Using TDMAs to make Measurements of Haze

Transcription

1 Welcome! 欢迎! 歓迎! 환영! Добро пожаловать! स व गत! Using TDMAs to make Measurements of Haze This webinar will begin at: Greenwich Mean Time (GMT) Thursday, 1:00am Beijing, China 8:00am Tokyo, Japan 9:00am US CST 7:00pm (Wednesday Evening) Tim Johnson Product Specialist Particle Instruments May 5, 2011 Note: you need to join the webinar in two ways: over the phone (audio) and on the internet (visual). Ready-Access phone numbers: link and information included with login information 2011, TSI Incorporated

2 Welcome! Willkommen! Bienvenue! Benvenuto! Recepción! Καλώς Ήρθατε! Добро пожаловать! Using TDMAs to make Measurements of Haze This webinar will begin at: Greenwich Mean Time (GMT): Thursday, 2:00pm UK, London 2:00m Germany, Berlin 3:00pm India 6:30pm US CST 8:00am Note: you need to join the webinar in two ways: over the phone (audio) and on the internet (visual). Ready-Access phone numbers: link and information included with login information 2011, TSI Incorporated Tim Johnson Product Specialist Particle Instruments May 5, 2011

3 Welcome! 欢迎! Willkommen! 歓迎! Bienvenue! स व गत! Using TDMAs to make Measurements of Haze This webinar will begin at: Greenwich Mean Time (GMT): Thursday, 5:00pm US PST 9:00am US CST 11:00am US EST 12:00pm (noon) Germany, Berlin 6:00pm Note: you need to join the webinar in two ways: over the phone (audio) and on the internet (visual). Ready-Access phone numbers: link and information included with login information 2011, TSI Incorporated Tim Johnson Product Specialist Particle Instruments May 5, 2011

4 Interactive Webinar Format 1. Connection Information: You need to join the webinar in two ways Audio: via telephone - phone numbers and link information included with login information Visual: via internet - link information included login information 2. Sound quality: For large groups, the sounds quality is much better if the conference is kept on mute. 3. Multi-media - Interactive chat: Please send questions via chat during and after the presentation. 4. Follow-up: including Adobe pdf file of presentation will be sent to registered attendees. 5

5 Outline What Is Haze? What instruments can measure haze? The use of TDMA to study haze (examples) Summary 6

6 What is Haze? Haze is an atmospheric aerosol that affects visibility Haze is where dust, smoke and other particles obscure the clarity of the sky Natural Sources include fog, mist, smoke, volcanic ash, dust, sand and snow Manmade Sources of Haze include farming, traffic, industry, and wildfires Haze particles may act as condensation nuclei for the subsequent formation of mist droplets Haze in meteorological literature generally is used to denote visibility-reducing aerosols Such aerosols commonly arise from complex chemical reactions that occur as sulfur dioxide gases emitted during combustion are converted into small droplets of sulfuric acid The reactions are enhanced in the presence of sunlight, high relative humidity, and stagnant air flow 7

7 What is Haze? Organic compounds (from burning) as well as sulfates are major contributors to haze A particles ability to grow (to a droplet) depends on it s chemistry, solubility and the availability of gases (such as water vapor) to condense on the particle The impact of particulate matter on visibility depends on its scattering efficiency as well as its abundance To obscure visible light particles need to be large enough to have sufficient scatter (>100 nm) Smaller particles form and grow and this contributes to haze Upper size is limited by the ability of large particles to stay suspended Above 40 to 50 microns setting rates are very fast 8

8 Instrumentation To Measure Haze Light Scattering Integrating Nephelometer Count Condensation Particle Counter (CPC) Size Submicrometer Aerosols are sized by Electrical Mobility Optical methods can be used for larger particles To learn about it s properties you can use: Tandem Differential Mobility Analysis (TDMA) systems 9

9 Count Instruments Most Haze particles are too small to detect optically Lower detection limit on most OPCs is 0.3 µm Condensation Particle Counters Grow Particles to Larger size so that they can be optically detected Both Butanol and Water CPCs can be used but there may be some differences due to material dependencies 10

