Aerosol Chemical Composition Using Aerosol Mass Spectrometry

ASCOS WorkshopLandskronaApril 9, 2008

R. Chang, J. Abbatt – University of TorontoK. Hayden, R. Leaitch, S.-M. Li, J. Liggio – Environment Canada

Objectives• characterize composition of surface aerosols

– physical properties, hygroscopic properties• source of air

– local natural aerosol• Does it correlate with biological activity?• Is there an organic component?• Are the aerosols neutralized? Is there enough ammonia

present?• Is there MSA in the aerosol?

– transported anthropogenic aerosol• Are the aerosols neutralized?• Is there an organic component?

Time-of-Flight Aerosol Mass Spectrometer

Mass Spectrum Mode

SOLAS 2007 in Canadian Arctic0.4

0.3

0.2

0.1

0.0

µg/m

3

12:00 AM12/10/2007

12:00 PM 12:00 AM13/10/2007

12:00 PM

Date and Time

Clean 2

Clean 1

OrganicNitrateSulphateAmmoniumChloride

10-5

10-4

10-3

10-2

10-1

100

101

102

Nitr

ate

equi

vale

nt m

ass

(µg

m-3

)

20015010050m/z

MSSD all 109.751 MSSD Air 108.976 MSSD Water 0.303935 MSSD NO3 0.0117742 MSSD SO4 0.0689265 MSSD Org 0.118997 MSSD NH4 0.0403764 MSSD Chl -0.00177612

Clean 1

800

600

400

200

dN/d

logD

p2 3 4 5 6 7

1002 3 4 5

Dmobility (nm)

0.8

0.6

0.4

0.2

0.0

dV/dlogD

p

Number

Volume

Sulphate MS Neutralized

Clean 1

20

15

10

5

0

x10-3

12010080604020

0.00

NISTH2SO4

Time-of-Flight Aerosol Mass Spectrometer

Particle Time of Flight Mode(PToF)

PToF Distribution in Southern Ontario

12

10

8

6

4

2

0

µg/m

3

101 102 103 104

PToF size, nm

ug_log_Orgav_temp ug_log_NO3av_temp ug_log_SO4av_temp ug_log_NH4av_temp ug_log_Chlav_temp

Sulphate OrganicAmmoniumNitrateChloride

J. Bottenheim, S. Netcheva – Environment Canada

ASCOS WorkshopLandskronaApril 9, 2008

Halogen Chemistry withOut On The Ice (OOTI)

Introduction

Spring time chemistryBr2 + hν → 2Br2(Br + O3 → BrO + O2) (O3 depletion)

BrO + DMS DMSOBr/BrO + Hg0 RGM mercury deposition

Question:Can this chemistry occur in the summer?

Instrumentation for Target Species

BrO: Multi-Axis Differential Optical Absorption Spectrometer (MaxDOAS, Ocean Optics)

O3: UV Absorption Based Monitor (2B)

Hg0: Atomic Absorption Mercury Vapour Analyzer (Gardis)