Variable trajectory model for regional assessments of air pollution from sulfur compounds.

Abstract

This report describes a sulfur oxides atmospheric pollution model that calculates trajectories using single-layer historical wind data as well as chemical transformation and deposition following discrete contaminant air masses. Vertical diffusion under constraints is calculated, but all horizontal dispersion is a function of trajectory variation. The ground-level air concentrations and deposition are calculated in a rectangular area comprising the northeastern United States and southeastern Canada. Calculations for a 29-day assessment period in April 1974 are presented along with a limited verification. Results for the studies were calculated using a source inventory comprising 61% of the anthropogenic S02 emissions. Using current model parameterization levels, predicted concentration values are most sensitive to variations in dry deposition of S02' wet deposition of sulfate, and transformation of S02 to sulfate. Replacing the variable mixed-layer depth and variable stability features of the model with constant definitions of each results in increased ground-level concentration predictions for S02 and particularly for sulfate.

Acid rain—an overview of the problem

“…Simulation of long-range transport and deposition with mathematical models can be a useful tool in analyzing the acid rain problem. The Battelle Pacific Northwest Laboratories PNL [46], Argonne National Laboratory ASTRAP [47,48], and the SRI International EURMAP-1 [49,50] regional air pollution models have been applied to areas encompassing the northeastern United States and eastern Canada. All three models use objectively generated, regional-scale wind fields based on interpolation of available upper-air data to simulate transport and diffusion of atmospheric emissions.…”

Health and environmental effects document for direct coal liquefaction - 1981.

“…The PNL Long-Range Transport (LTR) model is a regional-scale transport, tran sfor~ilati on and removal model developed by ~Jendell et al (1975) and adapted by for generation of air quality control region (AQCR) interregional transport matrices. Sensitivity and verification studies with the LRT model have been conducted by Powell et al (1979) and D. J. t4cNaughton (1980) for sulfur dioxide and sulfate air concentrations and depositions in the northeastern United States.…”

Pacific Northwest Laboratory annual report for 1978 to the DOE Assistant Secretary for Environment. Part 3. Atmospheric sciences

“…Wet deposition of S02 is a linear function of S02 mass and precipitation rate (Powell et al 1978). Wet deposition of sulfate is modeled after description by of a bergeron-type storm.…”

“…For each sampling interval, ~ts' contributions are calculated from each puff to the sampling grid square the puff is over. Contributions are calculated for ground-level air concentrations and for deposition of S02' sulfate and rainfall pH (Powell et al 1978). The area of the sampling grid square is used mathematically to simulate horizontal diffusion.…”

“…Past comparisons of MAP3S models and observed data (Powell et al 1978) have made use of long-term sulfate concentrations data available from the design phase of the SURE program (Hidy 1975). More refined data that are now available require modifications in the models to allow calculation of both long-and short-term concentrations.…”