10 Kelvin Diameter (nm) Temperature (C) Saturation (%) CPC Comparison - Alcohol and Water Traditional (Alcohol) WCPC Saturator Condenser Saturator, 39 C <- Saturation Centerline Axial Profiles Temperature --> S = P v /P sat S = P v /P sat 60 Kelvin Diameter --> Axial Distance/Tube Radius (z/r) 11

11 Sizing Instruments Submicrometer Aerosols are sized by Electrical Mobility Primary instrument for this is: Scanning Mobility Particle Sizer (SMPS) Supermicron Aerosol sized by Aerodynamic or Optical sizing Not the subject of today's webinar 12

12 Electrical Mobility Sizing Electrical Mobility Components Charger Bipolar charger for Monodisperse Generation (classified aerosol) and SMPS systems Unipolar Charger for Electrical Mobility Sizers using Electrometers Mobility Column Detectors Condensation Particle Counters Aerosol Electrometers Scanning Mobility Particle Sizer (SMPS) Stepping (DMPS) systems also used 13

13 Two Neutralizer Choices Aerosol In - - Traditional Kr-85 gas Kr-85 gas sealed stainless-steel tube Aerosol Out Kr-85 facts Kr-85 inert gas sealed in air-tight stainless steel Never absorbed by the body In US classified as a non-biological health hazard In US no handling limitations for amount used in SMPS 10.4 year half life Beta-emitter Advanced Aerosol Neutralizer Soft X-ray Nonradioactive Comparable SMPS sizing No transportation restrictions Does not decay over time

14 Advanced Aerosol Neutralizer Soft X-ray Solution Neutralizer Head Inlet Ionization Chamber X-ray Beam Block Outlet 15

15 Differential Mobility Analyzer (DMA) schematic DMA sorts particles by size Controls are Sheath Flow rate & Voltage on the Center Rod Small particles have higher mobility and are more easily moved in an electric field 16

16 Electrostatic Classifier Neutralizer DMA 17 Flow Control 17

17 FLOW FLOW Submicrometer Monodisperse Aerosol Generation Polydisperse aerosol Long DMA Model psi Model 3012 Aerosol Neutralizer compressed d air Model 3062A Diffusion Dryer HEPA Capsule Filter Model 3074 Clean Air Supply Model 3076 Constant Output Atomizer Excess Air Electrostatic Classifier Model 3080 Monodisperse aerosol 18

18 Scanning Mobility Particle Sizer (SMPS) 19

19 How do Particles Form and Grow? Form Particles form from gaseous precursors and condensation nuclei (outside the scope of this talk) Grow Particle growth depends on the ability of particles to adsorb gases such as VOCs and water Temperature also affects particle growth and shrinkage Particles grow differently (rates, amounts of growth) Measure particle change with temperature and humidity Tandem Differential Mobility Analyzer (TDMA) 20

20 Tandem Differential Mobility Analyzer Combination of two DMAs with components between them to condition the particles Allows laboratory measurements of what happens in the atmosphere DMA 1 Conditioning DMA 2 - SMPS Aerosol CPC 21

21 Conditioning Particles and/or the Sheath Air (for second DMA) can be conditioned Hygroscopicity (HTDMA) Control to a defined humidity Determine growth/shrinkage Volatility TDMA (VTDMA) Temperature conditioning Reactivity TDMA (RTDMA) Reaction rates (control gases in sheath air) 22

22 Humidified DMA Kramer Initial DMA Humidification Control Aerosol Sheath SMPS sizing Krämer, L., Ulrich Pöschl, U., Niessner, R., Microstructural Rearrangement of Sodium Chloride Condensation Aerosol Particles on Interaction with Water Vapor, J. Aerosol Sci. Vol. 31, No. 6, pp ,

23 Humidified DMA Kramer (Continued) Studying interaction of NaCl and PbS with water vapor Both crystalline materials NaCl shrinks at low humidity and grows at humidity's above ~75% Shape factor was evaluated to detect transformation from branched-chain to more compact agglomerates Krämer, L., Ulrich Pöschl, U., Niessner, R., Microstructural Rearrangement of Sodium Chloride Condensation Aerosol Particles on Interaction with Water Vapor, J. Aerosol Sci. Vol. 31, No. 6, pp ,

