GRADIENT TECHNIQUE MEASUREMENT OF AEROSOL PARTICULATES
OVER FRESH WATER: A COMPREHENSIVE REPORT
February 1987
for
U.S. Environmental Protection Agency
Great Lakes National Program Office
Grants Management Section
536 South Clark Street
Chicago, Illinois 60605
Attention: E. Klappenbach
by
Mark S. Watka
Analytical Chemist
AirTech Incorporated
-------
GRADIENT TECHNIQUE MEASUREMENT OF AEROSOL PARTICULATES
OVER FRESH WATER: A COMPREHENSIVE REPORT
February 1987
for
U.S. Environmental Protection Agency
Great Lakes National Program Office
Grants Management Section
536 South Clark Street
Chicago, Illinois 60605
Attention: E. Klappenbach
by
Mark S. Watka
Analytical Chemist
AirTech Incorporated
-------
FOREWORD
This report summarizes the meteorological data used to establish the
periods to analyze (via XRF, X-Ray Fluorescence) the 1985 discrete aerosol
samples taken at the Canadian Centre of Inland Waters (CCIW) "Waves Tower".
This research endeavor is a multi-joint effort which included the U.S. EPA
research funding, Ed Klappenbach, Governors State University, Mark S. Watka,
B.A., M.S., Dr. E. Cehelnik, Dr. J. Hockett; University of Colorado at
Boulder, Dr. H. Sievering; Clemson University, Dr. T. Tisue, Ruth Feeland
and the Canadian Centre of Inland Waters.
Respectfully submitted,
M.S. Watka, B.A., M.S.
Analytical Chemist
AirTech Incorporated
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TABLE OF CONTENTS
Page
FOREWORD i
INTRODUCTION ; 1
RESULTS 3
Periods to Analyze by XRF and Corresponding Meteorological Data
Table 1. Run 8 4
Table 2. Run 9 5
Table 3. Run 10 6
Table 4. Run 12 7
Table 5. Run 14 8
Table 6. Run 15 9
DISCUSSION 10
Appendix A. Master's Thesis "Gradient Technique Measurement of Aerosol
Particulates Over Fresh Water"
Appendix B. XRF Interim Report #1
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I. INTRODUCTION
The overall research project, goals and description are detailed in the
Master's Thesis entitled "Gradient Technique Measurement of Aerosol Particu-
lates Over Fresh Water" which is included in Appendix A of this document.
In reviewing Appendix A, there are two main efforts of this research endeavor.
The first centers around obtaining aerosol particulate samples at varying
heights (gradient) above a lake surface for an expected concentration
difference for any element, e_, over a period of time. The second effort was
to establish the condition of the gradient during the aerosol particulate
sampling period. In other words, the meteorological conditions which occurred
during aerosol sampling were recorded on magnetic tape and various statistical
procedures were used to establish the condition of the gradient.
This report further summarizes the meteorological data used to determine
the periods to analyze by XRF. As previously mentioned in the Master's
thesis, "the aerosol particulate sampling and meteorological monitoring are
intimately related" due to the fact that the aerosol particulate collected
has a corresponding meteorological gradient condition. However, meteoro-
logical data retrieval and aerosol sampling at the actual sampling site were
not in a corresponding mode throughout the discrete sampling period. This
was due to a limitation in the meteorological data retrieval system which
would not allow for a change in the statistical averaging procedure. In other
words, meteorological data was collected continuously throughout the discrete
sampling period, but, due to filter changes and/or routine maintenance of
the sampling equipment, aerosol sampling would lag behind the meteorological
data retrieval. There would be periods where meteorological data was
retrieved but no aerosol sampling was performed due to filter changes.
Furthermore, statistics from Summary of Synoptic Meteorological Observations
for Great Lakes Areas (also referred to as National Oceanic and Atmospheric
Administration, NOAA) indicated that only 32% of the time meteorological
conditions would favor a gradient. Hence, aerosol filter changes were
performed as quickly as possible in order to collect as many aerosol samples
as possible. These start-up times would occur on the hour, the quarter-hour
1
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or the half-hour. Nonetheless, meteorological data was obtained on magnetic
tape every ten minutes during the entire duration of the 1985 discrete
sampling period. Meteorological data (e.g., upper and lower wind speed, wind
direction, air temperature, relative humidity, and water temperature) was
obtained and averaged strictly on an hourly basis without standard deviations
by the CCIW computers. Two problems exist with this type of retrieval:
1) standard deviations are needed to properly interprete the condition of
the gradient, and 2) if the aerosol sampling start-up times commenced on the
quarter- or half-hour, the CCIW computer would not adjust accordingly. In
other words, the computers would continue to average on an hourly basis
without standard deviations. Hence, recalculation of these data (by hand)
are essential to properly interprete the XRF results so that the actual
condition of the gradient would be representing the aerosol sample collected.
For example, discrete aerosol sampling for Run 10 commenced on the half-hour.
This means that from 0030 GMT (Greenwich Mean Time) to 0130 GMT a duplicate
aerosol sample over fresh water was taken at two heights (2-m and 11-m) above
the lake surface. Meteorological data was recalculated to correspond with
this 0030 GMT to 0130 GMT aerosol sampling time instead of the previous
meteorological averaging standard of 0000 GMT to 0100 GMT. Overall, this
recalculation of meteorological data did not increase or decrease the number
of aerosol sampling periods to be analyzed by XRF. This recalculation merely
dictated that the aerosol sample collected from 0030 GMT to 0130 GMT had
meteorological data which were averaged over an identical sampling period
(i.e., 0030 GMT to 0130 GMT). Hence, this recalculation in the meteorological
averaging will benefit the gradient hypothesis for deposition velocities of
aerosol particulates.
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II. RESULTS
Tables 1 through 6 represent those periods to be analyzed by XRF and
the corresponding meteorological data for those periods.
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TABLE 1. RUN 8 PERIODS TO BE ANALYZED BY XRF AND CORRESPONDING METEOROLOGICAL DATA
Date
7/08/85
7/08/85
7/08/85
7/08/85
7/08/85
7/08/85
7/08/85
7/08/85
7/09/85
7/09/85
Time (GMT)
1615 to 1715
1715 to 1815
1815 to 1915
1915 to 2015
2015 to 2115
2115 to 2215
2215 to 2315
2315 to 0015
0015 to 0115
0115 to 0215
XRF
Spot
Number
1
2
3
4
5
6
7
8
9
10
Wind (m)
Speed
AVG ± STD
5.06 ± 0.473
4.42 ± 0.288
3.42 ± 0.521
2.34 ± 0.859
2.09 ± 0.479
3.41 ± 0.818
4.35 ± 0.169
3.54 ± 0.539
1.62 ± 0.763
1.53 ± 0.570
Wind (°)
Direction
AVG ± STD
30.80 ± 2.17
29.20 ± 2.94
33.82 ± 12.58
84.93 ± 12.51
92.78 ± 8.67
115.02 ± 4.22
113.40 ± 4.70
121.20 ± 10.60
55.13 ± 36.95
128.53 ± 6.93
Air
Temperature
(°C)
12.45
12.93
13.51
14.31
15.45
17.10
17.93
17.85
15.41
16.73
Relative
Humidity
(%)
96.85
95.97
95.68
95.77
95.40
94.72
92.05
91.73
92.12
95.25
Water
Temperature
(°C)
9.85
10.04
10.33
11.03
11.92
12.32
11.87
11.70
11.06
11.17
Lower
Wind Speed
m/sec
3.56
2.82
1.80
1.27
1.04
2.06
2.23
1.57
1.17
1.19
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TABLE 2. RUN 9 PERIODS TO BE ANALYZED BY XRF AND CORRESPONDING METEOROLOGICAL DATA
Date
7/10/85
7/10/85
7/10/85
7/10/85
Time (GMT)
1430 to 1530
1530 to 1630
1630 to 1730
1730 to 1830
XRF
Spot
Number
1
2
3
4
Wind (m)
Speed
AVG ± STD
3.19 ± 0.362
2.99 ± 0.198
3.75 ± 0.496
3.33 ± 0.385
Wind (°)
Direction
AVG ± STD
90.71 ± 29.51
111.62 ± 13.21
103.53 ± 9.96
117.91 ± 17.57
Air
Temperature
19.23
19.52
20.01
19.91
Relative
Humidity
(*)
83.82
82.12
77.32
74.78
Water
Temperature
13.29
13.94
14.74
14.51
Lower
Wind Speed
m/sec
2.13
2.38
2.56
2.32
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TABLE 3. RUN 10 PERIODS TO BE ANALYZED BY XRF AND CORRESPONDING METEOROLOGICAL DATA
Date
7/12/85
7/12/85
7/12/85
7/12/85
7/13/85
7/13/85
7/13/85
Time (GMT)
1530 to 1730
1730 to 1930
1930 to 2130
2330 to 0130
0130 to 0330
1330 to 1530
1530 to 1730
XRF
Spot
Number
1
2
3
5
6
12
13
Wind (m)
Speed
AVG ± STD
3.56 ± 0.454
4.29 ± 0.281
3.94 ± 0.785
1.90 ± 0.289
1.09 ± 0.351
2.26 ± 0.423
2.97 ± 0.890
Wind (°)
Direction
AVG ± STD
52.48 ± 20.50
104.60 ± 4.17
83.78 ± 14.13
39.00 ± 13.87
32.70 ±'19.44
56.40 ± 9.04
80.81 ± 23.82
Air
Temperature
(°C)
15.90
16.74
17.58
17.34
17.35
16.93
19.29
Relative
Humidity
(*)
90.69
91.47
91.92
86.91
95.08
84.88
93.15
Water
Temperature
(°C)
14.73
15.11
15.73
16.71
16.44
16.47
17.13
Lower
Wind Speed
m/sec
2.86
3.24
2.72
1.33
0.55
1.87
2.26
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TABLE 4. RUN 12 PERIODS TO BE ANALYZED BY XRF AND CORRESPONDING METEOROLOGICAL DATA
Date
7/17/85
7/17/85
7/17/85
7/17/85
7/17/85
7/17/85
7/17/85
7/17/85
7/17/85
7/17/85
7/18/85
7/18/85
7/18/85
7/18/85
7/18/85
7/18/85
7/18/85
7/18/85
7/18/85
7/18/85
7/18/85
Time (GMT)
1415 to 1515
1515 to 1615
1615 to 1715
1715 to 1815
1815 to 1915
1915 to 2015
2015 to 2115
2115 to 2215
2215 to 2315
2315 to 0015
0015 to 0115
1415 to 1515
1515 to 1615
1615 to 1715
1715 to 1815
1815 to 1915
1915 to 2015
2015 to 2115
2115 to 2215
2215 to 2315
2315 to 0015
XRF
Spot
Number
1
2
3
4
5
6
7
8
9
10
11
25
26
27
28
29
30
31
32
33
34
Wind (m)
Speed
AVG ± STD
1.53 ± 0.570
1.37 ± 0.418
1.75 ± 0.138
2.16 ± 0.308
2.46 ± 0.494
2.41 ± 0.459
2.26 ± 0.548
1.01 ± 0.679
1.14 ± 0.128
2.06 ± 0.605
2.33 ± 0.499
1.04 ± 0.670
1.55 ± 0.199
2.45 ± 0.676
2.22 ± 0.379
2.30 ± 0.595
2.49 ± 0.323
2.44 ± 0.417
2.47 ± 0.314
1.84 ± 0.533
1.78 ± 0.994
Wind (°)
Direction
AVG ± STD
128.53 ± 6.93
117.56 ± 24.42
74.36 ± 22.18
57.21 ± 11.22
92.27 ± 13.17
84.18 ± 17.49
70.26 ± 10.47
50.28 ± 12.12
60.50 ± 10.81
101.74 ± 12.14
122.76 ± 3.91
39.83 ± 17.19
61.54 ± 7.14
34.34 ± 4.09
80.71 ± 4.19
100.23 ± 9.25
106.64 ± 5.08
81.18 ± 14.78
84.12 ± 8.64
94.86 ± 19.16
177.97 ± 42.85
Air
Temperature
(°C)
17.39
17.79
18.03
18.25
18.80
19.09
19.16
19.42
19.23
18.73
18.73
19.99
17.39
17.87
18.32
18.80
19.08
19.16
19.42
19.23
18.73
Relative
Humidity
(%)
73.50
79.23
82.37
86.78
89.95
89.70
88.10
87.65
89.30
91.63
91.55
73.48
79.23
82.37
86.78
88.92
89.70
88.10
87.65
89.30
91.63
Water
Temperature
(°C)
15.67
16.39
16.81
16.70
17.16
18.20
18.37
18.31
17.81
17.84
17.84
15.67
16.39
16.81
16.70
17.16
18.20
18.37
18.31
17.81
17.84
Lower
Wind Speed
m/sec
1.12
1.29
2.17
2.19
