Award Abstract #0093853
CAREER: Investigation of Laser-Induced Breakdown Spectroscopy for Analysis of Airborne Particulate Matter

NSF Org:	CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems
Initial Amendment Date:	February 7, 2001
Latest Amendment Date:	July 11, 2003
Award Number:	0093853
Award Instrument:	Continuing grant
Program Manager:	Thomas D. Waite CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering
Start Date:	February 15, 2001
Expires:	October 31, 2003 (Estimated)
Awarded Amount to Date:	$234998
Investigator(s):	Steven Buckley buckley@ucsd.edu (Principal Investigator)
Sponsor:	University of Maryland College Park 3112 LEE BLDG COLLEGE PARK, MD 20742 301/405-6269
NSF Program(s):	ENVIRONMENTAL IMPLICATIONS
Field Application(s):	0118000 Pollution Control
Program Reference Code(s):	EGCH, 9197, 1359, 1187, 1045
Program Element Code(s):	1179

ABSTRACT

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.

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