Evaluation of Diffusion Denuder Coatings for
Removing Acid Gases from Ambient Air
-------
EPA-454/R-02-011
April 2002
Evaluation of Diffusion Denuder Coatings
for Removing Acid Gases from Ambient Air
By:
Dennis R. Fitz
College of Engineering-Center for Environmental Research and Technology
University of California
Riverside, CA 92521
Prepared For:
Office of Air Quality Planning & Standards
Emissions, Monitoring, and Analysis Division
Assistance Agreement #GX828663
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emissions, Monitoring, and Analysis Division
Research Triangle Park, NC 27711
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
Acknowledgments
The author would like to thank John Pisano, who did a marvelous job of constructing the test
apparatus, supervising the experiments and organizing the data. Irina Malkina operated the test
system, and her dedication resulted in nearly 100% data capture with all runs being completed
within a tight schedule.
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
Table of Contents
Acknowledgments i
1. Introduction 1
1.1 Background 1
1.2 Approach 1
2. Experimental 2
2.1 Coated Filters andDenuders 2
2.2 Test Gas Generation, Measurement and Data Recording 3
2.3 Experimental Matrix 8
3. Results and Discussion 10
3.1 Removal Efficiency 10
3.2 MgO-Coated Annual Denuder 10
3.3 Sodium Carbonate-Coated Annular Denuder 12
3.4 Sodium Chloride-Coated Annular Denuder 15
3.5 Magnesium Oxide-Coated Honeycomb Denuder 16
3.6 Sodium Carbonate-Coated Honeycomb Denuder 18
3.7 Sodium Chloride Denuders 19
3.8 Filter Testing 20
3.9 Additional QC Tests to Evaluate the NOy Analyzer Memory Effect 25
4. Summary and Conclusions 28
5. Recommendations and Future Research 29
5.1 Recommendations 29
5.2 Future Research 30
References 32
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Tables
Table 1. Test matrix for denuder evaluation 9
Table 2. Matrix of tests for evaluation 9
Table 3. Summary of removal efficiency for denuders 11
Table 4. Summary of filter data 22
Table 5. Data showing the first ten minutes after injection of zero air 27
Table 6. Summary of removal efficiencies 28
Figures
Figure 1. Schematic diagram of the apparatus to expose denuders and filters 3
Figure 2. Photograph of the test apparatus 4
Figure 3. Plot of the pH titration curve for diffusion tube B 5
Figure 4. Plot of the TDL NO2 and FDSTCb concentrations when
sampling from diffusion tube B 6
Figure 5. Plot of the pH titration curve for diffusion tube A 7
Figure 6. Summary of removal efficiency tests for MgO-coated annular denuders 11
Figure 7. Summary of removal efficiency tests for sodium
carbonate coated annular denuders 13
Figure 8. Time series plot of FDSTCb collection efficiencies, low humidity 13
Figure 9. Time series plot of FDSTCb removal efficiencies, high humidity 14
Figure 10. Time series plot of HONO removal efficiencies
and concentrations, low humidity 15
Figure 11. Summary of removal efficiency tests for sodium chloride-
coated annular denuders 16
Figure 12. Summary of removal efficiency tests for the magnesium oxide-
coated honeycomb denuders 17
Figure 13. Time series plot of HONO removal efficiencies,
high concentrations, high humidity 17
Figure 14. Summary of removal efficiency tests for the sodium carbonate-
coated honeycomb denuders 18
Figure 15. Time series plot of HONO removal efficiencies and concentrations,
high concentration, low humidity 19
Figure 16. Removal efficiency of sodium chloride-coated annual and honeycomb
denuders for 10 ppb of nitric acid at 30% RH 20
Figure 17. Summary of removal efficiency tests of the replicate nylon filters
for removing NO2, HONO, and PAN 21
Figure 18. Summary of removal efficiency tests of the NaCl-coated quartz filters
for removing NO2, HONO, and PAN 23
Figure 19. Summary of removal efficiency tests of the replicate Na2(CO3)-coated
quartz filters for removing NO2, HONO, and PAN 24
Figure 20. NOy measurements at the outlet of each denuder with NaCl coated filters added to
scrub any remaining nitric acid 26
Figure 21. Response of the chemiluminescent NOy analyzer to a change in concentration
from 45 to zero ppb 26
in
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
Appendices
Appendix A
Times series plots of concentration and efficiency for all denuders tested
Appendix B
Time series plots of concentration and efficiency for all filters tested.
IV
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
1. Introduction
1.1 Background
Diffusion denuders have been developed to concurrently remove nitric acid and permit particles
to pass unattenuated. The particulate matter may then be collected on specialized filters that
minimize further volatilization. This technique allows the measurement of nitric acid and
particulate nitrate with a minimum of removal artifacts caused by the volatilization and
condensation of ammonium nitrate. There is a significant body of literature describing the
suitability of using such denuders and filters for this purpose in studies using ambient air
(Allegrini et al., 1994). There is, however, little information on the quantitative testing of these
substrates to remove nitric acid while allowing other nitrogenous gases, such as nitrogen dioxide,
nitrous acid, and peroxyacetyl nitrate, to pass through freely. Removal inefficiency of the
denuder for nitric acid will bias the nitric acid low and the particulate nitrate high, while
collecting the other nitrogenous species will bias both high. In addition, there is little published
information on the removal efficiency of an aluminum honeycomb denuder that is currently
offered as a commercial product.
The primary objectives were to:
Determine the short-term efficiency and capacity of chemically coated filters and
diffusion denuders that are currently used in EPA's National PM2.5 Chemical Speciation
Network to collect nitric acid and related nitrogenous species under ambient air
conditions.
Assess the potential interferences associated with the collection of gases on reactive
filters that follow these denuders that were not efficiently removed by the denuders.
1.2 Approach
The efficiency of magnesium oxide (MgO), sodium chloride (NaCl), and sodium carbonate
(Na2CC>3) coated substrates in collecting nitrogenous species was determined by challenging the
substrates to synthetically generated gases. The removal efficiency was determined by measuring
concentration before and after the challenged substrate with a chemiluminescent NOy analyzer.
This type of analyzer has been shown to quantitatively measure all species of reactive odd
nitrogen containing compounds (Winer et al., 1974). The gases tested included:
Nitrogen dioxide (NC>2)
Nitric acid (HNO3)
Nitrous acid (HONO)
Peroxyacetyl nitrate (PAN)
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
2. Experimental
2.1 Coated Filters and Denuders
Filters and Denuders. Both honeycomb and annular denuders were evaluated. The annular
denuders were manufactured by URG (Chapel Hill, NC) and identified as part number URG-
2000-242-3CSS. These were 3-channel Teflon-coated stainless steel denuders with a length of
242 mm. Teflon adapters supplied by URG (URG-2000-30AE-7) were used on the inlet and
outlet of the denuders to provide a 3/8 inch female pipe fitting. Honeycomb denuders, part
number 8382, were manufactured by Met One (Grants Pass, OR) and were supplied in their
stainless steel housing (part number 8370).
Five combinations of denuders and coating types were tested for the removal efficiency.
Honeycomb with a MgO coating.
Honeycomb with a Na2COs coating.
Annular with a MgO coating.
Annular with a Na2COs coating.
Annular with a NaCl coating.
47mm diameter quartz fiber filters (Pallflex QAT) were coated as described below while 47mm
diameter Nylasorb nylon filters (Fisher part number 09-751-15) were used as is.
Coating Methods. The honeycomb denuders were coated and extracted according to directions
provided by the manufacturer. The denuder was cleaned with methanol and dipped in a slurry of
MgO in methanol (50g/160ml). They were then drained and partially dried with dry and filtered
compressed air. They were then allowed to dry in a rack overnight and sealed in polyethylene
bags until used. A similar technique was used for the carbonate coating except the coating
solution consisted of lOg of sodium carbonate dissolved in 1000 ml of deionized water to which
10 g of glycerol had been added.
Annular denuders were coated using a methodology developed by the Research Triangle Institute
that is the basis of the recommended procedure by the manufacturer. Approximately 5ml of the
MgO slurry described above was added to the denuder with the outlet capped. The other cap was
installed and the denuder gently rolled to distribute the coating mixture. The excess mixture was
then poured out, and the denuder was subsequently dried using dry, filtered compressed air. The
denuders were then capped for storage. The carbonate coating solution was the same as that used
for the honeycomb denuder and applied in a similar manner. The NaCl coating solution consisted
of 9% (w/w) NaCl dissolved in a 50/50 methanol-water solution (v/v) with 1% (v/v) added
glycerol.
Quartz filters were coated by being dipped in the coating solution, allowing the excess to drip
out, and then dried on aluminum foil set on the bench top. The coating solution consisted of 2%
(w/w) sodium carbonate or sodium chloride in a 50/50 methanol/water solution containing 1%
(v/v) glycerol.
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
2.2 Test Gas Generation, Measurement and Data Recording
Test Gas Exposure System. Figure 1 shows a schematic diagram of the apparatus used to expose
the denuders to various test gases. Figure 2 is a photograph of the assembly. Notice that the
denuders were positioned to minimize sample line length. The exposed surface of all connecting
plumbing was PFA Teflon. The system was designed to simultaneously challenge five denuders.
Purified air was humidified by splitting the flow and directing a portion through a bubbler filled
with distilled water and maintained at a constant 20°C. After the bubbler, the humidified and
dried air streams were remixed. Rotameters and needle valve were used to adjust and monitor the
flow to maintain the desired humidity and total flow rate. A General Eastern model Hygro MI
chilled mirror sensor was used to measure the dew point. Temperature of the laboratory was
monitored with a thermocouple. The relative humidity (RH) of the test gas was calculated from
the dew point and the laboratory temperature. Flow through all denuders was set and maintained
by needle valves and rotameters. A ThermoEnvironmental model 42C chemiluminescent NOX
analyzer was used to monitor the test gas concentration. A zero, span, and converter efficiency
check was performed on the instrument before and after each experiment using a
ThermoEnvironmetal model 46 dilution calibrator. The calibrator was supplied with ultra zero
grade air and a cylinder of NO calibration gas in nitrogen. Gas phase titration of NO with ozone
was used to test the converter efficiency. In addition, the background concentration of the
humidified air was checked before each experiment. All zero checks gave a concentration of less
than 0.3 ppb NOX.
14/35
L/min
70 L/min Pure Air
I
J I
J \
r\
56/35
1 L/min
r1
r
J
(-4
\
-)
Test Gas
NO2 , 60&300 ppb (NO 2 Cyl)
HNO3 6&30 ppb (Diffusion Tube)
HONO 2&10ppb (Fluidized Bed)
PAN 2&10 ppb (Photolysis Chamber)
r>
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Figure 2. Photograph of the test apparatus.
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Test Gas Generation and Purity Verification.
Nitrogen dioxide was generated by dilution of a 97.4 ppm compressed gas cylinder source in
ultrapure N2 (Scott Research Laboratories, San Bernardino, CA). Flow was maintained with a
McMillan Company model 50 (0-50ml range) electron volumetric flow sensor.
Nitric acid vapor was generated with one of two VICI Metronics (Santa Clara, CA) diffusion
vials (one model B for low range and one model C for high range) filled with reagent grade
constant boiling (70%) nitric acid. The vials were maintained at 40°C in a water bath.
For the low-level HNOs concentrations the diffusion rate was determined by standard pH
titration using NaOH as the base solution. Figure 3 is a plot of the pH titration of diffusion tube
B, the lower concentration source for the FDSTCb measurements employed in this experiment.
01
_3
ro
Concentration of used NaOH solution is 1 .OE-03 +/- 2E-5 mol/l
Volume of used NaOH solution 10.0 +/-0.2 ml
Time from start to point of inflexion 548 +/- 5
-- 0.25
Diffusion rate 1.15 +/- 0.03 micrograms HNO3/min
0.35
-- -0.25
-0.35
200 250 300 350 400 450
time (minutes)
500
550
600
Figure 3. Plot of the pH titration curve for diffusion tube B.
This diffusion rate as determined by the pH titration was also challenged by using the same
diffusion source as the source gas to a mid-infrared tunable diode laser. The tunable diode laser
system was operational for two-channel monitoring, one for NC>2 and the other for FINOs. Figure
4 depicts this investigation of the HNOs acid diffusion source. The TDL was calibrated for HNOs
using another diffusion tube source that generated 60 ppbV at 5 L/min. This source is used as
part of the normal TDL systems calibration. The diffusion tube source used for the low
concentrations was investigated for confirmation of the FINOs diffusion rate and for possible
contamination of NC>2. The diffusion tube FINOs was mixed with zero air and sampled by the
TDL at 7 L/min, resulting in a mixing ratio of 68.7 ppbV with a standard deviation of 3.9 ppbV.
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
This measured value from the TDL was within a single standard deviation of the pH titration
determined value for the HNCb diffusion tube B. Notice that during the measurement of the
HNOs diffusion source, simultaneous values of NO2 on average -0.3, were below the MDL of the
tunable diode laser (1.0 ppbV) and had a standard deviation of 0.7.
ou
75 -
70
/ \J
65 -
60 -
^^^ f f
> 55
a 50
3 45-
rt A »,
2 40
5 35
°> 30 -
x 25
E 20
15 -
10 -
5
0 t
C(
Average 68. 7 ppbVHNOS m f
_f
HNO3 Standard
deviation 3.9
» ppb N02
ppb HN03
^ *
Injection of Diffusion *
~ TubeHNOS »
*** » *
» ****** *
m Ambient Air Measurement '
1.15 micrograms ^
HNO3/min at 7 slm
yields 65 ppbVHNOS
Average -0.3 ppbV
Zero Air NO2 Standard Deviation 0.7 *-
-
& * * » ^" » *
! ! ! Mill ! ! ! ! ! ! !
. j« "i
^.^^- "
i i ITI i i i i u.
8:25 8:48 8:58 9:08 9:18 9:28 9:38 9:48
PSTTime(hh:mm)
9:58
Figure 4. Plot of the TDL NO2 and HNO3 concentrations when sampling from diffusion tube B.
The lack of NO2 was also confirmed from the observation of the normal concentrated aqueous
acid (70% by weight) in the diffusion tubes throughout the experiment. The solution is colorless
and only becomes yellow as a result of photochemical or thermal decomposition that yields NO2.
2HNO3
2NO2 + H2O
O2
The color of the solution showed no observable changes throughout the period of use. Although
NO was an unlikely interferent, NO measurements were conducted throughout the experiment as
a matter of the normal operational cycle of the TECO 42 with associated NOy converter. There
was never any detectable amount of NO.
