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AIRBORNE MONITORING AND SMOKECHARACTERIZATION OF PRESCRIBED FIRES
ON FOREST LANDS IN WESTERN WASHINGTONAND OREGONFINAL REPORT---Eo---LOCKHEED-EMSCO
PROJECT NUMBERS AM526 AND AM680
Lawrence F. Radke, Jamie H. Lyons,Dean A. Hegg and Peter V. Hobbs
Apri 1983
(corrected version)
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TABLE OF CONTENTS
1. INTRODUCTION
2. AIRCRAFT INSTRUMENTATION
2.1 Overview2.2 Particle Measuring System2.3 Trace Gas Measuring System2.4 General Meteorological Instrumentation2.5 Data Processing System
3. SUMMARY OF RESEARCH FLIGHTS
4. INSTRUMENT CALIBRATION AND QUALITY CONTROL
4.1 Di scussion of Interim Cal ibration PerformedIn-house (19 July 1982)
4.2 Research Triangle Institute Fi el d Audit4.3 Comparison of Pl ume-Ambient CO^ Concentrations
as Measured by OGU and Lockheed-EMSCO
5. FLIGHT PROCEDURES AND DATA PROCESSING
5.1 Fl ight Procedures5.2 Data Processing5.3 Physical Interpretation of b^at Al gorithms
6. PRELIMINARY RESULTS AND ANALYSIS
6.1 Characterization of Cross Sections of the Plumes6.2 Some Characteri sti cs of the Particles in the Plumes6.3 Analysis and Cross Comparisons of Bul k Ai r Samples6.4 Plume Tracers6.5 Emission Factors for Total Suspended Particulates (TSP)6.6 Aerosol Mass Fl ux
7. TOPICS FOR FURTHER STDY
8. SUMMARY AND CONCLUSIONS
REFERENCES
APPENDIX I Corrected Data Sets (Mi ssions 1-6)
APPENDIX II Sampl e Information Table (Missions 1-6)
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LIST OF TABLES AND FIGURES
TABLE
2 1 Speci fications of research instruments aboard theUniversity of Washington’s B-23 ai rcraft
3.1 Summary of research fl ights
4.1 Summary of audit of instrumentation
4 2 Comparison of OGC and Lockheed-EMSCO measurements of plumeminus ambient C02 concentrations col lected in stainless steelcanisters via the polyethylene bag
4 3 Compari son of OGC and Lockheed-EMSCO measurements of pl umeminus ambient C02 concentrations col lected in stainless steelcanisters via the stainless steel loop with those col lected
in stainless steel canisters via the polyethyl ene bag
5. 1 Al gorithms relating b ^to mass concentration
6.1 Compilation of ai r volume flux and its associated valueof light-scattering coeffi cient (bgcat)
6.2 Apparent density of particles in pl ume
6.3 PIXE analyses of the emissions from the sl ash burns
6 4 Comparison of Oregon Graduate Center and Lockheed-EMSCOmeasurements on ai r samples col lected in canisters fromthe polyethyl ene bag sampler
6 5 Comparison of Oregon Graduate Center measurements onsampl es col lected in canisters from the stainless steelsampl ing loop with the Lockheed-EMSCO measurements onsampl es col lected in canisters from the polyethyl ene bagsampler
6.6 Emission factors for TSP derived by carbon bal ance methodusing weighed fi lters
6. 7 Comparison of emission factors for particle mass usingthe carbon balance method and various techniques formeasuring particle mass concentration
6.8 Correlation coefficients for TSP emission factorsfrom data in Table 6.7
6.9 Particle mass fluxes in pl umes calculated from fi lters,mass monitor and particle size measurements
A.I The corrected data set used in cal cul ation of emissionfactors for Total Suspended Parti cul ate (TSP) derivedby the carbon balance method.
A.2 Sample Information Table. Mi ssions 1-6
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FIGURE
2 1 Aerosol and trace gas instrumentation aboard theUniversity of Washington’ s B-23 ai rcraft
2 2 Measurement ranges of the particle sizing instrumentsaboard the University of Washington’ s B-23 ai rcraft
2.3 The batch ai r sampler aboard the University ofWashington’ s B-23 ai rcraft
2.4 Fl ow chart for aircraft instrumentation tape to a7-track computer tape and voice transcripts
2.5 Flow chart for conversion of 7-track computer tapes andfl oppy di sks to 9-track tapes and prel imi nary analysishard copies
2.6 Fl ow chart for processing 9-track tapes into finalhard copy printouts and graphics
5. 1 A plot of the weighed fi lter mass concentration versus
^scat ^or the 0^9" data set
5.2 A plot of the weighed fi lter mass concentration versus^scat ^or t1ne Washington data set
5.3 A pl ot of the mass monitor mass concentration versus
^cat for the Q^0" data set
5.4 A plot of the mass monitor mass concentration versusbgcat for the Washington data set
6.1 Vertical cross section of the light-scatteringcoefficient of the plume from the 23 July 1982burn, sequence 1
6.2 Vertical cross section of the light-scatteri ngcoefficient of the pl ume from the 23 July 1982burn, sequence 2
6.3 Vertical cross section of the light-scatteringcoefficient of the pl ume from the 23 July 1982burn, sequence 3
6.4 Vertical cross section of the light-scatteringcoefficient of the plume from the 23 July 1982burn, sequence 4
6.5 Vertical cross section of the light-scatteringcoefficient of the plume from the 25 July 1982burn, sequence 2
6.6 Vertical cross section of the light-scatteringcoefficient of the pl ume from the 26 July 1982burn, sequence 5
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FIGURE PAGE
6 7 Verti cal cross section of the light-scattering 51coeffi cient of the pl ume from the 15 September 1982burn, sequence 4
6.8 Vertical cross section of the light-scatteri ng 52coefficient of the plume from the 23 September 1982burn, sequence 3
6.9 Particle size distribution measured 3.3 km downwind 58of burn on 23 July 1982
6.10 Number concentration versus size of particles measured 60near pl ume center on the 23 July 1982
6.11 Shadow images of airborne particles in plume on 6215 September 1982
6.12 Number concentration versus size of particles measured 64with laser camera near the center of the pl ume on15 September 1982
6.13 Number concentration versus size of particles measured 65with aerosol system near the center of the plume on15 September 1982
6.14 Characteristi cs of the particles near the center of the 67pl ume as a function of time after ignition on 23 July1982
6.15 Characteristics of the particles near the center of the 68plume as a function of time after ignition on25 July 1982
6.16 Characteristics of the particles near the center of 69the pl ume as a function of time after ignition on26 July 1982
6. 17 Characteristics of the particles near the center of 70the plume as a function of time after ignition on15 September 1982
6.18 Characteristics of the particles near the center of 72the pl ume as a function of time after ignition on23 September 1982
6.19 Volume concentration versus size of particles measured 76near plume center on 25 July 1982 and 23 September 1982
6.20 Emission factors for Total Suspended Particul ate (TSP) 89as a function of time after ignition for Oregon burns
^ on 23 July, 24 July and 26 July 19826.21 Emission factors for Total Suspended Particul ate (TSP) 90
as a function of time after ignition for Washington burnson 15 September and 23 September 1982
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Particle mass fl uxes derived from particle massmeasurements
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AIRBORNE MONITORING AND SMOKE CHARACTERIZATION OF PRESCRIBED FIRES
ON FOREST LANDS IN WESTERN WASHINGTON AND OREGON
1. INTRODUCTION
The combination of wi ld forest fi res prescribed burning of forest logging
wastes and agricultural burning, constitutes one of the largest sources of
di rectly injected particles into the atmosphere (SCEP, 1970). In a recent
report from the Southern Forest Fi re Laboratory (Ward et a1 1976) it was noted
that about 10 hectares of forest land are burned annual ly in the United States
but that estimates of the quantity of particles emitted into the atmosphere from
this source range from 0.5 to 50 mi ll ion metri c tons per year. The Envi ronmental
Protection Agency has estimated the total di rect emission of particulate from al
sources in the United States to be 20 mi ll ions metric tons per year (SCEP, 1970).
Cl early, the upper limit for estimates of particles from the burns of forest land
s inconsi stent with the EPA estimate for total emissions. The uncertainties are
due to the limited data base and al so to the di ffi culty of obtaining good
measurements of particle emission rates from large areal sources such as forest
fi res.
The present study is concerned with an effort to characterize particle
emissions from the prescribed burning of forest biomass (harvesting residues) as
functions of time, combustion character, fuels, and forestry practices. The
studies invol ved detai led ai rborne measurements of the pl umes from seven
prescribed burns in Washington and Oregon. Five of these tests were designed to
ncrease knowl edge of the effects of residue removal to various size
speci fications, on emissions (one of the major problem areas being researched by
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the USOA Forest Service, Forest Residues and Energy Program, Paci fic Northwest
Forest and Range Experiment Station. The other two tests were conducted to
examine "mass ignition" techniques (such as helitorch) as an emissions-reduction
method. It was hypothesized by the Forest Service that rapid ignition of areas
of timber harvest residues may be one way of reducing the composite emissions
factor and of limiting the period of smoldering combustion. The combined data
set suppl ements work completed duri ng 1981, in which two prescribed fi res were
sampled by another contractor. Results of this earl ier work have been reported
by Anderson et a1 (1982) Ward and Sandberg (1982) and Sandberg and Ward
(1982).
The University of Washington’ s (UW) role in this study was to obtain air-
borne measurements of the emissions from prescribed burns. The prel iminary
resul ts of this study which are reported here, are confined to the ai rborne
data col lected by the UW together with some di scussion of sampl es col lected by
the UW but analyzed by Lockheed Engineering and Management Services (Lockheed-EMSCO)
the Oregon Graduate Center (OGC) and the Crocker Laboratory of the University of
Cal fornia at Davis.
In this report we wi characterize the fi res with respect to pl ume
dimensions, particle size distributions, particle densities and particle
emission fluxes. In order that our analysis of the emissions be as independent
as possible, this prel iminary report was prepared without detai led information
on ignition techniques, "yarding" preparation, fuel moisture and other surface
measurements related to the prescribed burns. A report relating emissions to
ignition techniques and other factors wi be prepared at a later date.
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In addition to the emissions characterizations discussed in this report.
a large number of other types of data were col lected by a number of cooperators
working under the leadership of the USOA Forest Service, Pacific Northwest Forest
and Range Experiment Station. The overal data col lection, data reduction and
analysis is being coordinated by David V. Sandberg and Darold E. Ward of the
Forest Service (see Ward and Sandberg, 1982. The study was cooperatively funded
and administered by the U.S. Forest Service; the Envi ronmental Protection Agency
(EPA) Region X; the Department of Energy, Region X, through Bonnevil le Power
Administration; and the EPA Envi ronmental Monitoring Systems Laboratory of Las
Vegas Nevada.
