On the Linking of Aerosol and Gas-Phase Chemistry Modules for the Prediction of Ammonium Nitrate Particle Formation

Saturday, March 18, 2000 - 9:20am - 9:35am
Keller 3-180
William Stockwell (Jacob Blaustein Institute for Desert Research)
The coupling of gas and aerosol chemistry in air quality models and the relationship between the emissions of nitrogen oxides and organic compounds, gas-phase chemistry and the formation of aerosol particles will be discussed. A photochemical box model with gas-phase photochemistry, aerosol production and deposition was developed and applied to estimate the ammonium nitrate particle equivalent of NOx emissions. Yields of ammonium nitrate particles produced from gas-phase chemistry were estimated from parametric simulations made with an equilibrium aerosol model. For winter time in central California approximately 80% of the moles of nitric acid produced in the gas-phase was estimated to react with ammonia to yield particulate nitrate. The total fraction of NOx emissions converted to particulate nitrate was estimated to be 33% on a molar basis. This result is in reasonable agreement with field measurements made in central California.