Paul Davidovits
Department of Chemistry
Boston College
Chestnut Hill, MA 02167
617-552-3617
Fax 617-552-2705
paul.davidovits@bc.edu

D. R. Worsnop, J. T. Jayne, and C. E. Kolb
Aerodyne Research, Inc.

A series of experiments is taking place to study heterogeneous processes related to tropospheric oxidants and organic aerosols. Studies focus on the heterogeneous chemistry of oxidants, including nitrogen oxides, with organic aerosols and the interactions of volatile organic compounds (VOCs) with organic surfaces. Heterogeneous interactions with organic liquids/surfaces that are appropriate surrogates for organic aerosol constituents are studied using the droplet and bubble train flow reactor apparatuses. Experiments are specially focused on understanding the nature of interactions at the gas-liquid interface. The studies are organized into five projects:

• Experiments are performed to elucidate the nature of organic aerosol surfaces using gas uptake as a probe.

• Trace gas uptake studies for H₂O₂, NO₂, NO₃, HONO, HNO₃, OH, O₃, HO₂ on model organic compounds are performed. Attention is given to processes that may convert NO₂ to HONO and reduce HNO₃ to NO, or NO₂. with particular focus on organics that might be representative of soot and soot surface materials.

• Gas uptake studies for selected VOCs on model organic compounds are performed. Mass accommodation coefficients are determined.

• Co-deposition studies of the VOCs with H₂O₂, NO₂, NO₃, HONO, OH, O₃, and HO₂ on model organic compounds are conducted. Special attention is given to interactions occurring at the gas-liquid interface related to tropospheric NO₂ (and hence OH) chemistry.

• Uptake coefficients of water molecules on model secondary organic aerosol compounds are measured to gain insight into the hygroscopic nature of organic aerosol surfaces.

More information on the research conducted by the principal investigator can be found at:

http://ch03.bc.edu/Department/Faculty/davidovits/davidovits.html

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