ARB Research Seminar

This page updated June 19, 2013

Advanced Method for Measurement of the Solid Carbonaceous (Soot) Component of Mobile Source Particulate Matter

William D. Bachalo, Ph.D., President, Artium Technologies, Inc., Sunnyvale, California

April 01, 2010
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


This presentation will provide an overview of the laser induced incandescence (LII) instrument and demonstrate its suitability for measuring fine particulates (soot) associated with emissions from combustion systems including diesel, gas turbine (jet engines) and direct injected gasoline engines. In the LII method, soot particles are rapidly heated to high temperatures by a laser and the resulting incandescence signal is measured and analyzed to estimate the soot primary particle size and the soot volume fraction. The LII method has an exceptionally high dynamic range of over one million to one. The measurements are made in real time with high sensitivity and resolution and the instrument requires minimal maintenance. However, the biggest advantage of the method is that it can measure soot directly in exhausts without requiring expensive dilution tunnels or other treatment.

Under the ICAT funded program, the measurement sensitivity of the LII was enhanced to allow ambient soot particulate concentration measurements. The LII technology was also further developed into a useful portable instrument that now provides immediate time-resolved measurements of particulate emissions for a broad range of applications including diesel and gas turbine engine development, evaluation of particulate control systems, and compliance verification to particulate emissions regulations. During this effort, a NIST traceable calibration method was developed and refined to improve the reliability and to better define the instrument response to soot. At the same time, optical systems were developed to produce a more compact instrument which was thoroughly tested for operational integrity under typical industrial environments. Software was developed that included algorithms to fully automate the instrument set up functions and to automatically track the soot concentrations over a range of one million to one. The earlier LII 200 version was evaluated and tested at our industrial partners sites. As a result of these tests, several improvements were defined and implemented. From these results, a next generation LII 300 instrument evolved which is much more compact, has greater sensitivity and is easier to operate.

Comparisons were made to gravimetric measurements, the current EPA standard method, to demonstrate that the LII instrument is able to produce results are in acceptable agreement with the established EPA method. Measurement comparisons made with gravimetric results at our industrial partners' sites and after several round of instrument testing and refinement, showed excellent agreement. Results of tests acquired at our industrial partner sites will be presented and reviewed. A brief description of the on-road measurement capability of the instrument will be presented.

Speaker Biography

William D. Bachalo, Ph.D., is President and CEO of Artium Technologies Inc., Sunnyvale, California. Dr. Bachalo was founder and president of Aerometrics Inc. (1981 to 1995) where he invented and led the development of the phase Doppler interferometry technique for measuring the size and velocity of spray droplets which is now the worldwide standard for this purpose. Dr. Bachalo worked as vice president in charge of scientific affairs at Islet Technology, Inc. (1996 to 2005) developing encapsulation and transplantation the islets of Langerhans in an effort to cure juvenile diabetes. Dr. Bachalo cofounded Artium Technologies in 1998 with the goal of developing the laser induced incandescence method into a commercially viable instrument for measuring particulate emissions from combustion systems. Dr. Bachalo is led development of next-generation phase Doppler interferometer instruments for measuring clouds related to meteorological and aircraft icing phenomena. Dr. Bachalo has received several international awards including the international Tanasawa Award twice for his work in atomization and sprays and instrumentation development. Dr. Bachalo has co-authored over 150 technical papers.

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