1

Total OH reactivity at Cape Corsica during summer 2013

Nora ZannoniValerie Gros, Roland Sarda-Esteve,

Sebastien Dusanter, Vincent Michoud, Vinayak Sinha

OH reactivity: meaning and importance

CH4

?

Sources Sinks∙OHOzoneSOA

OH budgetUnmeasured/ Unknown species

Total OH reactivity

CO

2

Total OH reactivity: OH loss for reactive compounds in atmosphere

3

Measuring the Total OH reactivity:The Comparative Reactivity Method (CRM)

(Sinha et al., 2008)

• Glass reactor + PTR-MS • OH produced in situ• Pyrrole (m/z 68) reference compound• Competition between pyrrole and ambient reactive compounds

Pyrrole + zero air

Hg lamp N2 dry pump

To PTR-MS

14 cm

3 cm

20x103

18

16

14

12

10

8

6

pyrr

ole

conc

entr

atio

n (c

ps)

1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PMTime

1)31(

)23(CKp

CC

CCRair

C0 Lamp on

C1Wet N2 in

C2ambient air in

C3

Pyrrole + ambient air

N2 wet

Site of study

Ersa- Cape Corsica

4

5

Cape Corsica monitoring station (42.97°N, 9.38°E, alt 533 m)

6 km 2.5 km

Courtesy of J.Sciare

24/06/13

Installationand tests

01/07/13 08/07/13 13/07/13 16/07/13 05/08/13

Intercomparison with CRM MD

Plant experimentMeasurement campaign

OH REACTIVITY

Goal: (i) Measure reactivity of air masses enriched in anthropogenic compounds and their oxidation products;

(ii) Use missing reactivity as a tool for chemical closure

Total OH reactivity

• Total OH reactivity ranges between CRM LOD up to 20 s-1

•On average 5 s-1 during the whole campaign•Diurnal profile•Peaks when temperature increases

6Zannoni et al., in preparation + poster

20

15

10

5

To

tal O

H r

ea

ctiv

ity (

s-1

)

7/17/2013 7/22/2013 7/27/2013 8/1/2013 8/6/2013

35

30

25

20

Te

mp

era

ture

(°C

) 100

80

60

40

RH

(%)

Total OH reactivity Total OH reactivity_hourly avg

RH Temperature

7

Ancillary gas phase measurementsSpecies group Species nameAVOCs(44)

methane, ethane, propane, n-butane, n-pentane, n-hexane, n-octane, n-nonane, n-undecane, n-dodecane, 2-methylpropane, 2-methylpentane, 2-methylhexane, 2,2- dimethylbutane, 2,2-dimethylpropane, 2,3- dimethylpentane, 2,4- dimethylpentane, 2,2,3-trimethylbutane, 2,2,4-trimethylpentane, 2,3,4- trimethylpentane, cyclohexane, ethylene, propylene, 1-butene, 2-methylpropene, 2-methyl-2-butene, 3-methyl-1-butene, 1,3-butadiene, trans-2-butene, cis-2-butene, 1-pentene, trans-2-pentene, cis-2-pentene, hexene, benzene, toluene, ethylbenzene, styrene, m-xylene, o-xylene, p-xylene, acetylene, 1-butyne, acetonitrile.

BVOCs (7) isoprene, a-pinene, b-pinene, d-limonene, a-terpinene, b-terpinene, camphene. OVOCs (15) acetaldehyde, formic acid, acetone, acetic acid, mglyox, methyl ethyl ketone,

propionic acid, ethyl vinyl ketone, butiric acid, nopinone, pinonaldehyde, methacrolein, methyl vinyl ketone, formaldehyde, methanol.

Others (3) NO, NO2, CO.

11% 39%

16% 34%

BVOCs

AVOCs

othersOVOCs

21% 4% 24%

52%

BVOCs

AVOCs

others

OVOCs

Daytime OH reactivity speciation Nighttime OH reactivity speciation

i

iOHi XkR

Measured vs calculated reactivity

West Marine

West Marine

East (Italy)

East (Italy)North (France)

South SouthTransported air massesorigins

8

20

15

10

5

OH

reac

tivity

(s-1

)

7/17/2013 7/22/2013 7/27/2013 8/1/2013

OH reactivity_measured OH reactivity_calculated OH reactivity_measured_uncertainty OH reactivity_calculated_uncertainty

Significant missing OH reactivity

9

8

6

4

2

0

OH

rea

ctiv

ity (

s-1)

17/07/2013 22/07/2013 27/07/2013 01/08/2013

missing reactivity

20

15

10

5

OH

re

activity (

s-1

)

7/17/2013 7/22/2013 7/27/2013 8/1/2013

OH reactivity_measured OH reactivity_calculated OH reactivity_measured_uncertainty OH reactivity_calculated_uncertainty

West Marine

South

What can explain the missing OH reactivity?

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

mix

ing

ratio

(pp

bv)

17/07/2013 22/07/2013 27/07/2013 01/08/2013

missing MT total MT (PTR-MS) MT speciated

Missing monoterpenes?

10

What can explain the missing OH reactivity?

…In part yes!

apinene camphene bpinene

myrcene

limonene

cineole

camphor

borneol

Rosmarinus officinalis emissions map

Bracho-Nunez et al., 2011

8

6

4

2

0

OH

rea

ctiv

ity (

s-1)

17/07/2013 22/07/2013 27/07/2013 01/08/2013

limonene linalool myrcene ocimene camphor missing reactivity

Hypothetical influence of unmeasured monoterpenes expected for the Mediterranean shrubland based on the missing monoterpenes concentration

11

What can also explain the missing OH reactivity?