2. AIRCRAFT INSTRUMENTATION SYSTEM2.1 Overview
The ai rcraft used in this study was the DM B-23, which is maintained and
operated by the Cl oud and Aerosol Research Group of the Atmospheric Sciences
Department at the UW.
The trace gas and aerosol instrumentation aboard the ai rcraft is shown in
Fi g. 2. 1 and descriptions of the instruments are given in Table 2.1. The pri-
mary measurements of interest in this study were concentrations of ozone and
particle size di stributions. Measurements of total suspended particulates (TSP)
using weighed fi lters were augmented by a mi crobalance cascade impactor (with a
di ffusion drier) and a mass monitor (with a 2 pm diameter cutoff inlet impactor
and diffusion drier)
The overal performance of the compl ete measuring system was excel lent
during the several experiments.
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ASASP-X
BATCH SAMPLER
^-INTEGRATING NEPMELOMETERISOKINETICPROBE
STATICPRESSURETRANSDUCER
30L HEATEDCHAMBER
\ C
SEAT SEAT SEAT
^ISOKINETICPUMP
1 FB(
STAINLESS STEEL-HYDROCARBON SAMPLE
INTEGRATINGNEPHELOMETER- /-AX ALLY
^ SCATTERINGSPECTROMETERPROBE
HEATEDPLENUMCHAMBER
^ HYDROCARBON ’-CLOUD< STAINLESS STEEL WATERIDFTAI CAUDIMETAL BELLOWSSAMPLE PUMP SAMPLER-WAND FORIMPACTIONSAMPLING
ROYCO 245SAMPLE HEAD
Figure 2. 1 Aerosol and trace gas instrumentation aboard the University ofWashington’ s B-23 research aircraft. Meteorological navigational cloud andprecipitation instrumentation are not shown.
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TABLE 2.1 SPECIFICATIONS OF RESEARCH INSTRUMENTS ABOARDTHE UNIVERSITY OF WASHINGTON ’S B-23 AIRCRAFT
Parameter
Total ai rtemperature1’
Static airtemperature
Dew point
Pressureal titude1"
True ai rspeed1’
Ai r turbul ence1’
Liquid watercontent^
Electric field^
Instrument type
Platinum wi reresistance
Computer value
Dew condensation
Variablecapacitance
Variablecapacitance
Di fferential
Hot wi re resistance
Rotary field mil
Manufacturer
Rosemount Model102CY2CG + 414 LBridge
In-house
Cambridge SystemsModel TH73-244
RosemountModel 830 BA
RosemountModel 831 BA
MeteorologyResearch, Inc.Model 1120
Johnson-Wi iams
MeteorologyResearch, Inc.Model 611
Range (and error)*
-70 to 30C(< 0. 1 C)
-70 to 30C(< 0.5C)
-40 to 50CC)
150 to 1060 mb(< 0.2%)
0 to 230 m s-1(< 0.2%)
0 to 10 cm2/3 s-1(< 10%)
0 to 2 g m-30 to 6 g m"3
0 to 110 kV(< 10%)
Types and sizesof hydro-meteors1’
Ice particleconcentrations1’
Metal foi impactor
Optical polarizationtechnique
MeteorologyResearch, Inc.
Model 1220A
In-house
Detects particles(> 250um)
0 to 1000 &-1detects particles(> 50um)
* Al particle sizes refer to maximum particle dimensions.+ Data displ ayed or avai lable aboard the ai rcraft.++ Not relevant to this study.
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TABLE 2. 1 (CONTINUED
Parameter Instrument type Manufacturer Range (and error)^
Concentration ofcloud condensa-tion nucleus...spectrometer
Ice nucleusconcentrations^ t^
Ice nucleusconcentrations TT
Concentrations ofsodium-containingparti cles’*" "^Al titude aboveterrain1’
Weather radar1’
Ai rcraftposition andcourse pl otter1’
Time^
Time T
Ground communi-cation1’
Light-scatteringcoefficient1’
Four verticalthermal diffusionchambers
NCAR acousticalcounter
Polarizing
Fl ame spectrometer
Radar altimeter
5 cm gyro-stabi ized
Works off DMEand VOR
Time code generator
Radio WWV
FM transceiver
Integrating nephelo-meter
In-house
In-house
Mee Industries
In-house
AN/APN22
Radio Corp. ofAmerica AVQ-10
In-house
Systron DonnerModel 8220
Gertsch RHF 1
Motorola
Meteorology Res.Inc. Model 1567(modified forincreased stabil ityand better responsetime)
0 to 5000 cm-3(< 10%)Simultaneous measure-ments at 0.2, 0.5, 1.0,1.5% supersaturation
0.01 to 500 &-1
0.1 to 10,000 A-1
0 to 10,000 fc-11%)
0 to 6 km5%)
100 km
180 km(1 km)
h, min, s(1: 105)
min
200 km
0 to 1.0 x 10-4 m-1or
0 to 2.5 x 10-3 m-1
* Al particle sizes refer to maximum particle dimensions.!’Data displ ayed or avai lable aboard the ai rcraft.+t Not relevant to this study.
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TABLE 2.1 (CONTINUED)
Parameter
Heading1’
Ground speed anddri ft angle1’
Ul travioletradiation1’
Angle of attack1’
Photographs1’
Total gaseoussul fur
Ozone t"
NH3, NO. N02, N0^Si ze spectrum ofaerosol particles1’
Si ze spectrum ofaerosol parti cles1’
Si ze spectrum ofaerosol particles
Si ze spectrumof aerosolparticles
Si ze spectrumof aerosolparticles!
Instrument type
Gyrocompass
Doppler navigator
Barrier-layerphotoelectric cel
Potentiometer
35mm time-lapsecamera
FPD flamephotometric detector
Chemi umi nescence(C2H4)
Chemi luminescence(03)
Electric aerosolanalyzer
90 ight-scattering
Forwardight-scattering
Di ffusion battery
35-120 light-scattering
Manufacturer
Sperry Model C-2
Bendi x ModelDRA-12
Eppley Laboratory,Inc. Model 14042
RosemountModel 861
AutomaxModel GS-2D-111
Mel oy Model 285
Monitor LabsModel 8410 A
Monitor LabsModel 8440
Thermal Systems,Inc. Model 3030
Particle MeasuringSystem (LAS-200)
Royco 245(in-house modi fied)
Thermal SystemsInc. Model 3040with in-houseautomatic valves &sequencing
Particle MeasuringSystems, ModelASASP-X
Range (and error)*
0 to 3602%)
0 to 6 km altitude
0.7 J m-2 s-1(< 5%)
+/- 23(< 0.5)
s to 10 mi n
0.5 ppb ppm
0 to 5 ppm(< 7 ppb)
0 to 5 ppm10 Ppb)
0.0032 to 1.0 urn
0.5 to 11 urn
1.5 to 40 urn
0.01 0.2 urn
0.09 3.0 urn(
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TABLE 2. 1 (CONTINUED)
Parameter
Size spectrumaerosol andcloud particles!"
Size spectrumcloud parti cles
Si ze spectrum ofprecipitationparticles’*"
Images ofcl oud particles
Images ofprecipitationparticles^
Instrument type
Forward light-scattering
Diodeocculation
Diodeoccul tation
Diode occulationimaging
Diodeimaging
Manu1
ParticleSystems,FSSP
ParticleSystems,OAP-200X
ParticleSystems,OAP-200Y
ParticleSystems,OAP-2D-C
ParticleSystems,OAP-2D-P
’acturer
MeasuringModel
MeasuringModel
MeasuringModel
MeasuringModel
MeasuringModel
Range (and error)*
2 to 47 urn
20 to 300 urn
300 to 4500 pm
Resolution25 urn
Resolution200 urn
Concentrationsof Aitken nucl ei^
Concentrationsof Ai tken nuclei’*’
Si zes and typesof aerosolparticles f
Concentrations ofce nuclei^"*"
Mass concentrationaerosol particles1’
Particulate sul fur
SO^. NOg", C1 ",Na^ K^ NH^
++
Light transmission
Rapid expansion
Di rect impact ion
Di rect impact ion
Electrostatic depo-sition onto matchedoscil lators
Tefl on fi ltersCSI & Dionex XRFspectroscopy andion exchangechromatography
General El ectri cModel CNC II
Gardner
Glass sl ides
Nuclepore/Mi Hi port
Thermal Systems,Inc. Model 3205
In-house
102 to 106 cm-3(particles >0.005 urn)
2 x 102 to 107 cm
5 to 100 ym
0.1 to 3000 yg m"3(< 0.1 ug m-3)
0. 1 to 50 urn m"3(for 500 literair sample)
* A1 particle sizes refer to maximum particle dimensions.+ Data displayed or available aboard the aircraft.++ Not relevant to this study.
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TABLE 2. 1 (CONTINUED)
Parameter
Cl oud watersamples
Instrument type
Centri fuge
Manufacturer
In-house
Range
Col lectsdropletswith an> 50%.
*(and error)
cloud> 3 um radius
efficiency
Si ze-segragated-’concentrations ofaerosol particles
Cascade impactiononto matchedoscil lators
Cal iforniaInstruments
0.05-25 um
Size-segregatedconcentrationsof aerosolparticles
++ Cascade impactor Sierra InstrumentsInc.
0. 1 3 urn(6 size fractions)
HNO. ++
Hydrocarbons
CO^
co^Total suspendedparti cul ate
t+
Nylon fi lters withteflon pre-fi lterfol lowed by ionchromatography
Gas chromatograph(flame ionizationdetection)
El ectrochemicaloxidation
IR absorption
Hi gh volumesampler
Dionex
Analytical InstrumentDevelopment Inc.Model 511
EcoloyzerModel 2000
Foxboro Mi ran IA
Nucleom’c Corp.Model HA69
Variable
0.5(as
100 ppmCHJ
0.100 and 0.600 ppm
3 2x10 ppm
Total suspendedparticulate (TSP)
25 mm Teflon filter Analysis to be(electrobalance provided byanalysis) Lockheed-EMSCO
* Al particle sizes refer to maximum particle dimensions.+ Data displ ayed or avai lable aboard the ai rcraft.++ Not relevant to this study.
Suppl ied by EPA/Lockheed-EMSCO.
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2.2 Particle Measuring System
The particle light-scattering coefficient of ai r is measured with an
in-nouse modi fied, MRI 1567 integrating nephelometer, which samples from a 30
iter plenum chamber maintained at 5C above ambient temperatures. Outside
ambient air is introduced into this chamber isokinetical ly by means of a pump
connected to a static pressure transducer that maintains zero overpressure in
the head and line of the sample probe to the plenum chamber. The above ambient
temperature of the plenum chamber ensures that only dry particles enter the
*ntegrating nephelometer.
