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 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

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

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. Aerodyne Research, Inc. Aerosol Chemical Speciation Monitor ACSM-002 SN

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

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

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

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

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

NH 4 NO 3 Ionization Efficiency Calibration Calibration based on calculated mass delivered from atomizer/DMA/CPC system NO 3 = NO + + NO 2 + NH 4 = NH + + NH NH 3 + NO 3 NH 4

Spain, March 2009 – 3 weeks Houston, April 2009 – 6 weeks Queens, NY June 2009 – 8 weeks Recent Field Deployments of the ACSM NYSDEC

ACSM Data Sample Queens, NY weeks unattended continuous measurements Data upload to any FTP site (with valid credentials). cp µg m -3 average

ACSM vs HTOF-AMS Time Trends Queens, NY 2009 Qi Zhang, Yele Sun SUNY Albany SO 4 NO 3 NH 4 Chl Org

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

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

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

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/m 3 in 30 min. (3σ) Particle size transmission range nm. No sizing. Time resolution is fast for monitoring. Remote data access

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