United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S4-83-053 Jan. 1984
&ERA Project Summary
Air Quality Data for Metals
1977 Through 1979 from
The National Air Surveillance
Networks
E. G. Evans, G. F. Evans, D. B. Ray, T. Risher, V. A. Wheeler, S. L.
Cummings, J. E. Frazer, S. L. Harper, T. A. Hinners, W. A. Loseke, L. J.
Pranger, and John C. Puzak
The National Air Surveillance Net-
work, which has existed for over 20
years, provides air quality information
for many urban and nonurban locations
within the United States. The data in
this publication were collected with the
generous support of the many state and
local air pollution control agencies that
operate the National Air Surveillance
Network stations. Also, the ten EPA
Regional Offices have participated in
this program since 1973 by sending
weighted high volume filters to the
centralized laboratory for analysis.
This report summarizes the network
data for metals determined from high
volume samples collected from 1977
through 1979. Concentration values
are presented in the form of cumulative
frequency distributions. Arithmetic and
geometric sample statistics are also
reported, -as are measures of the
precision associated with the analytical
methods employed. This report is a
continuation in a series of publications
of network data.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Research Triangle
Park. NC. to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering
information at back).
Introduction
The U.S. Environmental Protection
Agency conducts a variety of air sampling
activities to obtain information about air
quality in the United States. Often this
work is accomplished with the assistance
and cooperation of state and local
agencies. One such program consists of
the National Air Surveillance Networks
(NASN) which have existed for over 20
years. Although pollutant monitoring is
decentralized, analysis and publication of
trace pollutant data remain the responsi-
bility of Environmental Monitoring Sys-
tems Laboratory, Research Triangle Park,
NC (EMSL/RTP).
Air quality samples are collected at
several urban and nonurban NASN sites
located across the country. Urban sites
are generally located within a city, town, or
adjacent suburb. Nonurban sites were
originally located in rural or remote areas,
although many of these rural areas have
become more heavily populated and were
influenced by spreading urbanization.
Concentrations of metals in particulate
matter form the National Air Surveillance
Network are presented in this report.
Measures of the analytical data quality
are also included. This report is a
continuation in a series of publications of
network data.
Laboratory Procedures
High volume filters exposed in the field
were returned to the laboratory by mail.
During shipment, each filter was folded in
half the long way with the soiled sides
facing each other. A 2.5-cm-wide strip
was cut from the edge of the filter to the
fold at the center. This yielded a 2.5- x
-------
20.3-cm strip which was folded with its
soiled sides together.
New laboratory procedures were
utilized beginning with the 1977 samples.
This was done because use of a new
optical emission spectrometer was begun
(to replace an obsolete unit) and the
desire for data on individual samples
rather than quarterly composites required
different approaches than had been
utilized in the past. The 1977 sample
strips, prepared as described above, were
extracted by the lead reference method
ultrasonic extraction technique using
mixed nitric and hydrochloric acids with
the hydrochloric acid present at the
maximum concentrations allowed in that
procedure. One deviation from that pro-
cedure was employed. All final solution
volumes were 50 ml rather than 100 m! to
bring more trace elements into the ex-
pected operating range of the new optical
emission spectrometer. The change was
first tested by analyzing strips with known
high lead content; lead was recovered
quantitatively.
Solutions obtained from this extraction
procedure were analyzed by aspiration
with the new Jarrell-Ash 975 Atomcomp
Optical Emission Spectrometer. It is a
direct-reading type spectrometer with
inductively coupled argon-plasma excita-
tion. The spectrometer was calibrated
with multielement standards in solutions
whose acid composition matched that of
the extracted filters. Interelement effects
were evaluated and corrections were
applied.
Minicomputer readouts of spectrometer
operation were transmitted to an associ-
ated PDP-11 data-accumulation computer
for storage permitting further computa-
tions and efficient transmittal to ultimate
data bank storage. The PDP-11 provided
the final computations and real-time
evaluation of two quality control standard
solutions for the benefit of the analyst.
Each solution contained all of the
elements capable of being analyzed by
the spectrometer. One solution contained
the elements at a low concentration in
the operating range of each element, and
the other solution had a much higher
concentration of the operating range of
each element. The solutions were run
alternately after every ninth sample. This
real-time evaluation permitted the analyst
to be certain of satisfactory spectrometer
operation before continuing with the
analyses.