1.40
1.87
1.71
1.73
1.61
1.31
1.12
1.11
1.29
2.17
2.19
1.40
1.87
1.71
1.73
1.61
1.31
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TABLE 5. RUN 14 PERIODS TO BE ANALYZED BY XRF AND CORRESPONDING METEOROLOGICAL DATA
CD
Date
7/23/85
7/23/85
7/23/85
7/23/85
7/23/85
7/23/85
7/23/85
7/23/85
7/23/85
7/24/85
7/24/85
7/24/85
Time (GMT)
1400 to
1500 to
1600 to
1700 to
1800 to
1900 to
2000 to
2100 to
2200 to
0900 to
1000 to
1100 to
1500
1600
1700
1800
1900
2000
2100
2200
2300
1000
1100
1200
XRF
Spot
Number
24
25
26
27
28
29
30
31
32
43
44
45
Wind (m)
Speed
AVG ± STD
2.88
3.32
3.43
4.61
5.18
5.59
5.83
5.73
2.87
1.60
2.11
1.24
± 0.626
± 0.113
± 0.624
± 0.058
± 0.274
± 0.517
± 0.247
± 0.442
± 0.319
± 0.223
± 0.398
± 0.325
Wind (°)
Direction
AVG ± STD
137.14 ±
127.95 ±
124.95 ±
115.85 ±
115.71 ±
107.10 ±
103.82 ±
109.94 ±
61.31 ±
277.83 ±
271.33 ±
310.83 ±
9.74
4.89
8.17
2.53
4.08
6.61
4.43
7.22
5.65
9.43
17.64
3.72
Air
Temperature
(°C)
14.80
15.40
16.20
16.70
17.80
18.40
18.30
18.30
18.80
13.80
21.20
21.70
Relative
Humidity
(*)
11.80
13.10
13.90
13.30
12.10
11.00
12.10
12.90
13.30
11.10
23.50
23.60
Water
Temperature
(°C)
12.20
12.50
13.00
13.20
13.10
14.20
14.20
13.90
14.00
9.60
12.50
12.30
Lower
Wind Speed
m/sec
1.834
2.351
2.117
2.876
3.225
3.695
4.107
3.688
3.935
1.923
2.555
2.156
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TABLE 6. RUN 15 PERIODS TO BE ANALYZED BY XRF AND CORRESPONDING METEOROLOGICAL DATA
Date
7/24/85
7/24/85
7/24/85
7/24/85
7/24/85
7/25/85
7/25/85
7/25/85
7/25/85
7/25/85
Time (GMT)
1500 to 1600
1600 to 1700
1700 to 1800
1800 to 1900
1900 to 2000
0000 to 0100
0100 to 0200
0200 to 0300
0300 to 0400
0400 to 0500
XRF
Spot
Number
1
2
3
4
5
10
11
12
13
14
Wind (m)
Speed
AVG ± STD
3.95 ± 0.420
3.97 ± 0.484
4.20 ± 0.521
3.17 ± 0.132
4.16 ± 1.860
4.08 ± 0.457
4.37 ± 0.314
3.07 ± 0.253
3.08 ± 0.690
3.54 ± 2.190
Wind (°)
Direction
AVG ± STD
64.49 ± 5.89
58.19 ± 6.04
46.30 ± 4.75
43.00 ± 7.45
13.79 ± 85.55
47.68 ± 9.95
33.59 ± 4.04
46.07 ± 5.97
40.23 ± 14.54
181.14 ± 44.09
Air
Temperature
(°C)
15.10
15.90
16.30
16.50
18.80
23.10
23.00
23.40
24.10
24.90
Relative
Humidity
(%)
15.60
16.30
16.50
17.00
20.20
20.10
20.50
20.50
20.20
20.10
Water
Temperature
(°C)
14.90
15.70
16.30
16.50
16.60
11.90
10.80
9.10
8.80
8.10
Lower
Wind Speed
m/sec
2.62
3.12
3.38
3.18
2.71
2.99
2.94
1.67
2.98
2.53
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III. DISCUSSION
Run 10 sampled aerosol participates for a two-hour period instead of
the standard one-hour period. This was mainly done to increase the aerosol
sample deposited on the filter for purposes of analyses (i.e., sensitivity
and detectability).
During Runs 14 and 15, streaker units were placed in reverse positions
to ensure that the units were not bias in collection of aerosol particulates.
More specifically, during all other runs, streakers B and C were mounted at
the 2-m height and streakers A and D were mounted at the 11-m height. During
Run 14, streakers B and D were mounted at the 11-m height and streakers A
and C were mounted at the 2-m height. During Run 15, streakers A and D were
mounted at the 2-m height and streakers B and C were mounted at the 11-m
height.
Appendix B contains the Interim Report #1, X-Ray Fluorescence Analyses
of Air Filters From Lake Ontario Tower. In this report, Dr. Tisue comments
on two points which should be addressed. First, the irregular spacings on
one or two of the streakers are due to a solenoid malfunctioning within the
streaker unit itself. This problem has been rectified by installing a new
solenoid. Unfortunately, this problem can only be corrected by sending the
streaker unit back to the factory, since the solenoid is internally sealed
within the unit. Secondly, the "filters dragging in the air sampler" resulted
from the orifice being seated too high in the air sampler (i.e., streaker
unit). This problem can be rectified by slightly lowering the orifice.
Further description of the streaker unit (air sampler) can be found in
Appendix A.
10
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APPENDIX A
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GRADIENT TECHNIQUE MEASUREMENT OF AEROSOL
PABTICULATES OVER FRESH WATER
By
Mark S. Vfatka
B.A., Augustana College, 1982
M.S., Governors State University, 1985
THESIS
Submitted in partial fulfillment of the requirements
for the Degree of Master of Arts in Science,
with a Major In Analytical Chemistry
in the
College of Arts and Science
of
Governors State University
University Park, Illinois 6<*66
1985
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TABLE OF CONTENTS
ABSTRACT i
LIST OF TABLES ii
LIST OF FIGURES iii
KEYWORDS iv
INTRODUCTION t
Basic principles
FIELD PROGRAM (OUTING IV)
Introduction
BRIEF CRITIQUE: Summer-Fall 1984 5
6
MODIFICATIONS
?
DISCRETE SAMPLING
FLOW VARIABILITY (l$85)
METEOROLOGICAL DATA (OUTING IV) 15
General observations
18
METEOROLOGICAL COMPARSIONS
23
PERIODS TO ANALYZE
24
SUPPORTIVE SAMPLING
31
CONCLUSION
APPENDIX A: OUTINGS I,II,HI 33
Field program
37
AEROSOL SAMPLING (1984)
40
FLOW VARIABILITY (1984)
43
METEOROLOGICAL DATA (1984)
46
METEOROLOGICAL CRITERIA
METEOROLOGICAL CONDITIONS (OUTINGS I,II,III) ^
General observations
57
REFERENCES
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GRADIENT TECHNIQUE MEASUREMENT OF AEROSOL
PARTICULATES OVER FRESH WATER
Mark S. Watka, M.S.
Analytical Chemistry
College of Arts and Science
Governors State University
University Park, 1985
ABSTRACT
The research centers upon a gradient technique to sample aerosol partic-
ulates in the atmosphere over a fresh water source on a stationary structure
to determine a deposition velocity, V,, for some trace metals.
a
Atmospheric sampling devices included continuous and discrete streakers
and some high-volume sampling. Flow variability and meteorological conditions
are also detailed in this research, along with data acquisition, analysis and
interpretation.
This research occurred periodically for two years, particularly the
Summer and early Fall periods.
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ii
LIST OF TABLES
Table 1-Page 12-- Mean flows and 90# confidence interval flow
variability for Summer, 1985.
Table 2-Page 20— Percentage of insector winds, Summer, 1985.
Table 3-Page 22— Alpha values, Summer, 1985.
Table 4-Page 25— Specifications report for glass fiher filters.
Table 5-Page 27— Total suspended particulate matter, Summer, 1985.
Table 6-Page 29— Muffling of control filters, % of weight loss.
Table 7-Page 42-- Mean flows and 90% confidence interval flow
variability for Summer-Fall, 1984.
Table 8-Page 50— Percentage of insector winds, Summer-Fall, 198*4-.
Table 9-Page 52— Alpha values, Summer-Fall, 1984.
•
Table 10-Page 56— Total suspended particulate matter, Summer-
Fall, 1984.
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iii
LIST OF FIGURES
Figure 1-Page 19—Graphical presentation of meteorological data
for Outing IV.
Figure 2-Page 3^—Location of CCIW tower.
Figure 3-Page 35~Sketch of waves tower (CCIW).
Figure ^a-Page Vl—Graphical presentation of meteorological data
for Outing II.
Figure ^B-Fage 45—Graphical presentation of meteorological data
for Outing III.
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iv
KEY WORDS
ACCUMULATION MODS - particles between 0.1 xm and 2.0 #m in diameter
AEROSOL - dispensed solid or liquid matter in a gaseous medium—here air
AEROSOL PARTICULATES - particulate matter mixed in a gaseous medium
ANTHROPOGENIC MATERIAL - man-made pollutants
BRAIN UNIT - master control unit which advances discrete streakers
BROWNIAN MOTION - the random motion which particles less than 1 m are
governed by
CCIW - Canadian Centre For Inland Waters
CASCADE IMPACTOR - collection device which segregates sample according to size
COAGULATION - a process by which aerosols collide and unite to form larger
aerosols
COARSE PARTICLE MODE - particles greater than 2.0/flu in diameter
CONDENSATION NUCLEI COUNTER - contamination detector
DEPOSITION VELOCITIES - rates at which pollutants are deposited onto a surface
DRY DEPOSITION - non-precipitive deposition; this may occur by sedimentation
of aerosols or by impaction
EDDY CORRELATION TECHNIQUE - an in situ technique to determine deposition
velocities
FINE PARTICLE MODE - nuclei mode and accumulation mode are collectively known
as this
FLOW VARIABILITY - degree to which flow rates changed
FULFILLED CRITERIA - meteorological data which was within specifications
GRADIENT MEASUREMENT TECHNIQUE - a technique to measure deposition velocities
via difference In concentration at two heign
HIGH-VOLUME SAMPLER - collection device
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IN-SECTOR - wind blowing from a range of 160° to 320 (North = 0 ); this
range coincides with winds blowing directly over the lake
LAKE FETCH - winds from a 160° to 320° range
METEOROLOGICAL CRITERIA - used to determine if meteorological data was within
specifications
NUCLEATION - smaller particles forming a single, large particle
NUCLEI MODE - particles less than or equal to 0.1,4m in diameter
OUT-OF-SECTOR - winds blowing over land or any other range than 160 to 320°
PARTICIPATE MATTER - aggregations of matter (solid or liquid), larger than
individual molecules
PIXE - Proton Induced X-Ray Emission
POLLUTION SOURCE SITE - industrial steel factories, west of sampling location
PRIMARY POLLUTANTS - pollutants which are directly emitted into the atraospherr
SAMPLE RECTANGLE - appearance of the collection sample on the streaker filter
which resembles a 1.5 mm x 8.0 mm rectangle
SAMPLING DURATION - length of period for which sample was collected
SAMPLING SPACINCS - distance between each collected sample
SECONDARY POLLUTANTS - pollutants wich undergo chemical or photochemical re-
actions in the atmosphere
SEDIMENTATION - the removal of aerosols by gravitation
STABLE CONDITIONS - periods when meteorological conditions are optimal for
gradient sampling
STREAKERS - sampling device to collect aerosol particulates
WAVES TOWER - sampling site for gradient measurement
WET DEPOSITION - preclpitative deposition
XRF ANALYSIS - X-Ray Fluoresence; used to detect trace metals on streaker
filters
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GRADIENT TECHNIQUE MEASUREMENT OF AEROSOL
PARTICIPATES OVER FRESH WATER
Outing IV
INTRODUCTION
Literally, voluminous amounts of literature have been written about air pol-
lution (i.e., mechanisms controlling air pollution, monitoring, analyzing,
adverse effects on vegetation and humans, just to name a few, Lodge et al..
