Long-Term Average Air Pollution over Cities: Operative Calculation Technique for Elevated Sources

Long-term average field of pollutant concentrations in the atmospheric surface layer is one of the criteria of air quality in different urban districts as well as a basis for accepting adequate city layout decisions. An applied technique for calculating such a field formed by urban multiple elevated point source emissions is proposed. Superposition principle for single source average fields is used. The technique takes into account a seasonal joint frequency for wind velocity, wind direction, thermal stratification and precipitation gradations, seasonal changes in emission rates, plume rise depending on seasonal emission characteristics and meteorological gradations, dry deposition of different spesies and washout. An original method of the stratification parameter calculation based on routine meteorological data is proposed. The whole algorithm is implemented as a set of FORTRAN routines.