Comparison of calculated and observed super- and sub-micrometer aerosol mass concentrations using St. Louis RAPS data base

A K-theory urban dispersion model has been used with the St. Louis RAPS data base to calculate super- and sub-micrometer aerosol mass concentrations. The model calculations showed relatively good agreement in phase and magnitude with dichotomous sampler data for the time period studied. The calculated sub-micrometer aerosol mass concentrations gave a much better correlation with observed values of optical extinction than did the observational values from the RAPS dichotomous sampler network. It is found that even on the urban scale, the dry deposition velocity is an important parameter for modelling both the sub- and super-micrometer aerosol mass concentrations.