1980). Detailed discussions and other related phenomena of air pollution
are beyond the scope of this text, hence, only basic principles and theories
will be highlighted. For a thorough discussion, one should consult the five-
volume series Air Pollution, edited by A. C. Stern (Academic Press, New York,
'1976). - -
BASIC PRINCIPLES
Air pollution can be divided into two classes, primary and secondary pollu-
tants. The former are pollutants that are directly emitted into the air.
The latter are pollutants which undergo chemical and photochemical reactions,
under the proper conditions (Williamson, 1973). Pollutants can be further
divided into three types, depending on their size. They include: the nuclei
node ( < 0.1/dm diameter), the accumulation mode (between 0.1 and 2.0x^n
in diameter), and the coarse particle mode ( > Z.O^m In diameter). The
nuclei mode and the accumulation mode are collectively known as the "fine
particle mode" (National Research Council, 1978). The fine particles are
formed by coagulation, nucleation and condensation of additional material
-------
and are poorly removed from the atmosphere by meteorological processes and
settling (Lodge, et al., 1980; and Willeke and Whitoy, 1975). Conversely,
the coarse particles (mechanically generated aerosols) are readily removed
by sedimentation and rainfall (Lodge, et al., 1980). Stern (i960) points out
that the fine particles are not affected by gravity but Instead experience
random or Brownlan motion. Hence, the smaller particles are removed by
diffusions to surfaces and by coagulation, forming larger particles. For
example. Lodge, et al., (i960) stated that
. . . deposition on water surfaces tends to be irreverse-
Ible. Falling rain and other hydrometeors also remove these
large particles with appreciable efficiencies. On the other
hand, deposition on very smooth surfaces can be reversed al-
most completely by strong winds.
This indicates that wet deposition will influence the aerosol particulate
differently than dry deposition (non-precipitation periods). Therefore, this
research effort focuses primarily on dry deposition periods, all other periods
(precipitation) are not used. Furthermore, this research effort was con-
ducted exclusively over a large body of fresh water, for which the rate of
deposition or the deposition velocity is not entirely understood (Slevering,
1978).
Basically, the rate at which equilibrium is established for any element
e, is proportional to its concentration, provided other factors remain con-
stant Ci«e«» temperature, volume, etc.). Varying any one particular factor
will Influence the rate and make concentration determination somewhat diffi-
cult. If several or all factors vary simultaneously as occurs in air pollu-
tion, determination of the rate becomes quite complex. When aerosol partic-
ulates are emitted into the atmosphere, they are diluted via the enormous
-------
volume of air. And the distribution of aerosol particulates throughout the
atmosphere is related to the meteorological conditions which are present and
the variation in the meteorological conditions over the course of tine (Hicks,
1980). More specifically, wind direction and wind speed will influence the
mixing of the aerosol particulate. This suggests an infinite combination of
aerosol particulates can be contained in any air mass, in any concentration.
When no horizontal gradient is present at the sampling site, the rate (also
referred to as deposition velocities) at which aerosol particulates are de-
posited onto a surface can be estimated (Slevering, 19751 1981). Estimating
deposition velocities over a large body of fresh water using wind tunnel
studies has been futile due to their inability to reproduce the surface of
the lake (Williams, 1982). Furthermore, changes in wind direction will force
a change in wave direction, which could resuspend more particles into the
atmosphere (Slevering, 198k). Aerosol particles can also escape from re-
moval (Pickett, I960), depending on what meteorological conditions are present.
This uncertain!ty in deposition velocities warrants better understanding. As
Williams (1982) states,
Since this range of uncertainty is approximately an
order of magnitude, it is clear that definitive direct
measurements of particle deposition velocities to water
are needed to refine and validate the model parameterization
before it can be applied in deposition monitoring networks
or in transport models.
The reader should refer to other various research papers which attempt
to clarify this uncertainty in deposition velocities (e.g., Sieve ring, 1975,
198ki Wesely and Hicks, 1976j Slino. et aJU 19781 Slinn and Slinn, 1980j
Lodge, et. aL, 1980} and Williams, 1982).
-------
The main effort of this research was to implement a gradient technique
to sample an expected concentration difference for any element £, over a
period of time. Of course, the estimation of deposition velocity would
only be valid under the meteorological conditions which prevailed at the
time of sampling. Hence, the condition of the gradient must be established,
which Is the secondary objective of this experiment. Hicks (1982) states
that, "When properly applied, the gradient technique is an excellent way to
obtain Information on pollutant fluxes."
TOPICS OF DISCUSSION
The following two sections document the field program used in the gradient
technique experiment (which includes flow variability of the aerosol samplers)
and the meteorological conditions which occurred during the Summer 1985 exper-
iment (Outing IV). A third section presents some of the supportive sampling
procedures and results which includes: total suspended particulate (TSP)
values, gravimetric analysis, and gas chromatography using a Perkin-Elmer
(Sigma 2B) chromatograph. This is followed by a conclusions/suggestions
section. Also, Appendix A summarizes the field programs, meteorological con-
ditions and the flow variability that occurred during Outings I-III (Summer-
Fall 198*0.
Field Program: Outing IV
INTRODUCTION
A variety of techniques have been developed to measure dry deposition and have
been critiqued (Hicks, et aL., 1980) and Hicks , 1982), each technique having
unique assumptions and problems. The main effort of this research was to
-------
implement a gradient technique to sample an expected concentration differ-
ence for any elenent e, over a period of time. Of course the estimation
of deposition velocity would only be valid under those meteorological con-
ditions which prevailed at the time of sampling. Hence, the condition of the
gradient must be established, which is the secondary effort of this experi-
ment. Hicks (1982) states that, "When properly applied, the gradient tech-
nique is an excellent way to obtain information on pollutant fluxes."
BRIEF CRITIQUE: SUMMER-FALL 1984
Although the reader is referred to Appendix A for a detailed discussion of
the logistics and theory which were dealt with during the first year's (19&0
field program, a brief critique will emphasize three main points:
A) Meteorological Criteria
B) Gradient Sampling
C) Experimental Parameters "
A) Meteorological Criteria
If sampling of the aerosol particulates is to occur, some meteorological pa-
rameters must be quantified. Principally, wind direction and wind speed
must be quantified for determination of the wind gradient and temperature
measurements for determination of temperature gradients. For all sampling
periods, meteorological data (I.e., wind direction, wind speed, air temper-
ature, water temperature, relative humidity and solar radiation) were ob-
tained every ten minutes. Averages and standard deviations were calculated
within each hour to establish the condition of the gradient.
B) Gradient Sampling
Theory and logistics for sampling remained constant throughout all outings.
-------
The sampling devices used in Outings I-III were continuously sampling the
aerosol particulate. Whereas Outing IV sampled the aerosol particulate dis-
cretely with respect to time.
C) Experimental Parameters
Experimental parameters include the type of filter media chosen, initial set-
ting on the flow controllers which regulate the flow of air, and the duration
of the sampling time. These parameters dictate the flow rates over the
course of the sampling period (not to mention the meteorological variations).
These flow rates appear as 90# confidence intervals to indicate that the flow
rates are within the specified limits.
This summarizes the main points which are dealt with during all outings.
However, a thorough understanding of Appendix A is advantageous to fully com-
prehend any discussion and for conclusions that are made about the second
year's (1985) sampling (also referred" to as Outing IV).
MODIFICATIONS
In general. Outing IV was conducted exactly like the first year's sampling
(Outing I-III), as stated previously. Various modifications were completed
on the aerosol sampling equipment (referred to as streakers) prior to the
beginning of Outing IV, so that: a) the volume of air sampled would be in-
creased; b) flow variability of each streaker system would be reducedj and
most importantly, c) the timing sequence of the Proton Induced X-Ray Emission
(FIXE) streakers was changed from a continuous mode to a discrete mode.
Increasing the volume of air sampled and reducing the flow variability
of the streakers was accomplished in two wayst
-------
l) New now controllers were used which would not restrict the rate
of air flow as much as the previous flow controllers.
2) Teflon filter media was used In place of the 0.3>ym Nuclepore
filter media; even though Teflon appeared to be less affected
by the meteorological changes. Teflon Is a woven filter and
may contain areas that have a "thick weave", whereby changing the
dimensions of the filter. This would then Induce variations in
the flow rates which are being monitored.
Further discussion about flow rates and 9056 confidence intervals of each
streaker during each run of Outing IV will proceed after a discussion about
the timing modification.
DISCRETE SAMPLING
Prior to Outing IV, the streakers operated continuously for a period of about
'seven days. A major problem with continuous sampling is the fact that the
filter was continuously moving and the exact position of any specific hour
of sample could not be definitively ascertained. With no clear distinction
between the start of one hour sample and the ending of another (since the
samples would appear to be "smeared" together) X-Ray Fluorescence (XRF) anal-
ysis would be more complex. Therefore, it would be advantageous to be able
to divide the sample into discrete periods (i.e. each hour of sample would be
represented by a specific spot on the filter). Through the use of highly
sophiscated electronics (referred to as the "brain unit", manufactured by
FIXE International Corporation) this type of timed, discrete sampling can
occur. Hence, the streakers can be commanded to sample for any length of
time desired and then commanded to move to a fresh location on the filter
-------
8
when Its sampling time Is completed. This continues until the fresh filter
media Is used up, which necessitates a filter change.
Basically, the discrete sampling unit Includes: the brain unit, four
discrete streaker samplers, four diaphragm type pumps, various electrical
cords and vacuum lines which operate in the following manner. First, after
having made the correct electrical connections to the streakers from the
brain unit and the necessary vacuum line hook-ups, the streakers are loaded
with a fresh filter disc. The streaker is then sealed and mounted into its
appropriate position on the tower (on the 11-m boom or the 2-m boom). With
the power source off on both the brain unit and the diaphragm pumps, the
brain unit is programmed for any length of sampling time and any distance be-
tween samples that is desired. However, once the sampling duration and sam-
ple spacings have been chosen and the run started, changes in these param-
eters cannot occur. Any adjustment to the brain unit after the power is on
will induce the brain unit to malfunction and sample irregularly. In other
words, the brain unit is "locked in" that mode until the run Is completed.
Finally, the brain unit is turned on and sampling is conducted.
As previously mentioned, the brain unit Is very flexible with respect
to the desired length of sampling time and distances between the samples
(sample spacings). The length of sampling time can range from one minute
to over a thousand minutes and the distance between samples can range from
overlapping samples to 50 mm spacings. A large variety of sampling options
are available with the brain unit. For example, the brain unit can be pro-
grammed to sample for six hours and then commanded to move 10 mm to a fresh
area on the filter disc and sample the next six hours, continuing in this
programmed mode until the filter disc Is used up (bearing in mind that all
-------
four streakers are being controlled by one brain unit, all simultaneously).
Similarly, during the next run, It is desired that the sample duration and
sample spacings are to be decreased. The brain unit can then be programed
to sample for one hour and then commanded to move 2 mm to fresh area on the
filter disc. This type of programming allows the sample to be collected dis-
cretely, with each sampling rectangle representing the specified sampling
duration, unambiguously. The sampling orifice slit width measures 1.5 mm x
8 mm, a rectangle is the observed appearance of the sample which is collected
on the filter for the specified time. Furthermore, when the brain unit
senses that the specified sampling duration is nearly completed and a move-
ment to the next specified area is about to commence, the brain unit briefly
closes the orifice inlet (to stop the flow of air), moves its specified dis-
tance and reopens the orifice. This continues until the filter disc is full.
Unfortunately, the brain unit does not know when the filter disc is full of
samples, and depending on what combination of sampling duration and sample
spacings are chosen the brain will determine how often the filter discs are
replaced. Optimally, the filter disc should use as much of the filter area
as possible. To Increase the number of sampling rectangles that can be
placed on a filter disc, the sampling duration should be increased (i.e.,
each sampling rectangle samples for a longer period of time) and the dis-
tance between sampling rectangles should be decreased. This allows the run
to last for a longer overall time and nearly all of the filter is used. Howr
ever, various circumstances may arise where the sampling duration and sample
spacings are "pre-determined". For example, this research effort used a
sampling duration of one hour to correlate the meteorological output with
respect to time. Also, a 1.5 mm spacing between sampling rectangles Is
-------
10
needed in order to allow the XRF beau, (used In XRF analysis) to have
enough space so that it would "see" one sample rectangle at a time (any
smaller distance would Induce a higher degree of error, since the beam
would be -seeing" sample obtained from a sample rectangle which was col-
lected before or after that hour). These conditions (one hour duration and
1.5 mm spaclngs) allowed for approximately 50 hours of sample to be collected
on each filter disc. In turn, this necessitated the filter discs be changed
every other day. During the weekend the streakers could not be monitored as
extensively as during the weekday periods and the filters could not be
changed as often. Fortunately, an infinite number of sampling combinations
can be obtained, even continuous and/or overlapping sampling rectangles.