The main fi lter sampl ing system consists of a ~500 iter polyethyl ene bag
whi ch is fil led nearly isokinetical ly by ram ai r through a 2 1/2" diameter
sampl e port, a fi lter sampl ing mani fold with fl owmeter, and an engine-driven
vacuum pump. The bag takes ~5 s to fi and entrains al parti cles 5 urn is not
quanti fied) After the bag is fi led, a sample of the ai r in the bag is pul led
through a 37 mm diameter Teflon filter. Sample fl ow rates and mass flow volumes
are measured by a TSI 2013B mass fl ow sensor interfaced with a microprocessor.
Post-fl ight analysi s of the fi lters was done at the Crocker Laboratory. The
results of these analyses are discussed in this report.
A major sub-unit of the UW particle measurement system is concerned with
measurements of the size spectra of the atmosphere aerosol Because the par-
ticles span a size range of nearly four decades in diameter, several di fferent
sensors must be employed. Thi s is il lustrated in Fig. 2.2 where a typical
* Ai r from the plenum chamber was automatical ly passed through fi lters when theight-scattering coefficient indi cated that the ai rcraft was in the plume
from a burn. These filters were sent for analysis to the Crocker Laboratory,University of Cal fornia, Davis.
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volume di stribution for a power pl ant plume is shown togetherwith the various
instruments that we employ to measure the sizes of the particlesin the
di stribution. These instruments (to be described below) have widely varying
response and analysis times. This variabil ity requi res that they al sample
from a common batch sample of ai r in order to obtain comparablemeasurements.
A batch sample is also necessary if sharp concentration gradientsof particles
exist in the ai r, such as the smoke pl umes described herein.The batch sampler
employed on the B-23 ai rcraft consists of a -90 iter cyl inder (-150 on in
height) with a freely-floating piston capping the sample. Ai r pressureforces
the piston upwards, fi ing the cyl inder with ambient ai r.Because the sample
offers negl igible resistence to the in-coming ai r, sampl ing is essentially
isokinetic. After fil ing, the various particle-sizing instruments samplefrom
the base of the cyl inder (to avoid sedimentation loss) A schematic of this
batch sampler is shown in Fig. 2.3. A brief description of the various
particle-size measuring instruments fol lows.
The smal lest particles measured are sized by means of an electrical aerosol
analyzer (EAA) and a di ffusion battery coupled to an Aitken nucleus counter.
The EAA operation is based on the relationship between a parti cle’ s charge,
size and electrical mobil ity. Particles entering the instrument are charged,
thei r mobi ities in an electrical field are measured, and thei r sizes are
thereby deduced. The diffusion battery measures particle sizes by determining
the number of fine-mesh screens through which the particles can di ffuse. The
greater the screen "penetration", the larger the size of the particles.
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AIR INLET
Figure 2. 3 The batch air sampler aboard the UW B-23 ai rcraft.
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Partide detection is achieved with an Aitken nucleus counter. In this study
the EAA generally functioned wel so the di ffusion battery data, which requi re
extensive computer processing, were not analyzed.
Particles of intermediate size (see Fi g. 2.2) are measured with a Particle
Measuring System’ s (PMS) active scattering laser probe (ASASP-X) This devi ce
is essentially an open-cavity laser; the measuring principle is based on the
fact that a parti cle passing through the pumping cavity of a laser wi ll "detune"
the laser to an extent proportional to the size of the particle.
Medium to large-sized particles are measured with a PMS laser aerosol
spectrometer (LAS-200) and a forward light-scattering spectrometer (Royco 245)
These instruments determine particle sizes by measuring, with a laser and a
fi lament light source, respectively, the quantity of light scattered in the for-
ward di rection.
A microbalance cascade impactor (MCI suppl ied by EPA, was fitted with a
diffusion drier and placed near the inlet port of the large di ffusion drier.
The total length of plumbing from the MCI to the batch sampler port was about 30
cm with a residence time of less than 1 s. The MCI had 10 stages, between 0.05
and 25 pm; however, because of the sampl ing inlet, only a smal fraction of the
aerosol
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The 0,-instrument measures ozone by monitoring the chemiluminescence from3
the ozone-ethylene reaction, excess ethylene being suppl ied to a reaction
chamber through which ambient ai r is drawn.
The NO/NO,, monitor is a dual-reaction chamber device; in one chamber
measurements are made of the chemi uminescence of the NO+Og reaction by
supplying excess 0, to ambient ai r drawn into the chamber. In the other
chamber, excess On s suppl ied to the ambient ai r that has passed over a
catalytic-reducing agent to reduce any NO. present to NO. The difference bet-
ween the NO concentrations measured in the two chambers is attri butable to N0^.
The regul ar sampl ing system for halocarbons and hydrocarbons aboard the B-23
ai rcraft consists of one-half inch diameter stainless steel sampl e loop about
25 cm in length, through which ai r is pumped into stainless-steel canisters with
electropol ished interiors. An over-pressure of roughly 1 atmosphere is pumped
into each canister. Some canisters, fi led through this system, were suppl ied
to the Oregon Graduate Center (OGC for analysis. However, since in this project
we required most of the canister samples to be coincident with the fi lter
samples, the canisters were general ly fi led from the 500 A polyethylene bag
(rather than the stainless steel system). These sampl es were analyzed after
each fl ight by Lockheed-EMSCO, using gas-chromatography coupl ed with appropriate
detectors. Use of the polyethyl ene bag compromised the measurements of some
trace constituents (see Section 4.2).
Measurements of the concentrations of CO? n the ai r (in real time) were
made with a Mi ran/Foxboro long path IR sensor. Carbon monoxide (CO) measure-
ments were made with an Ecolyzer electrochemical oxidation instrument.
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2.4 General Meteorological Instrumentation
The general meteorologi cal instrumentation aboard the B-23 ai rcraft for
measuring temperature, humidity, horizontal and vertical winds, and ultra-violet
ight intensity is isted in Table 2.1. It is al standard equipment.
2.5. Data Processing System
Data flow charts are shown in Figs. 2.4-2.6. In-fl ight comments by the
pilots and crew are recorded on the ai rcraft instrumentation tape (Fig. 2.4).
Later these are reproduced for transcript typing. Hi gh-resolution data and
computer serial digital products (backup to di sk data) are frequency-shift-keyed,
demodul ated and processed into appropriate engineering units on a Raytheon 704
minicomputer (Fig. 2.4) The 7-track computer tape from the Raytheon can be
di rectly reprocessed into printouts or strip charts of the high-resolution data,
or transferred, vi a a PRIME 400 mi ni-computer, to 9-track tapes for further pro-
cessing (Fig. 2.5).
Normal ly, the serial digital stream from the ai rcraft computer is not
recovered from the instrumentation tape but is taken di rectly from floppy di sks
(Fi g. 2.5) and converted to 9-track tape vi a a Computer Automation’ s A-LSI-2
minicomputer.
Major computational efforts and graphics products are al handled on the
A-LSI-2 computer from a 9-track tape (Fi g. 2.6).
This is a well-proven system, which provides both flexi bi ity and redundancy
n data recording and processing.
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Figure 2.4 Flow chart for ai rcraft instrumentation tape to 7-track computertape and voice transcripts.
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A1RCRAFTCOMPUTERFLOPPYDI SKS
COMPUTERAUTOMATIONALPHA LSI 2COMPUTER
Figure 2.5 Flow chart for conversion of 7 track computer tapes and floppy disksto 9 track tapes and preliminary analysis hard copies.
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COMPUTERAUTOMATIONALPHA LSI 2COMPUTER
GRAPHS(Versotec 1110-A)
PRINTOUTS(Tolly T-2000)
Figure 2.6 Flow chart for processing 9 track tapes into final hard copyprintouts and graphics.
-
-20-
3. SUMMARY OF RESEARCH FLIGHTS
On 2 July 1982 a prel iminary quality control check was made of the
instrumentation aboard the B-23 ai rcraft. The period between 22 July 1982 and
27 July 1982 was spent in Eugene, Oregon, where four research fl ights were made
through smoke plumes from the prescri bed areal burni ng of timber harvest resi-
dues ("broadcast slash burning") on units harvested to di fferent size specifica-
tions in the Wi lamette National Forest (Joule Sale area) During this period a
second qual ity control check was completed on the ai rborne instrumentation
system.
Two research fl ights were made during September 1982 over two prescribed
burns in the Twin Harbors area of Washington State.
Table 3.1 summarizes the research fl ights made in support of this
project.
-
-21-
TABLE 3. 1 SUMMARY OF RESEARCH FLIGHTS
Date"""OWFl ight Mi ssion Duration Activity
Number Number (Local times)
2 July 1982
19 July 1982 1052
22 July 1982 1053
23 July 1982 1054
24 July 1982 1055
25 July 1982 1056
26 July 1982 1057
(26 July 1982)
27 July 1982 1058
15 Sept 1982 1060
23 Sept 1982 1061
5 Oct 1982 1064
Qual ity control instrumentationcheck on ground.
1137-1506 Ai rborne Instrumentation fl ight check.
1312-1528 Ferry fl ight from Seattle to Eugene.
1 1449-1909 Slash burn fl ight (Oregon)
2 1508-1904 Sl ash burn fl ight (Oregon)
3 0809-1223 Sl ash burn fl ight (Oregon)
4 0926-1328 S1 ash burn f1 ight (Oregon)
Qual ity control instrumentationcheck on ground.
0858-1147 Ferry fl ight from Eugene to Seattle.
5 1313-1845 Sl ash burn fl ight (Washington)
6 1417-1806 Sl ash burn fl ight (Washington)
1310-1506 Sl ash burn fl ight (Washington).Fl ight aborted enroute to fi redue to aircraft enginemalfunction.
-
-22-
4. INSTRUMENT CALIBRATION AND DATA QUALITY CONTROL
4.1 Interim Calibration Performed In-house (29 June 1982)
(a) Ozone
This instrument was cali brated against a Monitor Labs 8510 Permacal 0^source (UV irradiation) which in turn was cali brated against neutral -buffered
potassium iodide. Ei ght points were used in the calibration. The data produced
the fol lowi ng cal ibration equation:
P (real 1.08 PQ (indi cated) 1.46 ppb
where P (real and Pn (indicated) are the actual concentrations of ozone and, the3 3concentrations as indicated by the instrument in ppb. The correlation coef-
ficient for the cal bration equation was 0.998.
(b) Nitrogen Oxides
The NO analyzer (both channels) was cal ibrated agai nst a Monitor LabsA
Permacal cali bration source (permeation tube and span gas dil ution) which in
turn was cal ibrated against gas-phase titration. Four points per channel were
used in the cal ibration. The resulting cal ibration equation was:
P.,. (real 1.65 P.,. (i ndicated) 7.876 ppb""X Xwhere the concentrations are in ppb. The correlation coefficient in this case
was 0.97.
