Modelling for the Estimation of Nitrogen Dioxide Concentration in the Atmosphere

Theoretical Investigation

Abstract

The transportation process of nitrogen dioxide in the atmosphere can not be simulated only by a general diffusion model, because of the chemical activity of nitrogen dioxide.
The great part of nitrogen oxides (NOx) emitted in the atmosphere is nitric oxide originally. Nitric oxide and ozone react mainly, to convert nitric oxide to nitrogen dioxide rapidly in the atmosphere.
In this study, a simple empirical formula to estimate nitrogen dioxide concentration was proposed, where nitrogen oxides, emission intensity, and background ozone concentration were used as independent variables. It is assumed that the background concentrations of nitric oxide, nitrogen dioxide, and ozone are uniform, and those are in chemical equilibrium in the atmosphere.
The procedure of model identification is as follows.(i) To get the numerical solution for several conditions of the diffusion equation which contains reaction terms.(ii) To identify several empirical formulas which hold to a good approximation for the numerical solution.(iii) To examine the characteristics of those formulas.