Intercomparison of Mobility Particle Size Spectrometers

Transcription

1 Intercomparison of Mobility Particle Size Spectrometers Project No.: MPSS Basic information: Location of the quality assurance: TROPOS, lab: 118 Delivery date: - Setup in the laboratory: December 16, 2015 Comparison period: December 17, 2015 December 18, 2015 Principal Investigator Home Institution Participant Instrument John Ogren NOAA/ESRL Global Monitoring Division 325 Broadway R/GMD1 Boulder, CO 80305, USA TROPOS-MPSS Alaska: homemade TSI CPC Model 3010 # 2326 Summary of Intercomparison: Pre-status: The TROPOS-MPSS Alaska was in a bad condition and not working. Therefore, an initial status check was not possible. Final status: The TROPOS-MPSS Alaska passed the quality standards of ACTRIS and GAW. 1

2 A TROPOS-MPSS Alaska with TSI-CPC Model 3010 (S/N: 2326) was sent to TROPOS under the following conditions: The TROPOS-MPSS Alaska was in a bad condition and not working. Therefore, an initial status check was not possible. It was shipped without radioactive source during the workshop we used a Kr85 source from TROPOS The NOAA TSI-CPC 3010 arrived in a bad condition at TROPOS. It was necessary to clean and fix the optics. The reason was that after manipulation from NOAA the optic was mounted back in the wrong position. After repairing, the NOAA TSI-CPC passed the quality standards of ACTRIS and GAW. - Status of the wick: The wick should be cleaned, because it was dirty and old. - Status of the CPC: The CPC was not working properly, repair was necessary. - Final CPC-Workshop: The CPC 3010 reached the 100% efficiency at 30 nm. The Dp50 is at 9.5 nm. The CPC efficiency curve corresponds to the standard. The DMA has been opened and inspected. A visible passivation layer has been observed in the negative electrode, as well as on the positive one. The mechanical workshop cleaned the DMA, mechanically removing the passivation layer from the electrodes. The DMA was not correctly mounted on the plate of the MPSS and screws were missing. The same for the whole MPSS system, screws were missing. It seemed like that the system had been accidentally dropped down on the floor. There are scratches on the DMA. It was necessary to disassemble the system. Before mounting the whole TROPOS-MPSS Alaska back, each part of the rack and fittings were cleaned and checked. All the aerosol lines have been wet cleaned in a sonic bath with a water based solution (distilled water + isopropanol + commercial surfactant), rinsed with distilled water and dried by means of compressed air. All the nylon ferrules were replaced with new ones in the mounting phase. The electronic box have been inspected by the electronic group to make sure that everything is in proper order. We installed a pressure sensor. The blower was broken. We replaced it with a new one. During the test phase, the 5V power supply from the blower crashed. We replaced it with a new one. The two HEPA filters installed in the TROPOS-MPSS Alaska have been opened and serviced. Filter holders have been wet cleaned and the inner filters and o-rings were replaced with new ones. HEPA filters have been tested for leaks against a TROPOS CPC 3772 (SN 70859) with the Zero count method. Hardware update: The TROPOS-MPSS Alaska got a completely new Hardware, including a Motherboard, RAM, CPU and hard disk. Software update: The TROPOS-MPSS Alaska got the latest version of the TROPOS software 6.1 under WIN7. The TROPOS-MPSS Alaska was calibrated: High voltage and PSL with Latex 203 nm. In the final run, the TROPOS-MPSS Alaska passed the quality standards of ACTRIS and GAW. 2

3 List of Components Specification Reference MPSS No.1 TROPOS-MPSS Alaska Position (Line) Company TROPOS TROPOS Software TROPOS 5.7 TROPOS 6.1 CPC Model 3772 Model 3010 Flow ratio 1.0 : : 5.0 Source Kr85 Kr85 HV cassette positive positive DMA Hauke medium Hauke medium Flow meas. Aerosol Dryer RH sensor Inlet T sensor RH sensor T sensor Sheath air Dryer p sensor Figure 01: Setup of the TROPOS-MPSS Alaska in the TROPOS lab

4 Laboratory setup aerosol standard - zero test - latex 203 nm total fow 20l/min rel. humidity: < 30 % atmosphere lab 118 LINE 1 2x perma pure dryer LINE TROPOS- MPSS Alaska TROPOS- MPSS CNR-Rome TROPOS- MPSS Malta Reference TSI CPC 3010 SN 2006 Reference MPSS No.1 Reference TSI CPC 3010 SN 2337 SMPS Reference Instrument Line2 Additional Equipment: vacuum flow Bubble flow meter Gilibrator, Gilian (Sensidyne) Thermo Scientific Nanosphere Size Standard PSL 203nm (±4nm) Aerosol nebulizer for PSL (homemade TROPOS) Voltcraft multimeter (0-1000V), Keysight Technologies 4

5 Pre-Workshop-Status of Reference Instruments in TROPOS Figure 02: Correlations of the TROPOS Reference MPSS systems and the Reference TSI CPCs Model 3010 of both lines (see laboratory setup). Multiple charge, internal diffusion loss and CPC flow corrections are included. Figure 03: Intercomparison between the two Lines. For each Line there is a TROPOS Reference MPSS and a Reference TSI CPC Model 3010, which are calibrated against an electrometer. Multiple charge, internal diffusion loss and CPC flow corrections are included. 5