For this research effort, the discrete sample collected during the weekend
runs have a sample spacing of 1.5 mm (due to XRF analysis requirements). The
only possible way to increase the total length of the run so that filters
would not have to be changed every other day would be to increase the dura-
tion of sampling fro. a one hour mode to a two hour mode. However, increasing
the duration of the sample collection period could Induce problems such as
increased now variability, since more sample is collected to clog the filter.
Pre-field testing indicated that this increase in duration would not signif-
icantly alter the flow variability, assuming that meteorological conditions
did not drastically change. If meteorological conditions did significantly
vary, sampling for extended discrete periods would be complicated. For ex-
ample, during the weekend, sampling duration lasted for two hours. If dur-
ing the first hour, meteorological conditions were in-sector and all criteria
was fulfilled, and during the second hour winds shifted violently and went
out-of-sector, the sample collected during the first hour would be "good",
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11
with "bad" sample collecting during the second half of the duration. This
sampling rectangle could not be used for gradient measurement since the sam-
ple was not collected entirely during an in-sec tor period. Clearly, the
probability that meteorological conditions will remain constant for two
hours is slim. Furthermore, the probability that the meteorological condi-
tions will not vary by the stated criteria (Appendix A) between each two hour
duration is even less. Hence, when possible, the duration of sampling should
be as short as possible to maximize all possible in-sector periods.
FLOW VARIABILITY
The discrete samplers used in Outing IV were monitored for flow rates in a
similar fashion as the samplers used in Outings I-III. Attempts at increasing
the volume of air sampled and decreasing flow variability have shown marked
Improvements (Table 1, this text). Clearly, the increase in the volumes of
air sampled (fc-5 times increase from previous outings) can only aid in ob-
serving a difference in concentration with respect to height. However, some
unintentional biasing may have occurred due to the meteorological conditions
and the periods when monitoring took place (even though monitoring periods
were randomly selected). Furthermore, due to the fact that the sum of the
discrete sampling periods is two-thirds shorter in time as compared with
continuous sampling (120 hours shorter) monitoring periods, the number of
cases used to calculate average flow rates and 9056 confidence intervals are
reduced. In other words, average flow rates and 9036 confidence intervals are
strongly affected by the number of monitorings used to calculate those numbers.
For example (referring to Table 1, this text), run 7 had high flow rates with
very low flow variability, expressed as a 9056 confidence interval! < 1.0£
indicates that flow rates were reasonably consistent.
-------
STREAKERS
8
10'
11
12
13
15
A (North) 1/min
C.I. of + 90?S
D (South) 1/min
C.I. of + 90&
B (North) 1/min
C.I. of + 90%
C (South) 1/min
C.I. of + 90%
4.67 4.45
+0.43# +0.54$
4.70 4.52
±0.72% ±0.73%
4.70 4.52
±0.57* 10.92*
4.70 4.48
+0.43$ +1.0058
4.47 4.55 4.55 4.64
±1.25* 12.38* *.»« 12.26*
4.50 ' 4.57 4.59 4.58
±0.77% +1.74J& +4.32# ±0.85%
4.42 • 4.59 4.65 4.31
±1.71% ±0.99% +4.45^ ±9.b2%
4.44 4.64 4.64 4.66
+ 1 ^ ^^ +1 1 (\&L +• ^ /i A^ + 1 ^fl^
*^ J. • J J/° A • J. tJ/SO * J •fcrU/w "^ J. • J\J/0
4.69 4.56
±2.!* 11.81*
4.70 4.66
+1.96^ +0.91#
4.70 4.43
+0.34^ +2.68?5
4.66 4.56
+1.85/0 +1.66^
4.58
11 . 02^
4.58
4.62
±1.67%
4.63
10.75^
Table 1. Mean flows and 90% confidence (C.I.) interval flow variability for Summer, 1985 sampling. L indicates that
the streaker was mounted at the 2-m boom, U indicates that the streaker was mounted at the 11-m boom. The
asterisk (*) indicates a weekend sampling run ( also referred to as an 2-hour mode).
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Run 7 was monitored six times throughout its 22 hour run, with no
periods which were in-sector. All monitoring took place when winds were out-
of-sector but not blowing from the pollution source site (PSS). Thus, flow
rates are high and flow variability is at its lowest point (compared with
all other runs). Run 11, on the other hand, had winds blowing directly from
the PSS, monitoring was able to be accomplished only three times, with the
last monitoring occurring during an in-sector period. In general, referring
to Table 1 , runs 10, 12 and 15 experienced increased 9056 confidence inter-
vals mainly due to the fact that monitoring occurred when winds were in-sector
and later when winds were from the PSS. Conversely, runs 11 and 1U initially
experienced winds from the PSS and later winds were in-sector. Variation in
the meteorological conditions (i.e., relative humidity, Hind speed, etc.)
while periodically monitoring could unintentionally bias the data (giving
.higher confidence intervals).. Naturally, the data could be unintentionally
biased to give lower confidence intervals, such as in runs 8 and 9. Monitor-
ing occurred in both cases, which could explain the increase in the 90$6 con-
fidence interval for the lower streakers (in both runs). Run 8 also experi-
enced a unique monitoring and meteorological phenomena, where flow rates were
initially high at the onset of monitoring (during an in-sector period) and
were slowly reduced as the winds creeped towards out-of-sector, from the PSS.
Interestingly enough, the flow rates were reduced for all four streakers and
by the last and fifth monitoring, flows were at their lowest value, after
which winds went out-of-sector. This indicates that there could be some re-
duction in flow rates due to the large amount of anthropogenic material in
the air. This point is again emphasized by comparing runs 7 and 13. Both
runs were monitored entirely during out-of-sector periods, however, the
-------
confidence interval, C.I., differs dramatically in run 13 due to the fact that
It was monitored when winds were from the PSS. (Noting that during run 12 and
part of run 13, pump B was malfunctioning, causing extremely bad 9Q£ C.I. for
run 12. Run 13 had extremely good 90?6 C.I., entirely due to the fact that
flow rates obtained from the malfunctioning pump were not used in calculating
9W C.I.).
Two, 2-hour runs were completed during Outing IV, runs 10 and 13. Com-
paring these two runs, the upper streakers appear to be functioning very
similarly. Whereas the lower streakers do not compare as well but do exhibit
a reduced 90% C.I. as compared with the upper streakers.
Runs 14 and 15 deviated from the conventional mounting of the streakers
(A and D on the upper boom, B and C on the lower) to observe any streaker
bias that nay have been present. During run 14, B and D streakers were
mounted on the upper boomj A.and C streakers were mounted on the lower boom.
During run 15, streakers A and D were mounted on the lower boomj B and C on
the upper boom (the reverse order In which they were mounted for all previous
runs). Based on these two runs, there does not appear to be any streaker
system bias, with respect to flow variability. However, XRF analysis is not
complete, hence, evidence to support an unbiased sampling system Is not con-
clusive .
In conclusion, the sequence of sampling runs recommended for XRF analysis
are placed in the following order using the least variability to the greatest
variability is as followsi runs ?. 8, 15, 9, 10. 13. 14, 12 and 11 for this
Outing. Comparing Outing IV with Outings I-III, in general, the flow vari-
ability is quite similar. Although the flow rates for Outing IV are four
times as great as the previous outings, there Is no unusual change in the flow
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15
variability. Extreme flow variability was not limited to one particular
time frame, but does appear to be affected by the meteorological conditions
present at the time of sampling and/or monitoring. Further correlation
Incorporating the flow rate aspect of each run and the meteorological con-
ditions present at the time of sampling is discussed at the conclusion of the
section (under the heading "Periods to Analyze").
Meterologlcal Data: Outing IV
INTRODUCTION
As previously mentioned, the aerosol particulate sampling and meteorological
monitoring are intimately related. Hence, the condition of the gradient can
be established for the period of time when aerosol particulate was collected.
The meteorological conditions obtained for the second year's sampling
(i.e., Summer 1985. also referred to as Outing IV) used identical parameters
and criteria as the first year's (198*4.) sampling (i.e., Outings I-IIl). The
reader Is referred to Appendix A for a full clarification of the meteorologi-
cal parameters used, meteorological theory as related to the gradient measure-
ment, and establishment of criteria used to analyze meteorological data. Also,
Included in Appendix A are the observed meteorological conditions that were
present during past outings (Outings I-III) and the calculated alpha values
(variation of wind speed with height). Therefore, a thorough understanding
of Appendix A is a necessity to completely comprehend any discussion about
meteorological data obtained for Outing IV and any comparisons that are made.
METEOROLOGICAL CONDITIONS i GBNERAL OBSERVATIONS
Meteorological data for Outing IV was obtained from July (fc to July 26, 1985,
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16
which is broken down into nine separate sampling runs (labelled run 7, 8,
9i etc. for continuity with previous runs). The observed meteorological con-
ditions present during Outing IV was as followsi
Outing IV/run 7 (July 0^, !6i30Z to July 05, 13«1^). This sampling
period experienced no precipitation and low relative humidity. Winds were
generally strong and out-of-sector. Cloud cover ranged from 0# to 90# with
a storm moving in from the South. The percent of white capping ranged from
zero to medium with a maximum of 0.5-m wave height. Air temperature ranged
from 21.5 to 27.1°C.
Outing IV/run 8 (July 08, 16:152 to July 10, 13:OOZ). This sampling per-
iod experienced five hours of precipitation during an out-of-sector period at
the beginning of the run. Humidity was generally high (80#) with light to
moderate east winds. Cloud cover ranged from 0# to 60#. Lake condition was
very calm with no white capping and at times, the lake surface was "glass-
like." Air temperatures ranged from 12.0 to 25.8°C.
Outing IV/run 9 (July 10, 1^:30Z to July 12, 13:^OZ). This sampling per-
iod experienced six hours of precipitation during an in-sector period near the
end of the run. Winds were cool and moderate from a northernly direction.
Relative humidity was l*0# with no cloud cover. The lake experienced no white
capping but did produce some small swells which ranged from zero to 1/8-m in
magnitude. Air temperatures ranged from 1^.0 to 24.3°C.
Outing IV/run 10 (July 12, 15«30Z to July.'15, lli^5Z). This period is
an extended 2-hour sampling mode run. Seven hours of precipitation during an
out-of-sector period occurred. Winds were light with ^0£ cloud cover. The
lake experienced a medium amount of white capping with some small swells which
were 0.5-m in magnitude. Air temperatures ranged from 15.1* to 27.9°C.
-------
17
Outing IV/run 11 (July 15, 13:OOZ to July 17, 13«15Z)- This sampling
period experienced no precipitation with light winds, generally out-of-sector
and cloud cover was about 5Q£. The lake condition was very calm with no
swells and no white capping. Air temperatures ranged from 15«4 to 2b.5 C.
Outing IV/run 12 (July 17. 1^»15Z to July 19, 13«OOZ). This sampling
period experienced no precipitation with 60£ cloud cover. Winds were moderate
and from shore, possible pollution source site contamination (contamination
period would have occurred during an out of sector period, near the end of
the run). Lake condition was calm, with no white capping or swells. Air
temperatures ranged from 15.2 to 21.2°C.
Outing IV/run 13 (July 19, 15:OOZ to July 22, 13:OOZ). This period is
an extended 2-hour sampling mode run. Six hours of precipitation occurred
during an out-of-sector period near the beginning of the run. Winds were
strong with 50# cloud cover. The lake experienced a large degree of white
capping and a large degree of swells, ranging from 1/8 to 1/2-m in magnitude.
Air temperatures ranged from 15.1* to 28.2°C.
Outing IV/run 14 (July 22, 15:OOZ to July 24, 13«OOZ). This sampling
period experienced no precipitation with 056 of cloud cover. Winds were light
and from a southernly direction. The lake was very calm with no white capping
and no swells. Air temperatures ranged from 9.3 (record low) to 21.3°C.
