ambient air is defined as ",,..that portion
Data to support these standards in terms
of the atmosphere, external to buildings,
of health effects, visibility restrictions,
to which the general public has access."
etc, have been provided”,
An arithmetic mean would be more
The primary ambient air standards define
Data
"levels which... are necessary, with an
desirable for predictive purposes.
adequate margin of safety, to protect the
from 19667" for nonurban locations indi-
public health, " The secondary standards
define “levels which... (are)... necessary
cate that the annual arithmetic mean is
to protect the public welfare from any
geometric mean,
(on the average} 120% of the annual
known or anticipated adverse effects ofa
pollutant.
"
Representative Calculations
These standards for particu-
Because one of the primary objects is
late matter are given below:
to derive an acceptable soil level for the
Nationai ambient air quality standards
for particulate matter, ug/m?’.
Annual
geometric
mean
Enewetak Islands, the approaches developed above were used to derive such
Max. 24-hr carentration
not to be exceeded more
levels for both soluble and inscluble
than once a vear
239
Primary:
75
60
Table 151.
Table 151,
260
Secondary:
The derived values are given in
The two methods agree within
a factor of two, at least for soil distributions like those found at the Nevada Test
150
Site,
The ambient air mags loading at
239
Acceptable soil levels of
Pu for a source which has weathered for
several years, Values are approximate and are subject to uncertainty.
Permissible Concentration in Air for 168-hr occupational exposure
(MPC,)25.
Insoluble
Acceptable air concentration, uCi/em?
.
Soluble
19714
6 x107!4
Resuspension-factor approach
4
1079
107?
Acceptable soil deposition®, uCi/m™”
10°
60
Acceptable soil concentration”, nCi/g
20
Assumed resuspension factor, m
My
o)
p2
Feb
{hf
nn
1
rs
——
c
'
9
1
anoreach
9
Assumed mass loading, ug/m°>
107
Acceptable soil concentration, nCi/g
10
a
.
;
2:
239
2
Equivalent to approximately 107 ue of insoluble 3 Pu/m”,
9
Ds ssumes same distribution of 23
the Nevada Test Site.
9
,
.
10°
0.6
Pu with depth and soil density as measured at
Hi—2]