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Therefore, we concluded that there was no generation of NO2 from this diffusion source and that
the diffusion rate measured was consistent within the estimated errors of the two independent
techniques.
For the higher HNCb concentrations, the diffusion rate was determined again by standard pH
titration using NaOH as the base solution. Figure 5 is a plot of the pH titration of diffusion tube
A, the higher concentration source for the FDSTCb measurements employed in this experiment.
This diffusion rate determined by the pH titration was challenged by repeating the pH test as the
rate was far too high to be in the linear range of the tunable diode laser. The repeat test yielded a
similar diffusion rate within the uncertainty of the measurement. Again we saw no discoloration
of the 70% aqueous solution HNOs in the diffusion tube used for the high concentration during
the experiments.
14
Q.
Concentration o
Volume of used
Time from start
**&*&*&
Diffus
fused NaOH solu
NaOH solution 10
o point of inflexior
ion is 1 .OE-03 +/- 2E-5 mol/l
.0 +/- 0.2 ml
1 1 13 +/- 2 minutes
I
*i^r<
**
3/~\
[ \
\
o °OOOrt^_
ion rate 5.85 +/- (
*«
).15 mocrograms
'
X.
*«
HNO3/min
***^*->
"*
'"*
0)
n n^ *^
- O.Ob
"53
Q.
n n^
"53
a
n 1 R
n 9^
n ^c
0 90 100 110 120 130 140
time (minutes)
Figure 5. Plot of the pH titration curve for diffusion tube A.
Nitrous acid was generated using the method of reacting hydrochloric acid vapor generated in a
diffusion tube with stirred granular sodium nitrite (Febo et al., 1995). Rotameters and needle
valves were used to maintain the various flow rates of this generation system. The HONO
concentration was stabilized by controlling both the flow rate and operating temperature of the
oven that contained the HONO generating equipment. This system has been used in our
laboratory for several years and has been found be to a stable and clean source of nitrous acid.
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
Regular maintenance on the HONO generating system requires a regular change of the sodium
nitrite.
The purity of the nitrous acid source was determined by measuring the total NOX concentration
and then adding a NaCl coated filter (to remove any nitric acid and determine the amount of
nitric acid by difference), followed by adding a sodium carbonate coated filter (to remove the
HONO, thus leaving residual NO2). These tests showed that the HONO contained approximately
3% of nitric acid and NO2. The NO2 concentrations were verified several times using a TDLAS
and a luminol-based NO2 analyzer. In addition, the NO channel of the NOX analyzer showed
about 3% NO in the test mixture.
Peroxyacetyl nitrate was generated in a 5 m3 Teflon chamber (Carter et al., 1995) by photolyzing
a mixture of 2ppm acetaldehyde, SOppb chlorine, and SOppb NO2. Acetaldehyde was maintained
in excess to limit the amount of NO2 remaining and the formation of HNOs. The concentration
was verified with a gas chromatograph with a luminol detector (Fitz et al., 2001) calibrated with
PAN generated in hexane (Holdren and Spicer, 1984). The PAN mixture was delivered to the test
apparatus using a Teflon diaphragm pump (Virtual Industries part #VMP1625MX-24-50-NC).
The flow rate was adjusted to obtain the desired concentration.
Analyzer Control and Data Logging. A Campbell model CR10 data logger was used to operate
the solenoid valves in the test apparatus and to log the data from the NOX analyzer. The data
logger was programmed to alternate between sampling the concentration of the test gas before
and after each denuder. Each sampling interval was six minutes, thus allowing the test gas
concentration below the denuder to be determined once per hour. The data logger recorded the
NOX concentrations as one-minute averages. Data from the fourth minute of averaging were
reported.
2.3 Experimental Matrix
A total of 21 denuder exposures were conducted varying the test gas concentration (from highest
potential ambient to approximately 20% of that value), relative humidity, and length of exposure.
Many of the 24-hour exposures showed no change in removal efficiency, and the next 24-hour
period of testing was considered a replication of the first. A number of additional replicates were
included. Table 1 shows the test matrix used. Experiment #2 used the same denuders that were
used in Experiment #1 without recoating. These denuders, therefore, were exposed to nitric acid
for two weeks. One test experiment (#5) was done using three denuders coated with the NaCl
solution to further evaluate this method for selectivity for nitric acid. Table 2 shows the test
matrix used for testing the nylon and sodium chloride and sodium carbonate coated quartz filters.
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Table 1. Test matrix for denuder evaluation.
Exp#
1
2
O
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Test
Length,
Hours
124
124
165
47
22
24
188
49
46
25
160
42
23
20
71
25
71
15
8
12
19
Test Gas
HNO3
HNO3
HNO3
HNO3
HNO3
HNO3
HNO3
NO2
NO2
NO2
NO2
HONO
HONO
HONO
HONO
HONO
HONO
PAN
PAN
PAN
PAN
Cone
High
High
High
Low
Low
Low
High
High
High
Low
Low
High
High
High
Low
Low
Low
High
High
Low
Low
RH
Low
Low
Low
Low
Low
High
High
High
Low
Low
High
Low
High
High
High
Low
Low
Low
High
High
Low
Comments
Using spent denuder for another week
Repeat of experiment 1
All denuders NaCl coated
Repeat of 13
Repeat of 16
Table 2. Matrix of tests for filter evaluation.
Exp#
22
23
24
24
26
27
Test Gas
NO2
NO2
HONO
HONO
PAN
PAN
Concentration
High
High
High
High
High
High
RH
Low
High
High
Low
Low
High
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
3. Results and Discussion
3.1 Removal Efficiency
The results of the experiments will be described by the efficiency of denuders and filters,
expressed as a percentage, to collect the test gas (whether removal of the test gas is desirable or
not). Removal efficiency is defined as follows:
E= 100*(Ci-C2)/Ci
where Ci is the concentration of the test gas prior to the denuder or filter and 2 is the
concentration after.
3.2 MgO-Coated Annular Denuder
Table 3 summarizes all the experiments performed exposing the annular denuders to the test
gases (the other denuders are included in this summary table). For nitric acid the removal
efficiency is generally over 80% even for tests periods of nearly eight days at 46ppb. The low-
concentration tests had generally lower efficiencies, but these are subject to more error due to
zero drift than are the high concentrations. The low-concentration, high-humidity test showed
significantly lower removal efficiency than the others. The removal efficiency for NC>2 was
consistently about 5%, indicating that this species is not readily removed. This few percent could
be due to minor impurities in the NC>2 such as HONO in the compressed gas cylinder. HONO
was removed nearly as effectively as nitric acid. Results from these two acid gases agreed in that
the lowest removal efficiency was the case with low concentration and high humidity. PAN was
removed with variable efficiencies, ranging from 40 to 80%. There was not any apparent trend
with either humidity or concentration. Note that the PAN tests were conducted for less than 24
hours due to the volume of the PAN mixture available in the chamber.
Figure 6 summarizes the results of all the experiments by presenting the initial denuder removal
efficiency and the efficiency after 1, 4, and 24 hours (or the last test point if the exposure lasted
less than 24 hours) and the average for the exposure period for all four test gases. Appendix A
contains the detailed time series plots. Except for a few outliers, there is little difference in
removal efficiency as the testing progresses. This indicated that the denuder has capacity to
remove high concentrations of nitric and nitrous acids. The high-RH, low-concentration test
indicated that the denuder was initially somewhat effective in removing NO2, but the efficiency
dropped to background within four hours. This was likely a valid result particular to the coating
material since the MgO-coated honeycomb denuder also showed this behavior for only this test
condition. Experiment #18 showed an unexplainable steep drop off in the removal efficiency for
PAN during the last two hours of the test.
10
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Table 3. Summary of removal efficiency for denuders.
Exp
#
1
2
3
4
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Test
Gas
HNO3
HNO3
HNO3
HNO3
HNO3
HNO3
NO2
NO2
NO2
NO2
HONO
HONO
HONO
HONO
HONO
HONO
PAN
PAN
PAN
PAN
Ave
Cone,
ppb
51.5
49.6
51.0
9.6
7.9
46.3
69.2
76.4
16.7
16.3
30.2
30.8
30.8
9.2
8.6
7.7
14.8
3.8
25.2
25.2
RH
30%
30%
30%
30%
70%
70%
70%
30%
30%
70%
30%
70%
70%
70%
30%
30%
30%
70%
70%
30%
Period Average Efficiency (%)
Annular
MgO
95.1
91.2
92.5
82.1
63.2
83.0
4.0
5.7
5.4
5.3
92.5
87.2
83.8
76.7
82.3
85.2
69.5
62.6
80.3
38.6
Annular
Na2CO3
84.1
26.6
76.7
81.2
64.3
77.4
3.9
5.3
4.9
4.5
85.9
88.1
85.3
78.3
80.7
72.8
27.4
22.7
32.7
9.0
Annular
NaCl
66.5
57.3
59.5
59.7
52.9
61.5
3.2
4.8
4.7
3.9
6.5
20.7
24.1
25.1
26.3
25.1
26.9
22.8
32.7
8.8
Honeycomb
MgO
92.4
88.0
89.9
82.3
52.1
79.6
2.0
4.4
2.1
3.6
91.9
79.2
85.3
66.6
80.5
81.0
77.6
66.9
80.5
44.2
Honeycomb
Na2CO3
93.1
87.9
90.0
81.4
64.9
82.1
0.0
3.0
1.7
2.2
60.3
86.8
78.4
70.0
79.3
79.9
27.7
19.9
32.4
4.5
10 11 12 13 14 15 16 17 18 19 20 21 22
Experiment Number
Figure 6. Summary of removal efficiency tests for the MgO coated annular denuders.
11
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
3.3 Sodium Carbonate-Coated Annular Denuder
Table 3 summarizes all the experiments performed exposing this denuder to the test gases. For
nitric acid the removal efficiency is generally over 70% even for tests periods of nearly 15 total
days (the denuders were not recoated after Experiment #1) at 50 ppb. As with the magnesium
oxide coating, the removal efficiency for NC>2 was low (5%) and that for HONO was high
(typically 80%). PAN, however, was collected at significantly lower efficiency than the
magnesium oxide coating.
Figure 7 summarizes the results of all the experiments by presenting the initial denuder removal
efficiency and the efficiency after 1, 4, and 24 hours (or the last test point if the exposure lasted
less than 24 hours) and the average for the exposure period for all the four test gases. Appendix
A contains the detailed time series plots. During Experiment #1 the nitric acid removal efficiency
at 24 hours dropped appreciably and was less than 40% when the same denuder was started for
Experiment #2. Figure 8 is a time series plot of the nitric acid concentration before and after the
denuder and the calculated denuder efficiency. After about two days of sampling 50 ppb of nitric
acid, the denuder removal efficiency started to drop, and the efficiency dropped from nearly 90%
to 50% over the next five days. This denuder had apparently used up much of its adsorption
capacity. This drop-off in removal efficiency was not observed in the parallel experiment that
used the magnesium oxide coated annular denuder, even after 13 days of exposure, thus
indicating that magnesium oxide coating has a much higher capacity than carbonate. A similar
efficiency drop-off was also observed in the replicate test (Experiment #3). Experiment #7 was
similar to Experiments #1 and #3, but at high humidity instead of low. Figure 9 is the time series
plot of efficiency for this test and a slower drop off is noted after two days. It appears that
humidity aids the carbonate in adsorbing nitric acid. This might be due to increasing the mass
transfer of carbonate to the surface of the denuder. Figure 10 shows a similar drop-off in
efficiency when HONO was the test gas and the RH was low. The efficiency drop was much less
under high RH conditions.
12
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
HN03
NO2
MONO
PAN
17 18 19 20 21 22
HRH HRH HRH LRH LRH HRH LRH HRH HRH HRH LRH LRH LRH HRH HRH LRH
Experiment Number
Figure 7. Summary of removal efficiency tests for the sodium carbonate coated annular denuder.
100.0
90.0
80.0
I
.fc
m
70.0
50.0
H, 40-°
O
I
30.0
20.0
10.0
HNO3
- Efficiency
..%*
100.0%
95.0%
90.0%
85.0%
80.0% "
75.0%
70.0%
65.0%
60.0%
55.0%
Effi
50.0%
28-Mar
31 -Mar
Date (2001)
3-Apr
Figure 8. Time series plot of HNO3 removal efficiencies and concentrations and before and after
the sodium carbonate coated annular denuders under low humidity conditions.
13
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
100.0
90.0
80.0
70.0
g
Q.
3 60.0
s
t:
m
g
o
o
50.0
40.0
30.0
20.0
10.0 -
0.0
24-Apr
HNO3
Efficiency
26-Apr
28-Apr
Date (2001)
30-Apr
2-May
100.0%
90.0%
80.0%
70.0%
60.0% o
50.0%
40.0%
30.0%
20.0%
10.0%
0.0%
Figure 9. Time series plot of HNO3 removal efficiencies and concentrations and before and after
the sodium carbonate coated annular denuders under high humidity conditions.
14
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
HONO Concentration (ppbV)
30 0 -
HONO
"'--_
"-
-
.
30 0%
21 -May 22-May 23-May
Date (2001)
Figure 10. Time series plot of MONO removal efficiencies and concentrations and before and
after the sodium carbonate coated annular denuders under low humidity conditions.
3.4 Sodium Chloride-Coated Annular Denuder
Table 3 summarizes all the experiments performed exposing this type of denuder to the test
gases. For nitric acid the removal efficiency, with the period average ranging from 53 to 67%, is
significantly lower than for the annular denuders with sodium carbonate or magnesium oxide
coatings. The removal efficiency for NC>2 was as low and similar to that observed with the other
two coating materials while that for HONO and PAN was much lower, approximately 25%.
These results show that NaCl coating, while somewhat less efficient in scrubbing nitric acid, is
much less efficient in removing HONO and PAN and, therefore, more selective.
Figure 11 summarizes the results of all the experiments by presenting the initial denuder removal
efficiency and the efficiency after 1, 4, and 24 hours (or the last test point if the exposure lasted
less than 24 hours) and the average for the exposure period for all of the four test gases.
Appendix A contains the detailed time series plots. For nitric acid the efficiency tends to drop
somewhat in the removal efficiency but remains at a constant level during the 13 days of
exposure conducted during tests #1 and #2. For other test gases the removal efficiency remains
fairly constant without any clear-cut trends.
15
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
10 11 12 13 14 15 16 17 18 19 20 21 22
LC LC HC
Experiment Number
Figure 11. Summary of removal efficiency tests for the sodium chloride coated annular denuders.