(c) Carbon Dioxide
This instrument was cal ibrated against an in-house dynamic di lution system
employing concentrated CO. and ultra-pure nitrogen, whi le seven cal bration
poi nts were employed, the inherent nonl inearity of the instrument rendered a
single li near cal bration over the entire range of cal bration (0-4000 ppm)
-
-23-
impractical For example, the cali bration equation for the enti re range (based
on inear regression) was:
P 7.395 x 103 (absorption) 323.6 ppmLi’ft
with a linear regression coefficient of 0.937. This equation predi cts values
of P.. as much as 68% too high at lower P^ (relative to the actual cal ibra-CO^ 2tion values). If the linear regression is appl ied only up to 1000 ppm (a value
sti much in excess of any CO^ measured during the study) the calibration
equation becomes:
P 3.6514xl03(abso^ption) 7.939 ppmLUrt
with a correlation coefficient of 0.99. This equation predi cts P^ to within
16% of the actual cal ibration values and was employed in the data reductionfor
this project.
(d) Carbon Monoxide
No attempt was made to cali brate this instrument prior to the audit per-
formed by the Research Triangle Institute (RTI Therefore, the RTI audit
constitutes the cal ibration. It should be noted that this instrument suffers
from excessive zero drift and must be constantly re-zeroed in order toobtain
accurate readings.
(e) Integrating Sephelometer
The integrating nephelometer was cal ibrated by comparing the instrumentout-
put when viewing clear ai r and Freon 12 with the expected b^ values for these
substances. The fol lowing results were obtained:
-
-24-
Clear Air Freon 12
Observed: (1 .8+/-1.0) x 10" m"
Expected: 1.5 x 10"
3.4 x 10"4 m"12.4 x 10"4.
The di fferences between the observed and the expectedvalues were used to adjust
the data col lected in this field project.
4.2. Research Triangle Institute Field Audit
The results of the second audit of the instrumentationused aboard the UM ’s
*B-23 ai rcraft and by Lockheed-EMSCO are summarized in Table
4.1. The audit was
made at Mahlon Sweet Ai rport at Eugene, Oregon on 26 and27 July 1982. The
table lists the name, model and serial number of theinstrument the parameters
that were subject to audit, the range of themeasurements, and the slope, inter-
cept and correlation coefficient of the regression equationcalculated from the
audit data.
(a) Uni versity of Washington’ s Ai rborne Instrumentation
The ambient ai r qual ity analyzers aboard the UW s B-23 aircraft were
audited for measurements of the concentrations of carbon dioxide,carbon
monoxide, nitrogen oxides and ozone. The carbon di oxide, carbonmonoxide and
the total oxide of nitrogen (N0^) measurements exhibited satisfactory perform-
ance. The ozone analyzer reads systematical ly 15% higher thanthe RTI standard,
* Data taken from Murdock, R. W. (1982) "Second Audit of Ai rborneMon1tonng
Prescribed Fi res in the Mi llamette National Forest". Research TriangleInstitute Report No. RTI/NIX 26/00-02F. No unresol ved di fferences were notedbetween fi rst and second audit.
-
Organization
Universityof Washington’sB-23 Ai rcraftInstrumentation(at MahlonSweet Field,Eugene, Oregon)
Total oxides
Model 3205
Ghia Fi lter Sampler
TAB
Manufacturer ofInstrument, Modeland Serial Number
Foxboro Mi ran1A
Ecolyzer 2700S/N 1686
Monitor Labs8440 S/N 169
Monitor LabsS/N 1686
MRI NephelometerModel 1567
Rosemount
Cambridge SystemsModel TH73-244
TSI Quartz CrystalMi crobalance
LE 4. 1 SUMM;
Parameter
Carbondioxide
Carbonmonoxide
Nitric oxideNitrogen dioxide 0-0.2 ppm
of nitrogenOzone
^cat
Temperature
Dew point
Flow rate
Flow rate
t\RY OF AUDIT OF IN
Range ofMeasurement
0-50000ppm
0-10 ppm
0-0.2 ppm
0-0.2 ppm
0-0.2 ppm
Satisfactory
0-1 Lpm
0-100 Lpm
ISTRUMENTATI
RegressicAudit
Slope (m)
0.8877^0.6097^0.8573
1.1685AUDIT INCOMPLETE (see0.9366
1. 1548
ii
,i
+14.5+263.9
+0.11
-0.011 0.9994
Satisfactory
ON
n of Instrumeor’s "Standar
Intercept
-0.007
+0.001
Satisfactory
Satisfactory
Satisfactory
ntation Response tod" (y=mx+c)
Correlation(c) Coefficient
0.99270.9645
0.9996
text)0.9974
0.9999
POen
a/ Linear regression of CO^ based only on lower range of concentrations (0-2700 ppm) measured by instrument.j)/ Linear regression of CO^ based on ful range of concentrations (0-5000 ppm) measured by instrument.
-
TABLE 4. 1 (CONTINUED)
OrganizationLockheed-EMSCO
Manufacturer ofInstrument Modeland Serial NumberByron 401S/N 0306
ParameterTotal hydro-carbons (asmethane)
Total hydro-carbons (aspropane)
Non-methanehydrocarbon
Methane
Carbonmonoxide
Carbondioxide
Range ofMeasurement0-20 ppm
0-20 ppm
0-10 ppm
0-5 ppm
0-10 ppm
0-500 ppm
RegressionAuditor
Slope (m)1.0821
0.8514
0.963
0.9247
0.9403
0.9709
of Instrumental’s "Standard"
Intercept (c)+0.18
+0.11
-0.46
-0.11
-0.28
-2.53
.ion Response to(y=mx+c)
CorrelationCoefficient
0.9997
0.9984
0.9936
0.9987 ^0.9973
0.9998
-
-27-
with excel lent traceabi lity (correlation coefficient 0.9999) If the RTI stan-
dard is accepted, then the ozone concentrations reported hereafter shoul d be
reduced by 15%.
The audit showed the fl ow rates on the quartz crystal mi crobalance and the
Ghia fi lter sampler to be satisfactory.
The Rosemount temperature sensor, Cambridge Instruments dew point sensor
and the integrating nephelometer aboard the B-23 ai rcraft exhibited satisfactory
performance. The problem with the nitrogen oxides analyzer was not resol ved; we
accept RTI ’s analysis that the converter (NO to N0^) does not function linearly.
This results in NO? measurements which are systematical ly low relative to the
cal ibration values. The error woul d be of order 10% for concentrations of
NO n the sub-ppm range. The measurements of N0^ were, however, in excel lent
agreement with the cal ibration. These problems have no impact on the data
presented in this report.
(b) Lockheed-EMSCO Instrumentation
The Byron Model 401 gas chromatograph operated by Lockheed-EMSCO was
audited for measurements of the concentrations of carbon monoxide, carbon
dioxide, methane, total hydrocarbons and non-methane hydrocarbons. The
carbon dioxide channel exhibited excel lent performance, and the methane, total
hydrocarbon and carbon monoxide channel s satisfactory performance. The non-
methane hydrocarbon channel exhibited unsatisfactory performance (based on
the intercept of the linear regression equation)
-
-28-
4.3 Comparison of Plume Minus Ambient C02 Concentrations Measured by the
Oregon Graduate Center (OGC and Lockheed-EMSCO
The data avai lable for the comparison of the CO^ measurements made by OGC
and Lockheed-EMSCO from ai r samples col lected in the stainless steel canisters
via the polyethyl ene bag are shown in Table 4.2. Each of the canister samples
isted was analyzed by both systems with the indicated results. These results
suggest an analytical di screpancy of about +/-20%.
Two samples are avai lable which al low comparison of the polyethylene bag
sampl ing system (employed most of the time) with the stainless-steel sample loop
system (used for some of the OGC samples) The results of these comparisons are
shown in Table 4.3. They suggest an additional di screpancy, this time
systematic, of -20-60%, with the Lockheed-EMSCO concentrations greater than
those of OGC. This could possibly be a bag contamination problem, although it
is unclear how such a large di screpancy coul d arise. The quantity of data is
insufficient to warrant further discussion.
-
-29-
TABLE 4.2 COMPARISON OF OGC AND LOCKHEED-EMSCO MEASUREMENTS OF PLUME MINUSAMBIENT CO? CONCENTRATIONS COLLECTED IN STAINLESS STEELCANISTERS VIA THE POLYETHYLENE BAG
Date
23 July 1982
24 July 1982
24 July 1982
24 July 1982
24 July 1982
24 July 1982
24 July 1982
24 July 1982
SampleNumber
261
147
155
308
186
112
283
292
OGC Lockheed-EMSCO (L)(ppm) (ppm)
62
43
16
46
9
14
18
74
41
18
50
8
8
22
Ratio L/OGC
1.19
0.95
1. 13
1.09
0.89
0.57
1.22
-
-30-
TABLE 4.3 COMPARISON OF OGC AND LOCKHEED-EMSCO MEASUREMENTS OF PLUME MINUSAMBIENT C02 CONCENTRATIONS COLLECTED IN STAINLESS STEELCANISTERS VIA THE STAINLESS STEEL LOOP WITH THOSE COLLECTEDIN STAINLESS STEEL CANISTERS VIA THE POLYETHYLENE BAG
Date OGC(ppm)
Lockheed-EMSCO (L) Ratio L/OGC(ppm)
25 July 1982 6
26 July 1982 17
13.3 2.22
25 1.47
-
-31-
5. FLIGHT PROCEDURES AND DATA PROCESSING
5.1. Flight Procedures
Each plume was studied by flying the UW B-23 ai rcraft at various altitu-
des across the width of the plume, generally at a range of 3.3 km (2 nautical
mi les) from the burn. The range was initial ly determined by use of vi sual
terrain references and quadrangle maps. In cases where the plume fanned, or
ground references became obscured, the range from the burn was computed in
real-time using data from the doppler radar aboard the B-23 ai rcraft. Overall
our position repeatabil ity appeared to be excel lent.
5.2 Data Processing
The traverses of the plume at various altitudes at a given distance down-
wind of a burn were labeled A, B, C, D and E. where A, C and E were the top,
center, and bottom penetrations, respectively. The top and bottom penetrations
were chosen visual ly such that ~10% of the vertical dimension of the pl ume was
above A and below E. The center of the pl ume was estimated visual ly, but it
was general ly about hal fway between A and E. If the plume had suffi cient ver-
tical extent to sample at five levels, the B and n samples were taken midway
between A and C and C and E, respectively. When the pl ume lacked suffi cient
vertical depth for five traverses, the B and D samples were omitted.
Each cross section of the plume presented in this report consists of at
east the A, C and E traverses. The next cross section (i n time sequence) at
the same range uses the previous traverse (either A or E) as the fi rst
traverse of the new cross section. It is assumed that the burns were suf-
ficiently steady state so that each cross section can be considered as if each
-
-32-
of the plume traverses that comprise it were madesimultaneously. The bag and
batch samples were obtained as close as possible to the centerof the plume.
