WIND TUNNEL TEST REPORT NO. 29

TEST OF THE RUPPRECHT AND PATASHNICK TEOM PM10 SAMPLER INLET,
                 THE SATURATION MONITOR INLET,
     AND THE MARPLE PERSONAL INHALABLE PARTICLE SAMPLER
                         AT 2 AND 24 KM/H
                           Prepared by:
                          D. W. VanOsdell

                      Research Triangle Institute
                          P. 0. Box12194
                  Research Triangle Park, NC  27709
                            May 1991
                     EPA Contract No. 68-02-4550
                    RTI Project No.  432U-4699-101
                           Project Officer
                         Kenneth A. Rehme

        Atmospheric Research and Exposure Assessment Laboratory
                  U.S. Environmental Protection Agency
                  Research Triangle Park, NC  27711

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                                 ABSTRACT

      Wind tunnel  tests of the Rupprecht and Patashnick (R&P) 10-^im inlet for the
TEOM Series 1400 PM-10 monitor have been conducted at 2 and 24 km/h. The purpose
of the test was to compare the R&P inlet to the Sierra-Andersen (SA) 246b Dichotomous
Sampler  inlet.   Simultaneously, the Saturation Monitor (SM) and  Marple Personal
Inhalable Particle Samplers (PIP) were tested.  The test program was conducted in the
EPA Aerosol Test Facility. The procedures used were those specified in 40 CFR Part 53
except that a reduced number of test particle sizes were used. All tests utilized liquid
challenge particles,  and tests were conducted at either 2 or 24 km/h.
      Based on these limited tests, the R&P inlet appears to be functionally identical to
the Andersen 246b Dichotomous Sampler Inlet. The cut-point was found to be about 9.8
\im at 2 km/h and 9.6 urn at 24 km/h (compared to 9.8 and 10.0 urn, respectively, for the
SA 246b.)
      Neither of the other samplers performed well under windy conditions. The SM was
found to have cut-points at 2 and  24 km/h of about 14.4 urn and 8.6 urn, respectively.
The Marple PIP, designed for indoor use, was found to have cut-points at 2 and 24 km/h.
of about 8.5 [AID and 6.5 nm, respectively.

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  TEST OF THE RUPPRECHT AND PATASHNICK TEOM PM10 SAMPLER INLET,
                    THE SATURATION MONITOR INLET,
       AND THE MARPLE PERSONAL INHALABLE PARTICLE SAMPLER
                            AT 2 AND 24 KM/H
                               SECTION 1
                             INTRODUCTION

      This report documents a test of the SA 246B 10-nm inlet for the dichotomous
sampler. The SA 246B has been commercially available for a number of years, and is
widely used. It was originally tested by McFarland and Ortiz (1984) of Texas A&M
University  (TAMU)  prior  to  the  promulgation  of the  PM10 sampler performance
specifications and test procedures in 40 CFR Part 53. McFarland and Ortiz tested the SA
246B with solid and liquid aerosols at wind speeds of 2, 8, and 24 km/h. They used liquid
test particles that were approximately 5.4, 7.6, 9.8, 11.8 and 14.0 nm in aerodynamic
diameter. Glass beads having 20 ^m aerodynamic diameter were used as solid aerosol.
The present work continued the test by adding 3, 5,10,15, and 25 jxm liquid aerosol test
results to the data set, along with  25 urn  solid ammonium fluorescein aerosols at 8 and
24 km/h.
      The purpose of the present test was to evaluate the SA 246B in the EPA Aerosol
Test Facility (ATF), following the procedures set forth in 40 CFR Part 53, and compare
the results  to the earlier TAMU data.   Should the agreement be satisfactory, the
combined data set (TAMU and ATF) was to be used to evaluate the performance of the
SA 246B.

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                                 SECTION 2

                               CONCLUSIONS
      Based on this test of various size-selective inlets, the following conclusions are

drawn:

      1.     The wind tunnel effectiveness performance of the R&P inlet is substantially
            the  same as that of the SA 246b inlet at 2 and  24 km/h, and the inlet
            appears to meet the requirements of 40 CFR for a PM-10 inlet. Because
            2 and 24 are the extremes of the measurement range, it can be reasonable
            inferred that the R&P inlet would also perform satisfactorily at 8 km/h.

