Lag baomer after AMS measuremetns 2009
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Lag baomer after AMS measuremetns 2009

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Israeli holiday where you burn shit. And it shows!

Israeli holiday where you burn shit. And it shows!

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  • Aerosols were measured during the intense fires of the lag baomer holiday in Israel and the following week, using an Aerodyne high resolution aerosol-mass-spectrometer (AMS) which allows to look at the specific mass composition of the air born aerosols during the intense fire events. The AMS sucks 85 cc/min of air into an aerodynamic lens, concentrating the aerosols into a tight (less then 1 mm) beam and then uses a two stages ionization process to make the measurement quantitative. The first stage included a tungsten oven which flash vaporizes the aerosol beam hitting it, and then the resulting vapor is ionized by electrons emitted from a filament. The measurements will be presented, compared to other in-situ measurements taken with other aerosol samplers, and discussed.
  • This is the location of the measurement tubing inlet. A aluminum foil covered funnel on the top of the Zusman building , connected with conductive tubing all the way into the building into several aerosol measuring instruments
  • A class of detecting schemes that has recently made aliya is the AMS. It's purpose is to quantify the chemical species making up the ambient aerosol population of equivalent diameters between 50-1000 nm. It is also used in a innovative lab experiment that aims to quantify the mass transfer properties of various aerosols through coating and denuding experiments assessed with the AMS. The AMS has 3 stages: 1. focusing the aerosol beam and pumping out most of the gas phase 2. measuring aerosol size. 3. flash vaporizing and ionaizing the NR species, and detecting them by TOF MS.
  • A class of detecting schemes that has recently made aliya is the AMS. It's purpose is to quantify the chemical species making up the ambient aerosol population of equivalent diameters between 50-1000 nm. It is also used in a innovative lab experiment that aims to quantify the mass transfer properties of various aerosols through coating and denuding experiments assessed with the AMS. The AMS has 3 stages: 1. focusing the aerosol beam and pumping out most of the gas phase 2. measuring aerosol size. 3. flash vaporizing and ionaizing the NR species, and detecting them by TOF MS.
  • focusing the aerosols in the air (or any gas stream) is done with a set of orfices dubbed “aerodynamic lens”. this scheme works well for certain sizes of aerosols, which is a result of the different inertia to drag ratio on one side, and brownian motion on the other side.
  • focusing the aerosols in the air (or any gas stream) is done with a set of orfices dubbed “aerodynamic lens”. this scheme works well for certain sizes of aerosols, which is a result of the different inertia to drag ratio on one side, and brownian motion on the other side.
  • sizing the aerosols is done in the final expansion stage. the settling velocity of the particle is related to it's diameter, and therefore measuring the time of flight (ms) can give what is called vacuum aerodynamic diameter. the result of this measurement is an aerodynamic vacuum size distribution of all ambient aerosols. Another popular sizing technique, used in lagBaomer measurements as well, is done with the DMA – dynamic mobility analyzer. the aerosols are usually charged. By inserting them into a tube with a uniform electric field, they quickly settle into a steady velocity, related to the drag and electrostatic force balance. scanning the voltages can give a size distribution
  • the final stage is the detection. In order for the ionization process to be reproducible, the vaporization and ionization are done in two separate stages. Flash vaporization is done with a tungsten oven at ~600 C. ionization is done by EI, with 70 eV electrons emitted from a filament. In other real time mass spectrometers the ionization is done in one step with UV lasers, which measures also refractory species, but not in a quantifiable way.
  • To appreciate the quantification capabilities of the AMS, shown is a comparison between 2 other near real time techniques , and the AMS. the AMS mass loading was multiplied by a single collection efficiency correction of 2.41 (typically ~2) to account for reproducible collection losses due to the aerodynamic lens cut off, and bounce effect on the vaporizer
  • Aerosols are defined as any liquid or solid particle smaller then 10 micro-meter. Aerosols have resident times of hours to days, and therefor affect local and global atmospheric radiation fluxes, and human health.

Lag baomer after AMS measuremetns 2009 Lag baomer after AMS measuremetns 2009 Presentation Transcript

  • Lag Baomer holiday aerosol measurements inWeizmann Institute with the Aerodyne Aerosol Mass Spectrometer Hanan Einav Levy
  • High resolution time of flight aerosol mass spectrometer HR-TOF-AMS
  • High resolution time of flight aerosol mass spectrometer HR-TOF-AMSAnimation of the Aerodyne Q-AMS. Credit: Matt Thyson (Lexington, Massachusetts)
  • High resolution time of flight aerosol mass spectrometer HR-TOF-AMS
  • Real time aerosol mass spectrometry Inlet design Zhang et al. 2004
  • Real time aerosol mass spectrometry Inlet design Zhang et al. 2004
  • Sizing Aerosols DeCarlo et al. 2004
  • Real time aerosol mass spectrometry quantification = separation of evaporation and ionization Canagaratna et al. 2007
  • Converting mass spectrum into UMR raw spectrum --> sticks
  • Converting mass spectrum into UMR
  • Effectiveness of AMS detection approach
  • Lag Baomer campaign WIS : AMS, SMPS, Grimm, Wellas, APS EPA: PM10
  • Lag Baomer measurements PM10 measurements from the Israeli EPA
  • Lag Baomer measurements PM10 measurements from the Israeli EPA
  • Size distributions time series AMS SMPS
  • OOA – CO2average ensemble MS HOA - C4H9
  • NR aerosol composition
  • Size resolved MS
  • Israel, Rehovot
  • what else can you measure? floorpaint evaporation (when is it safe to come back to work)
  • Acknowledgements Prof. Yinon Rudich, Prof. Jacob Karni, Dor Gefen, Enrico Segre, Michel Flores, Miri Trinic, Ali abu rizaq
  • Aerosolsaerosol particles collected on filters , scanned with a SEM source: University of Sao Paulo, Brazil