24 Nanosize Effect on the DRH & ERH of NaCl Conditioning Sizing Aerosol Generation DMA1 Biskos, G., Malinowski, A., Russell, L. M., Buseck, P. R. and Martin, S. T.(2006) 'Nanosize Effect on the Deliquescence and the Efflorescence of Sodium Chloride Particles', Aerosol Science and Technology, 40: 2,

25 Nanosize Effect on the DRH & ERH of NaCl (cont.) Studying the change in Deliquescence RH (DRH) and Efflorescence RH (ERH) with particle size Used two types of NaCl generation Vaporization-Condensation Aerosol Generation (Tube Furnace) Humidify and Dehumidify to condition Electrospray NaCl solution DRH and ERH increases for small (<40 nm) sizes Increase in diameter by several monolayer's (of water) is detected before Deliquescence Matches Coated-surface model of Russell and Ming Biskos, G., Malinowski, A., Russell, L. M., Buseck, P. R. and Martin, S. T.(2006) 'Nanosize Effect on the Deliquescence and the Efflorescence of Sodium Chloride Particles', Aerosol Science and Technology, 40: 2,

26 Examples of TDMAs (H-TDMA) First DMA Conditioner Sizing Mikhailov, E., Vlasenko, S., Niessner, R. and Pöschl, U., Interaction of aerosol particles composed of protein and salts with water vapor: hygroscopic growth and microstructural rearrangement, Atmos. Chem. Phys., 4, ,

27 Interaction of a protein and inorganic salts Evaluate the interaction of a protein and inorganic salts with water vapor BSA- Bovine Serum Albumin protein NaCl and Ammonium Nitrate salts BSA exhibits DRH and ERH at ~35% RH Mixtures (BSA and salts) show diameter reductions up to 20% Form porous agglomerates Pure NaCl NaCl-BSA Mikhailov, E., Vlasenko, S., Niessner, R. and Pöschl, U., Interaction of aerosol particles composed of protein and salts with water vapor: hygroscopic growth and microstructural rearrangement, Atmos. Chem. Phys., 4, ,

28 Effects of Size and Structure on Hygroscopicity of Nanoparticles HTDMA First DMA Either Long or Nano Humidification Scanning Mobility Particle Sizer Either Long or Nano Park, K., Kim J.S., Miller, A., A study on effects of size and structure on hygroscopicity of nanoparticles using a tandem differential mobility analyzer and TEM, J Nanopart Res (2009) 11:

29 Effects of Size and Structure on Hygroscopicity of Nanoparticles (Cont.) Determine size-effect of Nanoparticles for variety of particle types NaCl Sodium Chloride (NH 4 ) 2 - Ammonium sulfide SO 4 - Sulfate KCl - Potassium Chloride NH 4 NO 3 - Ammonium Nitrate MgCl 2 Magnesium Chloride CaCl 2 Calcium Chloride Two generation methods used (method affects shape) Tube furnace used for smallest sizes Atomizer used for larger sizes Growth Factors, DRH & ERH varies with both chemistry and generation method Park, K., Kim J.S., Miller, A., A study on effects of size and structure on hygroscopicity of nanoparticles using a tandem differential mobility analyzer and TEM, J Nanopart Res (2009) 11:

30 Hygroscopicity of Inorganic Aerosols Aerosol Generation Driers for Aerosol Neutralizer First DMA Humidification Aerosol Sheath SMPS Hu, D., Qiao, L., Chen, J., Ye, X., Yang, X., Cheng, T., Fang, W., Hygroscopicity of Inorganic Aerosols: Size and Relative Humidity Effects on the Growth Factor Aerosol and Air Quality Research, 10: ,

31 Hygroscopicity of Inorganic Aerosols Sulfates, Nitrates and Chlorides are a major portion of mass budget of atmospheric particles Investigation of hygroscopic properties of: Sulfates (NH 4 ) 2 SO 4 & Na 2 SO 4 (phase transitions) Chlorides NaCl (phase transitions) Nitrates NaNO 3 (smooth size transitions) Developed iso-gf (growth factor) curves combining size and RH Example: Relationship among growth factor, RH and particle diameter of: (a3) Na 2 SO 4 particles at the RH below deliquescence point (b3) Na 2 SO 4 particles at the RH above deliquescence point Hu, D., Qiao, L., Chen, J., Ye, X., Yang, X., Cheng, T., Fang, W., Hygroscopicity of Inorganic Aerosols: Size and Relative Humidity Effects on the Growth Factor Aerosol and Air Quality Research, 10: ,

