A Lagrangian Long-Range Transport Model with Atmospheric Boundary Layer Chemistry

Abstract

The present paper reports on the combination of a chemical model for the gas phase chemistry of the atmospheric boundary layer, with a Lagrangian model for the long-range transport of air pollutants. The resulting combined chemistry/transport model is applied in a case study where polluted air is transported toward Scandinavia. Calculations show good agreement with measured ozone concentrations, and strongly suggest that the measured ozone concentrations cannot be due to Scandinavian precursor emissions alone. In order to carry out the case study, the emissions of NOx and hydrocarbons were estimated for the different European countries. Such estimates will necessarily be uncertain. However, the degree of consistency obtained between calculations and measurements indicate that the estimated emissions by and large reflect reality. Various tests were carried out to investigate the sensitivity of the predicted ozone concentrations with respect to parameters such as advection wind, deposition velocity of ozone, and initial concentrations and emissions. The tests show that the emissions and the deposition velocity are the most important parameters that determine the ozone concentration.