3.5 Magnesium Oxide-Coated Honeycomb Denuder
Table 3 summarizes all the experiments performed exposing the honeycomb denuders to the test
gases. The period average removal efficiencies for all of the test gases were similar to that
obtained for this coating on annular denuders. The low-concentration/high-humidity experiment
(#15) with nitric acid also showed significantly lower removal efficiency than the others.
Figure 12 summarizes the results of all the experiments by presenting the initial denuder removal
efficiency and the efficiency after 1, 4, and 24 hours (or the last test point if the exposure lasted
less than 24 hours) and the average for the exposure period for all four subject gases. Appendix
A contains the detailed time series plots. With several exceptions during the PAN and HONO
testing, the removal efficiencies generally did not go down with sampling time. Experiment #11
showed a significant initial adsorption efficiency of NC>2 at low concentrations and high RH
followed by a rapid drop in efficiency. This is consistent with the behavior of the similarly coated
annular denuder. Figure 13 shows the time series plot for Experiment #13 with HONO as the test
gas (high RH, high concentration). In this figure the removal efficiency slowly and steadily
dropped as a function of time. This phenomenon was not observed in the replicate test (#14), but
it was in the low-concentration/high-humidity test (#15). Slow drops in removal efficiency were
also observed for all of the PAN exposure tests.
16
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
LRH LRH LRH LRH
HRH HRH HRH LRH LRH HRH LRH HRH HRH HRH LRH LRH LRH HRH HRH LRH
Experiment Number
Figure 12. Summary of removal efficiency tests for the magnesium oxide coated honeycomb
denuders.
>"
.a
Q.
a.
c
o
1
Concen
MONO
30 0 -
n n -
MONO
- Efficiency
" ~ - _
_
"**
30 0%
n no/.
I
o
s
3
C
Q
23-May
24-May
Date (2001)
Figure 13. Time series plot of MONO removal efficiencies and concentrations and before and
after the magnesium oxide coated honeycomb denuders under high concentration and humidity
conditions.
17
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
3.6 Sodium Carbonate-Coated Honeycomb Denuder
Table 3 summarizes all the experiments performed exposing the honeycomb denuders to the test
gases. The period average removal efficiencies for all of the test gases were similar to that
obtained for this coating on annular denuders. The low-concentration/high-humidity test with
nitric acid also showed significantly lower removal efficiency than the others.
Figure 14 summarizes the results of all the experiments by presenting the initial denuder removal
efficiency and the efficiency after 1, 4, and 24 hours (or the last test point if the exposure lasted
less than 24 hours) and the average for the exposure period for all four test gases. Appendix A
contains the detailed time series plots. A noticeable difference was that the removal efficiency for
nitric acid in Experiment #2 did not drop, as was the case for the similarly coated annular
denuder. This indicates that the honeycomb denuder has higher capacity than the annular denuder
does. For HONO Experiment #12 (low RH, high concentration) and #15 (high RH, low
concentration) the removal efficiency for HONO starting dropping almost immediately. Figure
15 shows the time series plot of concentration and removal efficiency for Experiment #12. This
drop-off is similar to that observed with the magnesium oxide coated denuder sampling HONO
in Tests #13 (see Figure 9) and #15. Only slight drop-offs were observed in the other HONO
tests.
LRH LRH LRH LRH
10 11 12 13 14 15 16 17 18 19 20 21 22
HRH HRH HRH LRH LRH HRH LRH HRH HRH HRH LRH LRH LRH HRH HRH LRH
LC HC HC HC LC LC HC HC HC LC LC LC LC LC HC HC
Experiment Number
Figure 14. Summary of removal efficiency tests for the sodium carbonate coated honeycomb
denuders.
18
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
70 0 -
|
1
0)
o
c
O
1 300 -
-
~ _
~
- - - _ . MONO
- _ - _ - Efficiency
_
-
70 0%
- 30 0%
21-May 22-May 23-May
Date (2001)
Figure 15. Time series plot of MONO removal efficiencies and concentrations and before and
after the sodium carbonate coated honeycomb denuder under high concentration and low
humidity conditions.
3.7 Sodium Chloride Denuders
While sodium chloride appeared to be a more selective denuder coating for nitric acid compared
with sodium chloride or carbonate, the removal efficiency when used to coat annular denuders
was never more than 80% and rapidly stabilized to about 60%. Clearly this would be a problem
in sampling ambient air as two or three denuders in series would be required. Experiment #1 with
nitric acid showed that the honeycomb denuder design appeared to have higher capacity to adsorb
nitric acid than the annular ones when sodium carbonate was the coating substrate. Therefore, a
test was conducted (Experiment #5) to determine the efficiency of sodium chloride-coated
honeycomb denuders. A combination of low concentration and humidity was used as this was
generally the combination that led to the lowest overall removal efficiencies for nitric acid
(regardless of the denuder type or coating substrate). Figure 16 shows the results. The removal
efficiency for the annular denuders drop from 80% and stabilize after 16 hours to 55% as
previously observed. The efficiency of the honeycomb denuder, however, remains near 80%. A
sodium chloride-coated honeycomb denuder may therefore be a viable combination with which
to determine nitric acid concentrations in the air.
19
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Denuder Efficiency
80.0%
?n n%
55 0%
HNO3 Concentration Approximately 10 ppb
Annular Denuder 2
» Honeycomb Denude
: t % % , ^^
i *:**»*»**»» 4 » * 4 % % * * % %
»
«
#
»
»
»
»
1 *
12:00 16:00 20:00 0:00 4:00 8:00 12:0(
Time (Data Taken April 19-20, 2001)
Figure 16. The removal efficiency of sodium chloride coated annular and honeycomb denuders
for 10 ppb of nitric acid at 30% RH.
3.8 Filter Testing
Nylon. Figure 17 summarizes the results of all the experiments by presenting the initial filter
removal efficiency and the efficiency after 1, 4, and 24 hours (or the last test point if the exposure
lasted less than 24 hours) and the average for the exposure period for all three test gases.
Appendix B contains the detailed time series plots. Although high initial removal efficiency was
observed for Experiments #22 and #24, the efficiency immediately dropped and remained stable
there after. Nylon filters appear to have a small efficiency (10-20%) to collect NO2 and HONO
but almost no affinity for PAN. These results for NC>2 and HONO are consistent with those
previously reported (Perrino et al., 1990). There was no significance difference in removal
efficiency due to RH. Table 4 list the overall collection efficiency determined by the NOX
analyzer and compares the amount of nitrate found on the filter with that calculated from the
average concentration difference before and after the filter. For NO2 the amount of nitrate on the
nylon filter was about half of that calculated. It is likely that the NO2 retained by the filter
decomposed to both nitrate and nitrite. In the absence of ozone, the nitrite would not be oxidized
to nitrate and therefore would not be accounted for in the chemical analysis. For HONO even less
was found on the filter compared to the calculated amount, thus indicating that most of the
HONO was retained as nitrite. With PAN this pattern was reversed, with the amount found on
the filter being greater than the amount calculated. This may be due to measurement errors due to
low PAN concentrations and possible hang up of nitrogenous species in the NOX analyzer.
20
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Filter 1
Filter 2
100-
8C
STc 6(
s
= 8
S>
3 4(
.2m 40 -
E
2(
(
0-
I Mr~i^"-)^ I Ur-iMr-i MUNU , DAM KAN |
r- -*^
*
1
^ ^^^^±
» Initial
1 Hour
A 4 Hours
x 24 Hours
* Period Average
1__
« 1
LKH1 HKH ' HKH ' LKH LKH HKH1 '
21 HC22 HC 23 HC 24 HC 2&C HC26 27
LRH HRH HRH LRH LRH HRH
HC HC Exp
-------
University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Table 4. Summary of filter data.
Filter
Type
Nylon
Nylon
NaCI Qz
C03-Qz
CO3-Qz
Nylon
Nylon
NaCI Qz
C03-Qz
CO3-Qz
Nylon
Nylon
NaCI Qz
C03-Qz
CO3-Qz
Nylon
Nylon
NaCI Qz
C03-Qz
CO3-Qz
Nylon
Nylon
NaCI Qz
C03-Qz
CO3-Qz
Nylon
Nylon
NaCI Qz
C03-Qz
CO3-Qz
Test
Gas
N02
N02
NO2
N02
N02
N02
NO2
NO2
N02
NO2
MONO
MONO
MONO
MONO
MONO
MONO
MONO
MONO
MONO
MONO
PAN
PAN
PAN
PAN
PAN
PAN
PAN
PAN
PAN
PAN
Nominal
Cone,
ppb
30
30
30
30
30
29
29
29
29
29
25
25
25
25
25
26
26
26
26
26
9
9
9
9
9
9
9
9
9
9
RH
30
30
30
30
30
70
70
70
70
70
70
70
70
70
70
30
30
30
30
30
30
30
30
30
30
70
70
70
70
70
Period Ave
Efficiency
%
17
14
8
3
4
12
11
6
5
3
29
23
45
68
71
13
11
32
82
83
5
6
NA
2
5
2
2
NA
3
4
Nitrate
Collected,
ugN
11.1
11.5
9.3
4.7
6.0
15.2
14.2
13.1
11.2
11.3
2.3
1.2
0.6
0.6
0.8
7.7
4.6
0.9
0.8
1.1
12.5
13.5
13.5
12.1
11.9
15.7
15.2
15.8
14.9
14.5
N from
Concentration
Difference, ugN
26.1
20.6
30.0
12.5
13.7
31.3
27.7
16.1
13.4
8.9
43.2
33.4
60.2
86.9
93.0
18.0
16.4
45.9
114.8
116.5
1.5
1.8
NA
0.7
1.5
0.9
0.9
NA
1.3
1.7
22
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
NaCl Coated Quartz. Figure 18 summarizes the results of all the experiments by presenting the
initial filter removal efficiency and the efficiency after 1, 4, and 24 hours (or the last test point if
the exposure lasted less than 24 hours) and the average for the exposure period for all three test
gases. Appendix B contains the detailed time series plots. NaCl coated filters also appear to have
a small efficiency (less than 10%) to collect NO2 while they were relatively efficient in removing
HONO (30-50%). There was no data available for PAN due to equipment failure. Table 4
compares the amount of nitrate found on the filter with that calculated from the NOX
concentration difference before and after the filter. The results are similar to that observed for the
nylon filter.
100 N02 HONO
"aT
5)
ency (percen
i C
U C
in
nHy
/\
N
PAN
Initial
1 Hour
A 4 Hours
x 24 Hours
x Period Average
21 22 23 24 25
LRH HRH HRH LRH
HC HC HC HC
Experiment Number
26 27
LRH HRH
HC HC
Figure 18. Summary of removal efficiency tests of the NaCl coated quartz filters for removing
NO2, HONO and PAN.
Coated Quartz. Figure 19 summarizes the results of all the experiments by presenting
the initial filter removal efficiency and the efficiency after 1, 4, and 24 hours (or the last test
point if the exposure lasted less than 24 hours) and the average for the exposure period for all
three test gases. Appendix B contains the detailed time series plots. The removal efficiency is
very low for NC>2 and PAN while that for HONO is nearly 80%. These results also appear to be
independent of the RH. Table 4 compares the amount of nitrate found on the filter with that
calculated from the NOX concentration difference before and after the filter. The results are
similar to that observed for the nylon filter and NaCl coated filters.
23
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Efficiency (percentage)
NJ -fc* (J> CO O
000000
Summary of Experimental Results Quartz Filter (Filter 4) NaC2CO3 Coated
NO2 HO NO PAN
/
/
1 *
1
/
\~-^^*
21 22 23 24 25 26 27
LRH HRH HRH LRH LRH HRH
HC HC HC HC HC HC
Experiment Number
Initial
1 Hour
A 4 Hours
X 24 Hours
X Period Average
Summary of Experimental Results Quartz Filter (Filter 5) NaC2CO3 Coated
NO2 . MONO PAN
"aT
ency (percent
^ c
D C
' '
E
11J
/
/
* *
i
t^\
\
\^<
Initial
1 Hour
A 4 Hours
X 24 Hours
X Period Average
21 22 23 24 25 26 27
LRH HRH HRH LRH LRH HRH
HC HC HC HC HC HC
Experiment Number
Figure 19. Summary of removal efficiency tests of the replicate Na2(CO3) coated quartz filters for
removing NO2, MONO and PAN.
24
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
3.9 Additional QC Checks to Evaluate the NOy Analyzer Memory Effect
It is likely that the reported nitric acid removal efficiencies were biased low due to the time lag of
the analyzer when switched from measuring nitric acid the before denuder to measuring it after
the denuder. This is known as the "memory effect" and has been routinely reported when
measuring NOy in the atmosphere. It was necessary to sample repeatedly before and after the
denuder to characterize the removal of nitric acid. We could have sampled only after the denuder
and allowed the analyzer to reach its actual zero point, but then we could not monitor any
changes in the input concentration. In addition, as nitric acid penetrated some of the denuders,
the memory effect would again become significant.
We did perform two experiments to evaluate the memory effect. In the first we stopped the
routine cycling between before and after the denuder and sampled only after the denuder. In
addition we added NaCl coated filters after the denuders, which have been shown to be specific
in removing nitric acid (Perino et al., 1990). By doing this we expected to scrub out most of the
HNOs prior to the entrance of the TECO NOy converter. The HNCb source response was
measured prior to the experiment and found to be on average 49.4 ppbV with a standard
deviation of 1.4 ppbV. The test was conducted at 30% humidity. Figure 20 shows the results of
four hours of sequentially sampling below all five denuders at a six-minute cycling interval. All
one-minute data are illustrated here since we do not expect a need for the instrument to
equilibrate since the sample is expected to be free of any nitric acid. Each of the denuder paths
displayed similar response, with initial values of about 0.8 ppbV of NOy and dropping to 0.5
ppbV after approximately 4 hours. This 0.3 ppbV drop is likely from the converter volatizing
deposited HNCb on its interior surfaces over the four-hour period. This shows that there are no
nitrogenous species exiting the denuder other than perhaps nitric acid.
In the second experiment we measured the response time for the NOy analyzer after it cycled
from measuring nitric acid to zero air. Figure 21 shows the result. The instrument sampled the
high diffusion source HNCb for a period of 24 hours and yielded an average concentration of
45.52 ppbV. After the introduction of zero air at 10:29 the HNCb measured value goes down to
the 0.8 level after five minutes. After 35 minutes the HNOs level is down to 0.65 ppbV. Table 5
lists the data found on Figure 21 and calculated the theoretical denuder efficiency as a function of
time. As a result of the long delay in the TECO analyzer, the efficiency measurement was
recorded by taking the fifth minute point after measuring the concentration of the exit gas from
the denuder.
