New Approach for the Efficient Collection of Airborne Particles down to 6 nm for Chemical and Toxicological Characterization

Transcription

1 New Approach for the Efficient Collection of Airborne Particles down to 6 nm for Chemical and Toxicological Characterization Arantzazu Eiguren Fernandez 1, Nicholas Buglak 2, Gregory Lewis 1, Ning Li 2, Patricia Keady 3, CRISTINA GUTIERREZ-CAÑAS 4 and Susanne Hering 1, 2 1 Aerosol Dynamics Inc., Berkeley, California, USA; 2 Michigan State University, East Lansing, Michigan, USA; 3 Aerosol Devices Inc., Fort Collins, Colorado, USA; 4 University of the Basque Country, Bilbao, Bizkaia, Spain Presented at RICTA 2015, the 3rd Iberian Meeting on Aerosol Science and Technology in Elche, Spain, June 29-July 1, 2015

2 Brief History of Condensation-enabled particle growth 1. Condensation-enabled particle detection is one of the oldest techniques in aerosol science (John Aitken, 1889) 2. Condensational growth enlarges nanometer particles to micrometer diameters 3. Initiation of Condensational Growth requires supersaturation (RH>100%) 4. Approaches differ in how supersaturation is achieved

3 Brief History of Condensation-enabled particle growth Instruments using the different approaches Adiabatic expansion Aitken, 1889; (drawing from B Vonnegut, 1954) Mixing Kousaka et al,1982; (drawing from R. Weber, 2001) Laminar Flow - alcohol condensate (Bricard et al, 1976)

4 Our approach: Laminar Flow, water-based condensation In 2003 we introduced the technology that allows Particle Growth through laminar flow water condensation Preconditioner cool wet-walled (5 O C) Condenser Warm (40 O C) It was developed for the water condensation particle counters (WCPCs) Although Water condensation is compatible with many applications... the output flow, like mixing instruments, is warm and humid... And the collection / concentrator applications require of an output flow closer to ambient Temperature and RH

5 Improvement for particle collection New Design: Cold Hot -Cold Conditioner Initiator Moderator (5 O C) (35 O C) (8 O C) Saturation Ratio: Same Supersaturation => obtain same activation & particle growth Water content of exiting flow reduced by a factor of 5 Growth region at 45 C throughout Centerline trajectories for input flow at 25 C, 50% RH

6 How particle collection is conducted Condensational growth --> droplet impaction Sample Inlet 1.5 L/min Conditioner 5 C Initiator 35 C Moderator 12 C Dry Collection Plate

7 Instrument Capabilities The Spot Sampler collects particles via impaction on a solid substrate or into a small volume of liquid. 1. Dry collection: Uninterrupted collection of concentrated spots (1-mm) in a 33-well disk Time-resolved collection: minutes to hours No bouncing artifact Automated extraction and injection for analysis (i.e. IC, HPLC) 3 concentrated spots (1-mm) 33-well disk No bouncing Automated extraction and injection

8 Instrument Capabilities 2. Liquid collection: Concentrated suspensions (~ µl) Changeable collection medium: water, culture media, virus growth medium Ready for chemical, toxicological, and virus viability analysis Liquid collection Collected Suspension

9 Results: Efficiencies >95% for solid and liquid collection Collection Efficiency (%) Particle Number Concentration (#/cm3) Collection Efficiency (%) Collection Efficiency (%) Calibration with Monodisperse Hydrophilic and Hydrophobic Aerosols Dry Collection into Well Plate Ammonium Sulfate Sebacic Acid (hydrophobic) Dry Collection onto Flat Surface Ammonium Sulfate Sebacic Acid Liquid Collector Sulfate Sebacic Acid (hydrophobic) Particle Diameter (nm) Particle Diameter (nm) x10 3 Ambient Aerosol Capture Efficiency using the Dry Collector Particle Collection Efficiency (by number) nuclei mode present (TSI-3788/TSI-3783 > 1.3) Upstream N >3nm (TSI-3788) 20 Upstream N >7nm (TSI-3783) :00 5/15/2015 Downstream N >5nm (TSI-3787) 01:00 5/16/ :00

