Analysis of Data from the 2009 SOOT Experiment

Transcription

1 Analysis of Data from the 2009 SOOT Experiment Renyi Zhang Department of Atmospheric Sciences and Department of Chemistry Center for Atmospheric Chemistry and the Environment Texas A&M University College Station, TX Presented at the SAC/HARC Meeting, March 4, 2014

2 Objectives Use observations derived from the 2009 SHARP/SOOT field study to characterize particulate matter chemistry, including the secondary formation of nitrous acid on soot. Inform a parallel modeling project by UNC (Project 1c) so that the impacts of PM chemistry on ozone formation can be simulated Subtask 1: Processing of the AACES chamber data of the aerosol aging and HONO formation experiments Subtask 2: Processing of ambient measurements of HONO concentrations and aerosol properties Subtask 3: Development of condensed mechanisms of aerosol aging and transformation and the associated impacts on their physical properties

3 2009 SOOT Activities Lab Experiments: Measurements of the uptake coefficients of NO x and HONO formation rate on fresh and aged soot with variable amounts of organics, sulfate, and nitrate Field Campaign: Simultaneous measurements of key nitrogen compounds (HONO, HNO 3, HNO 4, N 2 O 5, and NO 3 ) and aerosols during a one-month period In 2009 at the University of Houston s Moody Tower or from an upper floor of the Williams Tower

4 Instrumentation during SOOT Field Studies N 2 O 5 and NO 3 by cavity ring down spectroscopy (CRDS) HONO, HNO 3, and HNO 4 by ID-CIMS Soot aerosol content and mixing state by TDMA aerosol particle mass (APM) analyzer Aerosol optical properties by CRDS for extinction and a nephelometer for scattering Aerosol size, distribution, and hygroscopicity by tandem differential mobility analyzer (TDMA) A captured-air chamber for controlled heterogeneous HONO formation

5 Measurements of HONO by ID-CIMS Scroll Pump Flow meter Quadrupole Electron Multiplier Air Sample NH3 and SiF4 Drift tube SF6 Corona Discharge Rotary Pump Turbo Pump Turbo Pump Rotary Pump ID-CIMS signal (cps) y = x R 2 = HONO ID-CIMS with UV368(ppb) HONO + SF 6 - HONO F - + SF 5 Sensitivity of cps/ppb and a detection limit of 10-20ppt for a 1 s integration time

6 Atmospheric Chambers for Evolution Studies (ACES) Bipolar ions FEP Teflon From tower eptfe Teflon UVT Acrylic Monodisperse particles in To pump Filter To blower Outside [Gases] Inside

7 TDMA/DMA-APM system Operation modes: single DMA (scanning mobility particle sizer) DMA - DMA DMA - APM Drier Sheath flow in (6.5 LPM N 2 ) Po 210 CPC make-up flow (0.5 LPM) Pump (1.5 LPM) Sheath flow in (6.5 LPM humid N 2 ) DMA1 CPC DMA2 APM RH Sheath flow out (6.5 LPM) Sheath flow out (6.5 LPM) RH Aerosol path: DMA scan (size distribution) TDMA or DMA-APM scan H 2 SO 4 or organic reservoir Nafion humidifier Humidified make-up flow (0.05 LPM)

8 Differential Mobility Analyzer (DMA) Aerosol Particle Mass (APM) Analyzer Polydisperse aerosol sample High Voltage HV Sheath flow qe qe 2 mrw High voltage 2 mrω Polydisperse flow out Monodisperse aerosol DMA Particles of a certain electrical mobility can penetrate through the DMA for the fixed sheath to sample flow ratio and voltage nec Z p = 3πµ D APM Particles of a certain mass can penetrate through the APM for the fixed rotational speed and voltage Electrostatic force = Centrifugal force 2 mrω p 3 πdve 2 = ρ truerω = nee 6 APM

9 Optical Properties by DMA-DMA/Nephelometer/CRDS DMA-DMA system, CRDS, nephelometer, and connecting tubing kept at a constant temperature Relative humidities in the CRDS and nephelometer within 1% Laser CRDS cavity PMT Aerosol generation and conditioning Po 210 DMA1 Pump CPC Nephelometer Po 210 Aerosol path: DMA scan (size distribution) Optical measurements DMA2 Aerosol humidification and chemical/physical processing

10 Ambient PM Measurements (Levy et al., JGR, 118, 10,518, 2013)

11 Ambient PM Measurements (Levy et al., JGR, 118, 10,518, 2013)

12 Ambient PM Measurements (Levy et al., JGR, 118, 10,518, 2013)

13 Ambient PM Measurements (Levy et al., JGR, 118, 10,518, 2013)

14 Ambient HONO Measurements (Levy et al., to by submitted, 2014)

15 Ambient HONO Measurements (Levy et al., to be submitted, 2014)

16 Ambient HONO Measurements (Levy et al., to by submitted, 2014)

17 Ambient HONO Measurements (Levy et al., to by submitted, 2014)

18 Ambient HONO Measurements (Levy et al., to by submitted, 2014)

19 Ambient HONO Measurements (Levy et al., to by submitted, 2014)

20 Ambient HONO Measurements (Levy et al., to by submitted, 2014) Effects of NO 2 + Soot HONO (Lei et al., JGR, 2004)

21 The uptake coefficient is estimated to be in the range of 6 x 10-4 to 2 x 10-3 for the heterogeneous conversion of NO 2 to HONO on aerosol surfaces

22 Deliverables Levy, M., R. Zhang, A. Khalizov, J. Zheng, D. Collins, C. Glen, Y. Wang, X. Y. Yu, W. Luke, J. Jayne, and E. Olaguer, Measurements of submicron aerosols in Houston, Texas during the 2009 SHARP field campaign, J. Geophys. Res. 118, 10,518 10,534, doi: /2013jd50785 (2013). Misti Levy, Renyi Zhang, Jun Zheng, Annie L. Zhang, Wen Xu, Mario Gomez-Hernandez, Yuan Wang, Eduardo Olaguer, Measurements of Nitrous Acid (HONO) Using Ion Drift - Chemical Ionization Mass Spectrometry during the 2009 SHARP Field Campaign, to be submitted.