Precision
Table 1 presents precision estimates
for the various analyses. Measures of
Table 1. Measures of Precision For 1977-1979 NASN Filters
1977
1978
1979
Metal
Barium
Beryllium
Cadmium
Copper
Iron
Lead
Manganese
Molybdenum
Nickel
Vanadium
Zinc
ft Pairs
211
95
73
211
211
209
211
34
104
132
209
%CV
8
36
12
9
14
4
12
19
18
8
11
# Pairs
178
31
123
178
178
178
178
87
130
149
178
%CV
7
23
11
8
5
3
6
24
21
8
11
tt Pairs
137
100
118
137
137
137
137
89
109
124
137
%CV
50
41
54
19
25
15
27
29
17
15
38
precision are expressed as percentages
of concentration level because precision
is generally concentration dependent.
Precision estimates are based upon the
differences between analyses performed
on two filter strips taken from the same
filter. Thus, the measure of precision
includes variation caused by cutting,
extracting, and analytical processing, as
well as any actual variability between
filter strips. Precision measurements
were made throughout the analysis
period. Duplicate strips of every twentieth
sample were analyzed, and precision
estimates were obtained.
Precision was expressed as the percent
coefficient of variation (%CV), computed
as follows: .
%CV = "00) Vx2 A/2
100 GM / (1)
Where Xi,x2 = concentration values of
the analyses of duplicate
filter strips, //g/m3
sxi-X2 = standard deviation of a
set of differences between
duplicate strips, x,-x2
GM=grand mean of a set of
paired concentration val-
ues
Results
Data presented in Tables 2 and 3 are
annual cumulative frequency distributions
by metal of individual results for urban
and nonurban locations, respectively. In
the first "line of Table 2, the number, 4648,
is the number of valid 24-hour samples
analyzed for beryllium in 1977. The
minimum value detected that year
follows and "LD" indicates the value was
below the discrimination limit. The next
seven entries are the 10 through 99-
percentile values. For example, the 99-
percentile value of 0.445 indicates that
99% of the 4648 values, i.e., 0.99 x4648
= 4601, were equal to or less than 0.445
ng/m3. The next entry is the maximum
annual value. Arithmetic means and
standard deviation are presented in the
last two columns in the table. With the
exception of beryllium, all values an
expressed in micrograms per cubii
meter. Some of the year-to-year variabilit
in the national summary tables can bi
attributed to use of different sets of site
in the summarization, depending upo
the completeness criteria for valid dat
and changes in state and local agenc
participation in the networks over th
years.
-------
Table 2. Urban National Cumulative Frequency Distributions
Element
Beryllium11
Barium
Cadmium
Copper
Iron
Lead
Manganese
Molybdenum
Nickel
Vanadium
Zinc
"Expressed in ng/m3
''Less than delectable
Year
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1378
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
No
4648
3614
2507
4648
3614
2507
4648
3614
25O7
4648
3614
2507
4648
3614
2507
4648
3614
2507
4648
3614
2507
4648
3614
2507
4648
3614
2507
4648
3614
2507
4648
3614
2507
Mm 10 30
iD" LD LD
LD LD LD
LD LD LD
LD 0010 0015
LD LD 0007
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD OO51 0088
LD 0 042 0 086
LD 0031 0061
LD 034 0 64
004 035 066
LD 019 046
002 027 048
LD 0.21 039
LD O 15 0 28
LD LD LD
LD LD LO
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD O 037 0 063
LD 0 029 0 054
LD LD LD
50
LD
LD
LD
0021
0013
LD
LD
LD
LD
0133
0138
0096
098
043
073
069
057
043
LD
LD
LD
LD
LD
LD
LD
0006
LD
LD
LD
LD
0034
008S
LD
Percentiles
70
LD
LD
LD
0031
0021
LD
0.002
0002
0002
0212
0225
0162
1 46
1 37
1 13
096
os6
065
OO4
004
LD
LD
LD
