Long-term monitoring of VOCs in the free troposphere above the UK - - PowerPoint PPT Presentation

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Long-term monitoring of VOCs in the free troposphere above the UK - - PowerPoint PPT Presentation

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Long-term monitoring of VOCs in the free troposphere above the UK Shalini Punjabi a , James R. Hopkins a,b , Alastair Lewis a,b a University of York, York b NCAS, University of York, York sp575@york.ac.uk VOC monitoring : Aims To

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Long-term monitoring of VOCs in the free troposphere above the UK

Shalini Punjabia, James R. Hopkinsa,b, Alastair Lewisa,b

a University of York, York bNCAS, University of York, York

sp575@york.ac.uk

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VOC monitoring : Aims

  • To characterize seasonal and inter annual trends
  • To capture important features related to transport, mixing and

chemistry.

  • To utilise UK based research aircraft’s flying hours to the fullest for

long-term study.

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Sample collection

  • Silico-treated stainless steel

canisters

  • Max. filling pressure 40psi
  • Altitude preferably : 2000 -

5000m

  • Sampling frequency : variable, typically
  • nce in a month

1000 2000 3000 4000 5000 6000 7000 8000 9000 500 1000 1500 2000 2500 3000 3500 Ethane pptv altitude m 2009-11 data

The Whole Air Sampling System

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Technique and analytical configuration

C2-C8 Alkanes,C2-C5 Alkenes Aromatics (BTEX), Acetylene C2-C4 Oxygenated VOCs Dual channel gas chromatograph

  • Water removal

– condensation trap maintained at - 30oC

  • Preconcentration

– Trapping temperature : Peltiers cooling -23oC – Multi adsorbent bed: Carbopack B and carboxen 1000

  • Thermal desorption

– 320oC with carrier flow (helium)

  • Separation

– Two capillary columns 50 m PLOT and 10 m LOWOX

  • Detection

– FID 1 and FID 2

  • Calibration and standards:

– National Physical Laboratory (NPL)- 30 component mix – GAW-VOC standards

York FGAM dc-gc-fid

Hopkins, J.R., Lewis, A.C. & Read, K.A. (2003) , J. Environ. Monit., 5 (1), pp. 8-13.

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0.05 0.1 0.15 0.2 0.25 0.3 Ethane Ethene Propane Propene Iso-butane n-butane Acetylene trans-2-butene 1-butene cis-2-butene Iso-pentane n-pentane 1,3-butadiene trans-2-pentene 1-pentene 2+3-methylpentane n-hexane Isoprene n-heptane Benzene

  • ctane

toluene ethylbenzene m+p-xylene

  • -xylene

PCRF (pptv) NPL-30comp mix 2009 NPL GAW 28 comp mix NPL-30 comp mix 2008 CVO

Jan 2011 Oct 2009

System performance with time

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WCC-VOC intercomparison

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Seasonal trends : Ethane

500 1000 1500 2000 2500 3000 3500 Jan Feb Apr Jun Aug Oct Dec Feb Apr Jun Aug Oct Dec Feb Apr Jun 2009-2011 month Ethane pptv 2009-11 all datapoints Ethane mean U.K free troposphere study North Atlantic study Pallas study

U.K free troposphere,2009-11 y=1318.32 + 539.34(2π/365(day+46.25) North Atlantic study,1989 y =1715 + 505(2π/365(day+46.25) Pallas ,Baltic sea ,1994 y=1425.00 + 683.34(2π/365(day+16.25)

Laurila, T. and Hakola, H., 1996 ,Atmospheric Environment 30, pp. 1597–1607 S.A. Penkett, N.J. Blake, P. Lightman, A.R.W. Marsh and P. Anwyl, Journal of Geophysical Research 98 (1993), pp. 2865–2885

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Seasonal trends: Acetylene

100 200 300 400 500 600 700 800 Jan Feb Apr Jun Aug Oct Dec Feb Apr Jun Aug Oct Dec Feb Apr Jun 2009-11 month acetylene pptv 2009-11 all data ace avg U.K free troposphere study North Atlantic study Pallas study

U.K free troposphere study ,2009-11 y = 223.67 + 137.47 (2π/365(day+56.25) North Atlantic study ,1989 y = 399.5 + 273.5 (2π/365(day+56.25) Pallas study ,1994 y = 388 + 305.33.5 (2π/365(day+26.25)

Laurila, T. and Hakola, H., 1996 ,Atmospheric Environment 30, pp. 1597–1607 S.A. Penkett, N.J. Blake, P. Lightman, A.R.W. Marsh and P. Anwyl, Journal of Geophysical Research 98 (1993), pp. 2865–2885