However, since they were taken over a minimum of 300 m path length and required
some degree of anticipation, they can be considered as located randomlyabout
the central region of the plume. Si nce each fi lter requi redat least two bag
samples, at least two traverses of the pl ume were made at each altitude.A
canister sample and particle size di stribution measurement were obtainedcoin-
cident with each fi lter bag sample. The cani ster and si zedi stribution data
are averaged when they are compared with the fi lter data.
The light scattering coefficient (b^^) as measured by the integrating
nephelometer. was the parameter selected to be representative of the plume
boundaries. Plume cross sections were created graphical ly by pl ottingthe
value of b every 2 s (130 m path length) for each altitude that wasscat
traversed. Plume center was defined as that where b^ reached peak values.
Multiple traverses at the same altitude were averaged. In documented cases of
substantial pl ume fanning with height, and/or multiple plume cores, thecross-
sections were made logical ly consistent with the avai lable data.
To calculate emission fluxes of any parameter, we assume that the para-
meter can be linearly scaled to b^. Hi gh-resolution data (13 sampl es/sec)
were used for b averages which were computed for times when thebatch
S C3T
sampler switch was in the "fi position. Using a least-squares fit,an
algorithm was derived for the relationship between the average value of
b and each flux parameter.scat
-
-33-
In the cases of the mass fluxes derived from the fi lters and the mass
monitor, separate algorithms were developed for the Washington and Oregon
units. The b cross sections were contoured, and the grid areas, or areasS CdL
between b contours, were determined. The cross sections were thenS Cd C
divided elevationally by wi ndspeed (which was interpolated from soundings
taken with the pi lot bal loon closest to the time of the cross section). An
average windspeed was determined for each grid area. The emission flux is
given by:
F1 ux=E (gr1d area) x(windspeed) x(average parameter concentration in grid area)."’
where, indi cates the b contour level
Mass fluxes were derived from linear equations relating measurements of
b to the data from the weighed fi lters, the mass monitor (
-
-34-
TABLE 5.1 ALGORITHMS RELATING b^^ TO MASS CONCENTRATION
a) Filters-3\ i-t. /^~l\n f\ i m-’
*Mass concentration (ug m" [bscat (m" )] (1. 3 x 10 + 150Number of samples 44 (a1 data included)Correlation coefficient 0.78 5 _2Mean mass concentration/mean b ^
1.77 x 10 pg m
Oregon Samples
3 1 5Mass concentration (ug m" [bscat (m" )^ (2-32 x 10 + 24Number of samples 20 (2 extreme values deleted)Correlation coefficient 0.88 5 _^*Mean mass concentration/mean b^^ 2.44 x 10 yg m
Washington Sampl es5
Mass concentration (ug m" [bscat (m- ^ (1*68 x 10 119Number of samples 18 (4 extreme values deleted)Correlation coefficient 0.92 5 _g*Mean mass concentration/mean bscat 1’44 x 10 ^9 m
b) Mass monitor (
-
OREGON ONLY
5. 1. A plot of the weighed fi lter mass concentration versus the light scattering coefficient (b ^)together with the inear regression and the 95% confidence intervals for the Oregon data set.
-
NRSH INGTON ONLY
^.^p^^,^^^.^^^^^^
-
O R E G O N
0 .00083 .00167 .00250 .00333 .00417 .00500
BSCRT (m"1) ,Figure 5. 3. A plot of the mass moni tor mass concentration versus the light scattering
coefficient
(b ) together with the inear regression and the 95% confidence interval for theOregon data set.
scat 3
-
W A S H I N G T O N
-
-39-
5.3. Physical Interpretation of b^^ Al gorithms
It must be noted that the relationships between the light scattering
coefficient and aerosol mass that have been reported in the literature have
usual ly been the result of a very limited data set and thei r authors have merely
ratioed b and mass and averaged the result (cal led the ratio method). ForS CBL
2 -1example, in our earl ier work we found values between 1.3 and 5.8 m g for this
2 -1ratio. White (1981) reports a range of values from 1.5-15.4 m g for various
sources. Anderson et at (1982) reports b -to-aerosol mass ratios of
1.9-3.4 m2 g" from a study simi lar to the present one. In the present study2 -1 2 -1
the mean value was 5.6 m g with mean values of 4.1 and 6.9 m g for the
Oregon and the Washington fi res, respectively.
The ratio method assumes that each particle contributes to b^^ in propor-tion to its mass; in fact, we know that this is not the case. As described in
more detai in Section 6.5, for the size distributions observed in this study,
the submicron particle mass completely dominates b It is some combination
of the distribution of supermi cron particles and the data s inherent noise that
produces the signi ficantly non-zero intercepts of the algorithms in Table 5.1.
That this departure from a 1:1 relationship is mathemati cal ly secure for the
fi lter data is indicated by the number of sampl es (44) and the satisfactory
correlation coefficient (0.78). The correlation coefficients are signi ficantly
improved if the data is divided into Washington and Oregon sets and a total of 6
"extreme" values are excluded. The correlations coefficients for the Washington
and Oregon data sets are 0.92 and 0.88, respectively. However, there is no apparent
-
-40-
basis for excluding the extreme values other than that they appear to be
"outl iers". Thus, for the burns studied, the ^cat"1 1"6^ fit a1gorithm
provides, in some ways, a superior predictor of smoke mass than does the ratio
method. The disadvantage of the algorithm is its questionable value at the
edges of plumes, where b^^ is smal l For both reasons, and also because of
the historical use of the ratio method, we wi use both the ratio method and
the b -l inear algorithm method in later sections.s cdc
As an aside, the b -l inear algorithm that results from Anderson et al ^sS C^L
data is:
mass concentration (ug m’3) -0.042 (b^g^xlO" m" + 990
with a correlation coefficient of -0.13. This result has neither predictive
value nor does it support a 1: 1 relationship between b^^ and mass. This
further indicates the need for a substantial data set in order to reduce
statistical uncertainties.
-
-41-
6. PRELIMINARY RESULTS AND ANALYSIS
In this section we present some of the results of the ai rborne measure-
ments of the slash burns and some preliminary interpretationsof the data.
6.1. Characterization of the Cross-Section of the Plumes
Using the methods described in Section 5.2, all of the ai rborne measure-
ments (except those which were clearly unsuitable due to non-perpendicular
penetrations of the plumes or gross changes in burn characteristics) were
assembled into cross-sections of ight-scattering coeffi cient. Illustrative*
exampl es are provided below for each of the burns investigated in thisstudy.
6.1.1. 23 July 1982
This burn was on a hil lside, just below a ridgel ine in rough terrain.The
plume initial ly rose nearly verti cally through a boundary layerinversion, and
was then carried off horizontally, at an altitude of 1.7 km by the windsaloft.
The plume was initial ly only -250 m thick with a well-defined axial core(Fig.
6.1 Additional fuel added to the burn after -1640 PST increased thedepth of
the pl ume to -400 m (Fi g. 6.2) but by 1720 PDT the plume had stabil ized back to
a thickness of -280 m. By 1720 PDT the pl ume was substantial ly more complex
(Fig. 6.3) with light winds and terrain features introducing portions of the
pl ume from earlier times into the cross-section. The secondary coreof the plume.
located at an altitude of 1.65 km and 1.2 km to right of center (Fig. 6.3)
was part of the "old" plume. In post-analysis we removed from the data set
* A ful set of cross-sections is on fi le at the USDA Forestry SciencesLaboratory, 4043 Roosevelt Way NE. Seattle. WA, 98105. Copies can beobtained from that source.
-
2.0 .0 0 1.0 2.0
DISTANCE FROM PLUME CENTER (KM)
3.0
Fig. 6.2dicular toheavy barssection is
Verticalthe longindicatebased on
cross-section of the light-scattering coefficient (in units of 10-3 m-1) measured perpen-axis of the plume from the prescribed burn on 23 July 1982 at 3.3 km from the burn. Thethe regions over which the batch sampler on the B-23 ai rcraft was operated. The crossai rborne measurements taken during sequence Vif. between 1640-1723 POT.
-
L̂JQD
<
1.0 0 1.0
DISTANCE FROM PLUME CENTER (KM)
Fig. 6.3dicular toheavy varssection is
Vertical cross-section of the light-scattering coefficient (in units of 10-3 m-1) measured perpen-the long axis of the plume from the prescribed burn on, 23 July 1982 at 3.3 km from the burn. Theindicate the regions over which the batch sampler on the B-23 ai rcraft was operated. The crossbased on ai rborne measurements taken during sequence #3 between 1719-1745 POT.
-
-45-
we removed from the data set encounters with smoke that were obviously separated
from the main plume. However, in this case (and the fol lowing) whenever "old"
smoke merged with "new" smoke, we were unable to objectively partition the data.
Consequently, this cross section and the fol lowing (Fi g. 6.4) tend to exaggerate
the emission fluxes. When the plume sketches and photographs from the patrol
ai rcraft aloft become avai lable it may be possible, through further analysis, to
remove this ambiguity.
-
^Q=)
<
1.0 0 1.0
DISTANCE FROM PLUME CENTER (KM)
Fig. 6.4dicular toheavy barssection is
Verticalthe longindicatebased on
cross-section of the light-scattering coefficient (in units of 10"3 m"1) measured perpen-axis of the plume from the prescribed burn on, 23 July 1982 at 3.3 km from the burn. Thethe regions over which the batch sampler on the B-23 ai rcraft was operated. The crossai rborne measurements taken during sequence )jt4 between 1744-1814 POT.
-
-47-
6.1.2. 24 July 1982
Initially, this plume was low and did not rise above local ridgel ines,
making ai rborne sampl ing nearly impossible. An attempt was made to rectify
this by adding more fuel this caused the pl ume to ri se to more than 3500 m.
However, before a series of ai rborne cross-section measurements could be
completed, the plume col lapsed to much lower altitudes. As a result, a steady-
state assumption for this burn was not justi fied and no cross sections were
compiled.
6. 1.3. 25 July 1982
This burn produced a good stable plume for about 2.5 hours. The cross
sections al look similar to the one shown in Fi g. 6.5. Only sequence 3, taken
between 1037 and 1054 PDT, departed from a completely stable appearance; the
plume contained a significant amount of smoke ~300 m below the average base of
the plume at -1900 m MSL.
6. 1.4 26 July 1982
Stable weather conditions al lowed good measurements to be obtained on
23 and 25 July. However, on 26 July as broken ci rrus and ci rrocumul us and
towering cumulus on the horizon to the east invaded the sky, sampl ing conditions
deteriorated. Despite changes in atmospheric stabil ity seven cross sections of
good qual ity were obtained in the pl ume from this burn. Only sequences 3 and 4
(from 1114-1159 POT) show signi ficant deviations from an otherwise vi sual ly
steady plume. The thickness of the plume decreased during sequence 3, whi le it
increased during sequence 4; the other cross sections look very much like the
one shown in Fig. 6.6.