LD
0010
0011
0010
0013
0015
0016
0151
0141
LD
Arithmetic
90
LD
0 171
LD
0053
0047
LD
0004
OOO4
0004
0433
0430
0363
264
245
2 12
1 70
150
1 IS
008
009
007
0004
0005
LD
0024
0024
0022
0.040
0048
0053
0322
0333
LD
95
LD
0.234
0244
0.071
0077
LD
0007
0.007
0006
0625
0556
0519
350
329
294
236
1 97
1 54
012
012
011
0007
0008
0004
0033
0032
0030
0065
0078
0085
0.488
0.529
LD
99
0445
0.397
0401
0176
0170
LD
0.021
0028
0015
1 156
0975
0843
595
577
500
412
341
272
029
025
026
0023
0018
0015
0062
0068
oosa
0137
0153
0 170
1 176
1 366
0563
Max
1775
1 512
0985
2130
2.807
1 853
0350
0196
0178
3.296
4.625
1 627
1941
2252
1441
748
841
968
220
1 06
1 94
0213
0120
0275
0645
0917
0207
0339
O608
0425
6237
6199
9.051
Mean
00451
00749
00538
0.0316
00265
OO048
0.0022
00024
O0019
02075
02008
02593
1.308
1 273
1 018
0889
0765
0584
0043
0042
0038
00022
00021
OO015
00100
00110
00096
00165
00191
00208
01611
0.1637
00263
SO
00702
00895
O0758
00631
00827
OO681
00073
00083
0.0051
02417
02109
0 1785
1 191
1 272
1 049
0759
0688
0560
0068
OO52
0062
00056
OO049
00065
00209
00232
00128
0.0274
00335
00352
0.2599
0.3026
02379
Table 3. Nonurban National Cumulative Frequency Distributions
Element
Beryllium*
Barium
Cadmium
Copper
Iron
Lead
Manganese
Molybdenum
Nickel
Vanadium
Zinc
"Expressed in ng/m3
'Less than detectable
Year
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
1977
1978
1979
No
709
458
235
709
458
235
709
458
235
709
458
235
709
458
235
709
458
235
709
458
235
7O9
458
235
709
458
235
709
458
235
709
458
235
Mm 10 30
LD" LD LD
LD LD LD
LD LO LD
LD LD 0 004
LD LD LD
LD LO LD
LD LD LD
LD LD LD
LD LD LD
LD O.O38 0 069
LD 0040 0 095
LD 0012 0035
LD LD OO5
LD 0.05 0 12
LD LD LD
LD LD 0 029
LD LD 0 026
LD LD O024 -
LD LD LD
LD LO LD
LD LO LD
LD LD LD
LD LD LO
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
LD LD LD
50
LD
LD
LD
0007
LD
LD
LD
LD
LD
0120
0 179
0076
01O
0.21
011
0065
0056
0054
LD
LD
LD
LD
LD
LD
LD
LD
LD
LD
LD
LD
0023
LD
LD
Percentiles
70
LD
LD
LD
OO10
LD
LD
LD
LD
LD
0192
0290
0132
024
034
0 19
0107
O093
0090
LD
LD
LD
LD
LD
LD
LD
LD
LD
LD
LD
LD
0038
0040
LD
Arithmetic
90
LD
0.089
LD
0017
0.014
LD
LD
OOO1
LD
0450
0607
0322
052
060
035
0214
0 191
0.216
LD
LD
LD
LD
LD
LD
LD
0007
LO
0010
0018
0016
0076
0102
LD
95
LO
0134
LO
0023
0024
LD
0002
0.002
OO01
0.673
0.845
0476
0.72
082
046
0269
0261
0308
LD
LD
LD
0003
0004
LD
O010
0010
0.006
0.018
0027
0024
0116
0142
LD
99
LD
0217
0173
0040
0.057
0.485
0.005
0.005
0006
1 065
1 396
0.645
1 79
1 33
0.93
0439
0.520
0459
008
005
LD
0006
0.007
0002
0052
0.020
0013
0045
0059
0052
0323
0242
0326
Max.
0.568
0.292
0.173
0.137
0.096
0.485
0.037
0.011
O.031
1.670
2104
4OO3
3.03
6.44
2.29
0.951
1.037
0647
0.24
0.08
0.06
O.O16
0.011
0.004
0238
0.030
0018
0137
0089
0083
5623
1 738
0326
Mean
00389
0.0474
0.0386
00089
0.0057
00118
0.0008
o.oooa
00008
01932
02657
O.1417
0218
0307
0162
0.0920
00843
O.O842
0022
O.021
0021
OO011
OOO11
0.0008
OO048
00039
00032
O.0069
00085
OOO79
00466
00424
00134
SO
0.0387
00379
00199
OOO94
O.O1 18
OO70O
0.0016
O.O010
OO051
02194
02895
02899
0.326
0433
0.230
0 1O35
01100
0.1019
0013
OOO5
0003
O.O011
000/3
00004
00143
00035
00019
0.0082
00104
00085
02316
0 1101
00462
-------
The EPA author E. G. Evans (also the EPA Project Officer, see below) is with the
Environmental Monitoring Systems Laboratory, Research Triangle Park, NC
27711.
The complete report, entitled "Air Quality Data for Metals 1977 Through 1979
From the National Air Surveillance Networks," (Order No. PB84-110535; Cost:
$25.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
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