Aerosol Chemical Monitor Calibration Center

Interlaboratory comparisons results and future work

Overview of results from 2016 paper…

Aerosol chemical monitor calibration center

• Illustrated the benefits of using the new full scan calibration mode.

• Highlighted the importance of the separate RIE SO4 calibration.

• Tested the mz44/NO3 artefact correction (Pieber et al).

• Proposed a new correction based on aerosol chemical composition.

AMS user’ meeting, Lund # 20

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

frag_organic[44] = 44, -frag_air[44], -b*1.05*frag_nitrate[30], -b*1.05*frag_nitrate[46])

AMS user’ meeting, Lund # 20

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

frag_organic[44] = 44, -frag_air[44], -b*1.05*frag_nitrate[30], -b*1.05*frag_nitrate[46])

AMS user’ meeting, Lund # 20

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

frag_organic[44] = 44, -frag_air[44], -b*1.05*frag_nitrate[30], -b*1.05*frag_nitrate[46])

AMS user’ meeting, Lund # 20

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

This correction assumes the magnitude of the artefact is independent of chemical composition, basing the correction on measurements made with pure NH4NO3. During this intercomparison we performed calibrations at variable nitrate mass fractions (NO3_MF) using mixtures of NH4NO3 and (NH4)2SO4, and from this data we observe that the magnitude of the artifact varies as a function of NO3_MF

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

This correction assumes the magnitude of the artefact is independent of chemical composition, basing the correction on measurements made with pure NH4NO3. During this intercomparison we performed calibrations at variable nitrate mass fractions (NO3_MF) using mixtures of NH4NO3 and (NH4)2SO4, and from this data we observe that the magnitude of the artifact varies as a function of NO3_MF

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

This correction assumes the magnitude of the artefact is independent of chemical composition, basing the correction on measurements made with pure NH4NO3. During this intercomparison we performed calibrations at variable nitrate mass fractions (NO3_MF) using mixtures of NH4NO3 and (NH4)2SO4, and from this data we observe that the magnitude of the artifact varies as a function of NO3_MF

AMS user’ meeting, Lund # 20

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

This correction assumes the magnitude of the artefact is independent of chemical composition, basing the correction on measurements made with pure NH4NO3. During this intercomparison we performed calibrations at variable nitrate mass fractions (NO3_MF) using mixtures of NH4NO3 and (NH4)2SO4, and from this data we observe that the magnitude of the artifact varies as a function of NO3_MF

AMS user’ meeting, Lund # 20

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

This correction assumes the magnitude of the artifact is independent of chemical composition, basing the correction on measurements made with pure NH4NO3. During this intercomparison we performed calibrations at variable nitrate mass fractions (NO3_MF) using mixtures of NH4NO3 and (NH4)2SO4, and from this data we observe that the magnitude of the artifact varies as a function of NO3_MF

AMS user’ meeting, Lund # 20

Aerosol chemical monitor calibration center -2016 results

Organic aerosol

Uncorrected data

Data corrected using Composition independant Correction factor

Correction based on NO3 MF

AMS user’ meeting, Lund # 20

ILC 2016

ILC 2018

NO3_MF = 0.23 0.78

1 2 3 4 5 6

Ran additional mixtures Confirmed the stability of the

artefact at lower NO3 MF Confirmed the linear relationship

between points at higher MF. ? How do these artefacts vary for organic/inorganic mixtures

Mz 44 artefact: Organic and inorganic mixtures Long-term ambient comparison

AMS user’ meeting, Lund # 20

Levoglucason Succinic acid Glutaric acid

Mz 44 artefact: Organic and inorganic mixtures Long-term ambient comparison

• Pure organic solution, + 4 different mixtures with NH4NO3

• Distinctive average mass spectra. • Slight differences in instrument to instrument response

• 6 Q-ACSM (5 PM1 SV, 1 PM2.5 SV)

M-C. Minguillon, D. Green, L. Marmureanu, C. Marin, Z. Bibi, J. Ovadnevite

AMS user’ meeting, Lund # 20

Levoglucason

Glutaric acid Succinic acid

1 2 3 4 5 6

1 2 3 4 5 6

1 2 3 4 5 6

Ran additional mixtures High variability at low NO3 MF Highest artefact @ NO3 MF

between 0.4 and 0.6.

Mz 44 artefact: Organic and inorganic mixtures Long-term ambient comparison

AMS user’ meeting, Lund # 20

• 6 Q-ACSM (5 PM1 SV, 1 PM2.5 SV)

• 23rd November ‘18 to 7th January ‘19

Phase 2: Long-term ambient intercomparison

AMS user’ meeting, Lund # 20

No. 6 = PM25, SV

Phase 2: Long-term ambient intercomparison

AMS user’ meeting, Lund # 20

Phase 2: Long-term ambient intercomparison

Ciemat DWD KCL INOE SIRTA I-EPA NO3_MF never exceeded 25%

Unconstrained PMF SOFI : constrained PMF (HOA+BBOA) a =0.3

No. 6 = PM25, SV

AMS user’ meeting, Lund # 20

Phase 2: Long-term ambient intercomparison

AMS user’ meeting, Lund # 20

Other observations: Negative Chloride

Filament changed

AMS user’ meeting, Lund # 20

Negative Chl signal also observed by participants at their site. Tests: Increasing heater up to 850°C. Negative Chl signals unchanged

Other observations: Negative Chloride

AMS user’ meeting, Lund # 20

Filament changed

Filament failure mid way through sampling. Changed to a Tungsten filament (previous one was Iridium). Negative Chl signal was not directly observed after the filament change.

Other observations: Negative Chloride

AMS user’ meeting, Lund # 20

Other observations: Negative Chloride

Neg Chl does not appear to anti-correlate with any other principal species.

AMS user’ meeting, Lund # 20

Other observations: Negative Chloride

Neg Chl does not appear to anti-correlate with any other principal species.

AMS user’ meeting, Lund # 20

Other observations: Negative Chloride

AMS user’ meeting, Lund # 20