If we had waited longer, as 35 minutes, we would still be at 0.65 ppbV or 1.4% of the input
concentration. This memory effect clearly biased the efficiencies lower but represented on
average less than 1.8% of the original target gas. To facilitate the measurements with the
chemiluminescent analyzer to a point where the memory effect was reduced to 1% of the input
concentration would have required 3 hours between point instead of the 12 minutes employed in
the study. This would have reduced the resolution of the efficiency experiment and is clearly time
wise, beyond the scope of the experiment.
25
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
HNO3 Source 49.4
Standard Deviation 1.4 ppbV
Time (PST) (hh:mm)
Figure 20. NOy Measurements at the outlet of each denuder with NaCI coated filters added to
scrub out any remaining nitric acid.
n
o
13
'c
o
O
«
O
50
40-
30
20
9:
Injection of
/ Zero Air
^_ ^ I
Average Concentration 45.52 ppbV
X
Concentration
5 Minutes
After Zero
Air Injection
I S
iO 9:57 10:04 10:12 10:19 10:26 10:33 10:40 10:48
Concentration
35 Minutes
After ^ero
Air Injection
N^
10:55 11:02 11
time (PST) (hh:mm)
Figure 21. Response of the chemiluminescent NOy analyzer to a change in average injection
concentration from 45 ppbV of HNO3to zero air.
26
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
Table 5. Data showing the first ten minutes after injection of zero air into the Teco 42 NOy
converter.
Time
10:28
10:29
10:30
10:31
10:32
10:33
10:34
10:35
10:36
10:37
10:38
HNO3
(ppbV)
47.31
47.05
2.72
1.36
1.00
0.91
0.81
0.80
0.76
0.80
0.78
% Of Input
Concentration
103.9%
103.4%
6.0%
3.0%
2.2%
2.0%
1.8%
1.8%
1.7%
1.8%
1.7%
27
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University of California, Riverside, CE-CERT
Evaluation of Diffusion Denuder Coatings
4. Summary and Conclusions
Table 6 summarizes the removal efficiency for both the filters and denuders by averaging all the
test results for a given test gas and sampling medium. These averages provide a robust
comparison of each sampling method and allows for a direct comparison between methods.
Based on this table and the previously described data the following conclusions may be drawn:
Table 6. Summary of removal efficiencies.
Test
Gas
HNO3
NO2
HONO
PAN
Nylon
Filter
NA
14
13
3.8
Na2C03
Filter
NA
3.8
76
3.5
NaCl
Filter
NA
7.0
39
NA
Annular
MgO
85
5.1
85
63
Annular
Na2CO3
68
4.6
82
23
Annular
NaCl
60
4.2
21
23
Honeycomb
MgO
81
3.0
81
67
Honeycomb
Na2CO3
83
1.7
76
21
Nitric Acid
Both magnesium oxide and sodium carbonate coated denuders were generally efficient at
removing nitric acid while the sodium chloride coated annular denuder was not. None of the tests
showed over 95% efficiency, but this may have been due to residual nitric acid in the sampling
lines of the test apparatus. While the removal efficiencies for both the annular and honeycomb
denuders were similar, the honeycomb design possessed a much higher capacity. This was
evidenced by breakthrough using the carbonate coated annular denuder but not with the
carbonate coated honeycomb denuder when both were exposed to SOppb of nitric acid over
several days.
Nitrogen Dioxide
Except for the nylon filter and perhaps the sodium chloride-coated filter, none of the sampling
media removed more than a few percent of nitrogen dioxide. Since NO2 is often a dominant
nitrogenous species, the use of this filter for selectively collecting nitrate may, based on our data,
produce a positive bias.
Nitrous Acid
Both carbonate and magnesium oxide-coated denuders and carbonate coated filters effectively
removed nitrous acid. Sodium chloride was less efficient and nylon was even less effect in
removing this gas. Trace impurities of nitric acid (typically 3%) in the HONO no doubt
contributed to the apparent removal efficiency.
Peroxyacetyl Nitrate
Magnesium oxide was more efficient in removing PAN compared with sodium carbonate or
sodium chloride, which were about equally efficient. Neither nylon nor carbonate coated filters
removed a significant amount of PAN.
28
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University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
5. Recommendations and Future Research
5.1 Recommendations
The recommendations based on this study depend on whether the objective is to measure nitric
acid or total particulate nitrate.
Nitric Acid
When measuring nitric acid it is expected that denuders are renewed after each sampling period,
presumably no longer than 24 hours. The denuder would be expected to be efficient and selective
in removing this acid and easily extracted. While both annular and honeycomb denuders with
either carbonate of magnesium oxide coating would be efficient, the carbonate coating is less
efficient at removing PAN and is therefore preferred. In either case nitrous acid is also efficiently
collected and, therefore, the results will be biased high since the nitrite (and also PAN) collected
will be readily oxidized to nitrate by ambient concentrations of ozone (Perrino et al., 1990). It
should be noted that the honeycomb denuder holders were constructed of stainless steel, and
some of the removal efficiency for nitric acid in particular may be due to these surfaces. If this
denuder is to be used to measure nitric acid (as opposed to removing it for measuring particulate
nitrate), the recovery of nitric acid by the denuder itself should be evaluated. Sodium chloride-
coated annular denuders were found to not be sufficiently efficient in removing nitric acid under
these conditions.
If measuring particulate nitrate is desired using the same denuder to quantify nitric acid as the
gaseous stripper, the carbonate-coated filter is recommended over the nylon. Although the
carbonate-coated filter efficiently removes nitrous acid, this already has been removed by the
denuder. Particulate nitrate collected on nylon filters will likely be biased high due to the
collection of nitrogen dioxide.
Particulate Nitrate
When measuring particulate nitrate it is only necessary to remove the nitric acid and allow
particles to pass through. In this case the denuder does not need to be changed regularly and
preferably it is only renewed for cleaning purposes. Selectivity is not necessary, and depending
on the filter medium used, not even necessarily desirable. A denuder that strips all of the
nitrogenous gases would allow any filter that quantitatively traps ammonium nitrate be used to
collect particulate nitrate. Based on two weeks of exposure to over SOppb of nitric acid, the
annular denuder coated with magnesium oxide and the honeycomb with either coating can be
used for at least 16,800 ppb-hours. From past measurements in Claremont, CA, the highest daily
average we observed using a tunable diode laser absorption spectrometer was 12ppb. This
concentration corresponds to two months of sampling under these conditions. Since this was the
highest daily concentration observed in the peak smog season in a location that likely has the
highest nitric acid concentrations in the United States, this denuder should be capable of being
effective for significantly longer periods for other parts of the country. The magnesium oxide
coating is likely to have greater capacity than the carbonate. Because of this potential and its
ability to remove more PAN than carbonate, this coating is recommended for this application.
29
-------
University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
The honeycomb design is also likely to have more capacity, but this would require further
evaluation
With a magnesium oxide denuder to strip nitric acid, the best choice of a filter to collect nitrate
would be the carbonate coated since it is less likely to collect NO2 than nylon filters. Sodium
chloride coated filters may also be suitable, but we did not have results for this substrate on either
nitric acid or PAN.
5.2 Future Research
Previous research has shown that denuders coated with sodium chloride, sodium carbonate and
magnesium oxide are all nearly 100% efficient in removing nitric acid from ambient air (Febo et
al., 1990). Future research should focus testing removal efficiency using spiked ambient air.
Since ambient air will contain a variety of nitrogenous species, the use of a chemiluminescent
NOX analyzer for determining concentration before and after a test substrate would clearly not be
useful. More selective methods should be used, such as tunable diode laser absorption
spectrometers (TDLAS).
For nitric acid measurement both magnesium oxide and sodium carbonate-coated denuders will
bias the results high. Sodium chloride coating appears to be, as reported previously (Perrino et
al., 1990), much more selective in removing nitric acid, having very little affinity for nitrous acid
and slightly more for PAN. In our studies the nitric acid removal efficiency of the sodium
chloride-coated annular denuder was lower than the other substrates. The desirable selectivity of
the NaCl coating also may result in an apparent lower removal efficiency compared with other
coating substrates if significant amounts of other nitrogenous species are present in the nitric acid
test gas (since the chemiluminescent analyzer will also respond to them). Although we have
shown that our nitric acid source appears to contain little contamination, using a TDLAS to test
efficiency would be a more quantitative approach.
Since the honeycomb denuder design appeared to possess greater efficiency and capacity, we
recommend evaluating the use of sodium chloride coatings in removing nitric acid. As previously
mentioned, the effect of the stainless steel denuder holder must first be evaluated. Evaluation of
the lower capacity annular denuder showed a peculiar initial loss in denuder efficiency removal
efficiency followed by stabilization. Additional or substitute wetting agent may result in
maintaining high removal efficiency. Using longer annular denuder sections may also increase
the removal efficiency.
Both nylon and sodium chloride-coated filters appeared to collect small amounts of NC>2, HONO,
and PAN. Further evaluation is needed to confirm the significance of this, preferably using
spiked ambient air. The use of a TDLAS as a detector would provide a quantitative result since it
would be more selective and have less sample hangup than a chemiluminescent analyzer.
Carbonate-coated filters showed a high removal efficiency for HONO and, therefore, should be
avoided for collecting particulate nitrate without an effective nitric acid denuder, as the results
are likely to be biased high. Additional testing is recommended to determine the efficiency of
sodium chloride coated filters for collecting nitric acid. A more rigorous analysis of impurities
and sample line hold up (if a chemiluminescent analyzer was used for measurements) would
provide a more accurate removal efficiency determination.
30
-------
University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
Analysis of filter extracts by a method quantifying total nitrogen would improve the mass
balance when removal is compared with adsorption. Although the NOX analyzer showed low
removal efficiencies of PAN by the various filters, a significant amount of nitrate was found on
these filters after sampling. Further evaluation is needed to determine the fate of PAN on these
filters.
31
-------
University of California, Riverside, CE-CERT Evaluation of Diffusion Denuder Coatings
References
Allegrini, I; Febo, A.; Perrino, C.; and Masia, P. (1994) Measurement of atmospheric nitric acid
in gas phase and nitrate in particulate matter by means of annular denuuders. Intern. J. Anal.
Chem. 54, 183-201.
Carter, W.P.L.; Luo, D.; Malkina, I.L.; and Fitz, D. (1995) "The University of California,
Riverside Environmental Chamber Data Base for Evaluating Oxidant Mechanisms. Indoor
Chamber Experiments through 1993,' Report submitted to the U.S. Environmental Protection
Agency, EPA/AREAL, Research Triangle Park, NC, March 20.
Febo, A.; Perrino, C.; Gherardi, M.; Sparapani, R. Evaluation of a High-Purity and High-Stability
Continuous Generation System for Nitrous Acid; Environ. Sci. Technol. 1995, 29, 2390-2395.
Fitz., D.R.; Pankratz, D.V.; Bumiller, K.; Smith M. (2001) Measurement of NO2 and PAN by
Gas Chromatography with Luminol Detection. To be submitted to Atmospheric Environment.
Holdren, M.W.; Spicer, C.W. Field Compatible Calibration Procedure for Peroxyacetyl Nitrate.
Environ. Sci. Technol. 1984, 18:113-116.
Perrino, C.; DeSantis, F.; and Febo, A. (1990) Criteria for the choice of a denuder sampling
technique devoted to the measurement of atmospheric nitrous and nitric acid. Atmos. Environ.
24A, 617-626.
Winer, A.M; Peters, J.W.; Smith, J.P.; and Pitts, J.N., Jr. (1974) Response of commercial
chemiluminescent NO-NOX analyzers to other nitrogen-containing compounds. Environ. Sci.
Technol. 8, 1118-1121
32
-------
TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA-454/R-02-011
2
4. TITLE AND SUBTITLE
Evaluation of Diffusion Denuder Coatings for Removing Acid
Gases from Ambient Air
7. AUTHOR(S)
Dennis R.Fitz
9. PERFORMING ORGANIZATION NAME AND ADDRESS
College of Engineering-Center for Environmental Research and
Technology
University of California, Riverside, CA 92521
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 2771 1
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
April 2002
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
Assistance agreement #
GX82866301
13. TYPE OF REPORT AND PERIOD COVERED
Final, life of project 1 yr.
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
This report represents an initial study of the efficiency and capacity of denuders used in EPA's National
PM2.5 Chemical Speciation Trends Network. Additional work is needed to clarify uncertainty and
allow for additional quantitative results.
16. ABSTRACT
This study evaluated the efficiency and capacity of several commonly used denuder styles and coatings,
with an emphasis on denuders used in EPA's National PM2.5 Chemical Speciation Trends Network
(STN). Denuder styles included annular and honeycomb denuders coated with either magnesium oxide,
sodium carbonate, or sodium chloride. Collection filters included nylon or filters impregnated with
sodium carbonate (N^CC^) or sodium chloride (NaCl). Denuder coatings and reactive filters were
tested for their removal efficiency of nitric acid, nitrogen dioxide (NO2), nitrous acid (HNO2), and
peroxyacetly nitrate (PAN). Most important to the STN is the ability to collect ammonium nitrate with
minimal bias and interference from other nitrogen gases, such as, NO2, HNO2, and PAN. Results
indicated that MgO denuders were most efficient for removing HNO3, HNO2, and PAN with the largest
capacity and that honeycomb denuders had larger capacity than annular denuders. Nylon filters
adsorbed slightly more NO2 than those coated with Na^O;, or NaCl, but both of the latter adsorbed
significantly larger amounts of HNO2 Results suggest that a MgO coated honeycomb or annular
denuder followed by a Na2CO3 or nylon filter will minimize interferences for the collection of
ammonium nitrate. The choice between Na2CO3 and nylon may be based on expected concentrations of
HNO7, with nylon having a lower affinity for HNO7 than Na,CO3
17.
KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
nitric acid, denuders, nylon filters, impregnated
filters, sodium carbonate, ammonium nitrate
18. DISTRIBUTION STATEMENT
Release Unlimited
b. IDENTIFIERS/OPEN ENDED TERMS
Air Pollution control
19. SECURITY CLASS (Report)
Unclassified
20. SECURITY CLASS (Page)
Unclassified
c. COSATI Field/Group
21. NO. OF PAGES
32 + appendices
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 1 (Low Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
90.0
an n
7n n
fin n
50.0
40 n
on n
on n _
-inn
n n
____ _ __j__H--__-
_v->^- ---------
HN03
- Efficiency
% _....
