Sea salt quantification by the HR-ToF-AMS

Jurgita OvadnevaiteDarius Ceburnis, Manjula Canagaratna, Douglas R. Worsnop,

Harald Berresheim, Jakub Bialek, A. Manders, G. de Leeuw

and Colin O’Dowd

15th AMS Users Meeting

Sea salt detection by the AMS

Sea Salt:

To be, or not to be…

15th AMS Users Meeting

Atmospheric Research Station at Mace Head(53º20' N, 9º54' W)

t

15th AMS Users Meeting

15th AMS Users Meeting

The HR-ToF-AMS was calibrated using sea salt aerosol

generated from artificial seawater using SIGMA sea salt

dissolved in deionized water. The solution was nebulized

with a TSI atomizer, and a DMA configured to

generate a 300 nm monodisperse particle size distribution

flow from the nebulized polydisperse flow, fed directly into

the AMS inlet.

Experimental Setup for Laboratory Sea

Salt Calibration

Caution: risk of overloading!

Max ambient ~5 µg m-3, saturation at >20 µg m-3

15th AMS Users Meeting

Two approaches:

(1)

adding up all sea salt ions to obtain a new high

resolution sea salt “family’’

(23Na, Mg, 25Mg, 26Mg, 35Cl, H35Cl, 37Cl, H37Cl, K,

41K, Mn, Fe, Na35Cl, 24Mg35Cl, Na37Cl, 26Mg35Cl,

25Mg37Cl, 26Mg37Cl, 40Ca35Cl, 40Ca37Cl, Br, Na235Cl,

Na237Cl, 24Mg35Cl2,

25Mg35Cl2, 26Mg35Cl2,

24Mg37Cl2,

26Mg37Cl2)

Scaling factor equal to 2.5

15th AMS Users Meeting

Scaling factor equal to 51

25x10-3

20

15

10

5

0

Na3

5C

l

8x10-36420

Na37

Cl

reference Cl isotope ratio AMS measurements

09/01/21 09/06/20 09/11/17 10/04/16 10/09/13

Date

centered on using only the 23Na35Cl+ ion fragment as the

‘’fingerprint’’ of sea salt

(2)

15th AMS Users Meeting

15th AMS Users Meeting

Advantages: Drawbacks:

Sea salt family method

•Scaling factor equal to 2.5 •Very high background signal, long

evaporation delays

•Other sources than the sea salt

•Sensitive to the tuning (Na surface

ionization)

•Sensitive to the heater temperature

NaCl method

•Very low background signal

•Exclusively comes from the sea salt

•Not so sensitive to the tuning

•Not so sensitive to the heater temperature

•A large scaling factor of 51

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10-5

10-4

10-3

10-2

10-1

100

101

102

dF

[n

g m

-2s-1

]

3 4 5 6 7

0.12 3 4 5 6 7

12

Dm

Dva cut-off:

600 nm 700 nm 800 nm 900 nm 1000 nm

Seinfeld J. H. and Pandis S. N. (1998)

Atmospheric Physics and Chemistry. p.

416.

Caution: upper cut-off

15th AMS Users Meeting

Ovadnevaite et al., 2012 JGR

t

15th AMS Users Meeting

15th AMS Users Meeting

25

20

15

10

5

0

WS

Mac

e H

ead m

s-1

2520151050

WS ECMWF m s-1

R=0.96 R2=0.92

Data Linear fit 1:1 line

Local wind speed measured at Mace

Head was equal to 24.1 m s-1 (46.8

knots).

15th AMS Users Meeting

Ovadnevaite et al., 2012 JGR

15th AMS Users Meeting

600

500

400

300

200

100

0

dN

/dlo

gD

2 3 4 5 6 7 8 9

0.12 3

Ddry [m]

25

20

15

10

5

Win

d sp

eed [m

s-1]

15th AMS Users Meeting

2.0x106

1.5

1.0

0.5

0.0

dF

/dlo

gD

[m

-2s-1

]

2 3 4 5 6

0.12 3 4 5 6

12 3 4 5 6

Ddry [m]

2.0x106

1.5

1.0

0.5

0.0

F [

m-2

s-1]

8x106642

RHw

F1

F2

F3

F4

F5

a)

F1

F2

F3

F4

F5

b)

Data Fitted Flux

dF

𝑑𝑙𝑜𝑔𝐷=

𝐹𝑖(𝑅𝑒𝐻𝑤)

2𝜋𝑙𝑛𝑖

exp

−1

2 ln

𝐷𝐶𝑀𝐷𝑖

𝑙𝑛𝑖

2

5

𝑖=1

15th AMS Users Meeting

30

25

20

15

10

5

0

Pro

du

ctio

n f

lux

[n

g m

-2s-1

]

302520151050

Wind speed [m s-1

]

AMS Flux

SMPS+SPM Flux

SMPS Flux

Ovadnevaite et al., 2014 ACP

15th AMS Users Meeting

Ovadnevaite et al., submitted to JGR