32 VH-TDMA Method for Mixed Aerosol First DMA Volatilization First SMPS Humidification Second SMPS Johnson, G.R., Ristovski, Z., Morawska, L., Method for measuring the hygroscopic behaviour of lower volatility fractions in an internally mixed aerosol, Aerosol Science 35 (2004)

33 VH-TDMA Method for Mixed Aerosol Combining volatilization and humidification Observe behavior of non-volatile residue in sulphate aerosols Aerosols tested (single and mixtures): Di-2-EthylHexyl-Sebacate (DEHS) Sodium Chloride (NaCl) Ammonium Nitrate NH 4 NO Ammonium Sulphate (NH 4 )HSO 4 Sulphuric acid H 2 SO 4 Ammonium Bisulphate (NH 4 )HSO 4 Methane Sulphonic acid CH 3 SO 3 H Particle diameter after volatilisation (Dv) Diameter after hygroscopic growth (Dh) Diameter growth factor (Dh=Dv) vs. thermodenuder Temp. NaCl-seeded DEHS aerosol. Johnson, G.R., Ristovski, Z., Morawska, L., Method for measuring the hygroscopic behaviour of lower volatility fractions in an internally mixed aerosol, Aerosol Science 35 (2004)

34 Mass Measurement of Non-Spherical Particles First DMA (SMPS) Thermal Conditioner SMPS and ELPI Measure Mobility and Aerodynamic Diameters Ristimäki, J., Keskinen J.. Mass Measurement of Non-Spherical Particles: TDMA-ELPI Setup and Performance Tests, Aerosol Science and Technology, 40: (2006) 35

35 Mass Measurement of Non-Spherical Particles Combines TDMA with ELPI (Aerodynamic diameter measurement) to determine effective densities Agglomerates coated with Di-octyl-sebacate (DOS) oil Aerosol conditioner is a Thermodenuder Mobility constant between (a) and (b), change only in the effective density and mass (c) mobility diameter also increased Ristimäki, J., Keskinen J.. Mass Measurement of Non-Spherical Particles: TDMA-ELPI Setup and Performance Tests, Aerosol Science and Technology, 40: (2006) 36

36 Tandem DMA for VOC Thermal treatment to evaporate VOCs Heat to evaporate Volatile Organics Saleh, R., Shihadeh, A., Khlystov, A., Determination of evaporation coefficients of semivolatile organic aerosols using an integrated volume tandem differential mobility analysis (IV-TDMA) method, Journal of Aerosol Science 40 (2009)

37 Tandem DMA and Tandem SMPS Thermal treatment to evaporate VOCs Combines Integrated Volume (IV) measurement (this slide) with TDMA (previous slide) Determines Evaporation Coefficients (α) and Surface Free Energies (σ) IV method uses polydisperse aerosol SMPS upstream Thermodenuder SMPS downstream Saleh, R., Shihadeh, A., Khlystov, A., Determination of evaporation coefficients of semi-volatile organic aerosols using an integrated volume tandem differential mobility analysis (IV-TDMA) method, Journal of Aerosol Science 40 (2009)

38 Summary Haze is caused by airborne particles When particles grow they scatter more light and cause changes in visibility Changes in size are primarily caused by temperature changes and interactions with gases such as water vapor TDMA (Tandem Differential Mobility Analysis) is a powerful tool to study these changes Variations on the TDMA approach are widely used in this type of research 39

