Overview of CIMS Applications

Doug WorsnopARI/PKU AMS/CIMS Users Meeting

Tuesday, 9 May

Kulmala et al., 2013, Science

BSMA

API-ToFMS(Tofwerk)

Mikael Ehn, Heikki Junninen

Atmospheric (pressure) Ions

Negative ion spectra from Hyytiälä

DAY

NIGHT

C10H14O12N- ?

Negative ion spectra from Hyytiälä

DAY

NIGHT

C10H14O12N- ?

The short life of an ion

O2 O2-

X

X-

O2

A

A+

e-

…

…NO3- HSO4

-

Ions in Air: few minutes

The short life of an ion

O2 O2-

X

X-

O2

…NO3- HSO4

-

CIMS

APi-TOF

CIMS: High NO3- fraction of a second

Ions in Air: Low NO3- few minutes

Negative ion spectra from Hyytiälä

DAY

NIGHT

C10H14O12N- ?

CI-APi-TOF for neutral compound measurements

reflector

detector

3-stageturbopump

Scrollpump

Flowcontrol

Diaphragmpump

103

mba

r

Acquisition

Timing and control

Dataprocessing

Compressor

Filters , Flowcontrol

HNO3 ,Acetone etc

-”Eisele type” inletdesign.-Sheath flow 20 lpm,includes charger ions.-Total flow 30 lpm-> sample flow 10 lpm-Sample mixing withelectric field-APi samples 0.8 lpm

tofTools

ELVOCC10,C20 in the gas phase

O/C > 0.7

ELVOCC10,C20 in the gas phase

O/C > 0.7

Nucleation, ClustersNanoparticle growth

Ehn et al, Nature, 2014

also see Crounse et al, JPC Letters, 2013

Auto-oxidation

A-pinene + O3 addition of (NH4)2SO4 seedYield ~ 7+/- 4% reduces gas ELVOC increases condensed

SOA

0.4

0.3

0.2

0.1

0.0

m/z

44

/ org

ra

tio

2.01.51.00.50.0 O/C ratio

Oxalic Acid

Fulvic Acid

Oleic Acid + Ozone

PSI Chamber

AMS Observations

f44 vs O/C

2004

ELVOC SVOC

Kirkby,Curtius,Carslaw,Baltensperger,Kulmala,(Worsnop,

Donahue)

+theCLOUD KIDS

Negative Ion Composition

Schobesberger, et al, PNAS18

(C2H6N2)n(H2SO4)nHSO4-

(H2SO4)nHSO4-

(NH3)n(H2SO4)nHSO4-

(CaHbOc)n(H2SO4)nHSO4-

Boreal Forest

< 1 ppt

APi-TOF data confirm:Organics participate in cluster formation from

the very beginning

Riccobono et al., Sceince, 2014

Ionization Techniques

Electron Impact (“hard”)

R + e- R+ + 2 e- Ri+ universal

Chemical Ionization (“soft”)

proton transfer

PTRMS R + H3O+ RH+ + H2O hydrocarbons

Acetate RCOOH + C2H4O- RCOO- + C2H5O2 (carboxylic) acids

clustering

Iodide R + I- R.I- polarized species

Nitrate R + NO3- R.NO3- highly oxidized organics

[ H2SO4 + NO3- HSO4- + HNO3 ]

21

Particle-phase ON

Gas-phase ON

22

PAM Reactor Components

• UV lamps: λ = 185 and 254 nm wavelength• Humidifier, Autovalve, RH/T, Photodiode• Electronics box with ballasts and control board• Control software

AERODYNE RESEARCH, Inc. 45 MANNING ROAD, BILLERICA, MA 01821 (978) 663 9500www.aerodyne.com CACC_OPT_12_1

Potential Aerosol Mass(PAM) Oxidation FlowReactorA highly oxidizing environment thatsimulates oxidation processes ontimescales of days in the atmospherein minutes in real time.

• Laboratory or fie

l

d st udi es of secondar y aer osolgeneration via gas-phase hydroxyl (OH) radicalor ozone (O3) oxidation of gas-phase precursors.

• Heterogenous oxidation of primary aerosols.

• Compatible with gas and particle massspectrometry techniques.

• Complement to laboratory smog chamber techniques commonly used to generate secondaryorganic aerosol (SOA).

• Based on Penn State flo

w

react or desi gn int roducedby Kang et al. (2007) and further evaluated by Lambeet al. (2011).

• Field deployable.

• Wide range of oxidant exposure times attainable withdimmable UV lamps (primary emission intensity atλ = 254 nm) at high measurement throughput/resolution.

• OH/HO2 and OH/O3 ratios similar to troposphericratios. Amounts of OH, HO2, and O3 are 100 to

10,000 times larger than in the daytime troposphere,simulating days of atmospheric oxidation in minutes.

APPLICATIONS ADVANTAGES

Typical setup for measurements incorporating PAM reactor. Control software facilitates data-logging at 1 Hz and automated control with event sequencing for unattended operation (dashedgrey = analog input/output; dashed red = digital input/output)

24

Result 2b – Proof of Conceptisoprene + “high OH”

Result 4bα-pinene + “high OH”

25

26

36 ppb isoprene + “high” OH, low NOxcomparison with Krechmer et al.

Hyytiälä NO3- ToF-CIMSPMF Mass Spectral Factors

a-pinene+

O3, OH, NO (NO3)

HOM

“highlyoxidized

multifunctionalorganics”

Yan et al, ACPD, 2016