Verification of a mathematical model for aerosol nitrate and nitric acid formation and its use for control measure evaluation

Abstract

A mathematical model for the formation of atmospheric nitric acid and aerosol nitrate has been developed and employed to study the effect of emission controls.Based on a Lagrangian formulation of the atmospheric diffusion equation. the model computes nitric acid concentrations from a description of daytime photochemical reactions and nighttime reactions involving N0 3 and N 2 o 5 • Ammonium nitrate formation is computed at thermodynamic equilibrium between HN0 3 and NH 3• and heterogeneous reactions between HN0 3 and preexisting aerosol are considered. The accuracy of the air quality model's predictions is verified by comparison to o 3• N0 2 • HN0 3• NH~.

Source‐oriented model for air pollutant effects on visibility

“…The model has been assembled by embedding several aerosol process modules within the photochemical trajectory model previously developed for aerosol nitrate concentration predictions by Russell et al [1983] and Russell and Cass [1986]. These modules describe the size distribution and chemical composition of primary particle emissions, the speciation of organic vapor emissions, atmospheric chemical reactions, transport of condensible material between the gas and the particle phases, fog chemistry, dry deposition, and atmospheric light scattering and light absorption.…”

“…First, many components of the model have been tested separately. These include the underlying trajectory model and the ammonia emissions inventory [Russell and Cass, 1986], the aerosol thermodynamics module [Wexler and Seinfeld, 1991], improvements to the gas phase organics inventory [Harley et al, 1992], and the ability to model ozone, The meteorological data necessary to exercise the trajectory model for the August 27-28 SCAQS period were assembled by Harley et al [1993a], as part of an earlier study of photochemical smog formation. The input data required include hourly temperature, humidity, surface winds, mixing depths, total solar radiation, and ultraviolet radiation scaling factor fields.…”

Modeling the airborne particle complex as a source‐oriented external mixture

“…Mass emission rates and source locations for major gas-phase emission sources relevant to the Air Basin prepared by Gharib and Cass [1984], as summarized by Russell and Cass [1986], was used to represent NH3 emissions for the episode studied. Once the gas-phase mass emission rates of NO,, SO,, CO, VOCs and NH3 for each source were specified, speciation of the VOC emissions was calculated using the gas-phase emission model described in section 2.1.…”

Evaluation of the Effects of Emission Reductions on Secondary Particulate Matter in the South Coast Air Basin of California

“…5 ' 32 We applied the model for two receptor sites, Fontana and Rubidoux, both of which are located in the eastern part of the Basin; they are considered "model sites" for particulate matter control strategies evaluation. For each of the sites, 24 back-trajectories were constructed, one for each hour of August 31,1982.…”

“…Similar behavior has also been observed by other investigators. 32 Run 3 corresponds to a 64 percent decrease of reactive hydrocarbons (RHC) and a 50 percent decrease in oxides of sulfur (SO X ). Organics are predicted to decrease by about 55 percent and sulfates by 48 percent over the base case.…”