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Establishing Regular Measurements of Halocarbons at Taunus Observatory Tanja Schuck, Fides Lefrancois, Franziska Gallmann, and Andreas Engel Goethe University Frankfurt, Institute for Atmospheric and Environmental Sciences Taunus Observatory

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SLIDE 1

Establishing Regular Measurements of Halocarbons at Taunus Observatory

Tanja Schuck, Fides Lefrancois, Franziska Gallmann, and Andreas Engel

Goethe University Frankfurt, Institute for Atmospheric and Environmental Sciences

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SLIDE 2

Taunus Observatory

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 2

  • Regular halocarbon measurements in

Europe are made predominantly at clean air stations (NOAA and AGAGE network)

  • Data from a semi-polluted site in

central Europe will result in stronger constraints for emission estimates

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SLIDE 3

Taunus Observatory

3 NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017

  • Taunus Observatory is located at Kleiner

Feldberg at 50.22°N, 8.44°W at 825m altitude.

  • The site is influenced by emissions from the

densely populated Rhein-Main region.

  • Long-range transport is mainly from westerly

directions, including marine background air from the North Sea.

  • Regular measurements of halocarbons started

October 2013.

courtesy Dominik Brunner

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SLIDE 4

Current Status

4 NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017

  • Samples collected weekly in stainless steel canisters
  • Analysis by GC-MS (Agilent 7980A) using a quadrupole MS

(Agilent 5975C) and a TOF-MS (ALMSCO/BenchTOF) in parallel

  • Sample drying with Mg(ClO4)2
  • Cryo-trapping at -80°C (Stirling cooler), desorption at ≈ 200 °C
  • Data quality assessment by taking double samples and having

two analyses of each individual canisters

TOF-MS gas chromatograph

preconcentration unit ASCEND sample and stream selection Quadrupole-MS

calibration gas

Hoker et al., Atmos. Meas. Tech. 2015

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SLIDE 5

Sample Collection at Mace Head - Comparison with NOAA HATS data

5 NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017

75 80 85 90 95 100 105 75 80 85 90 95 100 105 IAU [ppt] NOAA [ppt] 21 22 23 24 25 21 22 23 24 25 IAU [ppt] NOAA [ppt] 232 234 236 238 240 232 234 236 238 240 IAU [ppt] NOAA [ppt] 480 520 560 600 480 520 560 600 IAU [ppt] NOAA [ppt]

24 25 26 27 24 25 26 27

IAU [ppt] NOAA [ppt] 3.0 3.5 4.0 3.0 3.5 4.0 IAU [ppt] NOAA [ppt]

HCFC-142b r=0.84 methylchloroform r=0.98 HFC-134a r=0.60 (0.99) chloromethane r=0.98 CFC-11 r=0.48 HCFC-141b r=0.66

  • sample collection at Mace Head twice per month (when wind is from

clean air sector)

  • comparison with NOAA data set @ Mace Head (sample collection for

us and NOAA is under background conditions within less than half an hour)

  • ur calibration is on AGAGE scales, scale conversion necessary for

most substances

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SLIDE 6

Time Series

6 NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017

2011 2012 2013 2014 2015 2016 2017 500 525 550 Taunus Observatory Mace Head AGAGE Global Mean

CFC-12 [pptV]

2011 2012 2013 2014 2015 2016 2017 2 4 6 8 10 Taunus Observatory Mace Head AGAGE Global Mean

CH3CCl3 [pptV]

2011 2012 2013 2014 2015 2016 2017 20 22 24 26 28 30 Taunus Observatory Mace Head AGAGE @ Mace Head

HCFC-141b [ppt]

2011 2012 2013 2014 2015 2016 2017 10 20 30 40 50 60 Taunus Observatory Mace Head AGAGE @ Mace Head

HFC_143a [ppt]

  • mixing ratios at Mace Head nicely represent background
  • good agreement with AGAGE data at Mace Head
  • higher variability at Taunus Observatory with many

polluted samples (includes data from all wind sectors, whereas Mace Head is from clean air sector only)

2013 2014 2015 2016 2017 25 50 75 100 125 150 175 200 Taunus Observatory Mace Head

dichloromethane [ppt]

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SLIDE 7

Seasonal Cycles

7 NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017

2013 2014 2015 2016 2017 25 50 75 100 125 150 175 200 Taunus Observatory Mace Head

dichloromethane [ppt]

2011 2012 2013 2014 2015 2016 2017 20 22 24 26 28 30 Taunus Observatory Mace Head AGAGE @ Mace Head

HCFC-141b [ppt]

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SLIDE 8

Trajectory Analysis

  • Back trajectory calculations were

performed for every single sample using

  • HYSPLIT4
  • 120 hours backward
  • 1° x 1° GDAS1 dataset

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 8

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Trajectory Analysis: CFC-11

  • HYSPLIT trajectories (120 hours

backward) for samples collected in 2015

  • color coded by CFC-11 mixing ratio
  • elevated mixing ratios correlate with

air mass origin from southwest

2010 2011 2012 2013 2014 2015 2016 2017 220 230 240 250 260 270 Taunus Observatory Mace Head AGAGE Global Mean

CFC-11 [pptV]

  • use of CFC-11 is regulated
  • atmospheric mixing ratios decrease
  • variability at Taunus Observatory is low

with few outliers

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 9

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SLIDE 10

Trajectory Analysis HCFC-142b

  • HYSPLIT trajectories for

samples collected in 2015

  • color coded by HCFC-42b

mixing ratio

  • elevated mixing ratios

correlate with air mass origin from southwest

2011 2012 2013 2014 2015 2016 2017 20 25 30 35 Taunus Observatory Mace Head AGAGE@ Mace Head

HCFC-142b

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 10

  • used as replacement for CFCs
  • use is regulated
  • mixing ratios have stabilized and are

expected to decrease in the future

  • ver our observation period atmospheric

mixing ratios have no significant trend

  • variability at Taunus Observatory is high

compared to Mace Head clean air samples

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SLIDE 11

Trajectory Analysis

  • HYSPLIT trajectories (120h backward) for each individual sample are

grouped by the direction from with they approach Taunus Observatory (> 50% of time spent in respective sector)

  • four main sectors were identified:

northwest (slow and fast trajectories) west (slow and fast trajectories) southwest (slow trajectories) east (slow trajectories)

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 11

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SLIDE 12

Trajectory Analysis

  • For most substances investigated

highest mixing ratios are measured in air masses arriving from the southwest sector.