10 Results: Good correlation with PILS and Filter collection Nitrate (µg/m 3 ) Sulfate (µg/m 3 ) Field Deployment 1 - Characterization of Sulfate and Nitrate Deployment at: San Gorgonio, Southern California June 12 July 5, 2012 Data from: Dr. Jeffery Collett (CSU) Dr. Arsineh Hocobian (CSU) Instruments: S3: mostly 1-hr resolution PILS: ~17 min resolution URG Denuder-Filter Packs: 12-hr samples Analysis: Dionex IC (automated extraction for S3) 30 Spot Sampler PIILS Filter /16/2012 6/21/2012 6/26/2012 7/1/2012 Spot Sampler PIILS Filter 5 0 6/16/2012 6/21/2012 6/26/2012 7/1/2012

11 PAH (pg/m3) Results: Time-resolved speciation of PAHs Field Deployment 2 - Characterization of p-pahs in Stockton Deployment: Stockton, California (Nov 2011 Feb 2012) Analysis: CTC-PAL autosampler: automated extraction and injection Agilent HPLC-FL: 15 EPA-PAHs Instruments: S3: 12hr 1.5 lpm for PAHs 170 continuous samples Parallel 48-hr filters (25mm, 9 lpm) Run unattended for a week at a time PHE BBF BAP IND BAA BKF BGP

12 Results: Significant increase in pro-inflammatory markers Field Deployment 3: Characterization of toxicological properties Data from: Dr. Ning Li (MSU) Deployment: Michigan State University (Michigan) May 6-9, 2014 TSP: 3 hr samples, morning and afternoon Instruments: Aerosol into Suspension collection Cells: Human Bronchial Epithelial cell line (BEAS-2B) Cellular Assays: Pro-inflammatory markers: IL-6 and IL-8 Ambient PM induced a: 10- to 34-fold increase in IL-6 5- to 25-fold increase in IL-8 Important diurnal and daily variability in the pro-inflammatory capacity of the collected aerosols

13 Summary 1. The Spot Sampler provides a new approach to efficiently collect airborne particles as concentrated, ready-to-analyze dry samples or liquid suspensions. 2. Unattended, time-resolved collection allows better characterization of the aerosol properties and dynamics. 3. Automated extraction and analysis reduces time and cost. 4. High collection efficiencies are obtained for both dry and liquid collections, down to 5 nm for hydrophilic particles, and 15nm for highly hydrophobic aerosols. 5. Ambient particle collections are achieved with efficiencies >95% for both configurations. 6. Directly collected Concentrated suspensions of airborne particles enable more precise characterization of their toxicological properties.

14 Acknowledgements Carl Camp (ARB) for his help during the Stockton Campaign Paula Palmiter for providing the space for ambient collection Dr. Ryan Lewandowski for his help during field deployment Grants: 1 RC3 ES & 1R43-ES For Product information, contact Pat Keady at: Aerosol Devices Inc. info@aerosoldevices.com Website: aerosoldevices.com

15 Collection efficiencies for particle sizes 10 nm to 10 µm

16 Comparison: S3 vs PILS & S3 vs. Filters Sulfate Nitrate

17 Plate (ng/m3) Comparison: S3 (average of 4, 12-hr) vs Filters (48-hr) 2.0 PHE FLT PYR BAA CRY BBF BKF BAP DBA BGP IND Filter (ng/m3)

18 Ambient PM: Cell viability 100 Cell viability (%Live cells) Ctrl 5/6/2014 5/7/2014 5/8/14 (am) 5/8/14 (pm) 5/9/14 (am) 5/9/14 (pm) At the 0.05 m 3 air/ml used on the BEAS-2B cells there was no significant cell death for any sample when compared to control