1 Extinction Spectroscopy for Characterization of Particulate Matter Size and Concentration in Fugitive Plumes Dr. Ram Hashmonay ARCADIS 4915 Prospectus Dr., Suite F Durham, NC 27713

2 Method Description n OP-FTIR is an accepted method for gas measurements n Particulate matter (PM) presence reveals a unique baseline structure (see below)

3 Method Description (cont.) n Baseline structure can be predicted for a given size distribution and optical constants using Mie theory n We developed an inversion algorithm to retrieve the aerosol size distribution from extinction (scattering+absorption) measurements n Optical properties (constants) of specific PM may be determined using a bench-top FTIR spectrometer

4 Mie Theory Size Parameter  d - particle diameter - wavelength

5 Mie Theory (cont.) Complex Refractive Index n – scattering term (refraction and reflection) k – absorption term m( ) = n( )-ik( )

6 Mie Theory (cont.) Extinction Efficiency:   Extinction efficiency of water in different part of the FTIR spectrum

7    e i - extinction for the i th wavelength   Q e ij - dimensionless extinction efficiencies   N j - number density for the j th aerosol size   d j - is the aerosol j th size class (diameter) Extinction as Function of Wavelength

8 Shower Experiment   OP-FTIR beam through water condensation aerosol   Size distribution confirmed by aerosol probe   Known optical constants (see below)

9 Shower Experiment Results

10 Predicted Smoke Extinction Spectrum

11 Smoke PM Extinction

12 Water Condensation Aerosol

 m Mean Size; 2  m SD Gaussian Fit

14 Sahara Dust Optical Constant

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16 Louisville Landfill Set-Up Landfill Dirt Road OP-FTIR Beam

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22 Diesel PM

23 Predicted Diesel Spectrum

24 Diesel Extinction Spectrum 9  m 3.9  m 2.3  m

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29 Path-Integrated Lidar

30 Enhanced Range Lidar

31 Conclusions n n The first open-path optical technique to obtain real-time fugitive dust measurement and sizing n n Measurement of liquid aerosol like water or pesticide drift n n OP-FTIR can be used in field to gather multiple gases and PM emission data simultaneously n n Extending the spectral range to the UV/VIS range will allow sizing of submicron PM