^^jp^lWlilJ11^ f... ^IM^twIfl^e**** 4* ___ _.%»_»*«,_ » _ *
^
- 95.0%
on no/
oc no/.
on r\OL
jc. no/
yn noA
RC no/
fin no/
cc no/
Kn no/.
28-Mar 31 -Mar 3-Apr
Date (2001)
Denuder Efficiency
-------
100.0
90.0
80.0
70.0
60.0
c
o
o
o
O
CO
o
50.0
40.0
30.0
20.0
10.0
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 1 (Low Humidity, High HNO3 Concentration)
HNO3
Efficiency
28-Mar
31-Mar
Date (2001)
100.0%
95.0%
90.0%
85.0%
80.0% u
0)
-- 75.0%
0)
3
70.0% S
Q
65.0%
60.0%
-- 55.0%
50.0%
3-Apr
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 1 (Low Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
on n
an n
7n n
en n
50.0
4n n
on n
on n -
-inn
n n
HNO3
- Efficiency
vw» m %
^"w «w < wp^^t fiJ^^c* ^*^ ^* m II*BH§
'"^"^"^
_ ~ ^.«^fi-
jv-~ _-__ _ -_~ ~-~~ ~-~~ ~
W^^M V,
^X.-o
.
«-
MM? NLJ^J^M^S.M%INVJM^>1,^
28-Mar 31-Mar
Date (2001)
QC
on
QC
on
JC.
70
cc
fin
cc
cn
3-Apr
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
Denuder Efficiency
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 1 (Low Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
qn n
80 0
70 n
en n
50.0
40 0
on n
on n
-inn
n n
HNO3
- Efficiency
___^-^^j-_-^---^----~^
-J"
^"*« *Wnj~r"i«-_
**.
*
qc r\OL
90 0%
QC no/.
on no/,
- 75.0%
?n n%
RC no/
fin n%
cc n%
en no/.
28-Mar 31 -Mar 3-Apr
Date (2001)
Denuder Efficiency
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 1 (Low Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
on n
on n _
70 0
fin n
50.0
40 0
on n
on n _
-inn
n n
HNO3
- Efficiency
_^__.^^---.--^^^
^^ ** >rf^ Itli i m i >M
--^---^^.^^^^^
28-Mar 31-Mar
Date (2001)
QC
on
QC
on
75
70
RC
fin
cc
en
3-Apr
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
Denuder Efficiency
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 2 (Low Humidity, High HNO3 Concentration) Using Spent Denuder
HNO3 Concentration (ppbV)
90.0
an n
7n n
en n
50.0
40 n
on n
on n -
-inn
n n
HN03
- Efficiency
«.**** ,nn^,nm* iM^^*^^>^^^*^>>l'>*^*^*^*J'L^Vit»%%»*^.?J%^«»'^V.'ttb**^>'
*~.w«.*
5-Apr 8-Apr
Date (2001)
- 90
on
vn
en
50
4D
on
on
m
n r
11 -Apr
0%
0%
0%
0%
0%
0%
0%
0%
0%
%
Denuder Efficiency
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 2 (Low Humidity, High HNO3 Concentration) Using Spent Denuder
HNO3 Concentration (ppbV)
on n
on n _
70 0
fin n
50.0
40 0
on n
on n _
-inn
n n
HNO3
- Efficiency
. ^^^ . m . vw "-/
"* ^^^^^^^^^^^^^^^^^^
~~~"~-~-~~-^_>^_^--_--x.--~ __-^-_ __-
on r\o/n
an no/
yn no/
en no/. u
i. en C
DOC
DOC
P vO v
^ 0^ C
inuder Efficien
Q
on no/
on no/
m n%
n no/.
5-Apr 8-Apr 1 1 -Apr
Date (2001)
-------
100.0
90.0
80.0
D.O
S
Q.
Q.
~ 60.0
on
5
£
0)
o
o
o
CO
O
50.0
D.O
30.0
20.0
10.0
0.0
5-Apr
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 2 (Low Humidity, High HNO3 Concentration) Using Spent Denuder
HNO3
Efficiency
8-Apr
Date (2001)
100.0%
90.0%
80.0%
70.0%
60.0% u
0)
-- 50.0%
0)
c
c
0)
a
30.0%
20.0%
D.0%
0.0%
11-Apr
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 2 (Low Humidity, High HNO3 Concentration) Using Spent Denuder
HNO3 Concentration (ppbV)
on n
an n
7n n
en n
50.0
4n n
on n
on n -
-inn
n n
HNO3
- Efficiency
5-Apr 8-Apr
Date (2001)
!«
on
on
70
fin
50
4D
on
on
m
n r
11 -Apr
0%
0%
0%
0%
0%
0%
0%
0%
0%
%
Denuder Efficiency
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 2 (Low Humidity, High HNO3 Concentration) Using Spent Denuder
HNO3 Concentration (ppbV)
on n
an n
7n n
en n
50.0
4n n
on n
on n -
-inn
n n
HNO3
- Efficiency
^P^^^p^^
^
d**!^^ M^^i^^*1^ J "" J^^^^^Vg,
^"* W~~^^i^9 1
,
5-Apr 8-Apr
Date (2001)
on
on
70
en
50
4n
on
on
m
n r
11 -Apr
0%
0%
0%
0%
0%
0%
0%
0%
0%
%
Denuder Efficiency
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 3 (Repeat of Experiment 1, Low Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
an n
70 0
en n
c.r\ n -
40 0
on n
on n -
m n
n n
HNO3
- Efficiency
__
~ - "-*" .-** ~
f
QC no/
on no/
QC nOA
on noA
yc; no/
yn no/
RC noA
fin no/
cc noA
Kn no/.
10-Apr 13-Apr 16-Apr
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 3 (Repeat of Experiment 1, Low Humidity, High HNO3 Concentration)
100.0
90.0
80.0
70.0
60.0
c
o
50.0
o
o
O 40.0
CO
o
30.0
20.0
10.0
0.0
10-Apr
13-Apr
HNO3
Efficiency
16-Apr
-- 90.0%
85.0%
100.0%
95.0%
80.0% u
0)
75.0% LU
i_
0)
3
70.0% S
Q
65.0%
60.0%
55.0%
50.0%
Date (2001)
-------
100.
10.0
0.0
10-Apr
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 3 (Repeat of Experiment 1, Low Humidity, High HNO3 Concentration)
13-Apr
16-Apr
100.0%
90.0%
80.0%
70.0%
60.0% o
0)
.0% IS
i_
0)
c
.0% S
Q
30.0%
-- 20.0%
10.0%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 3 (Repeat of Experiment 1, Low Humidity, High HNO3 Concentration)
100.0
90.0
80.0
70.0
60.0
c
o
50.0
o
o
O 40.0
CO
o
30.0
20.0
10.0
0.0
10-Apr
HNO3
Efficiency
13-Apr
16-Apr
-- 90.0%
-- 70.0%
100.0%
80.0%
60.0% o
0)
50.0%
i»
0)
c
40.0% S
Q
30.0%
-- 20.0%
-- 10.0%
0.0%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 3 (Repeat of Experiment 1, Low Humidity, High HNO3 Concentration)
100.0
90.0
80.0
70.0
60.0
c
o
50.0
o
o
O 40.0
CO
o
30.0
20.0
10.0
0.0
10-Apr
13-Apr
HNO3
Efficiency
16-Apr
-- 90.0%
85.0%
100.0%
95.0%
80.0% u
0)
75.0% LU
i_
0)
3
70.0% S
Q
65.0%
60.0%
55.0%
50.0%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 4 (Low Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
on n _
70 0
fin n
c.r\ n _
40 0
on n
on n _
-inn
1 U.U
n n
HNO3
- Efficiency
* *
qn noA
an no/
yn r\%.
en noA o
0)
'o
en no/ Uj
i»
0)
c
AH n°A ni
Q
on noA
on no/
-i n no/
1 U.Uvo
n no/.
17-Apr 18-Apr 19-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 4 (Low Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
90.0
on n
70 0
en n
c.r\ n -
40 0
on n
on n -
1 n n
n n
^ ^
HN03
- Efficiency
- 80.0%
fin n%
4n n%
on n%
n n%
on n%
4n n%
-fin n%
on no/.
i nn no/.
17-Apr 18-Apr 19-Apr
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 4 (Low Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
an n
70 0
en n
c.r\ n -
40 0
on n
on n
-inn
1 U.U
n n
HNO3
- Efficiency
_
-
- _ _ _ - -
.
qn noA
an no/
yn r\%.
en noA o
0)
|o
en no/ jS
i»
0)
c
AH n% ni
Q
on noA
on no/
-i n no/
1 U.Uvo
n no/.
17-Apr 18-Apr 19-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 4 (Low Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
on n _
70 0
fin n
c.r\ n _
40 0
on n
on n _
-inn
1 U.U
n n
HNO3
- Efficiency
.
***
qn noA
an no/
7D n%
en noA o
0)
'o
en no/ Uj
i»
0)
c
AH n°A ni
Q
on noA
on no/
-i n no/
1 U.Uvo
n no/.
17-Apr 18-Apr 19-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 4 (Low Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
on n
70 0
en n
c.r\ n -
40 0
on n
on n -
10 0
n n
HN03
- Efficiency
- 50.0%
- 0.0%
o
0)
'o
.en no/ Uj
i«
0)
3
c
0)
a
- -100.0%
- -150.0%
onn no/.
17-Apr 18-Apr 19-Apr
Date (2001)
-------
Experiment 5: Investigation of NaCI Coated Denuders
(Low Humidity, Low HNO3 Acid Concentration)
Denuder Efficiency
1 UU.U /O
qc no/
an n% _
oc (\OL
an no/
jc no/
70 n%
RE; n% -
fin n%
cc n%
en n%
HNO3 Concentration Approximately 10
l Annular Denuder 2
Honeycomb Denuder
1 l ,
A
' A - . * * , , A '* , ,
i
i
i
i
1 ,
i i
ii,
' '
ii" ii
:
12:00 16:00 20:00 0:00 4:00 8:00 12:OC
Time (Data Taken April 19-20, 2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
HNO3 Concentration (ppbV)
on n
yu.u
on n
7n n
Rn n
en n
4n n
on n
on n
m n
n n
HN03
- Efficiency
on no/
oU.Uvo
fin n%
4n n%
on n%
n n%
.on n%
4n n%
fin n%
.an n%
i nn no/.
19-Apr 20-Apr
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
HNO3 Concentration (ppbV)
on n -
on n
70 0
60 0
en n
40 0
on n
-inn
n n
HN03
- Efficiency
-
-
_ - - -
an n%
on n%
7n n%
fin n%
en n%
4n n%
on n%
on n%
1 n n%
n no/.
19-Apr 20-Apr
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
HNO3 Concentration (ppbV)
on n -
on n
70 0
60 0
en n
40 0
on n
-inn
n n
HN03
- Efficiency
-
-
~ -
an n%
on n%
7n n%
fin n%
en n%
4n n%
on n%
on n%
1 n n%
n no/.
19-Apr 20-Apr
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
HNO3 Concentration (ppbV)
on n _
on n
oU.U
70 0
60 0
en n
40 0
on n
on n
m n
n n
HN03
- Efficiency
on no/
on no/
oU.Uvo
yn (]%.
fin no/ o
.92
'o
£
en noA LLI
i_
-------
EPA Denuder Efficiency Evaluation Denuder 5
HNO3 Concentration (ppbV)
on n -
on n
70 0
60 0
en n
40 0
on n
-inn
n n
HN03
- 50.0%
- 0.0%
o
c
0)
'o
£
en r\o/n LU
c
i
- -100.0%
- -150.0%
onn no/.
19-Apr 20-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 6 (High Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
an n
70 0
en n
c.r\ n -
40 0
on n
on n -
10.0
n n
HNO3
- Efficiency
_ __ -~ -_--_- ~--~
qn n%
an no/
?n n%
fin n% o
0)
|o
en no/ Uj
i»
0)
c
Af\ Cl°/n fll
Q
on n%
on no/
- 10.0%
n no/.
22-Apr 23-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 6 (High Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
an n
70 0
c.r\ n -
40 0
on n
on n -
10.0
n n
HNO3
- Efficiency
~ - _
-
- - _ _ -
qn r\o/n
an no/
yn noA
>
en no/ o
DU.U/O g
a>
|o
en no/ jS
i»
0)
c
AH n% ni
Q
on noA
on no/
- 10.0%
n no/.
22-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 6 (High Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
an n
70 0
en n
c.r\ n -
40 0
on n
on n -
10.0
n n
HNO3
- Efficiency
^
"
qn (\OL
an no/
yn no/
en noA o
0)
'o
Kn no/ JS
i»
0)
c
AH n°A ni
Q
on noA
on no/
- 10.0%
n no/.
22-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 6 (High Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
an n
70 0
en n
c.r\ n -
40 0
on n
on n -
10.0
n n
HNO3
- Efficiency
_--___- -- - -
qn n%
an no/
?n n%
fin n% o
0)
|o
en no/ Uj
i»
0)
c
An n% ni
Q
on n%
on no/
- 10.0%
n no/.
22-Apr 23-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 6 (High Humidity, Low HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
an n
70 0
en n
c.r\ n -
40 0
on n
on n -
10.0
n n
HNO3
- Efficiency
~--~ " ~ - -_ - _ -
qn no/.
an no/
jn no/
en no/. o
0)
|o
Kn no/ JS
i»
0)
c
Af\ C\OL Q<
Q
on no/
on no/
- 10.0%
n no/.
22-Apr
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 7 (High Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
on n _
70 0
fin n
50 0
40 0
on n
on n _
10.0
n n
HNO3
- Efficiency
-=~-« ^^-rf^^-^^^^^-^^^^^^^,^^
****.« --"'V>^^w*^^Vxv^; r . '-'V~- » .
qn noA
an no/
yn noA
en noA o
0)
|o
50 0% IS
i_
0)
c
AC\ nOA fi«
Q
on (]%.
on no/
- 10.0%
n no/.
24-Apr 26-Apr 28-Apr 30-Apr 2-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 7 (High Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
nn n
on n
70 0
fin n
c.r\ n -
40 0
on n
on n
10.0
n n
HNO3
- Efficiency
*"^"e" "i*w-^-
v ~ -f ~
***» rf/V^ lA^.vV^^tf^^A^^'.'^ii^^X,^^**1^*1*'**' v*« *
" "* "^
Qn n%
on n%
7n r\%.
en n% o
a>
'o
en no/ H]
1»
0)
c
AH n°A ni
Q
on n%
on no/
- 10.0%
n no/.
