Fred J. Brechtel
Atmospheric Sciences Division
Environmental Sciences Department
Brookhaven National Laboratory
P.O. Box 5000, Building 18E
Upton, NY 11973-5000
631-344-6198
fax 631-344-2887
fredb@bnl.gov

This program addresses the measurement of ambient particle size distributions over the 2.7-nm to 50-micrometer diameter size range and particle water uptake during Atmospheric Chemistry Program (ACP) field campaigns. A focus of this work is to improve understanding of the health and visibility impacts of tropospheric aerosols. This research is a continuation of our efforts to develop superior techniques for measuring ambient particle size distributions and thermodynamic properties. Combined with our other aerosol measurement capabilities, these instruments will support BNL’s involvement in the Atmospheric Chemistry Program and our future research efforts aimed at understanding the interactions between trace gas species and aerosol particles in the troposphere. A suite of aerosol instrumentation consisting of a modified ultrafine condensation particle counter, a scanning electrical mobility sizing system, and optical particle counters will be deployed during ACP-related field campaigns performed in New York City, Philadelphia, South Korea, and during other urban and regional-scale aerosol and oxidant studies. Improvements to our current measurement capabilities will allow size distribution measurements to be performed at ambient relative humidity and with enhanced time resolution. This program also addresses the development of new instrumentation for ground-based measurements of the water uptake properties of ambient particles as a function of particle size and relative humidity. A new Humidified Tandem Differential Mobility Analyzer (HTDMA) system will be developed capable of measuring water uptake by particles over the 20 to 1000-nm size range at various relative humidities. The results from simultaneous measurements of ambient trace gas and aerosol concentrations will be analyzed together with meteorological data to develop process level understanding of the observed changes in the particle size distribution.

Some further information can be found in the viewgraphs from a presentation at the Atmospheric Sciences Program Annual Meeting held in February 2001.