-
c
1.2 .8 .4 0 .4 .8
DISTANCE FROM PLUME CENTER (KM)
Vertical cross-section of the light-scattering coefficient (in units of 10the long axis of the plume from the prescribed burn on 25 July 1982 at 3.3indicate the regions over which the batch sampler on the B-23 ai rcraft wasbased on ai rborne measurements taken during sequence #2 at 1021-1041 POT.
"3 m~1) measured perpen-km from the burn. Theoperated. The cross-
-
’
2.1
L̂U
2.0
<
.91.2 0.8 0.4 0 0.4 0.8 1.2
DISTANCE FROM PLUME CENTER (KM)
Vertical cross-section of the light-scattering coefficient (in units of 10~3 m~1 measured perpen-the long axis of the plume from the prescribed burn on .,26 July 1982 at 3.3 km from the burn. Theindicate the regions over which the batch sampler on the B-23 ai rcraft was operated. The crossbased on ai rborne measurements taken during sequence #5 between 1157-1219 PDT.
-
-50-
6.1.5 15 September 1982
This was the fi rst burn in Washington and it was significantly larger than
any of the Oregon burns. The pl ume was visual ly rather stable and steady. The
cross sections show a smal plume initially, fol lowed by a very steady period
from 1500 to nearly 1600 PDT, fol lowed, in turn, by a sl owly shrinking plume.
Fig. 6.7 is representative of the large and complex plume encountered.
6.1.6 23 September 1982
This plume showed large departures from visual steady state. This
situation was further compl icated by a substantial turning of the wind di rection
with height within the range of altitudes occupied by the plume. Obscuration of
surface terrai n features by smoke near the burn, and off-scale readings of the
ight-scattering coefficient at a range of 3.3 km, prompted us to move to a
range of 6.6 km in order to obtain cross-sectional measurements. The results
depicted in Fig. 6.8 are typical of the compl ex plume encountered.
6.1.7 Summary of Plume Cross-Sections
The cross sections shown in Figs. 6.1-6.8 are an important step in quan-
ti fying the nature of the plumes. Further quantitative information is provided
in Table 6.1 which lists the average values of b^^ between contours (shown in
the cross sections) and the area between that contour interval multipl ied by
the wind speed (the ai r volume fl ux) for al val id cross sections. The tables
can be used to compute the emission flux of any parameter that can be related to
^caf
-
’.
^Q=)
.8 .4 0 .4 .8 1.2
DISTANCE FROM PLUME CENTER (KM)
Fig 6 7 Vertical cross section of the light scattering coefficient (In units of 10-3 m-1) measured perpen-dicular to the long axis of the plume from the prescribed burn on 15 September 1982 at 3.3 km from the burn.
The heavy bars indicate the regions over which the batch sampler on the B-23 ai rcraft was operated.
The cross section is based on ai rborne measurements taken during sequence N between 1525-1610 PDT.
-
Fig. 6.8 Vertical cross-section of the light-scattering coefficient (in units of 10"3 m-1 measured perpen-dicular to the long axis of the plume from the prescribed burn on 23 September 1982 at 6.6 km from the burn.The heavy bars indicate the regions over which the batch sampler on the B-23 ai rcraft was operated. Thecross section is based on ai rborne measurements taken during sequence #3 at 1608-1647 POT.
2.0 1.6 1.2 .8 .4. 0
DISTANCE FROM PLUME CENTER (KM)
-
-53-
1 COMPILATION OF THE VOLUME FLUX OF AIR AND THE ASSOCIATED VALUE OFTHE LIGHT-SCATTERING COEFFICIENT (bg^) TAKEN FROM THE CONTOUREDCROSS-SECTIONS OF b AND THE MEASURED HORIZONTAL WINDS
SC3L
Cross-SectionSequence
ht Number
1982 1
2
3
4
1982 1
2
3
4
5
TimeInterval(PDT)
1606-1644
1640-1723
1719-1745
1744-1814
0950-1009
1021-1041
1037-1054
1051-1108
1104-1120
AveragebscatValue forContourInterval(10-3 m- )
2.451 .450.7250.225
2.7252.2251 .450.43
3.7253.2252.451 .450.43
3.7253.2252.451 .450.43
1 .2250.7250.225
1 .7251 .2250.7250.225
2.451 .450.7250.225
2.451 .450.43
2.2251 .7251 .2250.43
AreaofContourInterval
(105 m2)
0.1341 .5843.0402.638
0.2491 .2553.3088.968
0.1040.4202.8822.3343.650
0.0060.2191 .7312.3823.991
0.3510.9681 .545
0.3410.6851 .5452.723
0.0073.4213.4534.213
0.6173.0582.984
0.0361 .0332.5674.016
"TOO-Speed
(m s-1 )
5.04.64.74.8
3.03.03.13.5
1 .01 .61 .71 .71 .9
2.02.02.02.02.0
4.94.44.7
7.07.07.06.8
11 .09.7
10.010.1
10.810.810.8
9.010.410.010.2
Vol ume Fluxof Air
(105 m3 s-1
0.6707.28814.29012.664
0.7473.73510.25631 .390
0. 1040.6734.8993.9686.934
0.0120.4373.4614.7647.981
1 .7224.2607.263
2.3854.79410.81818.508
0.07933.18334.53242.555
6.66033.03032.227
0.32310.74025.67440.963
-
-54-
TABLE 6. 1 (CONTINUED)
DateMissionNumberUM FlightNumber
25 July 19823
105626 July 1982
41057
Cross-SectionSequenceNumber
6
1
2
3
4
5
6
7
TimeInterval(PDT)
1 11 7-1 1 33
1041-1059
1053-1118
11 14-1124
1140-1200
1 157-1219
1210-1231
1225-1245
Average^catVaTue forContourInterval(10-3 m-1
2.451 .450.43
1 .2250.7250.225
2.7252.2251 .450.43
2.451 .450.43
3.2252.7252.2251 .450.43
2.7252.2251 .450.43
2.7252.2251 .450.43
2.7252.2251 .450.43
AreaofContourInterval
(105 m2)
1 .3703.0004.430
0. 1580.8351 .122
0.0540.3161 .0081 .782
0.0140.4120.818
0.0320.3150.8351 .7612.980
0.0500.4121 .0221 .789
0.1580.5631 .1192.170
0.0970.5201 .1011 .972
"WTnd---Speed
(m s-1)
9.810.19.8
5.05.05.0
5.95.65.45.3
5.05.05.0
8.07.56.26.06.2
6.87.07.27.3
5.75.55.55.4
5.05.05.05.0
Vol ume Fl uxof Air
(105 m3 s-1
13.42630.30043.411
0.7894.1775.61 2
0.3171 .7675.4419.446
0.0722.0624.088
0.2572.3665.18010.56618.475
0.3412.8867.35813.062
0.9003.0966.154
11 .715
0.4842.605.5049.861
-
-55-
TABLE 6. 1 (CONTINUED)
DateMissionNumberUW Fligl-Number15 Sept
5191
1060
it
embi82
Cross-SectionSequenceNumber
er1
2
3
4
5
6
1416-1428
1421-1501
1459-1529
1525-1610
1608-1645
1644-1721
TimeInterval(PDT)
Averagebscat V811"8for ContourInterval(10-3 m-1
12.9010.908.906.903.250.725
10.908.906.904.902.901 .175
12.910.98.96.94.92.91 .175
12.910.98.96.94.92.91 .175
12.910.98.96.94.92.91 .175
10.98.96.94.92.91 .175
AreaofContourInterval(105 m2)
0.0570.0740.0950.1360.3730.151
0.3580.6461 .6572.4673.7033.641
0.2440.7671 .6352.3103.6792.9983.808
0.0360.2360.5601 .2901 .8502.8692.639
0.1510.1070.5021 .4993.0123.8513.292
0.1220.3230.7964.1743.4782.374
WindSpeed
(m s-1
16.016.016.016.016.016.0
13.311 .911 .811 .210.09.7
14.411 .311 .410.710.312.310.3
17.015.816.014.915.614.013.9
11 .011 .112.612.613.012.912.2
12.712.613.214.313.513.7
Volume Fluxof Air
(105 m3 s-1
0.9121 .1841 .5202.1765.9682.416
4.7617.68719:55327.63037.03035.318
3.5148.66718.63924.71737.89436.87539.222
0.61 23.7298.96019.34028.86040.16636.682
1 .6611 .1886.32518.88739.15649.67840.162
1 .5494.06910.50759.68846.95332.524
-
-56-
TABLE 6. 1 (CONTINUED)
DateMissionNumberUM Fl ightNumber15 September
19825
1060
23 September1982
61061
Cross-SectionSequenceNumber
7
2
3
4
5
TimeInterval(PDT)
1713-1735
1558-1 612
1608-1647
1642-1710
1709-1716
Average’’scat Valuefor ContourInterval(10-3 m-1 )
8.96.94.92.9
1 .175
6.455.454.453.452.451 .450.725
6.45*5.454.453.452.451 .450.725
7.456.455.454.453.452.451 .450.725
5.454.453.452.451 .450.725
AreaofContourInterval(105 m2)
0.0860.1150.6021 .0040.889
0.0210.2870.5960.6881 .1551 .5631 .112
0.0640.3660.5880.8901 .4121 .5071 .369
0.0430.3730.6091 .5641 .6062.61 12.4601 .879
0.1860.6820.4660.7030.9680.839
UmdSpeed
(m s-1 )
13.013.614.314.114.1
13.012.111 .912.011 .611 .811 .9
13.012.212.311 .911 .712.211 .6
12.012.212.211 .212.01 1 .41 1 .51 1 .6
10.010.110.310.210.210.4
Volof
(105 m3 s-1)
ume FluxAir
1 .1181 .5648.60914.15612.535
0.2733.4737.0928.25613.39818.44313.233
0.8324.4657.23210.59116.52018.38515.880
0.5154.5517.430
17.51719.27229.76528.29021 .796
1 .8606.3434.8007.1719.8748.726
-
-57-
6.2 Some Characteristics of the Particles in the Plumes
In a previous series of ai rborne measurements that we obtained in the
plumes from prescribed burns (Stith et at 1981) we noted that both the number
and the mass distri butions of the particles in the pl ume were generally domi
nated by a concentration peak at ~0.1 pm diameter; a much less prominent peak at
0.5 urn was also noted. However, with the instrumentation then avai lable,
information on particles > 10 urn present in number concentrations 10 ym can be obtai ned at concentrations down to
~10"3 cm"3. Al so, the avai labi ity of new particle-size measuring instruments(see Section 2) extends our measurements to particles ~3000 urn in diameter pre-
sent in concentrations down to -lO^cm" These new observational capabi itieshave resulted in a revision in our view of the role of supermi cron particles in
smoke from prescribed burns.