      2.     As a PM-10 inlet, the SM was found to have an unsatisfactorily high cut-
            point at 2 km/h and an unsatisfactorily low cut-point at 24 km/h.  While at
            some intermediate wind speed the SM may have a 10-^im cut-point, the
            magnitude of the cut-point change makes this inlet unsuitable for use on an
            PM-10 sampler.

      3.     The Marple PIP was also found to be unsuitable for outdoor use as a PM-
            10 size-selective sampler.  The cut-point was too low in the  presence of
            even 2 km/h winds, and was even worse at 24 km/h.

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                                 SECTION 3
                        EXPERIMENTAL PROCEDURES
                                                       »

      The test procedures used in the EPA Aerosol Test Facility were the same as those
used and reported previously. Individual tests met the requirements of 40 CFR Part 53.
Because the test program was designed primarily to compare the R&P inlet to the SA
246b, only 2 wind speeds and about half the number of particle sizes called for in 40 CFR
Part 53 were tested during the present work. A brief overview of the test procedures is
given below, and details may be found in the report by VanOsdell, Chen, and Newsome
(1988).

3.1  Wind Tunnel Arrangement.
      Figure 1 gives an overview of the EPA Aerosol Test Facility and the wind tunnel.
Flow in the wind tunnel was counter-clockwise.  There are few flow obstructions,  and a
number of  access doors are provided to allow all sections of the wind tunnel  to be
cleaned. The test aerosol was generated on top of the wind tunnel where indicated, and
injected through a distributor into the 1.83 m square cross-section region below. The
sampler test area is also  indicated in Figure 1.   At  the test area the wind tunnel
cross-section is 1.52 m wide by 1.22 m high.  The blower downstream of the sampler test
area is capable of driving the wind tunnel at speeds up to 50 km/h (1550 rrvVmin).
      Some wind tunnel arrangement details not shown on Figure 1 were required to
achieve acceptable particle and velocity uniformity at the 3 wind speeds. A plywood baffle
was placed about 1 m upstream of the 1.83 m square cross-section particle injection zone
to promote mixing. The baffle was 1.22 m square and mounted in the center of the wind
tunnel transverse to the air flow.  A counter-flow fan,  0.4 m in diameter and centered in
the cross-section, was operated about 1 m downstream from the injection zone to provide
additional mixing.
      At 24 km/h, the large blower in Figure  1  powered the wind tunnel,  and  the
filter/chiller was not turned  on except to clean the wind tunnel  air for 30 min before
beginning each day's testing. The large blower could not be slowed enough to power the

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Fluorometer/
Microscope

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Figure 1.  Schematic Drawing of the EPA Aerosol Test Facility

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wind tunnel at 2 km/h.  To operate at 2 km/h, the damper indicated on Figure 1  was
closed and the filter/chiller fan used to power the wind tunnel. To prevent flow channeling
along the wall of the wind tunnel during the 2 km/h tests, a center-hole baffle was placed
2 m downstream of the sampler test area (and about 1  m upstream of the filter/chiller
inlet^ This baffle blocked the wind tunnel except for the 30-cm square hole in its center,
and provided a symmetric flow profile at 2 km/h.
       The velocity uniformity and turbulence intensity in the wind tunnel were measured
at each wind speed before beginning tests. The results are given in Table 1. The flow
parameters are within acceptable limits for PM10 testing.
  Table 1. Wind Tunnel Set-Up for 2 and 24 km/h
Mean
Wind
Speed
2 km/h

24 km/h

Baffle
Arrangement
1 .22 m2
centered
1 .22 m2
centered
Mixing
Fan
On

On

Velocity
Uniformity
±5%

±4%

Turbulence
Intensity
in Test Zone
3 - 4%

4 - 5%

Note: Velocity uniformity was calculated as the deviation from the mean within the test
      zone.  Velocity was measured with a hot-film probe.
3.2  Aerosol Generation.
      The test was conducted with  monodisperse test aerosols generated using a
vibrating orifice aerosol generator (VOAG). The aerosol material, oleic acid, was tagged
with uranine, a fluorescent dye, and the oleic acid and uranine were both dissolved in an
ethanol carrier.  The concentration of nonvolatiles (oleic acid and uranine) in the ethanol
varied as required to obtain the desired particle size after the ethanol evaporated. Typical

