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© Crown copyright 2006 Page 1
Airborne Measurements During the Buncefield Incident
Dr Jonathan P Taylor
Air Pollution Forecasting Seminar, Culham Science Centre 22nd June 2006
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Acknowledgments
PeopleSteve Abel, Clare Lee – Met Office.Steve Ball – Head of FAAM.Aircrew and FAAM staff.James Allan, Hugh Coe – Aerosol Mass Spectrometer Univ of Manchester.Hazel Jones, Martin Gallagher – Cloud Particle Imager, Univ of Manchester. EMARC and dispersion teams at Met Office
AgenciesNERC Centre for Atmospheric Science - support to CPI and AMS instruments and staffNERC and Met Office – jointly run the aircraft.
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The Facility for Airborne Atmospheric Measurements
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FAAM Overview
The FAAM BAe146-301 is one of the most comprehensively instrumented atmospheric research aircraft in the world!Aircraft owned and converted by BAESAircraft operated by DirectflightFAAM is a collaboration between the Natural Environment Research Council (NERC) and the Met Office.FAAM operates from the airfield at Cranfield University, Bedfordshire.
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Aircraft CharacteristicsCrew
ScientistsLength
WingspanHeight
EnginesMax AltitudeMin Altitude
RangeCruise Altitude
Typical EnduranceMin Manoeuvring Speed
Payload
Two Pilots18 max31 m26 m
8.4m to top of tail4.4m to top fuselage
4 Honeywell LF507-1H turbofans35,000 ft
50 ft3,700 km27,000 ft5½ Hours
90 – 115 m s-1depending on payload
4,000 kg instrumentation
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FAAM BAe146-301 ARA Instrumentation
5 port turbulence probe
Total water probeJW Liq waterNevzerov total/liqwater probeRosemount temp probes
Air sample inlets
FAGE InletCVI on other side
Deimos or IR Camera
TAFTS ARIES
Cloud Physics Probes
Cloud Physics Probes
MARSS
SWS on other side
BBRs
LidarSHIMS
Upward and Forward Video Cameras
BBRs
SHIMS
Rearward and Downward Video Cameras
ADA on other side
Dropsonde on other side
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Basic Meteorology Measurements
• Air temperature• Position - latitude, longitude, pitch, roll, heading, altitude• Static pressure• Wind speed, turbulence and fluxes• Dew point temperature• Sea Surface Temperature• Dropsondes, Temp,humidity,winds• Video Cameras (4)• Satcom communications
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Radiometers
SWS - short wave spectrometer - 303.4 - 1706.5 nm pixel resolution 3.2 nm up to 948.7 nm, 6.3 nm thereafter.ARIES - infrared interferometer - 3.3-16μm max OPD = 1.037cm (~ 0.5cm-1) – 4800 channelsMARSS, Deimos - passive microwave radiometers - 24, 50, 89, 157, 183GHz – same as AMSU.TAFTS - far infrared interferometer 80-1000cm-1 - Imperial CollegeBBR - irradiance measurements, 0.3-3.0μm, 0.7-3.0μm and 4-50μmSHIM - Spectral Hemispheric Irradiance Measurement -303.4 - 1706.5 nm pixel resolution 3.2 nm up to 948.7 nm, 6.3 nm thereafter
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Cloud Microphysics
• Total water content• Cloud liquid water content• Cloud Ice Content
Cloud particle spectrum - FastFSSP (1-47μm), PMS 2D-C (25-800μm), PMS 2D-P (200-6400μm), Small Ice Detector (SID-1 and SID-2 - 1 to 25μm), SPEC Cloud Particle Imager (images of particles up to 2mm), Phase Doppler Particle Analyser ADA-100 (0.7 - 128μm), High Volume Precipitation Spectrometer HVPS (200 to 6400μm), Hallett Cloud Scope -water/ice images.
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Aerosols and Particulates
• TSI 3 channel nephelometer, • Particle Soot Absorption Photometer, • Cloud Condensation Nuclei Counter (static diffusion chamber), • Ice Nuclei Counter (continuous-flow diffusion chamber type), • PMS PCASP (0.1 - 3μm), • Condensation Particle Counter, • Millipore filter system, • Aerosol Mass Spectrometer, • Counterflow Virtual Impactor (CVI) for size-selective cloud particle measurements.
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Chemistry
• Ozone, • NO, • NOX, • CO, • SO2, • CO2• PAN, • Formaldehyde, • HOX, • Hydrocarbons, • CFCs etc. etc. • Species can be sampled in Tevlar Flasks
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The FAAM BAe146-301 Aircraft Response
Flew on Monday 12th and Tuesday 13thDecember. Monday flight around South Coast due to flight restrictions. Tuesday flight over source and 78km downwind.
First civil contingency use of BAe146, fortuitous in that aircraft was in the UK, had team of scientists in place and most of the useful instrumentation installed.
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NAME model prediction of plume valid at 1400
FAAM BAe146-301 Samples Smoke Plume on Tuesday 13thDecember
Heathrow
Gatwick
StanstedLuton
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Most of South East England is controlled airspace.
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78km away from the source the smoke mixes with clouds
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Still from forward facing video camera
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Communications
Direct satcom telephone communications with the aircraft allowed results of measurements in the air to be reported immediately to verify NAME model predictions and report on chemistry.We were able to report important results like: Aerosol Mass Spectrometer measured low levels of Polycylic Aromatic Hydrocarbons during entire sortie and low levels of particulate organics (~2µgm-3).Also useful for advising aircrew of status of air traffic control clearance negotiations.
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Structure of Smoke Plume.
