Dan G. Imre
Atmospheric Sciences Division
Environmental Sciences Department
Brookhaven National Laboratory
P.O. Box 5000, Building 815E
Upton, NY 11973-5000
631-344-4493
fax 631-344-2887
imre@bnl.gov

In this program we focus on the comprehensive thermodynamic, optical, and kinetic characterization of aerosols in three-dimensions: composition, temperature, and size. The single levitated particle program at BNL has long been a leading source of thermodynamic and optical data on atmospheric aerosol systems. We have expanded our aerosol research within the past few years, especially along the composition and temperature coordinates, by developing new tools that make possible studies of particles with realistic and complex composition over the entire atmospherically relevant temperature range. We have applied this system to a variety of internally mixed aerosols composed of deliquescent salts, organic compounds, and insoluble inclusions and used the low temperature system to derive equilibrium and metastability phase diagrams. We are now in position to take full advantage of the technical and scientific resources we have developed in order to generate a comprehensive thermodynamic and optical database. In order to make a contribution along the particle size coordinate we have developed a novel system that enables us to investigate the size dependence, of deliquescence, efflorescence and water activity in 3nm-50nm particles. The information derived from these studies, including valuable surface tension data needed by nucleation models, will greatly reduce uncertainties in the modeling and prediction of atmospheric particle formation.

In addition we have recently developed, constructed and deployed Single Particle Laser Ablation Time-of-Flight Mass Spectrometer. This instrument is capable of measuring in real-time the size and composition of individual particles in the range from 50 nm to 3.5 micrometer in diameter at a rate of 20 particles per second. Since its completion in May 2000, the instrument has participated in three atmospheric field programs: Texas 2000 Air Quality Study, Houston, TX, August - September 2000; ACE-Asia, Cheju Island, Korea, April 2001; and PM 2.5 Technology Assessment and Characterization Study (PMTACS), New York City, July 2001.

Some further information can be found in the viewgraphs from previously given presentations and the viewgraphs from a presentation at the Atmospheric Sciences Program Annual Meeting held in March 2002.