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,
etc. have been provided ~,
to which the general public has access, "
The primary ambient air standards define
"levels which... are necessary, with an
adequate margin of safety, to protect the-
An arithmetic mean would be more
desirable for predictive purposes. Data
from 1966°°
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 of a
pollutant,” These standards for particu-
Representative Calculations
late matter are given below:
Because one of the primary objects is
National ambient air quality standards
for particulate matter, ug/m”.
Annual
geometric
mean
Max, 24-hr carentration
not to bé exceeded more
than once a vear
Primary:
75
Table 151.
Enewetak Islands, the approaches developed above were used to derive such
levels for both soluble and insoluble
239 bu,
The derived values are given in
Table 151,
260
Secondary:
60
to derive an acceptable soil level for the
The two methods agree within
. afactor of two, at least for soil distributions like those found at the Nevada Test
150
ais
eur,
_~
Acceptable soil
levels of 239 Pu
Te
ns
ey Ce
adel atliniCin ait
v4
9?
ft
aasté ivadiny wii
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, pCi/ cm?
Soluble
10712
6 x 10744
10°?
10°
20
10°?
60
1
107
10
10°
0.6
Resuspension-factor approach
,
,
-1
Assumed resuspension factor, m
Acceptable soil deposition®, uCi/m?
Acceptable soil concentration?, nCi/g
Mass-loading approach
Assumed mass loading, ug/m°>
Acceptable soil concentration, nCi/g
“Equivalent to approximately 104 pg of insoluble
Passumes same distribution of 239 Pu
the Nevada Test Site.
239 m2,
with depth and soil density as measured at
14-26
tf