Source 78kmDistance downwind.
Hei
ght
500m
1500m
1000m
2000m
Plume 10km wideFilter Exposures 1 and 2Filter Exposures 3 and 4
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Passive Cavity Aerosol Spectrometer Probe
Wing mounted instrument that measures aerosol particles in the 0.1 to 3μm diameter range.
Calibrated with latex spheres so corrections need to be made to account for difference in refractive index of the black carbon.
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Measurements from overhead source
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Measurement of Mass Concentration near source
•Select 6 different sets of refractive indices and densities of black carbon from the literature
•Re-process PCASP data for each case
•Gives a range of mass concentrations which indicates uncertainty
•If assume PM2.5 is 60% of PM10 then PM10 ~ 768µgm-3
PM2.5Mean = 461µgm-3
Range = 300 - 576µgm-3
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Measurements from 78km downwind
•Data from 1458m near top of plume
•CO increases from background of 108ppb to peak of ~137ppb.
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Measurements from 78km downwind.
•Data from 550m near base of plume
•CO background levels are around 150 to 200ppb so plume barely detectable above background
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Dioxins, Furans and PCBs from the FAAM BAe146
Dioxins, Furans and PCBs analysed by Harwell Scientifics for filters exposed 78km down the plume
No PCBs detectedPolychlorinated dibenzodioxins and dibenzofurans –Committee on Toxicity Tolerable Daily Intake for children slightly exceeded, but this was at altitude and unless exposure was prolonged there would only be a slight impact on body burdens
PAHs analysed for filters 78km downwind and overhead source
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Filter Analysis – Harwell and HSL
Down plume = 0.012 and 0.046ngm-3
Over source = 0.1 and 0.4ngm-3
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The Aerodyne Aerosol Mass Spectrometer (AMS)
Vaporises particles and analyses the resultant gases online using mass spectrometry.
Designed for the study of particles less than 1 µm in diameter.
Typically measures sulphate, ammonium, nitrate and organic matter.
Cannot study refractory materials (e.g. elemental carbon, sea salt, dust).
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AMS Results
The AMS measured approximately 3 µg m-3submicron organic matter in the plumes, although much more mass probably existed within larger particles or in the form of elemental carbon (as shown by the PCASP and PSAP), neither of which are detectable with the AMS.
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0.20
0.15
0.10
0.05
0.00
Arbi
trary
uni
ts
807570656055504540353025m/z
C2H5+
C3H5+
C3H7+
C4H7+
C4H9+
C2H3+
Urban soot particles
Buncefield plume(filtered for detection limits)
Urban Soot Particles
Buncefield Plume(filtered for detection limits)
AMS Organic Mass SpectraThe peaks within the organic mass spectrum that possessed significant signal corresponded to hydrocarbon fragments and are considered typical of the organic matter present in soot.
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Enhanced PAHs? Data still being analysed by Manchester University Staff.
Polycyclic Aromatic Hydrocarbons (PAHs) are often produced in flames and are potentially very important to consider from a health perspective.Lab and field studies have shown that this can be measured using the AMS, the largest peak typically occuring m/z202, which corresponds to C16H10+ (pyrene).The fractional contribution of m/z 202 to the total organic signal was around 19 times greater in the fire plumes when compared to the approach and landing phase of the mission.This implies that there were much higher concentrations of PAHs per µg m-3 of organic aerosol in the plume compared to ‘normal’ polluted air, although exact quantification is difficult in this case.
m/z
202
(arb
itrar
y un
its)
2520151050Organics (µg m-3)
Smoke plumes
Approach & landing
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Filter Analysis – Harwell and HSL
Down plume = 0.012 and 0.046ngm-3
Over source = 0.1 and 0.4ngm-3
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CPI images
While the CPI is designed for the study of large ice particles, some soot particles were imaged. The approximate sizes (in µm) are overlaid on the images.The larger of these particles were irregular in shape and probably aggregate in structure.
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Appr
ox. c
once
ntra
tion
(dm
-3)
80706050403020Approx. size (µm)
Spherical Non-spherical
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Summary of Filter Analysis
Filter analysis confirms initial reports from the aircraft that pollutant levels were low.
This is probably the result of high combustion temperatures and/or the highly refined fuel being burnt.
Main constituent of smoke plume was “black carbon” (soot).
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Conclusions
The FAAM BAe146-301 was able to provide immediate information regarding the contents of the Buncefield smoke plume.
Subsequent analysis of data has confirmed that plume was mainly “black carbon” and did not pose a significant risk to health.
Aircraft data is now being used to analyse performance of the Met Office NAME model, hopefully leading to enhancements in the modelling of such events in the future.
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Any questions?
For more details on theaircraft please visit:
http://www.faam.ac.uk
AcknowledgmentsFAAM OverviewFAAM BAe146-301 ARA InstrumentationBasic Meteorology MeasurementsRadiometersCloud MicrophysicsAerosols and ParticulatesChemistryThe FAAM BAe146-301 Aircraft Response78km away from the source the smoke mixes with cloudsStill from forward facing video cameraCommunications Passive Cavity Aerosol Spectrometer ProbeMeasurements from 78km downwindMeasurements from 78km downwind.Dioxins, Furans and PCBs from the FAAM BAe146Filter Analysis – Harwell and HSLThe Aerodyne Aerosol Mass Spectrometer (AMS)AMS ResultsAMS Organic Mass SpectraEnhanced PAHs? Data still being analysed by Manchester University Staff.Filter Analysis – Harwell and HSLCPI imagesSummary of Filter AnalysisConclusions