6.2.1 Parti cle Size Distributions
The particle size distribution shown in Fi g. 6.9 il lustrates many of the
features that were found to be typical of the smoke from the prescribed burns
investigated in this study. The particle size distribution shown in Fig. 6.9
was obtained on 23 July 1982 at a range of 3.3 km for the burn and near the
plume center on traverse "C". Before discussing some of the features of this
distribution, we need to make a few caveats about the measurements.
* Al of the particle size distributions measured during this project, anda discussion of the di fferently weighted (number, surface and volume)distributions, are contai ned in Data Supplement #3.
-
-58-
o (5 E^S< i-.’j’i’C^ 2’j2a p.orca c^?
0)
0 -^0 +3"
00
c^"
00
(V"
m
sroy-a""’L3D
Do~-^o
Q0’L3
Sg
00-- \00
"- \\
00
rf-
00
in--------------|-------------n----------- |,.,i..,.,’-3.00 -2.00 -1 .00 0.00 1.00 2.
++
\ :\ t\ t\ t\ .\ .\\ .\ +\ ^\ + .+\ . .
\ 4 .\ ^\ ^ 0\
\ ^\\ .\
\\\
Fig. 6.9 Number concentration versus size of particle measured in the plumefrom the prescribed burn at 1742 PDT on 23 July 1982 3.3 km downwind of theburn. The dashed line shows a typical ambient particle size distribution.
-
-59-
As discussed in Section 2, the use of the batch samples shoul d resol ve
any timing difficulties resulting from the fact that the four particle-size
measuring instruments operate on di fferent time sequences. Nevertheless, some
oss of data accuracy can occur through operational errors. In order to be con-
sidered valid data, we requi re smooth transitions between the measurements from
the various particle-size measuring instruments. For the ranges shown in Fig.
2.2, each instrument is most accurate at the small size end of its range and
general ly least val id (due to counting statistics and sedimentation) at the
large size end. The most common points of concern in such data are poor tran-
sitions between the measurements obtained with the EAA and ASAS (about 20% of
cases) and a rough transition between the measurements from the ASAS and LAS in
the range 0.7 2 pm. The latter discrepancy is of some importance, since this
is the size range where our previous smoke studies (Stith et a1 1981) showed a
secondary peak in concentrations. Measurements obtained with the ASAS in this
present study tend to support a peak at 0.7 urn, but data from the LAS does not
show this peak.
The measured particle size distri butions showed simi lar shapes and gross
features throughout the duration of each burn, as well as for al of the burns
studied (see for example Fig. 6.10). However, some interesting di fferences were
noted from the studies of Stith et a1 (1981) Although there is a prominent
mass peak centered at 0.1 pm, the peak in the number concentration of 0.1 urn is
now a secondary feature. Measurements from the EAA show concentrations sti ll
increasing below 0.01 urn (the imit of this instrument) indicating the possi bi-
ity of a (nucleation) peak in the number distribution below 0.01 pm.
-
-60-
0
t^ ^< ccr Er- z ^UJ
^ j-8 "CPLU 0
=> -0; >10-2 10’ 10 10’ 102 10
PART ICLE D A METER D (/im)Fig. 6.10 Number concentrations versus size of particles measured near thecenter of the plume and 3.3 km downwind of the burn on 23 July 1982 at 1636PDT (heavy solid line) IT^tl PDT (dashed line) and 1759 PDT (solid line)The ambient particle size distribution is also shown (dotted line)
-
-61-
However, since the cumulative particle number from the EAA is in reasonable
agreement with the "total aerosol concentration measured by the Aitken nucleus
counter, the peak must be near 0.01 urn. Furthermore, most of the submi cron par-
ticle mass and ight scattering are stil associated with the 0.1 urn number
peak.
The most dramatic difference between the present measurements and those
reported by Stith et at (1981) has to do with the supermicron particle volume
di stribution, for which our new particle sampl ng system provides superior resolu-
tion for particles with diameters up to ~45 urn. Fi gure 6.10 shows that in our
current data the supermicron particle peak is not resol ved; the volume continues
to increase with increasing size to the limit of the measurements. Our previous
smoke data show a minor mass peak at ~10 pm and the vast majority of the mass
located in the submicron peak. The higher concentrations of supermi cron par-
ticles that we measured in this study, compared to Stith et al ’s measurements,
are almost certainly due to improved sampl ing techniques. These new observations
affect estimates of TSP, as wi be discussed below.
It shoul d be noted that a substantial fraction of the particles in the
plumes had diameters >45 pm; this was supported by the pi lot ’s observation that
we were col lecting mi imeter sized pieces (stil smoldering?) under the
wi ndshield wiper blades of the ai rcraft. The shapes of these parti cles are
shown in Fi g. 6.11. The largest particle in this sample is about 4 mm long.
-
-62-
FLT*1060. PROBE*5. ID*060. 17; 09:46
rnTirrNOT^^iiiiiirfrriiir’rrir^-";: ;?;; :?;;;s;;;;;;?; ?:i=>::s;;^;:;=;; ;;
FLT*1060, PROBE*4, ID*060. 17: 13:01
T#1060 PROBE*5 ID*060< 17; 13; 13 inii^i ynit/di iii m
ISyiaiiwiiiiwitflteTritLiHr’^HH ^f irWt r hWftLHHt’H l^tiiiiiPBiwff^^’LSiR&l^rl&^^FLT*1060^PROBE#4, ID#060. 17:20:55 1- 1- 11 A ^
^ ILr illLHt f It |l t l l! lilLrHtl[ H lhH4LF IHllKlllK HILWc\ T^IOCCT ponRFA^ TT^ftRfiB 17" 24" 50’’^BBi^raitH’ir^SirnS?ir^mii(H:ikir - iLiHtMrLUii4ii .L^]ri^iL"- ’-. ’-^^-^ ’If naFLi#\Q6Q, PROBE*5/ ID*060. 17:27:20
FLf*i060’," PROBE*5^"iD*060," 17:27:40
rt|i’i!
iH HLri^t [llNll ffiFL:^*1060^">’PROBE*4," ’ID*060. 17:27:45
?’ r i kl i l ^ n ;?-_
FLT*iaG0. PROBE*5, IDw060. 17:33:56
Fig. 6.11 Shadow images of ai rborne particles observed with the laser camera incross-section sequence #2 through the plume from the burn at ~1727 PDT on 15September 1982. For Probe 4, the vertical frame size is 800 urn, and for Probe 5,it is 3200 urn.
-
-63-
The other three laser cameras aboard the B-23 ai rcraft al so detected the
large particles. Although thei r counting statisti cs are only just satisfactory,
the shape of the distri bution can be seen in the raw data plot taken near pl ume
center at 1427 POT on 15 September 1982 (Fi g. 6.12). The measurements from the
instruments agree reasonably wel with simultaneous measurements obtained from
the aerosol system, but there is a change in slope at the overlapping intersec-
tion of the two data sets (Fig. 6.13). The point to note is that these curves
show that the peak in the volume of the supermi cron particles is stil0
not resolved even by our extended size measurements; the total volume of the
particles is sti increasing for parti cles above 1000 urn in diameter.
While the submicron particles dominate visibi lity reduction by the pl ume,
and the impact of the plume over large travel distances, it is clear that at
3.3 km downwind of the prescri bed burns that we studied the supermicron par-
ticles dominated the total mass of particles in the plume. This result has a
significant effect on our interpretation of the aerosol fi lter data and how we
define the emission factor (see Section 6.5).
-
-64-
00
OJ
0rS-
0̂0o
Od-0
QQ’^02LCD’T’-CD0
-00
(\1-
0C3
(T>-
00
=r
QQ
LD-
"0
A
..................A...
j!
00
^A
4s.A
............^......
^A
^00
00 2
^ 0̂o^0
00
00 3 00 4 0-’
Fig.. 6. 12 Number concentration versus particle size measured with a lasercamera on the B-23 ai rcraft near the center of the plume 3.3 km downwind of theburn at 1427 PDT on 15 September 1982.
-
-65.
10’2 0" 10 0’ \02 103PART IC LE DIAMETER D (/iM )
Fig. 6.13 Number concentration versus the size of particles measured withthe aerosol system near the center of the plume 3.3 km downwind of the burnon 15 September 1982 at 1K27 PDT (heavy line) and 1727 PDT (lighter line)The dashed extensions are measurements from the laser cameras.
-
-66-
6.2.2 Average Characterisitics of the Particle Size Distributions
The characteristics of the particle size distri butions are best seen
in the averaged and summed characteristics of the mean number diameter (MND) of
the particles, thei r mean volume diameter (MVD) and the total particle volume
(TPV) for particles < 43 pm in diameter. Plots of these parameters, as a func-
tion of time after burn ignition, reveal a number of signi ficant di fferences
between the burns that we studied.
Fi gure 6.14 indicates the generally steady-state nature of the pl ume from
the burn on 23 July 1982 over the period 50-140 min after ignition; the MND is
steady between 0.02 and 0.03 urn and the TPV is steady near 200 pm cm" The MVD
is more variable, ranging from 8 17 pm, and is evidently correlated with the
TPV. The altitude of the plume center rose by less than 150 m during this
period.
In contrast, on the 25 July 1982, which also featured a "wel l-behaved"
plume (although it gained substantial ly in altitude as the burn progressed)
shows a general increase in MVD and TPV as a function of time after ignition
(Fi g. 6.15). This behavior was repeated on 26 July 1982 (Fi g. 6.16). In both
cases the MVD was initially ~1 urn and increased to -10 urn by about 2 hours after
ignition. The MND’s show little variation.
The larger burn in Washington on 15 Spetember 1982 (Fi g. 6.17) shows
far more variabil ity, despite a visual ly fai rly steady plume.
-
SEQUENCENUMBER
iT
S0o
600^3.o^ttinr
400$ ^-i^? S0-1
200 1- 0TOTAL VOLUME
.03
.01
ALTITUDEOF PLUMECENTER
1.8
1.7
1.6
S
ûQ3-<
50 60 70 80 90 100 10 120 130 140
TIME ELAPSED AFTER IGNITION (MIN)
Pig. 6.14 Characteristics of the particles near the center of the plume on
traverse "C" 3.3 km downwind of the burn on 23 July 1982 as a function of
time after ignition.
-
40 50 60 70 80 90 100 110 120
TIME ELAPSED AFTER IGNITION (MIN)
Fig. 6.15 Characteristics of the particles near the center of the plume ontraverse "C" 3.3 km downwind of the burn on 25 July 1982 as a function oftime after ignition.
-
7 SEQUENCE(-1 NUMBER
o
u10
>00 3.J 2
^̂t000 $ ^Q. UJ0 ^ 3^2.2
2.0S
^UJQ
1.8 ?