6 Final Status of the Candidate ( ) Components and zero check Institute System Components CPC Model + Serial No. Line Flow Zero TROPOS Ref1 MPSS 3772 SN l/min 0 # cm -3 TROPOS Total CPC 3010 SN l/min 0 # cm -3 NOAA Alaska TROPOS-MPSS 3010 SN l/min 0 # cm -3 High voltage calibration Institute System [V] 0 V 5 mv 80 mv 800 mv TROPOS Reference Prestatus MPSS No final NOAA MPSS Alaska Prestatus final Latex 203nm ±4nm (pressure 1007 hpa, 23.0 C) Institut System Latex 203 [nm] slope TROPOS Reference MPSS No.1 Pre-status final NOAA MPSS Alaska Pre-status - - final Reference MPSS No Latex 203nm ± 4nm Peak bei Dp = nm final run MPSS Alaska Latex 203nm ± 4nm Peak bei Dp = nm final run raw concentration in #/cm³ raw concentration in #/cm³ particle diameter Dp in nm Figure 04: Measurement of latex 203 nm: Particle size distribution (raw concentration) for latex 203 nm on December 17, particle diameter Dp in nm

7 Time Series 8000 ambient_1 without screen ambient_2 with screen zero check N total N nm in [#/cm³] 0 Reference TSI CPC Model 3010 vs ± 10% Reference MPSS No.1 MPSS Alaska 20: :30 01: Figure 5: Time series (December 17, :00 pm December 18, :00 pm) of the integrated particle number concentration (N nm) of the MPSS and total number concentration (N total) of the reference TSI-CPC Model The inversion was performed using TROPOS software. Multiple charge correction, internal diffusion losses and CPC flow corrections are included. Particle Number Size Distribution 03:30 06:00 08:30 11:00 13:30 time Reference MPSS No.1 vs ± 10% MPSS Alaska dn/dlogdp in [#/cm³] Zeitraum: , 18: , 09: particle diameter Dp in [nm] Figure 6: Comparison of mean particle number size distribution of TROPOS-MPSS Alaska and TROPOS Reference MPSS No.1 from December 17, :00 pm until December 18, :00 am. The inversion was performed using TROPOS software. Multiple charge correction, internal diffusion losses and CPC efficiency are included. 7

8 Ambient_1: without screen Correlation between the total CPCs Model 3010 and TROPOS Reference MPSS No.1 Reference MPSS No.1 N nm [#/cm³] 0 Model: fit_reference_mpss_no_1 b = ± R² =0.97 without screen 0 Reference TSI CPC Model 3010 N total [#/cm³] Figure 07: Linear regression between the number concentrations of the TROPOS Reference MPSS No.1 and TROPOS Reference TSI CPC Model Multiple charge correction, internal diffusion losses and CPC flow corrections are included. Correlation between the TROPOS Reference TSI CPC Model 3010 and MPSS Alaska MPSS Alaska N nm [#/cm³] Model: fit_mpss_alaska b = ± R² =0.95 without screen 0 0 Reference TSI CPC Model 3010 N total [#/cm³] Figure 08: Linear regression between the number concentrations of the MPSS Alaska and TROPOS Reference TSI CPC Model Multiple charge correction, internal diffusion losses and CPC flow corrections are included. 8

9 Correlation between the TROPOS Reference MPSS No.1 and MPSS Alaska MPSS Alaska N nm [#/cm³] Model: fit_mpss_alaska b = ± R² =0.96 without screen 0 0 Reference MPSS No.1 N nm [#/cm³] Figure 09: Linear regression between the number concentrations of the MPSS Alaska and TROPOS Reference MPSS No.1. Multiple charge correction, internal diffusion losses and CPC flow corrections are included. Ambient_2: with screen Correlation between the total CPCs Model 3010 and TROPOS Reference MPSS No.1 Reference MPSS No.1 N nm [#/cm³] Model: fit_reference_mpss_no_1 b = ± R² =0.97 with screen Reference TSI CPC Model 3010 N total [#/cm³] Figure 10: Linear regression between the number concentrations of the TROPOS Reference MPSS No.1 and TROPOS Reference TSI CPC Model Multiple charge correction, internal diffusion losses and CPC flow corrections are included. 9

10 Correlation between the TROPOS Reference TSI CPC Model 3010 and MPSS Alaska MPSS Alaska N nm [#/cm³] Model: fit_mpss_alaska b = ± R² =0.97 with screen Reference TSI CPC Model 3010 N total [#/cm³] Figure 11: Linear regression between the number concentrations of the MPSS Alaska and TROPOS Reference TSI CPC Model Multiple charge correction, internal diffusion losses and CPC flow corrections are included. Correlation between the TROPOS Reference MPSS No.1 and MPSS Alaska MPSS Alaska N nm [#/cm³] Model: fit_mpss_alaska b = ± R² =0.96 with screen Reference MPSS No.1 N nm [#/cm³] Figure 12: Linear regression between the number concentrations of the MPSS Alaska and TROPOS Reference MPSS No.1. Multiple charge correction, internal diffusion losses and CPC flow corrections are included. 10