24-Apr 26-Apr 28-Apr 30-Apr 2-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 7 (High Humidity, High HNO3 Concentration)
HNO3 Concentration (ppbV)
Qn n
on n _
70 0
60.0
cn n
40 0
on n
20.0
-inn
n n
HNO3
- Efficiency
-
s.
B
~~ ^^^^^^^~*
ta
-*wy ~- ^^"NVrv^v-vvw^v^v^
24-Apr 26-Apr 28-Apr 30-Apr
Date (2001)
%A
Qn
on
?n
60
cn
4n
on
20
m
n r
0%
0%
0%
0%
0%
0%
0%
0%
0%
Denuder Efficiency
2-May
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 7 (High Humidity, High HNO3 Concentration)
100.0
90.0
80.0
70.0
|
1 60.0
c
o
5
£
>;'
26-Apr
28-Apr
Date (2001)
30-Apr
100.0%
90.0%
80.0%
70.0%
60.0%
50.0%
J.0%
30.0%
20.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
-- 10.0%
o.c
2-May
-------
100.0
90.0
80.0
70.0
60.0
c
o
50.0
o
o
O 40.0
CO
o
30.0
20.0
10.0
0.0
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 7 (High Humidity, High HNO3 Concentration)
HN03
- Efficiency
24-Apr 25-Apr 26-Apr 27-Apr 28-Apr 29-Apr 30-Apr 1-May 2-May
Date (2001)
100.0%
90.0%
80.0%
70.0%
60.0% u
0)
50.0% LU
i_
0)
3
40.0% S
Q
30.0%
20.0%
10.0%
0.0%
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 8 (High Humidity, High NO2 Concentration)
f
Q.
o
ration (|
Concent
\j
OJ
O
qn n
an n
70.0
fin n
en n
40 0
on n
on n
m n
n n
5-N
NO2
- Efficiency
lay 6-May 7-May
Date (2001)
90 0%
on no/.
- 70.0%
60 0%
en no/,
^.n n%.
on no/,
1 n n%
n n%
r i
Efficien
L.
0)
D
C
0)
a
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 8 (High Humidity, High NO2 Concentration)
f
Q.
o
ration (|
Concent
\j
OJ
o
on n
on n _
70 n
fin n
en n
40 0
on n
on n
m n
o.o -
5-N
NO2
- Efficiency
-s ,«t % % t 1 1 1 1 *t
*
lay 6-May 7-May
Date (2001)
qn noA
an no/
7n n%
en noA o
a>
'o
E
en noA LLI
i»
0)
c
4n n% a)
on noA
on noA
1 n n%
- 0.0 /u
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 8 (High Humidity, High NO2 Concentration)
f
Q.
o
C
O
5
Concent
VJ
OJ
o
on 0
an n
70 0
en 0
en 0
40 0
on n
90 0
100
0 0
5-N
NO2
- Efficiency
lay 6-May 7-May
Date (2001)
- 90.0%
- 70.0%
o
c
- 50.0% o
it
LU
0)
c
c
0)
- 30.0% °
- 10.0%
1 n n%.
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 9 (Low Humidity, High NO2 Concentration)
f
Q.
o
ration (|
Concent
\j
OJ
o
2
Qn n
on n
70 0
fin n
c.r\ n -
40 0
^n n
on n
-inn
On
7-N
N02
- Efficiency
"
-
lay 8-May 9-May
Date (2001)
qn n%
sn n%
?n n%
Rn n% o
0)
|o
en no/ H]
1»
0)
c
40 0% ^
Q
in no/
on n%
in n%
Ono/.
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 9 (Low Humidity, High NO2 Concentration)
f
Q.
o
ration (|
Concent
\j
OJ
O
qn n
80.0
fin n
en n
40 0
on n
on n
m n
n n
7-N
NO2
- Efficiency
lay 8-May 9-May
Date (2001)
90 0%
- 80.0%
7n n%
fin n% o
a>
'o
E
en n% LLJ
i»
0)
c
c
40 0% ^
Q
on n%
1 n n%
n n%
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 9 (Low Humidity, High NO2 Concentration)
f
Q.
o
ration (|
Concent
\j
OJ
O
qn n
800
fin n
en n
40 0
on n
m n
n n
7-N
NO2
- Efficiency
.....** *..... .**** "
lay 8-May 9-May
Date (2001)
Qn n%
- 80 0%
7n n%
Rn n%
en n%
4n n%
on n%
on n%
1 n n%
n n%
r i
Efficien
L.
0)
c
c
*1>
a
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 9 (Low Humidity, High NO2 Concentration)
f
Q.
o
ration (|
Concent
\j
OJ
O
qn n
80.0
fin n
en n
40 0
on n
on n
m n
n n
7-N
NO2
- Efficiency
. *
-
~ ~ - _ _
lay 8-May 9-May
Date (2001)
90 0%
- 80.0%
7n n%
en 0% o
0)
'o
E
en n% LLJ
i»
0)
c
c
40 0% ^
Q
on n%
1 n n%
n n%
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 9 (Low Humidity, High NO2 Concentration)
f
Q.
o
ration (|
Concent
\j
OJ
O
qn n
80.0
fin n
en n
40 0
on n
on n
m n
n n
7-N
NO2
- Efficiency
j
lay 8-May 9-May
Date (2001)
90 0%
- 80.0%
7n n%
en n% o
a>
'o
E
en n% LLJ
i»
0)
c
c
40 0% ^
Q
on n%
1 n n%
n n%
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 10 (Low Humidity, Low NO2 Concentration)
AC n
40 0
f
Q.
Q. on n
0
S p50
c
0)
o
c
,9 on n
OJ
O
15.0
m n
c n
n n
9-N
N02
- Efficiency
_
"
lay 10-May
qn n%
an no/
7n no/.
Rn n% o
0)
|o
en no/ jS
i»
0)
c
An n°/, ni
Q
- 30.0%
on no/
m n%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 10 (Low Humidity, Low NO2 Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
0
S p50
c
0)
o
c
,9 on n
OJ
O
i c n
m n
c n
n n
9-N
NO2
- Efficiency
~ - - _ - - - .----
lay 10-May
qn n%
an no/
7n n°A
fin no/, o
a>
|o
en no/ jS
i»
0)
c
AC\ Cl°/n fll
Q
30 0%
on no/n
m n%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 10 (Low Humidity, Low NO2 Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
0
S p50
c
0)
o
c
,9 on n
OJ
O
15.0
m n
c n
n n
9-N
NO2
- Efficiency
^
lay 10-May
qn n%
an no/
7n n°A
en noA o
0)
|o
en no/ jS
i»
0)
c
An n% ni
Q
- 30.0%
on no/
m n%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 10 (Low Humidity, Low NO2 Concentration)
AC n
40 0
oc n
f
Q.
o. on n
0
S 250
c
0)
o
c
,9 on n
OJ
O
-\ c n
m n
c n
n n
9-N
NO2
- Efficiency
_
lay 10-May
qn n%
an no/
yn noA
fin n% o
0)
|o
en no/ jS
i»
0)
c
c
a
on noA
on no/
m n%
n noA
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 10 (Low Humidity, Low NO2 Concentration)
AC n
40 0
oc n
f
Q.
Q. ^.n n
0
?
2 05 n
c
o
c
,9 on n
OJ
O
-\ c n
m n
c n
.u -
9-N
NO2
- Efficiency
_ _
T '
lay 10-May
qn n%
an no/
7n n°A
en noA o
0)
|o
en no/ jS
i»
0)
c
An n% ni
Q
30 0%
on no/n
m n%
.U%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 11 (High Humidity, Low NO2 Concentration)
50.0
45.0
40.0
35.0
1 30.0
o
£ 25.0
0)
o
c
O 20.0
15.0
10.0
5.0
0.0
100.0%
90.0%
80.0%
70.0%
60.0% u
0)
50.0% u
i_
0)
=
40.0% S
Q
-- 30.0%
20.0%
10.0%
0.0%
10-May 11-May 12-May 13-May 14-May 15-May 16-May 17-May 18-May
Date (2001)
-------
50.0
45.0
40.0
35.0
30.0
o
| 25.0
0)
o
c
O 20.0
15.0
10.0
5.0
0.0 4-
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 11 (High Humidity, Low NO2 Concentration)
NO2
Efficiency
100.0%
90.0%
80.0%
70.0%
60.0%
0)
50.0%
i_
0)
c
40.0% S
Q
30.0%
20.0%
10.0%
4- 0.0%
10-May 11-May 12-May 13-May 14-May 15-May 16-May 17-May 18-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 11 (High Humidity, Low NO2 Concentration)
50.0
45.0
40.0
35.0
30.0
o
| 25.0
0)
o
c
O 20.0
15.0
10.0
5.0
0.0
NO2
Efficiency
100.0%
90.0%
80.0%
70.0%
60.0%
0)
50.0%
i_
0)
c
40.0% S
Q
30.0%
20.0%
10.0%
0.0%
10-May 11-May 12-May 13-May 14-May 15-May 16-May 17-May 18-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 11 (High Humidity, Low NO2 Concentration)
50.0
45.0
40.0
35.0
30.0
o
| 25.0
0)
o
c
O 20.0
15.0
10.0
5.0
0.0
NO2
Efficiency
100.0%
90.0%
80.0%
70.0%
60.0%
0)
50.0%
i_
0)
c
40.0% S
Q
30.0%
20.0%
10.0%
0.0%
10-May 11-May 12-May 13-May 14-May 15-May 16-May 17-May 18-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 11 (High Humidity, Low NO2 Concentration)
50.0
45.0
40.0
35.0
30.0
o
| 25.0
0)
o
c
O 20.0
15.0
10.0
5.0
0.0
100.0%
90.0%
80.0%
70.0%
60.0%
0)
50.0%
i«
0)
c
40.0% S
Q
30.0%
20.0%
10.0%
0.0%
10-May 11-May 12-May 13-May 14-May 15-May 16-May 17-May 18-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 12 (Low Humidity, High HONO Concentration)
MONO Concentration (ppbV)
an n
yu.u
an n
yn n
fin n
en n
4n n
30 0
on n
10, n
n n
MONO
an no/
yu.u /o
an no/
yn n%
fin n%
en no/
4n n%
30 0%
on no/
m n%
n no/.
21 -May
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 12 (Low Humidity, High HONO Concentration)
MONO Concentration (ppbV)
90.0
an n
7n n
fin n
en n
4n n
30 0
on n
m n
n n
MONO
- 90.0%
an no/
?n n%
fin n% o
0)
'o
en no/ Uj
i«
0)
c
An n% ni
Q
30 0%
on no/
m n%
n no/.
21 -May 22-May 23-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 12 (Low Humidity, High HONO Concentration)
AC n
40 0
oc n
f
Q.
f 30.0
o
|
0)
o
0
O on n
o
O
1 K n
m n
c n
n n
HONO
- Efficiency
"--"-- -'- ___ __ --
~
on n%
an 0%
TO n%.
- 60.0% g
a>
|o
en no/ jS
i»
0)
c
AC\ nOA fi«
Q
30 0%
on no/
m n%
n no/.
21 -May 22-May 23-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 12 (Low Humidity, High HONO Concentration)
HONO Concentration (ppbV)
90
80
70
60
50
40
30
20
10
0
n
n
n
n
o
n
n
~ ~ ~ ~ - - _
"---.
-
HONO
- Efficiency
-_
.
..
21 -May 22-May
on
on
?n
fin
en
4n
30
on
m
n r
0%
0%
0%
0%
0%
0%
0%
0%
0%
Denuder Efficiency
23-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 12 (Low Humidity, High HONO Concentration)
MONO Concentration (ppbV)
on n
an n
70 0
en n
en n
40 0
30 0
on n
m n
n n
-
~ _
~--
- - - _ _ nor
~ - _ - _ - Effic
^JO
;iency
~~-__
21 -May 22-May 23-May
100.0%
D.0%
80.0%
60.0%
50.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
30.0%
20.0%
J.0%
0.0%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 13 (High Humidity, High HONO Concentration)
MONO Concentration (ppbV)
900
sn n
7n n
fin n
en n
4n n
30 0
on n
m n
On
MONO
- Efficiency
~ ~ - - -
- 90 0%
sn n%
7n n%
fin n%
en no/
4n n%
30 0%
on n%
m n%
n no/.
23-May 24-May
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 13 (High Humidity, High HONO Concentration)
MONO Concentration (ppbV)
on n
on n
yn n
en n
en n
4D n
300
on n
m n
n n
MONO
- Efficiency
~ ~ -
- _
on noA
on noA
yn no/
en noA o
0)
'o
Kn no/ JS
i»
0)
c
AC\ nOA fi«
Q
- 30 0%
on no/
m n%
n no/.
23-May 24-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 13 (High Humidity, High HONO Concentration)
50.0
45.C
3.0
35.0
f
Q.
Q.
** 30 0
c
o
0)
o
o
o
O
I
5.0
20.0
15.0
10.0
5.0
0.0
HONO
Efficiency
23-May
24-May
100.0%
90.0%
80.0%
70.C
60.C
D.0%
30.C
20.0%
J.0%
0.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 13 (High Humidity, High HONO Concentration)
HONO Concentration (ppbV)
90 0
an n
70 n
fin n
c.r\ n -
4n n
30 0
on n
m n
n n
-------..
HONO
Efficiency
90 0%
an no/
yn no/
fin n% o
0)
|o
en no/ jS
i»
0)
c
Af\ HO/. fi«
Q
30 0%
on no/
m n%
n no/.
23-May 24-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 13 (High Humidity, High HONO Concentration)
MONO Concentration (ppbV)
on n
an n
70 0
en n
en 0
40 0
300
on n
m n
n n
~ ~ ~
nor
- Effic
^JO
;iency
23-May 24-May
100.0%
90.C
80.0%
70.C
60.0%
50.0%
J.0%
30.0%
20.0%
J.0%
0.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 14 (High Humidity, High HONO Concentration)
MONO Concentration (ppbV)
qn n
Rn n
?n n
Rn n
en n
4n n
30 0
on n
m n
On
MONO
- Efficiency
' . *
qn n%
RD n%
7n n%
Rn n%
en no/
4n n%
30 0%
on n%
m n%
n no/.
24-May 25-May
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 14 (High Humidity, High HONO Concentration)
HONO Concentration (ppbV)
qn n
an n
yn n
en n
en n
4n n
30 0
on n
m n
n n
HONO
- Efficiency
^ ^ ^ ^ ^
. .
qn noA
an no/
7D n%
en noA o
0)
|o
en no/ jS
i»
0)
c
AH n°A ni
Q
30 0%
on no/
m n%
n no/.
