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Aerosol Chemical Speciation Monitor ACSM Instrument description and sample data

Aerosol Chemical Speciation Monitor ACSM Instrument description and sample data. N.L. Ng, T. Onasch, A. Trimborn, S. Herndon, M. Canagaratna, D. Sueper, D. Worsnop, J. Jayne Aerodyne Research, Inc. AAAR Meeting Oct 27, 2009. Aerosol Chemical Speciation Monitor ACSM.

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Aerosol Chemical Speciation Monitor ACSM Instrument description and sample data

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  1. Aerosol Chemical Speciation Monitor ACSM Instrument description and sample data N.L. Ng, T. Onasch, A. Trimborn, S. Herndon, M. Canagaratna, D. Sueper, D. Worsnop, J. Jayne Aerodyne Research, Inc. AAAR Meeting Oct 27, 2009

  2. Aerosol Chemical Speciation Monitor ACSM • Continuous monitoring of non-refractory aerosol composition by thermal particle vaporization aerosol mass spectrometry. • Sulfate, Nitrate, Chloride, Ammonium, Organics • Builds on ARI Q and ToF AMS Hardware and analysis concepts. • lower cost, lower sensitivity. • Designed for monitoring, long term unattended operation. • Performance demonstrations in progress

  3. No Sizing Commercial grade Mass Spectrometer Pfeiffer Prisma Pumps (x3) Slow scan rates, 1 sec/amu Aerosol Chemical Speciation Monitor Particle Beam Generation Particle Composition RGA Laptop Computer Thermal Vaporization & Electron Impact Ionization Aerodynamic Lens 40-1000 nm Particle Inlet (1 atm)

  4. Aerodyne Research, Inc. Aerosol Chemical Speciation Monitor Size: 19”D x 21”W x 33”H Weight: 140 lbs (64 kg) Power: 300W Data acquisition via Ethernet connection – basic laptop is sufficient. ACSM-002 SN 140-100

  5. RGA Internal Standard Naphthalene Effusive Source • m/z marker • Ion transmission • Ionization efficiency reference naphthalene molecules 1 µm pin hole 1011 s-1

  6. RGA Filter Filter mode Automated Valve System for Instrument Zero 3-way Valve Sample mode Filter Aerosol mass is determined from difference of ‘Sample – Filter”

  7. Aerosol mass is determined from difference of ‘Sample – Filter” mass spectra • Chemical species are determined following Allan et al, 2003 • Sulfate, Nitrate, Chloride, Ammonium, Organics

  8. Instrument Stability - Allan Variance Measured under (ideal) laboratory conditions 5 min

  9. Estimated 3σ Detection Limits • 1 hr DLs are < 0.2 µg m-3 • 24 hr DLs are < 0.05 µg m-3 Detection limits depend on background signal levels in the spectrum

  10. NH4NO3 Ionization Efficiency Calibration NH4 NO3 NH4 = NH+ + NH2+ + NH3+ NO3 = NO+ + NO2+ Calibration based on calculated mass delivered from atomizer/DMA/CPC system

  11. Recent Field Deployments of the ACSM • Spain, March 2009 – 3 weeks • Houston, April 2009 – 6 weeks • Queens, NY June 2009 – 8 weeks NYSDEC http://www.dec.ny.gov/chemical/54360.html

  12. ACSM Data Sample Queens, NY 2009 • 8 weeks unattended continuous measurements • Data upload to any FTP site (with valid credentials). 15.9 µg m-3 average cp5

  13. ACSM vs HTOF-AMS Time Trends Queens, NY 2009 Org NH4 Chl NO3 SO4 Qi Zhang, Yele Sun SUNY Albany

  14. Mass Spectrum, Source 1 Mass Spectrum, Source 2 Mass Spectrum, Source 3 x x x = + … + + . . . Contribution (ug/m3), Source 2 Contribution (ug/m3), Source 3 Contribution (ug/m3), Source 1 Mass Spectrum Time Deconvolution of Organic SpectraUlbrich et al, 2009 • Positive Matrix Factorization (PMF) • Lanz et al. 2007, Ulbrich et al, 2009

  15. Results from PMF Analysis of Organic Mass Spectra OOA and HOA Factors OOA – Oxidized Organic Aerosol “Photochemically Aged Aerosol” HOA – Hydrocarbon-like Organic Aerosol “Primary Particles” Queens Data, 2009

  16. OOA and HOA Time series ACSM and AMS Comparison OOA HOA Qi Zhang, Yele Sun SUNY Albany

  17. Summary • ACSM reports chemically speciated aerosol mass loading Sulfate, Nitrate, Chloride, Ammonium, Organics • Data analysis builds on AMS methods. PMF analysis • Stable unattended operation over long periods (months). • Sensitivity of ~0.2 µg/m3 in 30 min. (3σ) • Particle size transmission range 40-1000 nm. • No sizing. • Time resolution is fast for monitoring. • Remote data access

  18. Acknowledgements • Instrument development support • -US EPA and DoE SBIR • Queens Data • -SUNY Albany group (Demerjian, Schwab, Zhang, Sun) • -NYSDEC

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