Outing IV/run 15 (July 24, 15-.OOZ to July 26, 13:OOZ). This sampling
period experienced no precipitation with light winds and no cloud cover. The
lake was calm with no white capping or swells. Air temperatures ranged from
15.5 to 29.3°C.
GRAPHIC PRESENTATION
A graphical presentation of the meteorological data was also done for this
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18
Outing (Figure l) as well as Outings II and III (Appendix A, which also
describes these graphs in greater detail). Noting that the "extreme spikes",
which are circled (referring to Figure 1, this text) are due to mechanical
malfunctions of the meteorological equipment and are not caused by actual
meteorological conditions. Data points which are lost during this malfunction
are computer interpolated from values before and after the hour in question.
METEOROLOGICAL COMPARISONS
These data do not compare as expected with Outings I, II and III with respect
to in-sector times versus total length of run (referring to Table 2, this
text and TableS , Appendix A). However, a true comparison of meteorological
data can only be accomplished when comparing meteorological data obtained from
similar time frames (i.e., Outing I, June 25 to July 09, 1985 as compared to
Outing IV, July OU, 1985 to July 26, 1985). Based on the cumulative averages
of run 1 and run 2 as compared with runs 7 and 8, the percentage of in-sector
periods are 30g to 3?# respectively. Furthermore, statistics from Summary
of Synoptic Meteorological Observations for Great Lakes Areas (also referred
to as National Oceanic and Atmospheric Administration, NOAA, data) indicates
that a maximum expected in-sector period for July exists 32& of the time
(based on a sector range of north to southeast). If all the runs during
Outing IV were average for in-sector periods versus total length of run, the
NOAA value of 32* is attained. This indicates that Outing IV had meteorologi-
cal conditions which were typical for this sampling period.
Looking at the individual runs, only four fall below the NOAA maximum
value of y&. they Include runs ? (Og). 11 (1356), 13 (H#) and 15 (22£).
Principally, the Inherent randomness of the meteorological conditions greatly
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— [
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20
Percentage of Each Run's Time
Overal1
Run Number 7 8 9 10 11 12 13 14 15 X.1985
In Sector Times 0 54 33 36 13 69 14 41 22 32
as % of Total
Run Time
In-Sector Periods
with all
Criteria Fulfilled
28 25
44
33
46 60
33
Fulfilled Criteria
as % of Total
Run Time
15
8 16
23
19 13
11
Neutral
Unstable
Stable
0% 13% 4% 0% 3% 0% OX 20%
0% 6% 4% 0% 0% 0% 0% 0%
100% 82% 92% 100% 97% 100% 100% 80%
Table 2. The percentage of time when in-sector winds and fulfilled
criteria occurred. Neutral, unstable and stable percentage
occurrence is also shown (based on in-sector periods only).
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21
affects these percentages (Table 2). For example, lake breezes (i.e., good
lake fetch) usually occur in the early to late mornings (8:00 a.m. to noon
or 12:OOZ to l6tOOZ).
In general, those runs with percentages above 32$, had periods where lake
breezes occurred (at 12:OOZ) more than once during the run (runs 9 and 14)
and/or continued throughout the next sampling day (runs 8, 10 and 12). Since
there is not assurance that a lake breeze will continue or even occur, the
percentages will be affected.
Percentages for fulfilled criteria versus total length of run and in-sec-
tor periods for Outing IV (Table 2) are slightly reduced as compared with
Outing I (Table 8, Appendix A). This is mainly due to changes in wind direc-
tion beyond the stated criteria (from Appendix A). Low alpha values (Table 3)
also contributed to the lower percentages. For example, Outing IV had 69 data
points where the wind speed was less than 2 m/s and a slightly positive alpha
value (+0.0124), whereas Outing I had only 41 data points less than 2m/s and
a better alpha value (Table9 , Appendix A). Although Outing IV lasted for
nearly twice the length of Outing I, which would account for the Increased
number. Nevertheless, the percentage of frequency for wind speeds which are
less than 2 m/s for all in-sector periods deviates significantly from the NOAA
data. Outing I had 42# and Outing IV had ^1% frequency for low wind speeds
( < 2 m/s). The NOAA average for percentage of frequency for wind speeds less
than 2 m/s (north to southeast sector range) is only 4.5* of the time. This
clearly indicates that a slippage problem is occurring near the tower and the
streakers should be extended further out in length and sample closer to the
lake surface. Wind speeds 2 m/s did not significantly alter Outing I data
-------
22
UH Range,
m sec'l
<
1 <
2 <
3 <
4 <
5 <
6 <
1
2
3
4
5
6
7
a Values
1984 Sampling,
Outinq I
<0.0
+0.05
+0.10
+0.16
+0.19
+0.14
+0.20
(15)
(26)
(22)
(12)
(17)
( 1)
( 4)
1985 Sampling
<0.0
+0.01
+0.15
+0.19
+0.21
+0.24
+0.22
(29)
(40)
(37)
(24)
(12)
( 5)
( 1)
Table 3. Variation of a values for Outing I of the 1984
sampling and for 1985 sampling at the Lake Ontario
tower. Number of hourly cases are indicated in
parentheses.
-------
23
because wind speeds which were < 2 m/s In magnitude had already been rejected
based on previous criteria. Outing IV, on the other hand, has a few data
points <,2 m/s wind speeds which fulfilled all criteria. This will re-
duce the percentages for fulfilled criteria even further.
Recalling from Appendix A, an established gradient will be observed
when stable conditions exist. Stable conditions existed predominately through
Outing IV (runs 8, 11, 13 and 1U), with neutral and unstable conditions arising
from the cool air temperatures in the early morning hours (runs 9, 10 and 12)
and precipitation (run 9) from Table 2. (Note that in an cases of neutral
and unstable conditions only one data point is involved except neutral condi-
tions of runs 10 and 12 which involve two data points. Hence, the percentages
appear to be inflated only due to the reduced number of in-sector periods and
not the increased number of neutral and/or unstable conditions.)
In conclusion, based on meteorological.criteria, the runs of Outing-IV
can be ranked according to meteorological aspect which are the most conducive
for gradient measurement. These runs are as follows: runs I**, 8, 12, 10, 9,
15. 13. 11 and 7 based entirely on meteorological data.
PERIODS TO ANALYZE
Correlating meteorological data and flow variability data together, the best
possible periods to be analyzed by XRF can be determined. Meteorological
input will have a heavier bearing on the ultimate times to be analyzed. For
example, flow variability suggests that run ? is the best run to be analysed
but meteorological input indicates that no periods could be analyzed, since
no in-sector periods exist. Bearing this in mind, highest priorities for
analysis by XRF are as follows: runs 8, 9, 10, 15, 14, 12, 13, 11 and ?.
-------
2ft-
In general, runs 8, 9 and 10 were chosen on the basis of good meteorological
conditions and little flow variability. Runs 15, 1U and 12 had comparatively
good meteorological conditions, but experienced a higher degree of flow
variability. Runs 13, 11 and 7 experienced poor meteorological conditions,
where winds were not in-sec tor, even though flow variability was not extreme.
Supportive Sampling: Outing IV
INTRODUCTION
The Federal Register (1971) stated five pollutants which required standards:
sulfur dioxide (SOg), carbon monoxide (CO), photochemical oxidants (Ox), nitro-
gen dioxide (N02) and total suspended particulate (T3P). Supportive sampling
for the research effect included determination of TSP as outlined by the
Intersociety Committee (1972). The high-volume sampler used by the research
effort utilized a constant flow controller (manufactured by Sierra instruments)
which would increase or decrease flow rates as designated by the meteorological
conditions. A seven day timing mechanism was also used to automatically turn
the sampler on or off at the desired time period. The high-volume sampler was
calibrated in the field prior to the Outing and rechecked after completion of
the Outing. The sampler remained calibrated throughout the Outing.
The sampler was mounted on the eastern face of the waves tower (sampling
location) and was programmed to sample in a random fashion during the Outing
period. Samples were collected on prenumbered Gelman Spectro-grade glass fiber
filters (Specification Report, Table U). Filters were desiccated at room
temperature for 48 hours prior to initial weighings. Weighing occurred in a
tared, zeroed, desiccated matter balance utilizing an air pollution weighing
chamber, especially designed for weighing 8" x 10" sheets. Weighings con-
-------
2}
TABLE wefcW ^SIWHIIll I^"«M 1 In nflCUlUU *«ODf
^Vbove SOOoram (Federal Sacc. No. ULimB)
• • • ••— ww*« *««^v ^§fl «•••« \f WV9 •• w^^li^a I^WL W Wr w 1 Of
• • • «4,0 i 3 Qrwn
• e • • /«A * /*3 \Ue>f^neMl e^TOCCCUe^Br
. — A. 500 ml distilled water.
8. Add IS drops saturated KQ Solution.
C Shred one 8" x 10" Sheet and soak in
prepared water for one hour.
0. Run pH at ambient temperature.)
. . . JO mm HjO maximum
. . . .500* C for 8 hour maximum exposure
"Analysis of Selected Elements in Atmospheric Pvticulan Matter by Atomic Absorption.'* Volume 7. Initniment
Society of America, pp. 9 -17 (1969).
GELMAN INSTRUMENT COMPANY
• TWX J10-223-«a37
-------
26
tinued until a stabilized weight was obtained. Weighed filters were placed
in a transport folder and sealed in a watertight plastic bag. At the field
site, each filter was mounted in a filter frame as they were needed. This
Included the actual collecting filter (sample filter) and also a control
filter which was subjected to the same conditions as the sample filter (except
no sample was collected on this filter). After sample collection, the filters
were folded in half (to prevent any loss of particulate matter), wrapped in
aluminum foil to prevent loss of volatile sample, returned to its respective
plastic bag and was stored at 40°F until weighed again later. Subsequent
weighings of the filter papers indicated weight loss which could be attributed
to loss of water vapor. Since the surface area of the glass fiber filter is
quite large and hygroscopic, variations in weighings can readily occur. To
determine the amount of organics present in the glass fiber filter, the filter
was muffled at 550°C in a muffle oven for U5 minutes (initially) and 30 minutes
thereafter. After the initial muffling, the filter was cooled, desiccated and
weighed in a tared, zeroed, desiccated Mettler balance.
Six high-volume samplers were obtained for the entire four weeks of
sampling, with an average 1*9.28 gm~3, (referring to Table 5). This con-
centration is at a level which is expected for a nearshore, shoreline pollu-
tion source which is west of the waves tower. This is nearly identical to
the average TSP value for Outings I-III, 49.1 gm~3 (Table 10, Appendix A).
Looking at the Individual high-volume samplings, filter 52 experienced
lake fetch with 2.% of those hours related to sampling when all criteria was
fulfilled and a TSP value which is lower than the average value was obtained.
Filters Ul and 51 had similar TSP values (U2.2 and 41.5 g»~3» respectively)
eventhough some rain occurred. Filter 55 had a relatively low TSP value,
-------
28
28.4 gm~J. This was caused by winds not blowing from the pollution source
site (PSS), but by winds blowing from a residential area southwest of the
waves tower. Filters 48 and 54 had relatively high TSP values, 7*4-.1 and 73.4
gnT-*, respectively. This was mainly due to winds coming from the PSS when
they weren't in-sector.
Following TSP determinations, filters 41, 51 and 55 were further analyzed
via muffling to determine the concentration of organic particulate sampled, as
previously discussed. Furthermore, since each sample filter had a duplicate
control filter, the control was muffled to determine the organic background
quantity. Table 6 also represents a composite of the muffled control filters
along with filters which were not taken into the field. It was observed that
the control filters lost 1.098& by weight of material. This value (1.09856
by weight) was subtracted from the sample filters to determine how much or-
ganic material was contained in the sample. Muffling indicated the loss of a
large amount of sample, possibly volatile organics.
However, the hygroscopic nature of the glass fiber filter could have in-
troduced error in the determination of organic amounts using a muffle furnace.
Also, carbonates which may have vaporized off due to the high temperature in
the muffle furnace. This could be an additional source of error in determining
concentration of organics. For example, filter 55 lost more weight than sam-
ple collected (Table 5) via muffling. Similarly, filters 41 and 51 lost nearly
all the sample via muffling. Since the mufflings showed some type of weight
loss, gas chromatographic analysis was performed to investigate the nature
of organics sampled. Chromatographic conditions used are as followsi
-------
29
PONTROT INITIAL MUFFLED DIFFERENCE ,, . . ... .
