Steven G. Buckley, Ph.D. - US grants

Recent and pending Federal air pollution regulations for particulate matter (PM) require the development of continuous emissions monitors to measure the size and composition of airborne particles. Laser-induced breakdown spectroscopy (LIBS) is a promising method for real-time measurement of joint size and composition of primarily inorganic airborne aerosol particles in the size range 100 nm - 10 nm. These nanoparticles have been shown to be linked to a series of significant health effects, including decreased lung function, increased incidence of asthma, alterations in lung tissue and structure, increased hospital admissions, and premature death. In LIBS, a high-energy pulsed laser is utilized to create a spark, or breakdown, in the sample media. Recent field trials of this technique on incinerators and thermal treatment units show that LIBS measurements follow trends of emissions well and can capture transient events that are not observed by extractive, integrating type samplers. Due to the possibility of joint particle composition and sizing, LIBS also is attractive forsource apportionment, that is, determination of the source of particular particles in an airshed by compositional fingerprinting.

The primary objectives of the proposal are:
1) to understand the joint influences of the particle matrix, of the gas matrix, and of plasma size and temperature on the LIBS measurement,
2) to determine the upper and lower size limits for particle measurements using LIBS, and the variation in optimal laser power, optimum spark size and temperature, and optimum detector gate delay and width for various particle sizes,
3) to model the particle / plasma interaction for typical particle compositions, as enabled by the previous two objectives,
4) to perform real-time, accurate, full-spectrum LIBS measurements of ambient aerosol, as enabled by the previous three objectives.

The career development plan includes a strong educational component involving both high school students, high school teachers, and college students. It is suggested that some of the attrition among promising young science students is due to a perceived lack of connection between current scientific problems and the basic science classes that dominate high school / early college years. The proposed educational plan involves the creation of interactive, web-based teaching tools that use illustrations from familiar atmospheric phenomena such as photochemical smog, the ozone hole, acid rain, and migration of airborne aerosol particles to teach basic science concepts linked to real problems. Undergraduate engineering and science students from the University of Maryland with an interest in teaching would be recruited to assist AP Chemistry and AP Environmental Science teachers from local high schools in curriculum development and computer/web programming to develop interactive learning modules for the AP classes. It is hoped that these efforts promote promising high school students to remain motivated to study science, while some college students with a teaching aptitude may have a rewarding experience that stimulates interest in science education. We plan to tie the education plan with the research plan by bringing the LIBS unit to schools to make ambient aerosol measurements as part of an aerosol curriculum module in the 4th and 5th years of the project.

0403829 Buckley The objective of this research is the development of a novel aerosol spectrometer that is able to quantitatively measure both size and composition of suspended aerosol particles. Size selection will be performed by a combination of fluidic separation and electronic mobility; particles will be charged and separated in a flowing stream using a variable electric field designed for point spectroscopy measurements. Composition determination will be accomplished with two-tone ultraviolet (UV) micro Laser-Induced Breakdown Spectroscopy (u-LIBS). The u-LIBS diagnostic head will selectively sample spatially size-segregated aerosol. Light will be dispersed into a new echelle spectrometer with a CCD camera, an optional relay lens intensifier and a high framing rate. Submicron particles are important in many areas of science, from the development of new materials with unusual properties, to pharmaceutical applications, to environmentally important suspended aerosol particles that are implicated in human morbidity and mortality. Real-time methods that can provide both size and composition information are urgently needed in all of these areas, and the availability of these methods would represent an enabling technology that could catalyze further advances in our understanding of nanoscale particle science. The particular example of atmospheric and combustion aerosol source-apportionment outlined in the technical proposal highlights one of the areas in which the proposed aerosol spectrometer could contribute to revolutionary fundamental advances.
There are three specific areas of innovation that are expected provide improved performance for this new spectrometer design. They are:
1) The combination of fluidic and electrostatic size classification of particles coupled for point spectroscopic measurement,
2) The use of UV u-LIBS to provide highly spatially-resolved (and thus size-resolved)
aerosol diagnostic with potentially improved detection limits over typical LIBS arrangements, and
3) The use of a sensitive, high frame-rate echelle spectrometer to provide elemental composition over a wide spectral range, allowing nearly total composition determination and identification of elemental associations in the aerosol population. As detailed in the proposal, both (2) and (3) and are particularly high-risk.
UV u-LIBS has never been attempted on aerosol particles, and it is not known if the expected benefits will accrue. In addition, the high frame-rate echelle spectrometer is a new product and its applicability and sensitivity for this problem has yet to be determined. Previous approaches to point sizing and composition of submicron aerosol particles have met with limited success, particularly for sizes below 300 nm. The approaches outlined in the proposal have strong justification and promise, but this is clearly exploratory research. Lower risk options are in place to ensure meaningful results from the project should the higher-risk technologies fail to perform as expected.
The proposed research would also have a substantial impact on the education and training of students in the interdisciplinary intersection of spectroscopy and nanoscale science. The resulting aerosol spectrometer would itself provide significant improvement in the instrumentation available for simultaneous particle composition and sizing analysis, which would open new avenues in both education and research. In particular, the proposed instrument could have an enormous impact on the identification and eventual mitigation of unhealthy atmospheric nanoparticles.