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VOAG operation utilized a 20 pirn orifice, 0.165 mL/min feed rate, and a frequency of
about 70  kHz.   Particle size  was calculated from  the VOAG  and particle solution
parameters, and verified microscopicaliy using  Nye-Bar treated glass  slides and  a
flattening  coefficient determined  by Olan-Figueroa et  al. (1982). The liquid particles
generated for the test had nominal diameters of 5, 9,  10, 12, and 25 urn. ^
      The test aerosol  was blown down into the wind tunnel  through a  dispersion
manifold, and dispersed  across the wind tunnel cross-section within the 10 m between
the injection site  and test  zone.  The uniformity of particle  dispersion  and particle
challegne concentration were evaluated during each test using an array of four isokinetic
samplers  placed within the test zone and operated simultaneously  with the samplers
being tested.  The results of a day's tests were rejected if the particle mass collected by
each  individual  isokinetic sampler that day was not within +/- 10 percent of the mean
particle mass from the 4 isokinetic samplers. The isokinetic samplers are described more
                    *T
fully below.
      At 2 km/h the background aerosol was always negligible compared to the mass
of aerosol captured by the samplers. At 8 and 24 km/h this was not always true. The test
aerosol was generated at a fixed rate from the VOAG,  and therefore the concentration
of test aerosol was inversely proportional to wind speed. In addition, higher wind speeds
have  been shown to entrain more background particles. Thus increases in wind speed
give  inherently higher  backgrounds while  the  available test aerosol  concentration
decreases. The aerosol background varies between  days and  at different times during
each  day  too  much to  allow simple  subtraction of  the background.   Rather,  the
background concentration was computed and used  to indicate when data sets were
suspect. At both 8 and 24 km/h, some 25 |4.m particle test runs were deleted as unreliable
because the aerosol  mass collected on the filters was too low  compared to  the
background.

3.3 Sampler Position and Operation
      The inlet of each sampler was positioned in the same  axial  plane of the wind
tunnel (the same distance from the particle injection point.) That is, the upstream edges
                                       8

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PIPl
                               DP2-
                               n
                           T3
\a
2..
     of
             I

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Figure 2.  Arrangement of Samplers in Wind Tunnel

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of the R&P inlet, the SMs, and the PIPs were all in the same plane as the upstream ends
of the isokinetic sampler nozzles. Figure 2 shows the arrangement of the samplers in the
wind tunnel in a view along the direction of wind flow.
                                         /
      The isokinetic samplers were 47 mm filter holders fitted with sharp-edged conical
nozzles, and were operated isokinetically. The suction pipe at the back of each sampler
was clamped to a support frame to hold the sampler in position wiht the nozzle inlet about
25 cm upstream of the support frame.  At 2 km/h, the nozzles' inlets were 2.94 cm in
diameter and the samplers were operated at 22.6 L/min.  At 24 km/h 1.22 cm diameter
nozzles operated at 46.8  L/min were used. The flow rate through each sampler was
controlled with a manual valve that was preset to the required flow rate.  During a test,
the total flow through each sampler was measured with a dry gas meter.  The house
vacuum manifold was used to draw the sample through the isokinetic samplers.
   The R&P inlet was attached to a 3.2 cm OD aluminum riser tube and supported in the
wind tunnel as shown in Figure 2.  A 47 mm filter holder was mounted at the bottom of
              r
the tube, and a Gelman AE glass fiber filter collected the aerosol. The flow rate through
the R&P inlet was controlled manually with a valve that was adjusted to the required 16.7
L/min prior to the  test.  During a test, the total flow measured using a dry gas meter.
Suction was provided by the house vacuum manifold.
      Saturation monitors 1 and 2 were positioned as shown in Figure 2. They were
held in place using 3-fingered laboratory clamps that were themselves clamped  to the
support frame.  Flow measurement was provided  by calibrated mass flow meters and
controlled manually using a valve. Valve adjustments were made as required to maintain
the flowrate at  5 L/min.  A PIPS pump system with a bleed valve was used as a vacuum
source for the  saturation monitors.
      PIPS 1  and 2 were positioned as shown  in Figure 2 and held in place using 3-
fingered laboratory clamps attached to the support frame.  The position of the inlet holes
in the PIPs caps was not controlled. Flow through the PIPs was maintained at 10 L/min
using the PIPs control  system.

