing Plant
November 15, 2012
36
For the purpose of reference, the PM
10
standard is met when the expected number of days per
calendar year with a 24-hr average concentration above 150 µg m
-3
is equal to or less than one.
The PM
2.5
standard is met when:
•
The annual arithmetic mean concentration (averaged over three years) is less than or
equal to 15 µg m
-3
, or
•
The 98
th
percentile 24-hr concentration is less than or equal to 65 µg m
-3
.
The 98
th
percentile is defined in 40 CFR 50 Appendix N as the daily value out of a year of PM
2.5
monitoring data below which 98 percent of all daily values fall.