C2SSq WEIGHT WEIGHT * of Initial
FILTERS wt. organic
42 3.79531 - 3-74777 = 0.04754 1.2532
50 4.06260 - 4.02521 = 0.03739 0.920*
60 3.73882 - 3.69726 = 0.04156 1.111%
61 3.73603 - 3.69566 = 0.04037 1.081*
62 3.74567 - 3.69975 = 0.04592 1.226*
56 3.69395 - 3.65721' = 0.03674 0.995*
AVG % of initial wt. loss during muffling 1.098#
TABLE 6. This table indicates the average amount of weight loss
which occurred via muffling at 550°C for high-volume
filters with no sample collected on them.
-------
30
GAS CHROMATOGRAPHY USING A PERKIN-SLMER,
(SIGMA 2B) GC UNDER THE STATED CONDITIONS
TEMPERATURE PROGRAMMED ISOTHERMAL
Injection Port Temperature 250°C 250°C
Detector Temperature 300°C 300°C
Oven Temperature 100-200°C 230°C
(Referring to the programmed run, a rate of 10°C /minute where
the initial temperature was at 100°C for 1 minute and the final
temperature was at 200 C for 5 minutes.)
Helium Carrier Gas
Rate: 30 ml/min. 30 ml/min.
General Purpose 3P 2100 SP 2100
Injection Amount 1.0 1 1.0 1
Sensitivity 10 10/1
Attenuation 32
Samples used in gas chromatographic analysis were obtained by the fol-
lowing method, using filters U?, U8 and &, 55, which contained the greatest
amount of TSP material. The filters were weighed, shredded and soaked for
96 hours in 200 ml of ethyl acetate. The ethyl acetate extract was decanted
and concentrated down to about 1 ml by a rotary evaporator. The above ex-
traction was repeated with a fresh 200 ml ethyl acetate on the same filters to
ensure that all the organ! cs soluble in ethyl acetate were extracted. The
second extract was also concentrated down to about 1 ml. Temperature pro-
grammed GC was performed on all the ethyl acetate extracts for filters ^7, 1*8,
5*v and 55. Instrumental sensitivity for the isothermal run was increased to
detect any organic material that might be present. Also, amount of sample
injected was increased to 2.0 1. The GC analysis indicated that no organics
-------
31
were present in the extracts. However, this does not Indicate that organlcs
were not present in the sample. For example, volatile organics would have
been lost during the concentration of ethyl acetate extracts on the rotary
evaporator and during sample storage and handling. Furthermore, variation
in the GC conditions (i.e., N2 carrier gas at a higher flow rate, using a
different column (15^0 carbowax) and a benzene solvent extraction Instead of
ethyl acetate). Various other techniques could have been performed on the
high-volume sample as outlined by Warner (1976).
Conclusion
The two main efforts of this research were to implement a gradient technique
to sample an expected concentration difference for any element e, over a
period of time and also to establish the condition of the gradient during
sampling. Both of these efforts have been detailed in previous sections.
Conclusive evidence of a concentration gradient still depends on XRF analysis,
therefore, only refinements in the above sampling procedure will be discussed.
Gradient measurement of aerosol particulates necessitates meteorological
quantification and flow monitoring, two principles which should be improved
upon. Meteorological data acquisition should occur at a faster rate. In the
present system, data are acquired every ten minutes due to the slow response
of the equipment. Continuous acquisition and computer averaging of the
meteorological data would save time and improve statistical confidence.
Similarly, continuous flow rate monitoring, coupled with fast responding
meteorological acquisition would determine exactly which samples should be
analyzed. Furthermore, the flow rates would be more representative of the
actual flow rates for any specific time period. This would improve the
statistical confidence intervals.
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32
Referring to the sampling site itself, the backwash problem could be re-
duced If the booms are extended further out from the waves tower and brought
nearer to the lake surface, primarily referring to the lower boom. It should
be noted that only two stationary platforms over fresh water exist in the
North American Continent. Ideally, a stationary platform should be erected
in the middle of a fresh water lake. This would allow for aerosol sampling
to be established in any direction. Hicks (1980) states,
It is now possible to interpret concentration infor-
mation of a wide range of airborne constituents, in order
to determine dry deposition rates, provided adequate mete-
orological and surface information is available. Methods
of calculating site-specific and time evolving deposition
velocities now exist.
Hicks discusses techniques to determine dry deposition with optimism and
assurance that it is only a matter of time before a suitable technique is
established.
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33
TECHNIQUE MEASUREMENTS OF DRY DEPOSITION OVER
FRESH WATER FOR ATMOSPHERIC AEROSOLS
Appendix A: Outings I, II and III
Various methods for measuring aerosol flux have been developed (i.e., the
eddy correlation method), however, a proven technique for sampling over a
lake surface is often difficult (William et al . , 1980). This research
effort utilizes a gradient technique to measure the concentration of ele-
ment e_, at two specific heights above the lake surface. That is, for ele-
AC
ment £, -r will be observed with a reasonably high degree of statistical
confidence. At the Canadian Center of Inland Waters, CCIW , tower the mea-
surement heights were 2- and 11-m so Ce (11) - Cg (2) must be "seen" by X-Ray
Fluorescence, XRF, analysis (being performed by Dr. T. Tisue at Clemson Uni-
versity). XRF analysis is now underway. The field work has been successfully
completed and will here be described in detail.
FIELD PROGRAM
The CCIW is referred to as the "waves tower" and is located directly on Lake
Ontario (see Figure 2). The waves tower is comparable in appearance to a
mini -oil rig with a lower catwalk about 3-5-m above the lake surface and
an upper platform about 6-m above the lake surface (see Figure 3). The
waves tower is ideal for this gradient effort because of its location and
its ability to be utilized as a two-level aerosol sampling station without
backwash disturbance caused by the structure (except at very low wind speeds).
-------
TORONTO
Figure2 : Location of tower, CCIW and pollution source site.
Scale is 2000 meters per inch.
-------
Vn
Figure 3: The waves tower showing the 11-m and 2-m height booms.
SLrP^rPrc A n H f ha ^ *» rv 1 * /•>« *«^«
and their placement with respect to the tower
Also depicted are the
(not drawn to scale).
four (A, B, C, and 0)
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36
Aerosol sampling Is made up of four Proton Induced X-Ray Emission, PIXE,
(Larson et al., 1979) aerosol samplers (also referred to as "streakers"), a
cascade Impactor sampler, a HI-volume sampler, a condensation nuclei counter
which detects local aerosol contamination (e.g., boats passing by the tower)
during sampling, along with a precipitation detector to assure dry period
sampling. Since the size of the waves tower is large enough to cause some
structural backwash, the streakers were retro-fitted to two booms. It should
be noted that each boom held two streakers. These streakers were labelled as
duplicates throughout the research effort. Hence, at both heights (2-m and
11-m) two identical systems were sampling at the same time. On the 11-m
boom, streaker A was on the north side of the boom and streaker D was on
the south side. Likewise on the 2-m boom, streaker B was on the north side
and streaker C was on the south side (see Figure3 ). Both booms were de-
signed and constructed by the Canadians (Donneland and Beesly, 198^), given
specifications needed to avoid structural backwash and to allow for the
greatest vertical separation between measurement heights. The 11-m boom
resembled a goal post turned parallel to the water. The 2-m boom also re-
sembled a goal post except that an "L" bracket was attached to the one end
to allow for the mounting of the boom to the tower platform (see Figure3 ).
The "L" configuration of the 2-m boom allowed the boom to be lowered to the
2-m height above the lake level and as the average lake level dropped from
outing to outing, the 2-m boom was adjusted to compensate for this drop.
Furthermore, since the 2-m boom incorporated this "L" configuration, access
to the duplicate streakers was afforded without the use of a boat; thus re-
ducing the risk of local contamination and also aiding in set-up and dlsman-
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37
tling. Unlike the 2-m height boom which was pulled up and then rotated for
set-up and dismantling, the 11-m height boom only had to be pulled Into the
tower mast for set-up and then pushed out for sampling.
Aerosol sampling was conducted for three separate 2-week periods.
Outing I was from June 25 to July 09, 198^, Outing II was from August 13 to
August 2?, 198**, and Outing III was from October 23 to November 3, 19&%.
To clarify any ambiguity which may occur later, each streaker can sample
for up to 168 hours or one week. Thus each outing was subdivided into
1-week runs, appropriately labelled run 1, run 2, run 3, run k, run 5, run 6,
so that runs 1 and 2 pertain to Outing I, etc. During each of the three
outings, Canadian support was appreciated during initial set-up and final
breakdown. This was supplemented via CCIW boat support, since the tower Is
two miles off shore and five miles distant from the CCIW (see Figure 2).
Besides providing transportation and manpower for the research effort, the
Canadians were also in charge of set-up and monitoring of their own meteo-
rological station located directly on the tower. This Included solar radi-
ation, wind direction, wind speed, and relative humidity on the 11-m boom
and wind speed on the 2-m boom, not the mention water and air temperature.
While this research group monitored the aerosol sampling equipment, the
Canadians provided a technical operations assistant to monitor the meteo-
rological station. All meteorological data was recorded on magnetic tape.
Aerosol Sampling
Aerosol Sampling was accomplished through the use of PIXE streakers. The
streaker is a continuous time sequence filter sampler which operates for a
period of one week. The filter Is continuously advanced (1 mm per hour) by
-------
38
an internal timing motor which is accurate to ± 15 minutes for the total
duration of the run (168 hrs.). PIXE samplers are designed to measure
properties of aerosol particulates, more specifically, elemental compo-
sition, particle size distribution and their variation in time. The
streakers utilized three types of filter media, the first of which is termed
the "plug" filter. It is about the size of a U.S. quarter and used vaseline-
coated mylar filter media to prefilter 10 /m diameter particles (and
larger). In essence, the plug filter sets an upper size limit to the
aerosol which is entering the streaker. As air enters the streaker through
an 2 mm circular hole, 10 /tfrn and larger aerosol particulates impact on
the plug filter. This air inlet is centered with respect to the streakers
and the plug filter is located directly behind this inlet. The outlet for
this stream of air is located on the same plane as the plug filter but
slightly off center. This arrangement allows the smaller particles to make
a 90 turn and continue onto the next stage. Bearing in mind that the larger
particles are unable to make this turn, they are then impacted on the plug
filter. The next filter is a mylar impactor filter (also vaseline-coated)
and referred to as the coarse particle filter which collects 10 ^m to
2x/m diameter particles. At this filter stage, the aerosol inlet operates
in the same manner as the inlet for the plug filter. Basically, as the
stream of aerosol passes through the inlet orifice, the velocity of the
aerosol is increased. This acceleration in velocity induces the larger
particles to be impacted on the coarse particle filter, since they cannot
make the 90° turn to the next filter aown. Of course, the smaller particles
can make this sharp deviation and are then collected on the next and final
-------
39
filter stage. The last filter uses Q.J/im P°re slze Nuclepore material
which collects essentially all paxtlcles < 2 #. m in diameter. Unlike the
two previous filters where the aerosol is impacted, the Nuclepore filter or
fine particle filter allows air to pass through it. It should be noted that
2/^fm
size. On the other hand, if an impaction filter was not used, then the
particulate matter would be deposited on the fine particle filter. This
would then interfere with the analysis of the sample. During runs 1 and 2,
no Impaction filter was used. Runs 3 and b were then run with one "dupli-
cate" streaker utilizing the Impaction filter and the other not using it
at both heights. Runs 5 and 6 were all run with the Impaction filter. All
runs utilized 0.3/#« Nuclepore filter media as the fine particle filter ex-
cept during run 5. In this run, Zefluor filter media was used instead of
-------
Nuclepore filter for the purpose of Increasing flow rate. This
Increase In the flow rate was observed during laboratory testing of the
Zefluor media. Having proven Itself In the laboratory, Zefluor was used
as the fine particle filter on streakers A and C f streakers B and D con-
tinued using 0.3>fm Nuclepore. Remembering that streakers A and B re-
present the north gradient and streakers D and C the south gradient, fil-
ter media Is used so that the north gradient used Zefluor and the south
gradient continued to use 0.3/*m Nuclepore. Although the flow variability
for the Zefluor media streakers was relatively small In comparison to the
Nuclepore media streakers, collected sample appeared to be in less magni-
tude than on the Nuclepore. This could have been caused by the fact that
Zefluor traps particulate matter within the body of the filter, whereas
Nuclepore filters operate primarily by surface capture. More importantly,
the Zefluor media was torn from its frame on streakers A rendering the
filter useless. Therefore, the use of Zefluor filter media was abandoned
and O^^m Nuclepore material was used as the standard filter media for
further streaker runs.