3.4  Inlet Tests
                                      10

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      Three sequential tests of the inlets were conducted on the same day using the
same test aerosol for most particle sizes.  The R&P inlet, two SMs, two PIPs, and 4
isokinetic filter samplers were operated simultaneously during  each of the three tests.
The  duration  of each test was set to ensure that the aerosol mass captured on the
sampler filters was sufficient to provide a reliable measurement.  Most runs lasted 1 hour,
but the 5 and 25 urn particle runs at 24 km/h were 3 hours long.
      The sampling effectiveness for each sampler was computed as the ratio of the
mass concentration measured by that sampler to the mass concentration measured by
the closest isokinetic samplers.  Table 2 identifies the isokinetic samplers used as the
challenge concentration measurement for each sampler.
  Table 2. Isokinetic Samplers Averaged for Challenge Concentration
Sampler
R & P 10 urn Inlet
Saturation Monitor 1
Saturation Monitor 2
PIPS1
PIPS 2
Isokinetic Samplers
Averaged to Get
Challenge Concentration
Average of all 5
2 and 4
3 and 5
1 and 4
2 and 5
3.5 Analysis of Mass Collected on Filter Samples.
      Following the EPA Aerosol Test Facility standard procedures, the uranine was
extracted from the filters into 0.1 N NaOH solutions (liquid aerosol) or 0.1 N NH4OH (solid
aerosol) by soaking overnight. The mass of test aerosol collected on the filters was
determined fluorometrically using standard ATF procedures. The nozzles of the isokinetic
samplers were washed and the uranine found in the wash was added to the uranine
                                      11

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collected on the filter to obtain the total challenge aerosol mass. The inlet sections of the
R&P inlet, SMs, and PIPs were not washed to collect inlet losses.

3.6 Data Analysis
      The raw effectiveness data from the samplers was analyzed using the PM10 data
analysis normally used at the ATF. The three effectiveness values for each test were
averaged to obtain a value at each test particle size.  These effectiveness values were
then input to the PM10 data analysis computer program (VanOsdell, Chen, and Newsome,
1988).  For each sampler and wind  speed,  the effectiveness data were  adjusted to
account for the presence of multiplets  of the primary challenge particle. A robust-spline
curve (in log-normal space) was then fit to the multiplet-corrected data.  The PM10 data
analysis procedure outlined in 40 CFR Part 53 requires that the effectiveness-particle size
data be fit with a smooth curve and that the ends of the curve be smoothly extrapolated
to 100 percent at 1 urn and 0  percent at  50  urn, and this requirement has been
implemented  mathematically in the data analysis program.  The program usually fits
effectiveness data well, especially in the region of the cut-point,  and  it provides an
impartial estimate of an inlet's  performance parameters.  (Because the  curve fit is
generated in log-normal space, values above  100 percent are suppressed.) The robust
spline curve-fit process does not impose  any  preconceived functional form on the data.
The Dgo, expected mass collection for the  PM10 ambient particle size distribution (40 CFR
Subpart D, Table D-3), and expected mass ratio were all computed based on the robust-
spline curve.
                                      12

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                                 SECTION 4

                         RESULTS AND DISCUSSION

4.1  Effectiveness Results
      A summary of the test program results is presented in Table 3. Most effectiveness
values in Table 3 are the mean of three individual effectiveness determinations made
during a given test. The Expected Mass and Mass Ratio to Ideal Sampler are values

  Table 3.  Summary of Multiplet Corrected R&P Test Results


2 km/h Da,, urn
2 km/h Expected Mass,
2 km/h Mass Ratio to Ideal
PM10 Sampler
24 km/h Da,, jim
24 km/h Expected Mass,
ng/m3
24 km/h Mass Ratio to Ideal
PM10 Sampler
R&P
Dichot
9.82
148.0
1.028
9.58
147.8

1.027

SM 1

14.03
184.3
1.281
8.36
140.2

0.974

SM2

14.44
184.2
1.280
8.89
150.0

1.043

PIP 1

8.45
131.6
0.914
6.57
114.6

0.796

PIP 2

8.74
133.6
0.929
6.32
111.5

0.775

    Note: All values computed using standard PM10 Data Reduction Program.  All
    effectiveness values were corrected for multiplets.
                                     13