39 References B.Y.H. Liu, D.Y.H. Pui, K.T. Whitby, D.B. Kittelson, Y. Kousaka, R.L. McKenzie, The aerosol mobility chromatograph: A new detector for sulfuric acid aerosols, Atmospheric Environment (1967), Volume 12, Issues 1-3, Proceedings of the International Symposium, 1978, Pages Yue, Z. W. and Fraser, M. P.(2004), Characterization of Nonpolar Organic Fine Particulate Matter in Houston, TexasSpecial Issue of Aerosol Science and Technology on Findings from the Fine Particulate Matter Supersites Program, Aerosol Science and Technology, 38: , Chow, J. C.,Watson, J. G., Fujita, E. M., Lu, Z. Q., Lawson, D. R., and Ashbaugh, L. L. (1994). Temporal and Spatial Variations of PM2.5 and PM10 Aerosol in the Southern California Air Quality Study, Atmos. Environ. 28: Hegg, Dean A., Covert, David S., Jonsson, Haflidi and Covert, Paul A.(2007) 'An Instrument for Measuring Size-Resolved Aerosol Hygroscopicity at both Sub- and Super- Micron Sizes', Aerosol Science and Technology, 41: 9, Stolzenburg, Mark R. and McMurry, Peter H. (2008) 'Equations Governing Single and Tandem DMA Configurations and a New Lognormal Approximation to the Transfer Function', Aerosol Science and Technology, 42:6, M. Gysel, G.B. McFiggans, H. Coe, Inversion of tandem differential mobility analyser (TDMA) measurements, Journal of Aerosol Science, Volume 40, Issue 2, February 2009, Pages Rader, D. J. and McMurry, P. H. (1986), Application of the tandem differential mobility analyzer to studies of droplet growth or evaporation. J. Aerosol Sci. 17,

40 References - continued Dick, William D., Ziemann, Paul J. and McMurry, Peter H.(2007) 'Multiangle Light- Scattering Measurements of Refractive Index of Submicron Atmospheric Particles', Aerosol Science and Technology, 41: 5, McMurry, P. H. and Stolzenburg, M. R. (1989). On The Sensitivity of Particle Size to Relative Humidity for Los Angeles Aerosols, Atmos. Environ. 23(2): Hämeri, K., Väkevä, M., Hansson, H.-C., and Laaksonen, A. (2000). Hygroscopic Growth of Ultrafine Ammonium Sulphate Aerosol Measured Using an Ultrafine Tandem Mobility Analyzer, J. Geophys. Res. 105: Snyder, David C., Rutter, Andrew P., Collins, Ryan, Worley, Chris and Schauer, James J.(2009) 'Insights into the Origin of Water Soluble Organic Carbon in Atmospheric Fine Particulate Matter', Aerosol Science and Technology, 43: 11, Russell, L. M. and Ming, Y. (2002). Deliquescence of Small Particles, J. Chem. Phys. 116: Krämer, L., Ulrich Pöschl, U., Niessner, R., Microstructural Rearrangement of Sodium Chloride Condensation Aerosol Particles on Interaction with Water Vapor, J. Aerosol Sci. Vol. 31, No. 6, pp , 2000 Biskos, G., Malinowski, A., Russell, L. M., Buseck, P. R. and Martin, S. T.(2006) 'Nanosize Effect on the Deliquescence and the Efflorescence of Sodium Chloride Particles', Aerosol Science and Technology, 40: 2,

41 References - continued Mikhailov, E., Vlasenko, S., Niessner, R. and Pöschl, U., Interaction of aerosol particles composed of protein and salts with water vapor: hygroscopic growth and microstructural rearrangement, Atmos. Chem. Phys., 4, , 2004 Park, K., Kim J.S., Miller, A., A study on effects of size and structure on hygroscopicity of nanoparticles using a tandem differential mobility analyzer and TEM, J Nanopart Res (2009) 11: Hu, D., Qiao, L., Chen, J., Ye, X., Yang, X., Cheng, T., Fang, W., Hygroscopicity of Inorganic Aerosols: Size and Relative Humidity Effects on the Growth Factor Aerosol and Air Quality Research, 10: , 2010 Johnson, G.R., Ristovski, Z., Morawska, L., Method for measuring the hygroscopic behaviour of lower volatility fractions in an internally mixed aerosol, Aerosol Science 35 (2004) Ristimäki, J., Keskinen J.. Mass Measurement of Non-Spherical Particles: TDMA-ELPI Setup and Performance Tests, Aerosol Science and Technology, 40: (2006) Saleh, R., Shihadeh, A., Khlystov, A., Determination of evaporation coefficients of semi-volatile organic aerosols using an integrated volume tandem differential mobility analysis (IV-TDMA) method, Journal of Aerosol Science 40 (2009)

42 Thank You For Your Attention Any Questions? 2011, TSI Incorporated Tim Johnson 43

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