24-May 25-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 14 (High Humidity, High HONO Concentration)
AC n
40 0
oc n
f
Q.
^ 30 0
o
|
0)
o
0
O on n
o
O
1 K n
m n
c n
n n
HONO
- Efficiency
'
......*.....".
*
--" - " -"--" "--
Qn n%
on 0%
TO n%.
60 0% ""
a>
|o
en no/ jS
i_
0)
c
AH n°A ni
Q
30 0%
on no/
m n%
n no/.
24-May 25-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 14 (High Humidity, High HONO Concentration)
HONO Concentration (ppbV)
on n
an n
yn n
fin n
Kn n
4n n
?n n
on n -
m n
n n
_ ~
^
HONO
Efficiency
. *
on noA
an no/
?n n%
fin n% o
0)
'o
Kn no/ Uj
i»
0)
c
An n°A ni
Q
?n no/
on no/
m n%
n no/.
24-May 25-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 14 (High Humidity, High HONO Concentration)
100.0
90.0
80.0
70 0
f
Q.
f 60.0
o
5
£
0)
o
o
o
O
z
O
I
50.0
D.O
30.0
20.0
10.0
0.0
24-May
25-May
100.0%
90.C
80.0%
70.0%
60.0%
50.0%
30.0%
20.0%
J.0%
0.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 15 (High Humidity, Low HONO Concentration)
MONO Concentration (ppbV)
qn n
on n
OU.U
7n n
fin n
en n
4n n
on n
on n
m n
On
MONO
- Efficiency
~~~~~ -_-_
qn n%
on no/
oU.Uvo
7n n%
fin n%
en no/
4n n%
on n%
on n%
m n%
n no/.
25-May 26-May 27-May 28-May
Denuder Efficiency
Date (2001)
-------
100.0
90.0
80.0
70 0
f
Q.
f 60.0
o
5
£
0)
o
o
o
O
z
O
I
50.0
J.O
30.0
20.0
10.0
0.0
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 15 (High Humidity, Low HONO Concentration)
MONO
Efficiency
25-May
26-May
27-May
Date (2001)
28-May
100.0%
90.C
80.0%
70.0%
60.0%
50.0%
J.0%
30.0%
20.0%
J.0%
0.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 15 (High Humidity, Low HONO Concentration)
MONO Concentration (ppbV)
qn n
an n
7n n
en n
en n
4n n
on n
on n
m n
n n
MONO
- Efficiency
__- _ -_-__ " -~ ~~~~~~-_-~__ __-
qn noA
an no/
yn no/
fifl n% o
a>
|o
en no/ jS
i»
0)
c
AC\ nOA fi«
Q
on noA
on no/
m n%
n no/.
25-May 26-May 27-May 28-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 15 (High Humidity, Low HONO Concentration)
MONO Concentration (ppbV)
an n
yu.u
on n
7D n
fin n
en n
on n
on n
-inn
n n
MONO
- Efficiency
_~ ~ ""-"-___ -
~_~ _~_ _
a
an no/
yu.u /o
on noA
70 0%
>
cn r\Q/n o
0)
|o
^n n% LU
k.
0)
o
AC\ C\°/n m
Q
30 0%
on no/n
1 n n%.
n no/_
25-May 26-May 27-May 28-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 15 (High Humidity, Low HONO Concentration)
MONO Concentration (ppbV)
an n
yu.u
an n
7n n
en 0
en n
40 0
on n
on n
100
0 0
MONO
- Efficiency
-^
"~ -"-_
-- _
c*
an no/
yu.u /o
an no/
7n no/.
>
en n°/, o
0)
|o
en no/ Uj
i«
0)
c
c
Q
on no/
on no/
10 0%
n no/.
25-May 26-May 27-May 28-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 16 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
qn n
sn n
?n n
fin n
en n
4n n
on n
on n
10 0
MONO
- Efficiency
~ .. - -----
_
qn n%
an no/
7r\ n%
fin n%
Kn no/
4n n%
on n%
on n%
1 0 0%
.0 H 1 - u.ir/o
29-May 30-May
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 16 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
on n
an n
yn n
en n
Kn n
4n n
on n
on n
100
MONO
- Efficiency
_ (
-
on noA
an no/
7D n%
en noA o
0)
|o
Kn no/ JS
i»
0)
c
AH n°A ni
Q
on noA
on no/
1 0 0%
0.0 -I 1 L U.U7o
29-May 30-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 16 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
qn n
an n
yn n
en n
en n
4n n
on n
on n
10 0
n n
MONO
- Efficiency
-
_ - _ - -
^
qn noA
an no/
7D n%
en noA o
0)
|o
en no/ jS
i»
0)
c
AH n°A ni
Q
on noA
on no/
1 0 0%
n no/.
29-May 30-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 16 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
on n
an n
yn n
en n
Kn n
4n n
on n
on n
10 0
-____ ~ ~ .. ~ .
- -
MONO
Efficiency
on noA
an no/
yn no/
en noA o
0)
|o
Kn no/ JS
i»
0)
c
AC\ nOA fi«
Q
on no/
on no/
1 0 0%
0.0 -I 1 L U.U7o
29-May 30-May
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 16 (Low Humidity, Low MONO Concentration)
100.0
90.0
80.0
70 0
f
Q.
f 60.0
o
5
£
0)
o
o
o
O
z
O
I
50.0
D.O
30.0
20.0
10.0
0.0
29-May
30-May
100.0%
90.0%
80.0%
70.C
60.0%
50.0%
J.0%
30.0%
20.0%
10.0%
0.0%
>
o
0)
'o
s
L.
0)
c
C
0)
a
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 17 (Low Humidity, Low MONO Concentration)
100.0
90.0
80.0
70 0
f
Q.
f 60.0
o
5
£
0)
o
o
o
O
z
O
I
50.0
D.O
30.0
20.0
10.0
0.0
MONO
Efficiency
100.0%
95.0%
90.C
85.0%
D.0%
5.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
J.0%
55.0%
30-May
31 -May
1-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 17 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
on n
an n
yn n
en n
Kn n
4n n
on n
on n
100
MONO
- Efficiency
~--~-___-
-__~_-~_ __
on noA
an no/
yn no/
en noA o
0)
|o
Kn no/ JS
i»
0)
c
AC\ nOA fi«
Q
on no/
on no/
- 1 0 0%
0.0 -I 1 1 L U.U7o
30-May 31 -May 1-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 17 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
qn n
an n
yn n
en n
en n
4n n
on n
on n
zu.u
100
n n
MONO
- Efficiency
-_ -^
qn noA
an no/
yn r\%.
en noA o
0)
|o
en no/ jS
i»
0)
c
AH n% ni
Q
on noA
on no/
ZU.U /o
1 0 0%
n no/.
30-May 31 -May 1-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 17 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
qn n
an n
7n n
en n
en n
4n n
on n
on n
100
_- ---__
-
~-~_- _ _ HOMO
~~~_ _~_ Efficiency
~-
-
qn noA
an no/
yn no/
en noA o
0)
'o
Kn no/ JS
i»
0)
c
AC\ nOA fi«
Q
on no/
on no/
- 1 0 0%
0.0 -I - , , L 0.0%
30-May 31 -May 1-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 17 (Low Humidity, Low MONO Concentration)
MONO Concentration (ppbV)
on n
an n
7n n
en n
en n
4n n
on n
on n
100
~_-~~-~--__
_--~_-_~~_
MONO
- Efficiency
on noA
an no/
yn no/
en no/.
en noA
4n n%
on noA
on no/
- 1 0 0%
0.0 -I 1 1 L U.U7o
30-May 31 -May 1-Jun
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 18 (Low Humidity, Low PAN Concentration)
AC. n
40 n
oc n
f
Q.
Q. on n
c
.0
?
re
i PR n
0)
o
Oon n
z
<
Q.
i c n
-inn
1 U.U
c n
On
PAN
- Efficiency
_ - -
-
''-. .
qn r\%.
an no/
7r\ n%
en n%
Kn no/
4n n%
on noA
on no/
ZU.Uvo
m n%
n no/.
18-Jun 19-Jun
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 18 (Low Humidity, Low PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
C
.0
ID
i OK n
c ^'U
0)
o
Oon n
Q.
-\ c n
m n
c n
n n
PAN
- Efficiency
-
-
s
.
on n%
on 0%
TO n%.
fin n% o
0)
|o
^n n% LU
k.
0)
o
40 0%. fli
Q
30 0%
on no/
m n%
n no/.
18-Jun 19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 18 (Low Humidity, Low PAN Concentration)
AC n
4n n
oc n
f
Q.
Q. on n
c
.0
?
re
i PR n
0)
o
Oon n
z
<
Q.
i c n
m n
c n
n n
PAN
- Efficiency
-
_ -
^
_
' .
. ....
. .
...'
AC (\OL
4n n%
2C no/
on no/ o
0)
|o
OK n% UJ
i»
0)
c
on noA S
Q
1 ^ n%
1 n n%
c noA
n no/.
18-Jun 19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 18 (Low Humidity, Low PAN Concentration)
AC n
4n n
oc n
f
Q.
Q. on n
c
.0
?
re
i PR n
0)
o
Oon n
z
<
Q.
i c n
m n
c n
n n
PAN
- Efficiency
- - _ _
-
_
."*'...
AC (\OL
4D 0%
2C no/
on no/ o
0)
|o
OK n% UJ
i»
0)
c
on noA S
Q
1 ^ n%
1 n n%
c noA
n no/.
18-Jun 19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 18 (Low Humidity, Low PAN Concentration)
AC n
4n n
oc n
f
Q.
Q. on n
c
.0
?
re
i oc n
0)
o
Oon n
z
<
Q.
i c n
m n
c n
n n
-
- »PAN
_ - Efficiency
^
..
..
.
'..
AC (\OL
4D 0%
2C noA
on no/ o
0)
|o
oc no/ m
i»
0)
c
on noA S
Q
1 ^ n%
1 n n%
c noA
n no/.
18-Jun 19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 19 (High Humidity, Low PAN Concentration)
AC. n
Ar\ n
oc n
f
Q.
Q. on n
c
.0
ID
i OK n
c ^'U
en n% o
0)
|o
en no/ jS
i»
0)
c
AH n% ni
Q
30 0%
m n%
n no/.
19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 19 (High Humidity, Low PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. *?n n
^5 OU.U
c
.0
ID
i OK n
c ^'U
a)
o
Oon n
Q.
-\ c n
m n
c n
n n
PAN
- Efficiency
-
- _
on noA
an no/
7n n°A
en no/ o
OU.U/o g
0)
|o
en no/ jS
i»
0)
c
AH n°A ni
Q
30 0%
on no/
m n%
n no/.
19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 19 (High Humidity, Low PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
C
.0
ID
i OK n
c ^'U
0)
o
Oon n
Q.
-\ c n
m n
c n
n n
PAN
- Efficiency
_
-
'
on noA
an no/
7n n%
en noA o
0)
|o
Kn no/ JS
i»
0)
c
c
a
30 0%
on no/n
m n%
n no/_
19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 19 (High Humidity, Low PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
C
.0
ID
i OK n
c ^'U
0)
o
Oon n
Q.
-\ c n
m n
c n
n n
PAN
- Efficiency
- -
on no/,
«0 0%
TO n%.
en no/, o
0)
|o
^n n% LU
k.
0)
o
40 0%. fli
Q
30 0%
on no/
m n%
n no/.
19-Jun 20-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 19 (High Humidity, Low PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
C
.0
ID
i OK n
£ 25-°
0)
o
Oon n
Q.
-\ c n
m n
c n
n n
PAN
- Efficiency
_
_
*
on noA
an no/
7n n%
fin n% o
a>
'o
£
cn no/, UJ
k.
0)
D
40 0%. fli
Q
30 0%
on no/
m n%
n no/.
19-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 20 (High Humidity, High PAN Concentration)
PAN Concentration (ppbV)
qn n
sn n
7n n
en n
en n
4n n
on n
on n
m n
On
PAN
- Efficiency
-
-
-
.-.
qn n%
sn n%
7n n%
fin n%
en no/
4n n%
on n%
on n%
in n%
n no/.
21-Jun
Denuder Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 20 (High Humidity, High PAN Concentration)
PAN Concentration (ppbV)
qn n
an n
yn n
en n
en n
4n n
on n
on n
m n
n n
PAN
- Efficiency
-
-
* * *
9
,
qn noA
an no/
7D n%
en noA o
0)
|o
en no/ jS
i»
0)
c
AH n°A ni
Q
on noA
on no/
m n%
n no/.
21-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 20 (High Humidity, High PAN Concentration)
PAN Concentration (ppbV)
qn n
an n
yn n
en n
en n
4n n
on n
on n
m n
n n
PAN
- Efficiency
_ ~
'
. .*.
*.*
qn noA
an no/
yn r\%.
en noA o
0)
'o
en no/ jS
i»
0)
c
AH n°A ni
Q
on noA
on no/
m n%
n no/.
21-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 20 (High Humidity, High PAN Concentration)
PAN Concentration (ppbV)
qn n
an n
yn n
en n
en n
4n n
on n
on n
m n
n n
PAN
Efficiency
~ ~
.
* .
-.......
qn noA
an no/
yn r\%.
en noA o
0)
|o
en no/ jS
i»
0)
c
AC\ nOA fi«
Q
on noA
on no/
m n%
n no/.
21-Jun
Date (2001)
-------
100.0
90.0
80.0
70.0
|
S 60.0
c
o
5
£
0)
o
o
o
z
<
Q.
50.0
D.O
30.0
20.0
10.0
0.0
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 20 (High Humidity, High PAN Concentration)
100.0%
90.0%
80.0%
70.C
60.0%
50.0%
30.0%
20.0%
J.0%
0.0%
>
o
0)
'o
s
L.
0)
c
c
0)
a
21-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 1
Experiment 21 (Low Humidity, High PAN Concentration)
PAN Concentration (ppbV)
qn n
an n
7n n
en n
en n
4D n
on n
on n
10 0
n n
PAN
- Efficiency
_ ~ _
*.'.'.'
qn no/
an no/
7n no/.
en noA o
0)
'o
en no/ jS
i»
0)
c
AH n% ni
Q
on noA
on no/
1 0 0%
n no/.
22-Jun 23-Jun 23-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 4
Experiment 21 (Low Humidity, High PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
C
.0
ID
i OK n
c ^'U
0)
o
Oon n
Q.