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used to compare PM,0 samplers. The ideal sampler effectiveness performance curve and
the ambient particle mass distribution are given in 40 CFR Part 53. The expected mass
is obtained by multiplying the mass in each size fraction of the size distribution by the
sampler's effectiveness and adding over the size distribution.  The ratio is  self-
explanatory.  The complete data sets for each wind speed are given in the Appendix.
Also given in the Appendix are the test particle size parameters and the particle uniformity
data for each test.
      Figure 3 shows the data and curve-fits for the R&P inlet at 2 and 24 km/h.   The
data are seen to be well behaved, and the D^, expected mass, and mass ratio values
given in Table 3 provide good representations of the R&P sampler's behavior. Within the
limits of this  data  set,  the R&P 10-jAm  Inlet appears to easily meet the wind tunnel
sampling requirements of 40  CFR Part 53. While the 8 km/h data were not gathered, the
2 and 24 km/h data span the limits of interest and at the most likely velocities for a
sampler to fail the test procedure.
      Figures 4 and  5 show  the data and curves for the saturation monitors at 2 and 24
km/h.   The saturation monitors oversampled  S-^im  particles  at both wind  speeds.
Because values above  100 percent do not exist in log-normal space, these points were
treated  as 99.99 percent in the data analysis.
      The significance of the measured oversampling is unclear. The saturation monitors
have  not been tested  in  a quiesent  atmosphere to determine the cut-point of the
sampler's impactor.  A wind  tunnel test necessarily reflects both the sampling and the
size-selective characteristics of an inlet.  While theoretically possible, the physical shape
of the saturation monitors does not appear likely to encourage the flow patterns that could
cause oversampling. However, the 5 L/min flow rate of the saturation monitors, which is
lower than the other sampling rates, caused the mass collected on the filter to be  low.
Consequently, measurement errors may have been significant.  Contamination may have
occurred and the  variability  in the fluorometry measurement  would be much more
important than it is normally.  Fortunately, the potential errors become less significant as
the test particle size increases, and  the  curves shown  in Figures 4 and 5 should
adequately represent the performance of the saturation monitors for particles larger than
                                       14

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      120
          Effectiveness (Multiplet Corr.), %
                                                2 km/h Data
                                                2 km/h Fit
                                            A  24 km/h Data
                                            - -  24 km/h Fit
                                      10
                                Particle Size, um
100
Figure 3. R&P 10-nm Inlet Performance at 2 and 24 km/h
                                   15

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     130
         Effectiveness (Multiplet Corr.), %
                                               D  SM1 Data
                                                   SM1 Fit
                                               A  SM2 Data
                                              	SM2Fit
                                     10
                               Particle Size, um
Figure 4.  Saturation Monitor Performance at 2 km/h.
100
                                  16

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     120
         Effectiveness (Multiplet Corr.), %
                                               LJ  SM1 Data
                                                   SM1 Fit
                                               A  SM2 Data
                                              	SM2Fit
                                     10
                               Particle Size, urn
100
Figure .5.  Saturation Monitor Performance at 24 km/h.
                                  17

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5 urn.
      The data and effectiveness curves for the PIPS are shown in Figures 6 and 7 at
2 and 24 km/h, respectively. The cut-points measured for the PIPS in the wind tunnel are
smaller than expected. PIPS cut-points have been measured in a wind-free chamber and
found to be approximately 10 urn.  The PIPS were designed as indoor size selective
samplers, and not for use in wind.  They do not have a wind screen.  The sample is
drawn into the region above the impactor jets through four 13 mm holes, and the impactor
jets sample from that region.  Wind entering through the inlet hole may simply jet across
the sampler and out the  other side.  Under these conditions the  air available to the
impactor jets may become depleted of challenge particles. This explanation seems  more
likely at 24  km/h than at 2 km/h.
      However, as was true  of the saturation monitors, at 5 ^m the mass collected by
the sampler was relatively low. Thus the low effectivenss at 5 urn may have been caused
by errors in the measurement.  The very low effectiveness values at 24 km/h for  7 ^m
particles are unexplained. The tests were not repeated because the PIPS are not really
suitable for application in any case.