A three-year partnership of the UCSD Jacobs School of Engineering and the San Diego Supercomputer Center focuses on getting approximately 22,000 sixth- through ninth-grade students and 360 teachers involved in using information technology through gaming in order to solve complex problems related to STEM content. It provides summer experiences for girls through established area summer camps such as TechTreck and Sally Ride Science and in-service on the related content and activities for San Diego area teachers so the project can influence all the students of those teachers. A greater, but less intense impact on students is through encountering the game on the web. The game will be a problem-solving game bringing the students as avatars in contact with environmental problems they must solve. The solutions will require using virtual tools that have been used in the classroom and involve consulting with scientists.

Award Number: CBET - 0714409
Title: Support for 5th US Combustion Meeting
Principal Investigator: Buckley, Steven G.
Institution: University of California-San Diego

This award will provide partial support for the Fifth Joint Meeting of the US Sections of the Combustion Institute, renamed the "5th US Combustion Meeting," which will be hosted by the University of California San Diego at the Town and Country Hotel in San Diego, CA, from 25-28 March 2007. In 1999, the three United States sections of the international Combustion Institute - Eastern States, Central States, and Western States - initiated a biennial series of national meetings on combustion. These meetings have been highly successful, based on the attendance and the number of presentations. Consequently, this biennial event has gained a prominent stature and become the premier national conference in fundamental and applied combustion.

The NSF funds will be targeted to provide partial travel support to graduate students and young researchers who make podium or poster presentations. The information about the availability of travel support to graduate students will be provided in all the meeting announcements and on appropriate websites. In addition, an announcement about the availability of travel support will be mailed to members of the Combustion Institute.

This Small Business Innovation Research Phase I project aims to enhance and fuse the best of several technologies to achieve a highly sensitive and flexible measurement system for both size and composition of particulate matter (PM). If successful, this research will establish the feasibility of a device that will sample aerosol particles at ambient pressure, size particles using light scattering, and measure particles using a laser-initiated plasma. The envisioned system will overcome the problems with variability and uncertainty associated with aerosol measurements by Laser Induced Breakdown Spectroscopy (LIBS). The goal is to provide highly accurate measurements of both coarse and fine PM as a continuous emission monitor (CEM) for stack and/or ambient monitoring. The longer term commercial goal is a rugged, low maintenance device with a significant cost reduction over currently available real-time systems.

The broader/commercial impact of this project, if successful, is the availability of a tool that will address an immediate need to continuously monitor metal emissions from municipal solid waste and hazardous waste combustion facilities, while quantifying speciated coarse and fine PM, important for future EPA regulations. Such a tool will enable research in support of EPA regulations for more stringent emission control. Furthermore, the tool can also be a CEM used for enforcement as well as process control in hazardous waste treatment, power generation, and other industrial applications.