title: The Use of Ambient Measurements To Identify which Precursor Species Limit Aerosol Nitrate Formation.
abstract: A thermodynamic equilibrium model was used to investigate the response of aerosol NO3to changes in concentrations of HNO3, NH3, and H2SO4. Over a range of temperatures and relative humidities (RHs), two parameters provided sufficient information for indicating the qualitative response of aerosol NO3. The first was the excess of aerosol NH4+plus gas-phase NH3over the sum of HNO3, particulate NO3, and particulate SO42-concentrations. The second was the ratio of particulate to total NO3concentrations. Computation of these quantities from ambient measurements provides a means to rapidly analyze large numbers of samples and identify cases in which inorganic aerosol NO3formation is limited by the availability of NH3. Example calculations are presented using data from three field studies. The predictions of the indicator variables and the equilibrium model are compared.
authors.affiliation: a Envair , Albany , California , USA.
authors.forename: Charles L
authors.initials: CL
authors.lastname: Blanchard
authors.affiliation: a Envair , Albany , California , USA.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Roth
authors.affiliation: a Envair , Albany , California , USA.
authors.forename: Shelley J
authors.initials: SJ
authors.lastname: Tanenbaum
authors.affiliation: b Chevron Research and Technology Company , Richmond , California , USA.
authors.forename: Steve D
authors.initials: SD
authors.lastname: Ziman
authors.affiliation: c Division of Engineering and Applied Science , California Institute of Technology , Pasadena , California , USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Seinfeld