4. Dispersion in the Atmosphere

When a bioaerosol is introduced to the atmosphere, the concentration will decrease when the aerosol is transported and diluted by wind and turbulence. Other processes, like deposition and biological decay will also act to diminish the concentration. Many important aspects of this take place in the turbulent atmospheric boundary layer i.e. basically within the lowest km the atmosphere. After a brief review of the subdivision of the atmospheric into different layers, we demonstrate by using results from a relatively simple dispersion model for the boundary layer, how different processes affect the resulting concentration. Finally we discuss the implications of sparse and highly fluctuating observed data on the meteorological modeling process. We discuss phenomenological and behavioral models, and we classify errors into model error, input data error and numerical error. We discuss the payoff between the explanatory power and the difficulties of estimating parameters for a detailed model.