FLOW VARIABILITY
One of the major concerns in sampling aerosol partlculates is the amount
of aerosol passing through the filter (e
-------
changes in meteorological conditions, leaks in the vacuum lines, etc.).
Hence, the flow rates are periodically checked and averages calculated
along with flow variability. Flow variability numbers are presented here
in the form of 90$ confidence intervals. These confidence intervals indi-
cate the amount of flow variability and one should be concerned when these
values exceed ± 1.00$. Values over + 1.00$ could be considered high flow
variability and values above ± 2.00$ could be classified as unacceptably
high flow variability. Ideally, flow variability (stated as a 90$ con-
fidence interval) should be less that + 1.00$. This ideal situation oc-
curred during various runs but never occurred for all four streakers at the
same time. Referring to Table 7, runs 1, b, and 6 contain some of the less
extreme flow variabilities which were experienced during the three outings.
Likewise, runs 2, 3i and 5 experienced some very extreme flow variabilities,
specifically run 2 which experienced flow variabilities greater than + 5.00$.
This was mainly due to an intense fog which lasted the entire week of sam-
pling. It should be noted that the use or nonuse of the mylar impaction
filter (which was used on some streakers and not on others) does not appear
to affect flow rates of any of the streakers. But it does appear that cer-
tain meteorological conditions do affect the flow rates (e.g., high humid-
ity which was experienced during run 2). This would include temperature
changes which could possibly change orifice and flow controller dimensions
and heights, not to mention sudden heavy loadings which could occur when the
wind direction and wind speed changed. In general, the sequence of least
variability to greatest variability is as follows: Runs 1, b, 6, 5t 3» 2,
respectively. It is interesting to note that during each of the three out-
ings, ene run could be classified as having low flow variability and the
-------
Streakers
A
11-m C
0
C
B
2-m C-
C
C.
X North)
.1. of ±
(South)
.1. of ±
(North)
I. of ±
(South)
I. of ±
1 /mi n
902
1 /mi n
902
1/min
902
1 /mi n
902
Outing I
Run 1
1
.052
±0.732
1
±0
1
±1
1
±1
.052
.372
.025
.202
.038
.532
Run 2
0.987
±5.212
0.903
±10.632
0.919
±1.622
0.934
±9.082
Outinc
Run 3
1
±8
1
±9
0
±1
.090
.882
.045
.302
.983
.562
0.992
±1
.032
II
Run 4
1.065
±2.172
1.080
±1.402
1.076
±0.632
1.058
±0.842
Outing
Run 5
1
.692(Z)
±0.322
1
±2
1
±2
1
±1
.045
.892
.009
.982 ,
.623(Z)
.652
III
Run 6
1.141
±1.782
1.110
±0.852
1.159
±2.562
1.115
±1.002
TABLE 7. Mean flows and 90# confidence interval (C.I.) flow variability
for Summer, 1984 sampling. Z indicates which runs used Zefluor.
All other runs used Q.^nm nuclepore.
-------
other run, high now variability. -Julte reasonably, these variations
are attributed to the meteorological conditions preSent at the time of
sampling.
METEOROLOGICAL DATA
Graphic Presentation
Meteorological data were obtained for six different meteorological param-
eters, they are as follows: 11-o wind speed and wind direction, relative
humidity (RH), 2-m wind speed, and air and water temperature. Every ten
minutes each parameter would be recorded on magnetic tape for the entire
duration of each outing. Hourly means and standard deviations were calcu-
lated for 11-m and 2-m wind speed, wind direction; averages for air and
water temperature were also calculated. Along with the raw data, a graph-
ical presentation of the meteorological data Is .also included. Unfortunate-
ly, a graphical presentation was not done for Outing I, hence only Outing II
and Outing III are presented (see Figure 4a,b). These graphs generally
summarize the meteorological conditions which were present during Outings
II and III. The graphs display each of the six meteorological parameters
previously mentioned with respect to time. They are listed as 11-m wind
speed, 11-m wind direction, air temperature, relative humidity, water temper-
ature, and 2-m wind speed, respectively on the vertical axis and the day of
the week on the horizontal axis.
Upon looking at 11-m wind speed as compared to 2-m wind speed on Fig-
ure 3a, one notes that at the 11-m height winds are stronger than at the
2-m height. This would make sense because of the effects the frlctional
-------
WflVES TOWER RUG 13-28/84 .. .REC NO.
213.. .2130 DflTfl POINTS.
^^^^^
1 21 22
13 14 IS 16
Out,,, .1, -«»r.,.,1e.l
start of the next Run.
16 19 20
vs.
23 24 2S 26 21 Zl
-row „«««., and of . .. «d tk.
-------
WAVES" TOWER. .-SEO C.-.TRflNS NOV 20/84 ,.
2308 OflTfl POINTS...GOOD DRTfl
. Outing III; meteorological parameters vs. time, arrow Indicates end of a Run and the start
of the next Run.
-------
46
layer has close to the surface. Therefore, the two graphs are similar and
differ only in magnitude. Similarly, relative humidity and air temperature
(areas 3 and fc) appear as near mirror-images and are inversely related.
Water temperature (area 5) Is straight forward and relatively constant.
But wind direction (area 2) gives the impression that the winds shifted
violently. In general this is untrue, since the "spikeness" of the graph
only happens when the wind direction is hovering around the northerly direc-
tion. A 2° shift in wind direction (e.g., 359° to 1°) would cause such a
spike. To compensate for this problem the scale was expanded by
-------
periods of time which axe dealt with, all other periods are out-of-sector
and not considered.
In-sector periods prevailed at least 50$ of the time in all runs except
two; run 2 and run **• (6$ and 30# respectively). This indicates that a good
lake fetch is obtainable during any summer or fall period provided that
some meteorological conditions are met (e.g., no rain or fog).
There are also some other criteria which must be met, using only in-
sector periods as the main data base.
a) When the standard deviation (ff) of wind direction
during each hour varies by more than 20 , that
hour is questionable. If the standard deviation of
wind direction varies by more than 30 , that hour is
not considered for further analysis.
This criterion helps assure that a well-developed steady-state surface layer
for gradient measurement does, indeed, prevail.
b) An in-sector area was pre-determined by the 1 to
100 rule (as previously explained), this in turn
establishes the in-sector area and also an out-of-
sector area (again, in-sector means that aerosol
particulates were well mixed over the lake sur-
face and a sufficient lake fetch is obtained). But
there could be periods of time when the wind direc-
tion is out-of-sector and then falls back into
sector (e.g., 339° falls bacri to 3^1°)• The range
in which this variation was considered allowable is
given by:
-------
WD, - 6MD| > 335° or wv GMD < 165°
where WDflis the average wind direction for
that specific hour and £u_ is the standard
"un
deviation of that average.
Therefore, wind direction must be greater than 335 and less than 165 to
be classified as in-sector. This assures that all possible in-sector areas
are analyzed.
c) During each hour, winds should not vary by more
than 20°. This criterion assures that the vari-
ability from hour to hour in wind direction does
not significantly deviate from the previous hour.
This is represented by the equation:
A(WD2 -WD1)>^WD
where WD^ is the average wind direction for the
present hour
WD2 is the average wind direction for the
previous hour ( the hour in question)
and Gyrj and 6"uD are their respective standard
deviations .
If the change in wind direction is greater than the sura of their stan-
dard deviations the previous hour is flagged. This assures that a constant,
steady -state surface layer exists from hour to hour.
d) During periods of wind fluctuations the mixing
of the aerosol particulates over the lake surface
is distorted. Hourly wind speed variability is then
-------
checked by using 90£ confidence limits where:
t
-------
Outing I Outing II Outing III
Run 1 Run 2 Run 3 Run 4 Run S Run 6
Total Length of Run
vs. In-Sector Times
Total Length of Run
vs. Fulfilled Criteria
In-Sector Periods with
Fulfilled Criteria
Neutral
Unstable
Stable
SIX 61
21% 31
422 502
1*
7J
922
702
382
532
22
682
302
302 51*
162 252
522 502
32
792
182
682
352
512
Table $. The percentage of time when in-sector periods are established
as well as fulfilled criteria. Neutral, unstable and stable
' conditions are also shown (based on In-sector periods only).
-------
51
expected (?& in Outing I, 66$ in Outing II ). This suggests that future
sampling of aerosol gradients should be conducted before raid -July, if not
sooner.
The variation of wind speed with height may be expressed with the
common power law. The power law (exponent « ) is expressed by:
where: u^ = average 2-m wind speed
U2 = average 11 -m wind speed
h2 = 11 meter height
h^ = 2 meter height
In general, as the exponent approaches 0, unstable conditions prevail.
Likewise, as a -* 1 , stable conditions prevail. For Outing I it was con-
cluded that when wind speeds were < 2 m/s , those data would not be used
since. (X values are unusually small (referring to Table 9). This stipulation
did not significantly alter the data base for Outing I, mainly because wind
speeds which were < 2 m/s had been flagged based on previous criteria.
For Outing II alpha values were slightly smaller overall as compared
with Outing I. This is due to slippage which occurs near the tower. To
minimize slippage the length of the 2-m boom should be extended and the
streakers should sample closer to the lake surface. Unfortunately, low
winds and unstable conditions induced this slippage problem to be enhanced
during Outing III. This in turn produced negative alpha values which means
that winds were greater at the 2-m height boom than at the 11-m height.
This is clearly unacceptable for gradient measurement and data obtained for
wind speeds less than 5 m/s is not valid. This point only reinforces the
necessity for outings early in the year.
-------
52
Range of
Upper G
rasec-1
<1
l-<2
l-<3
3-<4
'
4-<5
5-<6
6-<7
7-<8
8-<9
9-<10
10-<11
Ot VALUES
Outing I
(n)
(15)
40.05 (26)
40.10 (22)
40.16 (12)
40.19 (17)
40.14 (1)
40.20 (4)
—
—
—
""
Outing II
(n)
(2)
40.077 (15)
40.075 (32)
40.059 (34)
40.047 (20)
40.029 (18)
40.023 (18)
40.031 (4)
40.077 (3)
40.058 (3)
— —
Outing III
(n)
01)
-0.072 (30)
-0.016 (29)
-0.009 (19)
-0.047 (14)
40.054 (13)
40.053 (7)
40.071 (4)
40.065 (3)
40.116 (4)
40.122 (1)
Table 9 . Variation of a values for each of the three outings.
-------
53
As previously mentioned, in-sector periods must fulfill all criteria.
With respect to total length of run, in-sector periods occupied over 50#
of the time in all runs except two; run 2 (6#) and run b (30$) (see Table 3).
Also, of the established in-sector periods, all criteria were fulfilled
&yy& of the time in all runs except run 1 (42$). With respect to total
running time of each run, fulfilled criteria were established over 20$ of
the time on all runs except two, run 2 (31$) and run <* (16$). This indicates
that depending on the meteorological conditions present, fulfilled criteria
can occur frequently (as high as 30$) with respect to length of run. More
importantly, if winds were in-sector, there is an &50$ chance that all
criteria would be fulfilled. This produces high optimism for the gradient
effort, mainly because it is clear that lake fetch occurs quite frequently
and fulfilled criteria can be established. Hence, the correct meteorological
conditions are present for aerosol gradient sampling a substantial percentage
of the time.
Meteorological Conditions: General Observations
The observed meteorological conditions present during the three outings are
as follows:
Outing I/run 1 (June 25 to July 03). This one-week period may be
classified as the ideal summer week with only seven hours of rain and
moderate to light cloud cover. Winds were strong to moderate and the per-
centage of white capping was small to none. Air temperatures ranged from
16 to 21.1*°C.
Outing I/run 2 (July 03 to July 09). This one-week period may be
referred to as a typical summer week with hot, humid, hazy, and foggy con-
-------
dltions. Cloud cover was 100&, air temperature ranged from 9.3 to 22.6°C.
The lake was very calm with no white capping.
Outing II/run 3 (August 13 to August 20). This 1-week period also
experienced high humidity and haziness but warmer temperatures than those
during Outing I. Cloud cover was also similar to Outing I with no rain.