4.2  Sampler Performance In Various Challenge Particle Size Distributions
      The significance of the effectiveness curves in Figures 4 through 7 was addressed
for the PM10 challenge particle size distribution in Table 3. The mass ratio compares the
mass that the tested sampler would have collected to that the ideal PM10 sampler would
have collected. Figure 8 is a presentation of all the sampler performance curves at 2
km/h.  The PM10 ideal sampler curve was obtained from 40 CFR Part 53.  Figure 9
presents the same information at 24 km/h.  The R&P Inlet is fairly close to the ideal inlet
at both 2 and 24 km/h. On the other hand, SM1 goes from collecting a great deal  more
aerosol  than the ideal sampler at 2 km/h to overlapping performance at 24 km/h, and the
PIP1 sampler goes from  overlapping at 2 km/h to collecting a good  deal less aerosol at
2 km/h.
      The significance of the differences evident in Figures 8 and 9 can be evaluated by
extending the mass ratio analysis to other challenge size distributions. Figure 10 is a
                                      18

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          Effectiveness (Multiple! Corr.), %
                                                A   PIP2 Data
                                               	PIP2Fit
                                       10
                                Particle Size, urn
100
Figure 6. Performance of PIPS at 2 km/h.
                                    19

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     120
         Effectiveness (Multiple! Corr.), %
                                                D   PIP1 Data
                                                    PIP1 Fit
                                                A  PIP2 Data
                                               	PIP2 Fit
                                      10
                                Particle Size, um
100
Figure 7. Performance of PIPS at 24 km/h.
                                   20

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  1

0.9

0.8

0.7
                                   Sampling Effectiveness at 2  kra/h
                                             V
£
a  0.6
£0.4
t,
a.0.3

                                                    \     \
 '0.2

   0.1

    0
    1
                                                   10
                                            Particfe Size,  urn
                                                                                              100
         - PMIO Ideal Sampfer - RiP 10 urn
                                                       PIPS 1
                                                                            SMI
F.

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Figure 8.  Comparison of Tested and Ideal Samplers at 2 km/h.
                                  21

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    1

  0.9

  0.8

  0.7
                                 Sampling Effectiveness at 34 km/h
                                     S
I 0.5
lo.3
  0.2

  0.1

    0
                                        \
                                                 10
                                          Particle Size, ura
         	PM10 kkal Smpter	RfcP 10 urn
                                                   •PffSi
                                                                       •91 1
                                                                                            100

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Figure 9.  Comparison of Tested and Ideal Samplers at 24 km/h.
                                  22

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   0.8
                                        SZE DistributJoos ised in Sampler
                                           Colfected U» Comparaom
   0.5
\0.3
   0.2
   O.t
                                                                                               \
\
     0.1
                                                ParUcie Size,  era
                          • Accumulation Mode	Cora Ifccfe
                                                                      - Combination Uode

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Figure 10. Size Distributions for Sampler Comparison.
                                   23

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differential mass plot of two primary distributions and a third distribution formed by adding
the primary distributions in equal proportions.  The accumulation mode aerosol has an
MMD of 0.5 nm and og of 5.0, while the coarse mode aerosol has a MMD of 20 urn and
og of 2.0. This distribution was described by Lundgren and Paulus  (1975). The primary
and combined distributions were mathematically collected by the samplers to obtain
quantities analogous to the mass ratios presented in Table 3. The effectiveness curve
of the ideal PM10 sampler was obtained from 40 CFR Part 53.  The effectiveness values
for each size interval were multiplied by the mass in that interval and added to obtain a
total relative mass collected by that sampler. This process was carried out for the ideal
sampler, the R&P sampler, SM1, and PIP1 for all three distributions. (Collection of all the
particles in a size distribution would give a relative mass of 1.0.  The samplers collect
only a portion of the distributions, so their relative mass collections were less than 1.0.)
The relative mass collected by the tested samplers was then divided by that collected by
the ideal sampler to obtain mass ratios  for each sampler and size distribution.   The
results are given in Table 4.
      As would be expected, Table 4 shows that all the samplers collect most of the fine
mode aerosol. On the other hand, there are significant differences  between samplers in
the coarse mode aerosol collection. As they should, all samplers collected considerably
less than 100 percent of the coarse aerosol. The R&P inlet  and the ideal sampler collect
about the same fraction of the coarse aerosol, and the results are the  same at both wind
speeds.  The PIP1  sampler collected less coarse mode aerosol than the ideal  sampler
at both wind speeds, with the difference being especially large at 24 km/h. SM1, on the
other hand, collected substantially more coarse mode aerosol than the ideal sampler at
2 km/h and about the same at 24 km/h. Thus the behavior of these two samplers in the
wind depends greatly on both the size distributions to which they are exposed and the
wind speed.  Despite this, the overall performance on the combined  size distribution is
not as bad as the individual distribution results suggest it might be.  SM1 at 2 km/h gave
the greatest discrepancy, oversampling by  15 percent relative to the ideal sampler. At
24 km/h, the PIP1 sampler undersampled by 8 percent while SM1 was close.  This
calculation suggests that the wind dependent performance of a sampler is likely to be
                                      24