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y = 2.334x - 52.151 R2 = 0.8231 200 400 600 800 1000 1200 1400 100 200 300 400 500 600 acetylene pptv propane pptv 2009-11 data y = 0.3811x + 1.0777 R2 = 0.6566 y = 0.3925x + 0.3421 R2 = 0.3179

  • 2.00
  • 1.00

0.00 1.00 2.00 3.00 4.00 5.00

  • 5.00
  • 4.00
  • 3.00
  • 2.00
  • 1.00

0.00 1.00 ln[propane] ln [propane/acetylene] 2009-11 data North Atlantic data

Ratios and source profile variation

Our study and intercept =1.07 North Atlantic study and intercept =0.34 ln[P]/{A] = (kP-kA/kP) ln[P] + C slope=rate constants Where C = ln [P]0 / [A]0-( kp-ka/kp) ln[P]0 intercept= source profile

Goldan, P. D., D. D. Parrish, W. C. Kuster, M. Trainer, S. A. McKeen, J. Holloway, B. T. Jobson, D. T. Sueper, and F. C. Fehsenfeld (2000), J. Geophys. Res., 105(D7), 9091–9105, doi:10.1029/1999JD900429. Gong, Q., and K. Demerjian (1997), J. Geophys. Res., 102(D23), 28059-28069.

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y = 1.5475x + 7.8624 R2 = 0.9247 y = 1.2993x + 8.3649 R2 = 0.9958 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

  • 4.00
  • 3.50
  • 3.00
  • 2.50
  • 2.00
  • 1.50
  • 1.00
  • 0.50

0.00 ln[propane/ethane] ln[propane] 2009-11 data B458-60 June samples B457 June samples y = 1.4615x - 0.6902 R2 = 0.8232

  • 7.00
  • 6.00
  • 5.00
  • 4.00
  • 3.00
  • 2.00
  • 1.00

0.00

  • 4.00
  • 3.50
  • 3.00
  • 2.50
  • 2.00
  • 1.50
  • 1.00
  • 0.50

0.00 ln[propane/ethane] ln[butane/ethane] 2009-11 data B458-60 June samples B457 June samples

Ratios and aging pattern: another source

Flight B457 Atlantic ocean Flight B458 continental influence ln [butane/ethane] vs ln[propane/ethane] ln [propane/ethane] vs ln [propane]

Parrish, D. D., et al. (2004), J. Geophys. Res., 109, D23S18, doi:10.1029/2004JD004978

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y = 0.297x + 0.8372 R2 = 0.9066 y = 0.3342x + 8.2283 R2 = 0.5623 50 100 150 200 250 100 200 300 400 500 600

Acetylene pptv Benzene pptv

2009 data 2010-11 data

y = 6.9413x - 22.134 R2 = 0.8722

y = 6.7636x - 30.742 R2 = 0.6991 200 400 600 800 1000 1200 1400 1600 50 100 150 200 250

Benzene pptv Propane pptv

2010-11 data 2009

Ratios : source characterization

Natural gas as a main source for propane emission Vehicular exhaust responsible for benzene and acetylene emissions.

Russo, R. S.; Zhou, Y.; White, M. L.; Mao, H.; Talbot, R.; Sive, B. C. Volume 10, Issue 1, 2010, pp.1083-1134

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Hydrocarbon Processing and ozone

y = 28.463x + 114.34 R2 = 0.8956 10 20 30 40 50 60 70 80 90 100

  • 4.00
  • 3.00
  • 2.00
  • 1.00

0.00 ln propane/ethane

  • zone ppbv

LT data from other seasons July data y = 0.8381x - 32.191 R2 = 0.9304 10 20 30 40 50 60 70 80 90 100 40 60 80 100 120 140 160 CO ppbv

  • zone ppbv

July 2010 data

Low NO levels or mixing of polluted air with clean marine air could be the reasons for ozone destruction.

Helmig, D., D. M. Tanner, R. E. Honrath, R. C. Owen, and D. D. Parrish (2008), J. Geophys. Res. , 113 , D20S91, doi:10.1029/2007JD008930.

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  • Hydrocarbon ratios as a tracer
  • Free tropospheric study provides useful information on transport,

mixing and chemistry

  • Continue to collect data over longer timescales and monitor

instrument performance

  • Improve data coverage by collecting and analysing more samples.

Summary and further plans

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Acknowledgements

My supervisors Ally Lewis and Jim Hopkins University of York and NCAS for funding FGAM for dc-gc-fid Staff at FAAM ,Avalon and Directflight limited Research group people