Unmeasured OVOC’s? Probably also! Courtesy of Agnes Borbon

Chromatogram 24/07/13 mono and multifunctional carbonyls

0h

3h

6h

9h

12h

15h

18h

21h

12

Take home message(s):

- Total OH reactivity varied between LOD-20 s-1

- Main influences from BVOCs

- Significant missing reactivity during 23-30/07:

-unmeasured MT-OVOCs

-Research question not completely answered: few anthropogenic events and low loadings of anthropogenic pollutants

-Further investigate OVOCs

13

14

OH reactivity in biogenic environments:

High OH reactivity measured in the Mediterranean basin (even at a site not supposed to be “forested”)

Cape Corsica site very complex: budget not constrained, highest influence by BVOC’s…

...what about the OH reactivity at other remote and continental Mediterranean sites?

806040200Total OH reactivity (s-1)

Di Carlo et al., 2004

Ren et al., 2006

Sinha et al., 2008

Ingham et al., 2009

Sinha et al., 2010

Noelscher et al., 2012

Mao et al., 2012

Noelscher et al., 2013

Edwards et al., 2013

Hansen et al., 2014

Charmex 2013

CANOPEE 2014

temperate tropical boreal mediterranean

15

...and you for your attention!

ANY QUESTION?

Acknowledgments:

LSCE: Bernard Bonsang, Cerise Kalogridis, Cyril Vuillemin, Eric Hamonou, Francois Dulac

Mines Douai: Stephane Sauvage, Vincent Michoud, Sebastien Dusanter, Nadine Locoge, Thierry Leonardis,

LAMP: Aurelie Colomb

LISA: Agnes Borbon

16

Diurnal pattern

2500

2000

1500

1000

500

0

Vol

ume

Mix

ing

Rat

ios

(ppt

v)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Diurnal Pattern of total BVOCs (10-90 % whiskers)

Diurnal pattern of total OH reactivity well resembles the one of total BVOC’s, with a maximum at 15.00

17

12

10

8

6

4

2

0

Tota

l OH

reac

tivity

(s-1

)

1 2 3 4 5 6 7 8 9 10 1112 13 14 15 1617 18 19 20 2122 23 24Hour of Day

Diurnal pattern of total OH reactivity (10-90% whiskers)

Species contributions for each period

18

West Marine

West Marine

East (Italy)

East (Italy)North (France)

South South

15%

20%

21%

44%

BVOCs

AVOCs

others

OVOCs

10%

34%

19%

37%

BVOCs

AVOCs

others

OVOCs 13%

29%

22%

37%

BVOCs

AVOCs

others

OVOCs

10% 41%

16%

33%

BVOCs

AVOCs

others

OVOCs

10% 43%

11%

36%

BVOCs

AVOCs

others

OVOCs

12%

42%

12% 34%

BVOCs

AVOCs

othersOVOCs

BVOC’s relative and absolute reactivity100

80

60

40

20

0

Re

lativ

e c

on

trib

utio

ns

to O

H r

ea

ctiv

ity (

%)

00:0023/07/2013

00:0024/07/2013

00:0025/07/2013

00:0026/07/2013

00:0027/07/2013

a-terpinene a-pinene b-pinene camphene g-terpinene isoprene limonene

100

80

60

40

20

0

Rel

ativ

e co

ntrib

utio

ns to

OH

rea

ctiv

ity (

%)

00:0027/07/2013

12:00 00:0028/07/2013

12:00 00:0029/07/2013

12:00 00:0030/07/2013

a-terpinene a-pinene b-pinene camphene g-terpinene isoprene limonene

8

6

4

2

0

OH

rea

ctiv

ity (

s-1)

16/07/2013 21/07/2013 26/07/2013 31/07/2013 05/08/2013

limonene camphene a-terpinene g-terpinene b-pinene isoprene a-pinene monoterpenes

BVOC Day (%) Night (%)

a-pinene 7.69 20.73

b-pinene 16.49 16.05

limonene 12.03 11.36

camphene 1.48 3.05

a-terpinene 31.08 31.33

g-terpinene 1.28 5.04

isoprene 29.96 12.45

19

Atmospheric dynamics during ChArMEX

20

3228242016

[°C

]

17/07/2013 22/07/2013 27/07/2013 01/08/2013 06/08/2013

100806040

[%]

600400200

0

[W/m

^2]

300

200

100

0

[°]

100

80

60

40

[pp

bv]

1.20.80.40.0

[pp

bv]

12

8

4

[m/s]

86420

[Bq

/m3

] 0.8

0.6

0.4

0.2

[km]

Temperature

WS

RH

Radon_activity

isoprene Ozone

Solar Irradiance

Wind direction

BL height

What can explain the missing OH reactivity?

OVOC’s? Probably also!

West (>36 h of processing)

South

North east (12-18h of processing)

North west

West South North East North-West

Courtesy of Vincent Michoud21

OH reactivity from gas phase measurements

22

Instrument Measured species

GC-FID AVOC’s C2-C13

a-pinene, b-pinenePTR-TOF-MS CH3OH,CH3CN, CH3CHO, HCOOH,

CH3COOH, CH3COCH3, MVK+MACR, MGLYOX, MEK, CH3CH2COOH, EVK, CH₃CH₂CH₂-COOH, nopinone, pinonaldehyde

GC-MS Limonene, camphene, a-terpinene, g-terpinene

NOx analyser

NO, NO2

AEROLASER (Hantzsch method)

HCHO

Picarro CH4, CO

i

iOHi XkR