-\ c n
inn
I U.U
c n
n n
PAN
- Efficiency
- _ _
,
V
s
Qn n%
on 0%
TO 0%.
>
en n°/* O
0)
|o
^n n% LU
k.
0)
D
40 0%. m
Q
on (]%.
on no/
ZU.U /o
\ n noA
n no/.
22-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 3
Experiment 21 (Low Humidity, High PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
C
.0
ID
i OK n
c ^'U
0)
o
Oon n
Q.
-\ c n
m n
c n
n n
PAN
- Efficiency
B
'
*""'....
_ -
on noA
an no/
7n n°A
fin n% o
0)
|o
en no/ H]
i»
0)
c
An n% ni
Q
30 0%
on no/
m n%
n no/.
22-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 2
Experiment 21 (Low Humidity, High PAN Concentration)
50.0
40.0
S 30.0
c
.0
?
0)
o
O 20.0
10.0
0.0
22-Jun
PAN
- Efficiency
-- 90.0%
80.0%
-- 70.0%
60.0%
100.0%
a>
50.0% UJ
0)
3
40.0% S
Q
-- 30.0%
20.0%
-- 10.0%
0.0%
Date (2001)
-------
EPA Denuder Efficiency Evaluation Denuder 5
Experiment 21 (Low Humidity, Low PAN Concentration)
AC n
40 0
oc n
f
Q.
Q. on n
C
.0
ID
i OK n
c ^'U
0)
o
Oon n
Q.
\ K n
m n
c n
n n
PAN
- Efficiency
" " "* ' % * » * % 1 t . -
» *
-" --- _ _ ~
on no/,
on 0%
70 C\°/n
>
en n°/^ O
0)
|o
^n n% LU
k.
0)
D
40 0%. m
Q
on no/.
on no/
m n%
n no/.
22-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 22: Low Humidity NO2 Test for Filter 1
NO2 Concentration (ppbV)
qn n
an n
7n n
en n
en n
on n
on n
m n
n n
N02
- Efficiency
....
"* ***
~ ~ ~ ~ ~ «
qn noA
an no/
7n no/.
en noA »_
o
c
0)
'o
en noA c
LU
i»
0)
H
4n n% iZ
on noA
on no/
m n%
n no/.
23-Jun 24-Jun 24-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 22: Low Humidity NO2 Test for Filter 4
NO2 Concentration (ppbV)
Qn n
on n _
70 0
fin n
c.r\ n _
40 0
on n
on n _
-inn
n n
NO2
- Efficiency
~~ _ _ ~ ~ ~ ~
qn noA
an no/
yn r\%.
fin n% -^
o
c
0)
'o
en noA c
LU
i»
0)
£
4n n% iZ
on noA
on no/
m n%
n no/.
23-Jun 24-Jun 24-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 22: Low Humidity NO2 Test for Filter 3
NO2 Concentration (ppbV)
on n
on n
70 0
en n
c.r\ n -
40 0
^n n
on n
-inn
n n
N02
- Efficiency
** .
" ,
~ ~
on no/.
on n%
fin n%
en n%
4n n%
^n n%
on n%
1 n n%
n no/.
23-Jun 24-Jun 24-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 22: Low Humidity NO2 Test for Filter 2
NO2 Concentration (ppbV)
Qn n
on n
70 0
fin n
4n n
30 0
on n
-inn
n n
NO2
- Efficiency
."'
----- - _ ~ - - - _ - - -
qn r\%.
on r\OL
?n n%
Rn n%
en n%
4n n%
on n%
on n%
in n%
n no/.
23-Jun 24-Jun 24-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 22: Low Humidity NO2 Test for Filter 5
NO2 Concentration (ppbV)
Qn n
an n
70 0
en n
c.r\ n -
40 0
on n
on n
-inn
n n
NO2
- Efficiency
»**%***%%
\ + *
>
~ ~ - - - -___-_-___
23-Jun 24-Jun
Date (2001)
Qn
on
en
c:n
4n
on
on
-in
n r
24-Jun
0%
0%
0%
0%
0%
0%
0%
0%
0%
o/
Denuder Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 23: High Humidity NO2 Test for Filter 1
NO2 Concentration (ppbV)
qn n
an n
7n n
en n
en n
on n
on n
m n
n n
N02
- Efficiency
qn noA
an no/
7n no/.
en noA »_
o
c
0)
'o
en noA 'f
LU
i»
0)
£
4n n% iZ
on noA
on no/
m n%
n no/.
24-Jun 25-Jun 25-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 23: High Humidity NO2 Test for Filter 4
NO2 Concentration (ppbV)
Qn n
an n
70 0
fin n
c.r\ n -
40 0
on n
-inn
n n
NO2
- Efficiency
^« «. i % I
>%%«
- _ -
qn noA
an no/
yn noA
en noA »_
o
c
0)
'o
en noA c
LU
i_
0)
£
4n n% iZ
on no/.
on no/
m n%
n no/.
24-Jun 25-Jun 25-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 23: High Humidity NO2 Test for Filter 3
NO2 Concentration (ppbV)
on n
on n
70 0
en n
c.r\ n -
40 0
on n
-inn
n n
N02
- Efficiency
.
»%.%.:.** '
-~-~~_---- _- -~--~--__
on no/.
on n%
7n n%
fin n%
en n%
4n n%
on n%
on n%
1 n n%
n no/.
24-Jun 25-Jun 25-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 23: High Humidity NO2 Test for Filter 2
NO2 Concentration (ppbV)
Qn n
on n
70 0
fin n
40 0
on n
OU.U
on n
1 n n
n n
NO2
- Efficiency
.*.
qn r\%.
on r\OL
?n n%
Rn n%
en n%
4n n%
on no/
oU.Uvo
on n%
1 n no/.
n no/.
24-Jun 25-Jun 25-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 23: High Humidity NO2 Test for Filter 5
HNO3 Concentration (ppbV)
Qn n
an n
70 0
fin n
c.r\ n -
40 0
on n
-inn
n n
NO2
- Efficiency
- - - ~ -_- ~- ~ ~ - --------
qn noA
an no/
yn r\%.
en noA o
0)
|o
en no/ jS
i»
0)
c
Af\ HO/. fi«
Q
on no/.
on no/
m n%
n no/.
24-Jun 25-Jun 25-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 24: High Humidity HONO Test for Filter 1
MONO Concentration (ppbV)
qn n
on n
7n n
fin n
en n
4n n
on n
20 0
m n
n n
-
MONO
- Efficiency
- ~ - ~
.
""."'
* *
**
::.*
on ncv
en r\Q/
Ar\ r\Q/n
on no/.
On%
_on no/.
40 0%
-60 0%
80 0%
-i nn no/_
26-Jun 27-Jun 27-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 24: High Humidity HONO Test for Filter 4
MONO Concentration (ppbV)
qn n
an n
?n n
fin n
en n
4n n
on n
on n
10.0
n n
MONO
- Efficiency
----- ~~ ----- ~ ~ -
m
....
*
on n%
fin n%
4n n%
on n%
n n%
on r\%.
4n n%
-fin n%
- -80.0%
i nn no/.
26-Jun 27-Jun 27-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 24: High Humidity HONO Test for Filter 3
MONO Concentration (ppbV)
on n
on n
70 0
en n
c.r\ n -
40 0
^n n
on n
-inn
1U.U
n n
MONO
- Efficiency
~ - - - - _
.
*
on no/.
Rn n%
4n n%
on n%
n n%
on n%
-4n n%
Rn n%
on no/
-oU.Uvo
i nn no/
26-Jun 27-Jun 27-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 24: High Humidity HONO Test for Filter 2
MONO Concentration (ppbV)
an n
on n
?n n
en n
en n
4n n
on n
on n
in n
n n
MONO
- Efficiency
-
_
' * . . ' * . . '
' ' ' . .-.
' ' *...
so n%
fin n%
4n n%
on n%
On%
.on n%
4n n%
fin n%
on n%
i nn no/.
26-Jun 27-Jun 27-Jun
Date (2001)
Filter Efficiency
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 24: High Humidity HONO Test for Filter 5
MONO Concentration (ppbV)
qn n
an n
7n n
en n
en n
4D n
on n
on n
m n
n n
MONO
- Efficiency
- -
- -
qn no/
an no/
7n no/.
en noA o
a>
|o
en no/ jS
i»
0)
c
AC\ nOA fi«
Q
on noA
on no/
m n%
n no/.
26-Jun 27-Jun 27-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 25: Low Humidity MONO Test for Filter 1
MONO Concentration (ppbV)
an n
on n
7n n
en n
en n
4n n
on n
on n
in n
n n
MONO
- Efficiency
^ ^
: ...:
*..... .
so n%
en n%
AD n%
on n%
On%
.on no/.
4n n%
en n%
on n%
i nn no/.
27-Jun 28-Jun
Filter Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 25: Low Humidity MONO Test for Filter 4
MONO Concentration (ppbV)
90.0
an n
?n n
fin n
en n
4n n
on n
on n
m n
n n
MONO
- Efficiency
* . . '
- 80.0%
fin n%
4n n%
on n%
n n%
on n%
4n n%
-fin n%
sn n%
i nn no/.
27-Jun 28-Jun
Filter Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 25: Low Humidity MONO Test for Filter 3
MONO Concentration (ppbV)
on n
on n
7n n
en n
en n
4n n
in n
on n
m n
n n
MONO
- Efficiency
" ---.___-
-..
.
' ....'. ' .
on no/.
Rn n%
4n n%
on n%
n n%
on r\%.
-4n n%
Rn n%
.an no/
i nn no/.
27-Jun 28-Jun
Filter Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 25: Low Humidity MONO Test for Filter 2
MONO Concentration (ppbV)
an n
on n
7n n
en n
en n
4n n
on n
on n
in n
n n
MONO
- Efficiency
- _ _ -
' ' ' .
. ' '
so n%
en n%
4n n%
on n%
On%
.on n%
4n n%
en n%
on n%
i nn no/.
27-Jun 28-Jun
Filter Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 25: Low Humidity MONO Test for Filter 5
MONO Concentration (ppbV)
qn n
an n
7n n
en n
en n
4n n
on n
on n
m n
n n
MONO
- Efficiency
- ~ _ _ ~~----~-_~
-
.
* . *
qn noA
an no/
yn no/
en (")OA o
0)
|o
Kn no/ JS
i»
0)
c
AH n% ni
Q
on noA
on no/
m n%
n no/.
27-Jun 28-Jun
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 26: Low Humidity PAN Test for Filter 1
18.0
16.0
14.0
£1
a.
S 12.0
c
o
re
| 10.0
0)
o
c
O 8.0
1
6.0
4.0
2.0
0.0
28-
PAN
- Efficiency
\
«
' * * *" ' ' '. %
~ _
Jun 29-Jun
- 90.0%
- 80.0%
- 70.0%
- 60.0%
- 50.0%
- 40.0%
- 20.0%
- 10.0%
- 0.0%
>
o
f
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 26: Low Humidity PAN Test for Filter 4
-ion
1R n
14. n
f
Q.
Q. -ion
c
.0
?
re
i inn
0)
o
OR n
z
<
Q.
6n
4 n
9 n
n n
PAN
- Efficiency
%
* ' *
.
.
' * - s . .
qn n%
an n%
?n n%
en n%
en no/
4n n%
on n%
on no/
m n%
n no/.
28-Jun 29-Jun
Filter Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 26: Low Humidity PAN Test for Filter 3
MONO Concentration (ppbV)
on n
on n
7n n
en n
en n
4n n
in n
on n
m n
n n
MONO
- Efficiency
on no/.
Rn n%
4n n%
on n%
n n%
on noA
-4n n%
Rn n%
.an no/
i nn no/.
28-Jun 29-Jun
Filter Efficiency
Date (2001)
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 26: Low Humidity PAN Test for Filter 2
18.0
16.0
14.0
£1
a.
S 12.0
c
o
re
| 10.0
0)
o
c
O 8.0
1
6.0
4.0
2.0
0.0
28-
PAN
- Efficiency
.
*
* * * * *
" ~ ~
Jun 29-Jun
- 90.0%
- 80.0%
- 70.0%
- 60.0% >
o
c
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 26: Low Humidity Pan Test for Filter 5
-ion
ifi n
14. n
f
Q.
Q. -ion
c
.0
?
re
i m n
0)
o
OR n
z
<
Q.
6n
4 n
9 n
n n
PAN
- Efficiency
,
.
"' ' ' ' '. «. s
__-_ - ~
qn n%
an n%
?n n%
en noA o
0)
|o
en no/ jS
i»
0)
c
40 n% ni
Q
on noA
on no/
m n%
n no/.
28-Jun 29-Jun
Date (2001)
-------
18.0
15.0
12.0
Q.
Q.
C
.0
?
0)
o
o
o
9.0
CL 6.0
3.0
0.0
29-Jun
EPA Denuder Efficiency Evaluation Filter Section
Experiment 27: High Humidity Pan Test for Filter 1
%
30-Jun
Date (2001)
100.0%
80.0%
60.0%
40.0%
o
a>
0)
c
C
0)
a
20.0%
0.0%
-20.0%
-------
EPA Denuder Efficiency Evaluation Filter Section
Experiment 27: High Humidity Pan Test for Filter 4
18.0
15.0
12.0
C
o
'I
9.0
o
C
o
o
CL 6.0
3.0
0.0
29-Jun
% «
100.0%
80.0%
60.0%
40.0%
o
C
0)
'o
£
0)
c
3
C
20.0%
0.0%
-20.0%
Date (2001)
-------
18.0
EPA Denuder Efficiency Evaluation Filter Section
Experiment 27: High Humidity Pan Test for Filter 2
-- 90.0%
15.0
5- 12.0
£1
Q.
C
o
0)
o
C
o
o
9.0
6.0
3.0
-- 60.0%
o
C
0)
'o
E
LU
L.
0)
C
0)
a
-- 30.0%
0.0
29-Jun
0.0%
Date (2001)
-------
18.0
15.0
12.0
Q.
Q.
C
.0
?
0)
o
o
o
9.0
CL 6.0
3.0
0.0
29-Jun
EPA Denuder Efficiency Evaluation Filter Section
Experiment 27: High Humidity Pan Test for Filter 5
PAN
- Efficiency
%
*.
Date (2001)
100.0%
80.0%
60.0%
40.0%
o
a>
0)
c
C
0)
a
20.0%
0.0%
-20.0%
-------
United States Office of Air Quality Planning and Standards Publication No. EPA-454R-02-011
Environmental Protection Emissions Monitoring & Analysis Division April 2002
Agency Research Triangle Park, NC
------- |