It should be noted that the lake level was beginning to drop as compared
with Outing I and the lake was experiencing large swells and no white cap-
ping. Air temperatures ranged from 14.3 to 28.9 C.
Outing II/run 4 (August 20 to August 2?). In general, run 4 was very
similar to run 3 on all points except for cloud cover. Run 4 experienced
no cloud cover with a heavy front coming in from the North on the last sam-
pling day. As in run 3i run 4 experienced large swells but also a large
percentage of white capping was occurring. Air temperatures were 15.0 to
22.9°C.
Outing Ill/run 5 (October 23 to October 30). The lake level dropped
again since Outing II although the lake condition was calmer. Cloud cover
was heavy with a light fog and very cool temperatures. Heavy thunderstorms
occurred one day. Air temperatures were 7.8 to 15.2°C.
Outing in/run 6 (October 30 to November 3). During this 1-week period
the lake condition changed from calm during the beginning of the week to very
large swells during the latter half of the week. There was no cloud cover
with strong winds and very cool temperatures, a classic fall week. Air
temperatures were 1.8 to 14.2°C.
In general, run 1 and run 4 proved to be two of the better runs with
respect to flow variability and meteorological conditions. Run 6 had flow
variabilities similar to run 4, but it was plagued with unstable conditions
-------
55
and negative alpha values. Hence, the probability that a gradient exists
for some trace elements will be reduced. Presently, this is only an assump-
tion since XRF and PIXE analysis hasn't been completed. Run 2 is definitely
a run which will not be analyzed because of the intense fog which occurred
during the entire run. The high variability in flows is clearly related to
this meteorological condition. Unfortunately, run 3 had a good percentage
of in-sector periods but very high flow variability at the 11-m height.
Likewise, run 5 had a good percentage of in-sector periods, but Zefluor
filter media was used on two of the streakers. This, along with bad alpha
values, made Outing III one of the worst periods for sampling. During run 6
there was a 20-hr period in which all criteria was fulfined and winds were
about 5 n/s.
-------
56
Sample Duration of y^p
Filter 9
1269
1279
1289
1299
1309
1319
1329
1339
1349
1359
Taken
During:
Run 1
Run 1
Run 3
Run 2
Run 4
Run 4
Run 4
Run 5
Filter
Run 6
~
ili-Vol Run
(Minutes)
2579
1540
2610
4352
1437
4046
4313
2755
not used
1303
% Lake
Fetch
8
45
24
0
45
0
36
52
—
95
AVG.TSP
Rain
16
0
0
10
0
0
71
0
—
0
49.1
• •* •
(wg nf )
53.2
40.5
68.6
6.6
37.8
41.9
49.6
56.3
--
"" 45.2
± 10.1 wg m"
TABLE 10. TSP (total suspended particulate) in g m~^ is shown
for nine high-volume samples which were collected
during various runs. Also shown is the duration of
each high-volume run, percentage of lake fetch, and
% of rain.
-------
57
Title ±0 Protection of Environment. "National Primary and Secondary Ambient
Air Quality Standards." Federal Register, 36 (8^), 8186-8201 (30 April
1971 ) •
Hicks, B.B., M.L. Wesely, and J.L. Durham, 1980: Critique of methods to
measure dry deposition. Workshop Summary. USEPA Report EPA-600/9-
80-050, 69 pp. , availible from MTIS as PB81-126WJ.
Hicks, B.B., 1982: Comments on "Interpretation of flux-profile observations
at ITCE (1976)", by R.J. Prancey and J.R. Garratt, J. Appl. Meteorol?,
in press. '
Intersociety Committee (1972) Tentative method of analysis for suspended
particulate matter in the atmosphere: (high-volume method). Method
501 in methods of Air Sampling and Analysis, pp. 365-372. Amer. Pub.
Health Assn., Washington.
Lodge, J. P., Waggoner, A.P.. ELodt, D.T. and Grains, C.N. (l98l) Non-health
effects of airborne particulate matter. Atmospheric Environment ,15_,
M'— * ~"
National Research Council. Subcommittee on Airborne Particles. Airborne
Particles. University Park Press, Baltimore, 19?8. -
NOAA, 1975. Summary of Synoptic Meteorological Observations for Great
Lakes Areas. , volume 1, Lake Ontario and Lake Erie. Nat'l Climatic
Center, Asherville, H. C.
Sievering, H. . 1975: Dry Deposition Loading of Lake Michigan by Airborne
Particulate Matter, Water Air and Soil Pollution. 5_, 309-318.
Sievering, H. , 1978, Eniv. Sci. and Tech., 12, 1^35-1^37.
Sievering, H. , (1981 ). Profile measurements of particle dry deposition
velocity at an Air-land interface. Atmospheric Environment. 16, 301-
~~~^~~~^^^^~
Sievering, H. , 198*4. : An Experimental Study of Lake Loading by Aerosol
" the ^ *** Basin' USEPA Report
Slinn,U.G.N.,Hasse, L., Hicks. B.B.. Hogan, A.W., Lal.D., liss.P.S.. Munnich,
K.D., Sehmel. G.A. and Vittori, 0. (1978). Some aspects of the tr^Sfer
of atmospheric trace constituents past the air-sea interface. Atmospheric
Environment. 12 . 2055-2087. - p
-------
58
REFERENCES (cont.)
Slinn, S.A. and Slinn, W.G.N. (i960). Predictions for particle deposition
on natural waters. Atmospheric Environment. Ik, 1013-1016.
Stern, A.C.. "Fundamentals of Air Pollution," Academic Press, five-volume
series, New York, New York, 1976.
Warner, P.O.(1976) Analysis of Air Pollutants. Wiley & Sons, New York.
Wesely, M.L., and Hicks, B.B. (1976) An eddy-correlation measurement of
particulate deposition from the atmosphere. Atmospheric Environment,
ii, 561-563.
Willeke, K., and K.T. Whitby. Atmospheric aerosols: size distribution inter-
pretation. J. Air Pollut. Control Assoc. 25: 529-5>f 1975.
Williams,R.M. (1982). A hodel for the dry deposition of particles to natural
water surfaces. Atmospheric Environment,l6, 1933-1938.
Williamson, S.J. (1973). "Fundamentals of Air Pollution," Addison-Wesley
Publishing Company, Inc. Philippines.
-------
APPENDIX B
-------
X-Ray Fluorescence Analyses of Air Filters
from Lake Ontario Tower
Interim Report
submitted by
Thomas Tisue, Associate Professor
Ruth Felland, Chemist I
Department of Chemistry
Clemson University
Clemson, SC 29634-1905
(803)656-3065
September 11. 1986
0068r
-------
INTRODUCTION
We have begun to examine the set of filters collected by H.
Sievering and M. Watka during the summer of 1985. The '85 sampling
period entailed new sampling conditions including: a change in filter
medium from Muclepore to teflon; sample areas on the filters are discrete
spots rather than the continuous streaVcs as in the past; and an increase
in air flow rate. These changes in sample collection technique were
undertaken to achieve greater aerosol loadings, and to sample at
discrete time intervals, rather than continuously.
The filters presently in Clemson are from run 07 and are being used
to refine our analytical methodology. Based on preliminary examination
of these filters, we addressed several aspects of the analysis
procedure: instrument modification; sample holder modifications; and,
very briefly, sampling procedure verification. At this time, the
conclusions drawn from these observations should be regarded as tentative
but indicative, if these filters are representative of the entire set.
INSTRUMENT MODIFICATION
The filters at hand indicate no need for instrument modification.
As discussed below, automated filter placement in the X-ray sample
chamber does not seem to be practical. Therefore, plans to modify the
electrical circuitry controlling the sample changer will not be
implemented. The sole purpose of this change was to have been the
automation of filter positioning in the spectrometer.
-------
SAMPLK HOLUER H001K1CATION
The sample holder was built of Al, which is light and relatively
free of contaminants. A thin insert of high purity Sn or U was set In a
5 cm x 5 cm recess cut half way through the base of the sample holder. A
smaller, 3 cm x 3 cm, aperture was cut entirely through base, centered In
the 5 cm x 5 cm recess at the location where the X-ray beam strikes the
sample. A slot 3 mm wide x 10 mjn • long was machined into the insert,
allowing the spectrometer to view only a single sample spot at one time.
The streaker filters are mounted in plastic caps which allow them to
be positioned over this slot without touching the holder platform, while
being protected from objects above. A system of two pulleys adapts the
motion of the sample changer rotation mechanism to that necessary for the
positioning of the filters. The first 'pulley cable (1/8 in width
nitrile) is located between the sample changer rotation shaft and the
upper portion of a compound pulley located on the holder shaft. A cable
on the lower portion of the compound pulley turns the plastic cap
containing the streaker filter. The ratio of the pulleys is such as to
move the filter about 0.8 ran per turn of the sample changer shaft.
The holder is positioned in the sample chamber to obtain optimum
response by means of a set of screws and brass washers. The best
position was determined by observing the effect of x-y-z motions on the
intensity of the observed spectra. At the optimum response rate
observed, the slot in the mask in the base plate of the sample holder was
located at. the Intersection of the "lines of sight" for the irradiating
beam and the detector collimator aperture.
-------
A brief description of the 1985 filters we examined will be
presented before modifications to the sample holder are addressed. The 4
filters were exposed concurrently. Each filter was positioned over its
respective air sampler orifice to have air pumped through it, then
repositioned to expose a new surface to the air stream. On each 1984
Nucleopore filter, where the collection surface was continuously rotated
to obtain a streak of aerosol matter., the edges of the sample areas were
straight, well-defined, and equidistant from the center of the filter.
These characteristics were not found in the 1985 teflon filters. The
sample areas had rounded, fuzzy edges, and varied in distance from the
filter's center. The spacing between neighboring sample areas also
changed from approximately 2 mm to four times that distance on a single
filter.
The roundness of the sample area edges may be the result of suction
through the filter causing stretching of the material. Both the degree
to which the sample areas do not form perfect arcs around the filter
circumference, and the unequal spacing between them, appear to be due to
the filter being dragged (or otherwise stressed). One filter even
appears to have become wrinkled as it changed positions in the air
sampler: 4 neighboring sample areas have "clean" swaths running through
them.
Two points were addressed in considering sample holder modifications
based on these observations. The first concerned the dimensions of the
apertures in the Sn and W masks; the second dealt with the pulley system
currently used to position each filter over the slot in the mask.
-------
Uocau-jv of the utirvoti placement of sample areds on tho individual
filtois with respect to the filter center, the apertures m«iy need to be
elongated Three of the filters had all of their sample areas correctly
placed for irradiation (though individu.il spot positions varied) The
fourth filter (7-BN-l) did not. Approximately half of its spots were
positioned in such a manner as to be partially shielded from the
irradiating beam when they should have been fully exposed to it If this
fourth filter is indicative of what can be expected from air sampler B,
the masks will have to be modified. Until the other filters have been
examined, however, no changes will be made in the masks.
The irregularities in spacing between neighboring sample areas
preclude any thou&ht of automating filter positioning. It appeals that
each spot will have to be positioned manually over the aperture This
will result in a more time-consuming protocol than was anticipated
VERIFICATION OF SAMPLING PROCEDURE
The issue of sampling procedure verification has not yet been fully
addressed Our X-ray fluorescence spectrometer (XRH) has been down
recently, thus delaying efforts on the project this summer. When the
entire collection of 1985 filters has been examined visually, and the
modifications, if any, to our sample holder have been completed, we shall
proceed with sampling procedure verification.
SUMMAKY
We hdvr had th«. opportunity to oxjMirn: a lest eel of the filler:;
col iL-cli'd 'Juririfc Die '.JiiTmer of 1985 IJ|I.I«T the1 new <:anipliii£ f-uurti I uurj
] I OT impiuvir*. XHK aii.ilyiJi-; «c h.jyc nol 11 i*d what .jj>po.jrc lo
-------
be a problem of filleis dragging in the an- sampler, resulting in
somewhat irregular placement of the samplr arcds on tho filters
themselves. We are presently delaying any equipment modification until
we have seen more of the new filters Automation of filter positioning
in the sample chamber does not appear to be feasible
-------
•»
J
•-Q
X ray Sample Chamber sample holder. A: Cidc View Q: Top View
(1) High purity Sn or W mask.
(?) ramp ling aperture.
(3) S.jmplo rotation ull(^.
------- |