  • Background conditions are

experienced when air mass transport towards the site is from the northwest.

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 12

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Future Development: in-situ GC-TOF-MS

  • In summer 2017, an in-situ GC-MS system will be

installed.

  • Measurements will be every 2h (following AGAGE

protocol)

  • The mass spectrometer to be deployed is a medium

resolution time-of-flight mass spectrometer

  • Large substance range: 90+ known species in the

chromatogram

  • High measurement precision:

0.2-1.5% typical (multiple species) 0.15% at best (CFC-12)

  • Linear detector tested up to 5 ppb (25 ng) CFC-12

(~4 orders of magnitude)

  • Open data format
  • Complete mass scan will allow retrospective

analysis (digital air archive)

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 13 Obersteiner et al., Atmos. Meas. Tech. 2016

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SLIDE 14

Summary

14 NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017

  • We started regular collection of air samples at Taunus Observatory in 2013
  • Our measurement are linked to global networks through flask sampling at Mace Head

(Ireland)

  • Mace Head represents baseline for Taunus Observatory
  • Trajectory analysis shows a distinct polluted / clean air sector
  • Data from a medium-polluted site have the potential to better constrain European emission

estimates

  • Data from Taunus Observatory will be used for inversion modelling
  • In summer 2017, an in-situ GC-TOF-MS system will be installed – rapid growth of the

dataset

  • Measurements will be every 2h (following AGAGE protocol) – now we have one data point

per week

  • Complete mass scan of the TOF-MS will allow retrospective analysis (digital air archive)
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SLIDE 15

Thank you for your attention!

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Instrumentation: Stream Selection Unit

  • sample selection with multiposition Valve (Valco)
  • stream selection (sample, blank, calibration gas) with pressure
  • perated on/off valves (Valco)
  • drying tube Mg(ClO4)2
  • 2 x 2l reference volume for sample volume determination
  • mass flow controller for sample flow regulation (Bronkhorst)

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 16

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Instrumentation: Preconcentration Unit

  • sample enrichment is done on a sample loop filled with

HayeSep D

  • sample loop is embedded into a cooled aluminium block
  • cooling works cryogen-free, based on a Stirling Cooler
  • trapping at -80°C (flow 150 ml/min)
  • desorption at ca. +200°C

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 17

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SLIDE 18

Instrumentation: Gas Chromatography

  • column: 30m GasPro PLOT column (7.5m pre-column,

22.5m main column), inner diameter 0.32mm

  • total duration: 17.95 min, backflush after 12.6 min
  • ven temperature 50 – 200°C
  • carrier gas: purified Helium 6.0

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 18

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SLIDE 19

Time Series

− mixing ratios of substances for which use is regulated decrease − very similar mixing ratios at Mace Head and at Taunus Observatory − low variability at Taunus Observatory with only few polluted samples (includes data from all wind sectors, whereas Mace Head is from clean air sector only)

2010 2011 2012 2013 2014 2015 2016 2017 220 230 240 250 260 270 Taunus Observatory Mace Head AGAGE Global Mean

CFC-11 [pptV]

2011 2012 2013 2014 2015 2016 2017 500 525 550 Taunus Observatory Mace Head AGAGE Global Mean

CFC-12 [pptV]

2011 2012 2013 2014 2015 2016 2017 2 4 6 8 10 Taunus Observatory Mace Head AGAGE Global Mean

CH3CCl3 [pptV]

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 19

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SLIDE 20

Time Series

2011 2012 2013 2014 2015 2016 2017 10 20 30 40 50 60 Taunus Observatory Mace Head AGAGE @ Mace Head

HFC-143a [ppt]

− mixing ratios of substances still widely uses increase at Taunus Observatory − mixing ratios at Mace Head represent background − good agreement with AGAGE data at Mace Head − high variability at Taunus Observatory with many polluted samples (includes data from all wind sectors, whereas Mace Head is from clean air sector

  • nly)

2011 2012 2013 2014 2015 2016 2017 20 40 60 80 100 120 140 160 180 200 Taunus Observatory Mace Head AGAGE @ Mace Head

HFC-134a [ppt]

2011 2012 2013 2014 2015 2016 2017 20 22 24 26 28 30 Taunus Observatory Mace Head AGAGE @ Mace Head

HCFC-141b [ppt]

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 20

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SLIDE 21

Time Series

2013 2014 2015 2016 2017 25 50 75 100 125 150 175 200 Taunus Observatory Mace Head

dichloromethane [ppt]

2013 2014 2015 2016 2017 300 400 500 600 700 Taunus Observatory Mace Head

COS [ppt]

2013 2014 2015 2016 2017 400 450 500 550 600 650 700 750 800 Taunus Observatory Mace Head

chloromethane [ppt]

− similar seasonality of chloromethane and dichloromethane at Mace Head and Taunus Observatory − higher variability at Taunus Observatory − amplitude of seasonal cycle somewhat larger at Taunus Observatory − lower mixing ratios of COS at Taunus Observatory

NOAA ESRL Global Monitoring Annual Conference 23/24 May 2017 21