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  Table 4.  Relative Mass Collected and Mass Ratios for Artificial Size Distribution.

Ideal Sampler
R&P at 2 km/h
SM1 at 2 km/h
PIP1 at 2
km/h
Ideal Sampler
R&P at 24
km/h
SM1 at 24
km/h
PIP1 at 24
km/h
Fine
Mode
REL
MASS
0.94
0.95
0.95
0.97
0.94
0.95
0.93
0.95
Coarse
Mode
REL
MASS
0.17
0.19
0.13
0.31
0.17
0.19
0.09
0.17
Comb.
Size
Oist.
REL
MASS
0.56
0.57
0.54
0.64
0.56
0.57
0.51
0.56
Fine
Mode
RATIO

1.01
1.03
1.01

1.01
1.01
0.99
Coarse
Mode
RATIO

1.10
1.82
0.76

1.12
0.96
0.51
Comb.
Size
Dist.
RATIO

1.03
1.15
0.97

.1.03
1.00
0.92
fairly robust for the usual challenge aerosols, even if the performance curve deviates
considerably from ideal performance.
                                       25

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                                 SECTION 5


                               REFERENCES
VanOsdell, D. W. and F.-L Chen. The PM10 Sampler Evaluation Program: Annual Report
      August 1988 to July  1989.   U.S. Environmental Protection Agency, AREAL,
      Research Triangle Park, NC, K.A. Rehme, Project Officer, 1989.

Ranade, M. B. and E. R. Kashdan (1984a).  An Evaluation of a Sierra-Andersen 10-fim
      Dichotomous Sampler Inlet  (RTI Wind  Tunnel Test  Report No.  1)  Research
      Triangle Institute, P. O. Box 12194, Research Triangle Park, NC 27709, Report to
      K. Rehme, AREAL, US Environmental Protection Agency, Research Triangle Park,
      NC (Revised January  1987).

Ranade, M. B. and E. R. Kashdan (1984b).  An Evaluation of a Sierra-Andersen 10-n.m
      Dichotomous Sampler Inlet  (EPA Wind Tunnel Test Report No.  7)  Research
      Triangle Institute, P. 0. Box 12194, Research Triangle Park, NC 27709, Report to
      K. Rehme, AREAL, US Environmental Protection Agency, Research Triangle Park,
      NC (Revised January  1987).

Kashdan, E. R., Ranade, M.B., Purdue, L J., and Rehme K. A. Interlaboratory Evaluation
      of Two Inlets for Sampling Particles Less Than 10 urn. Environ. Sci. Technol.. 20:
      911-916, 1986.

Lundgren, D. A. and Paulus, H. J. The Mass Distribution of Large Atmospheric Particles,
      JAPCA. 25:12, pp. 1227-1231.

McFarland,  A. R. and Ortiz, C.A.   "Characterization of Sierra-Andersen PM-10  Inlet
      Model  246b."   Air  Quality Laboratory  Report 4716/02/02/84/ARM, Texas
      Engineering Experiment Station, Texas A&M University System, College Station,
      Texas. November 1983, Revised February 1984.

Olan-Figueroa, E., McFarland, A. R. and Ortiz, C. A. Flattening Coefficients for DOP and
      Oleic Acid  Droplets Deposited on Treated Glass Slides. Amer. Ind. Hvq. Assoc.
      Jy 43:  395-399.

VanOsdell,  D. W., Chen, F.-L., Newsome, J. R.  The PM10 Sampler Evaluation Program:
      AnnuaT Report August 1987 to July 1988. US Environmental Protection Agency,
      AREAL, Research Triangle Park, N.C., K. A. Rehme, Project Officer, 1988.
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