1-6 <
50 60 70 80 90 100 10 120 130 140 150
TIME ELAPSED AFTER IGNITION (MIN)
Fig. 6.16 Characteristics of the particles near the center of the plume ontraverse -C" 3.3 km downwind of the burn on 26 July 1982 as a function oftime after ignition.
-
Pig. 6.17 Characteristics of the particles near the center of the plume ontraverse "C" 3.3 km downwind of the burn on 15 September 1982 as a functionof time after ignition.
120 140 160 180
TIME ELAPSED AFTER IGNITION (MIN)
-
-71-
The second Washington burn on 23 September 1982, was studied at 6.6 km
downwind (Fig. 6.18). Visual ly, the plume was less steady than the pl ume on
15 September; again there was only sl ight correlation between MVD and TPV.
The MVD decreased throughout the duration of the burn; it had an initial value
~6 urn and finished at ~2 urn, with a discontinuity at ~100 min after ignition
when both MVD and TPV increased sharply. The MND shows signs of being anti-
correlated with MVD.
An interesting feature of the data sets are the two cases where there is a
clear positive correlation between MVD, TPV and plume rise, and the other three
cases where this is correlation was not evident. The two cases where there was
a positive correlation seem to indi cate a relationship between the intensity of
the burn (as indicated by pl ume rise) and the lofti ng of ever larger debris into
the plume. The fact that there are weak indi cations that the MND decreases as
MVD and TPV increase (see also the 25 and 26 July cases) suggests that com-
bustion efficiency al so played a role. Thus, as the intensities of the burns
increased, more complete combustion produced smal ler "combustion nuclei but
simultaneous increases in the velocity and turbul ence of the ai r increased the
concentrations of partial ly combusted fuel and other debris in the pl umes.
-
Pig. 6.18 Characteristics of the particles near the center of the plume ontraverse "C" 6.6 km downwind of the burn on 23 September 1982 as a functionof time after ignition.
-
-73-
6.2.3 Apparent Density of the Particles
Simultaneous measurements of the particle volume distribution, the
particle mass distribution (with the cascade microbalance) and the mass of
particles
-
-74-
TABLE 6.2. APPARENT DENSITY OF PARTICLES IN PLUME
a) Mass Monitor Data_o
Mass concentration (ug m"3) 2.6 (aerosol volume in urn cm ) + 38Number of sampl es 247Correlation coefficient 0. 90 _^Density of particles 2.6 +/-0.08 g cm"
b) Cascade Microbalance Data
Mass concentration (ug m"3) 2.2 (aerosol Volume in urn3 cm"3) + 35Number of samples 115Correlation coefficient 0.63Density of particles 2.2 +/-0.25 g cm-3
-
-75-
distributions. we divide by a (rounded-off) particle density of 2.0 g cm"
(We wi use this density in the remainder of this report. However, we must
emphasize both the uncertain value of this density and the fact that it is not
clear to us how the accuracy of the value can be improved. Some results are
shown in Fig. 6.19, where it can be seen that the cascade microbalance reprodu-
ces the submicron mass peak detected by the particle size-measuri ng system.
However, as expected, the very smal sample flow for the cascade mi crobalance
prevents it from col lecting a weighable sampl e for particles >5 urn.
we bel ieve that the measurements of the size spectra of particles converted
to a mass distribution, using a derived apparent particle density, is the more
general ly valid and defensible approach to obtaining size-segregated mass
distributions in the plumes than are the measurements from the cascade
microbalance.
-
n
160
^ 120=to0>0
o
>̂
80
40
(c)
-3
9/23/821718
-2 0
LOG D (/xM)
Fig. 6. 19 Vol ume concentration versus size of particles measured with the aerosol sizingsystem near the center of the pl ume from the burns (a) at 0954 POT on 25 July 1982; (b)at 1605 POT on 23 September 1982; (c) at 1718 POT on 23 September 1982; and (d) at 1700 PDTon 23 September 1982. The dashed lines show resul ts derived from the cascade microbalanceimpactor (mass/density of particles
-
-77-
6.2.4 Aerosol Elemental Analysis
In addition to weighing the filters Crocker Laboratory performed an elemen-
tal analysis by Proton Induced X-Ray Emission (PIXE ). Me have appl ied the
matrix correction factors for Na. A1 Si and C1 which had correction factors
>10%, al other elements had correction factors
-
TABLE 6.3 P.XE ANALYSES OF EMISSIONS FROM THE SLASH ^NS (The numbers 1n th. body of the table are the concentrations or the specified element in .9 m-3)-3,*
(a) UM Flight 1054 on 23 July, .1982 (V. Br- and Ti wre not detected.)
Filter
A5(Amb)A6A7ASA9A10
Time
1526-15351603-16211631-16511733-17451753-18101818-1825
Na’
2.511.3
Mg
0.77t0.391.0U0.68
(b) UW Fl
Al’
1.610.53.710.941.210.95
ight 1055
Si’
1.710.70l.OtO.581.410.443.1t0.712.5t0.721.2tl.O
on 24 July 1982
P
1.6t0.342.1*0.552.010.532.210.65
S
0.510.41.510.41.710.372.510.563.2t0.761.910.74
(Filter A3
C1’
11.72lU.460.8810.411.810.67
had Hi-’ 1
K
2.910.53.210.57.610.94.910.85.96t0.9
.710.55
Ca
6.510.7419.712.043.H4.417.4H.815.111.7
ug m-
Pb
Br’ was
Cr
0.3t0.250.3710.27
1.110.39
not detected
Mn
1.5t0.362.0t0.315.410.682.410.432.610.55
on remaining filters
Fe
5.6t0.65.710.654.810.557.910.908.610.975.310.72
Ni
0.47t0.20.33i0.10.5710.2
.)
Zn
0.4410.1810.7ll.l60.4510.220.64*0.28
Cu
0.26t0.15
Filter
Al(Amb)A2A3A4AllA12A13 1745-1754A14 1801-1824A15(Amb)1820-1824
Time
1557-16011612-16211633-16411650-165917101723-1735
Na+ Mg
4.2H.41.310.76
1.410.92
1.610.68
A!’
1.OtO.77
1.910.933.712.5
2.9H.O
Si’
0.7610.662.610.86
2.210.87
1.910.59
P
0.4610.34
1.310.881.610.595.3H.5
2.510.730.6810.500.7710.37
S
0.6110.401.510.64
1.810.69
1.510.82.910.611.210.610.9110.54
C1’
0.8610.541.710.94
2.1H.4
0.6210.52
K
1.H0.381.610.476.1H.14.910.726.411.42.410.727.210.921.910.490.7010.32
Ca
2.H0.342.210.4116.8H.817.611.912.5U.67.510.9916.9H.84.510.73
Pb
2.9H.1
6.712.2
0.5310.33
0.3410.28
Cr
0.4610.26
Mn
3.2*0.654.H0.642.010.762.010.503.410.520.7210.23
Fe
4.810.592.810.497.710.997.510.905.4H.O4.410.624.510.602.810.482.710.41
Ni
0.5910.251.410.400.4610.22
0.5H0.220.3710.23
Zn
15.6H.7
6.410.90
Cu
0.2310.16
Filter Time Ha Mg A1 Si
(c) UM Flight 1056 on 25 July 1982
s C^ K Ca Pb Cr Mn Fe Ni Zn CuA17A18
1.210.58 2.410.83 1.H0.52 1.010.54 0.8310.38 0.5810 281.810.88 1.410.65 1.310.77 2.610.68 1.H0.44 1.210.46
2.710.432.210.45
Na^!^"^^!^" S^l.^l^" ^’09; C^.O^T^O^ they are 10’- The correction factors are:
-
TABLE 6.3 Continued
(c) UU Flight 1056 on 25 July 1982 (Continued)Fnter T’"le Na+ "9 Al’ Si’ P S Cl’ K r---__________________________________________________ M" Fe N1 z" cuA19A20A21A23
2.311.9 3.411.8 2.711.0 2.8H.1 Q.O 7S0.92t0.45 n 77n ?;n o’5 5.2l0.98 1.8l0.60
^-^-^^ :: .-.--j;:;i(d) UW Flight 1057 on 26 July 1982 (No Cu measured on this flight.)Filter Time Na’ Mg A1’ Si’ p s Cl’ K r.cl K ca f>b Cr Mn Fe Ni Zn Br-A36A3A38A39A40
:: 2:9^5 2w90 :: :: ?:^423 :: 0-^0-JO ^^J/ 3oto85 o32t()26 37to46 ^0.451.8tl.6 2.210.85 5.3tl.7 5.2U.5 2t0 71 y’lin K3 2’2^’" 2.4*0.372.5tl.l ? o.o lo 410 49 3’Lo’54 M^’. ^56>05() 2.610.51 0.7210.35
1.310.87 1:0-0:82 2 0-54 ^^L l5to34 33to45 2.010.37 1.H0.33Ktn .4 .’., 3-3 0-64 3.510.67 0.7210.34 2.210.58
^ s..;;., "3’ i:f;;:;< ’:^^ -..... I.;;;.;; ^ ,.... :: ;.^ ^"""" ,,;,, ;::::;;:g :: ^J;iK^^^-’" l^ls H 2-"4 :-0-^^;:K!; ";"5 ;-0:"A47(no vol. given) ’-"^"" l./tU.Oi) 3.1tU.56 9.2tl.O 0.8910.33 1.H0.32 2.9+/-0.46 0.73+/-0.22(e) UW Flight 1060 on 15 September 1982 (No Cr or Cu measured on this flight.)Filter Time Na+ Mg A^ Si’ P S C^+ K rCl K Ca Pb v Mn Fe Ni Zn Br"
I1"1 ^^^Si: ?:;f S! Hi;js:r gjf ;:s^;i, |:%!L^:i!;: o""\!S^"w-5 l.^"."^ 4.211.2 4.110.76 1.610 48 4 5t0 71 3 ^0 2 I ’4 11 ^} R d;n 7S o25t()18 24+/-03Z 4lt()46 0.8H0.17 3.810.53s :-- ^^^ ;:;;s:i; 2:;;s:;; ^;^ iij:j !:;isi - j;sS:!s ^S "’:." ;;;^.^S
-
TABLE 6.3 Continued
,^ ^ ^ ^(e) UH;:^
106U " - ----- 1932 (. . o. .^ on .is ^t.) (confine------------____________________L cl K Ca p v Mn Fe Ni Zn Br-UW-8UM-9UW-10UM-11UW-12UH-13UU-14UW-15UM-16
i^iii ;;^:ls ISiHS^iiii ^T -^..i^pii^^...,i. :^ ,-SH "’"l ?^’ !.l;-^’S:S:^ 1:;^ ;:^ ;:^": ^ & . S S;; ..;.... !:^ j:i;S:Ii S:!!;S:?5 ^^ ii-"M