HR: 1330h
AN: A32A-0112    [PDF]
TI: Aqueous Reaction of Methanol and Nitric Acid: Formation of Methyl Nitrate via Aerosol Chemistry
AU: * Iraci, L T
EM: liraci@mail.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035 United States
AU: Stephenson, R M
EM: rstephenson_47@hotmail.com
AF: Bay Area Environmental Research Institute, 560 Third St. West, Sonoma, CA 95476 United States
AB: Biogenic emissions of methanol are estimated to provide more than 75% of the global sources of this oxygenated VOC, and oceanic (possibly biological) contributions have also been postulated. Methanol has an atmospheric lifetime on the order of 10 days, allowing it to reach the upper troposphere. It is soluble in water and acidic solutions, which make up the majority of particles in this region. Thus, the chemical behavior of methanol in aerosol particles and cloud droplets warrants consideration. As a first step in our laboratory investigation of the atmospheric multiphase chemistry of methanol, we will present spectroscopic evidence for reaction between methanol and nitric acid in aqueous sulfate solutions. Under acidic conditions, methyl nitrate is released, suggesting that some fraction of NOx may be liberated from nitric acid before it is removed from the atmosphere by wet deposition. Preliminary temperature-dependent studies suggest a significant reduction in rate as the temperature is reduced from 20\deg C to 10\deg C. Data for solutions of varying composition will be presented to allow evaluation of this reactive pathway over a variety of tropospheric conditions. Implications for methyl nitrate formation and HNO$_{3}$-to-NOx recycling will also be discussed.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0315 Biosphere/atmosphere interactions
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting