SELMA - Version PROKAS - Calculation of Traffic Induced Air Pollution
PROKAS consists of the modules PROKAS_V and PROKAS_B. PROKAS_V is used for the calculation of the traffic induced background concentration by road nets and the calculation of the additional street concentration in terrain without major buildings. PROKAS can handle an arbitrary number of road segments. PROKAS uses a Gaussian dispersion model according to the VDI guideline 3783/1 'Dispersion modelling for air quality management' with special modifications to account for vehicle traffic.
- For the determination of the additional street concentration in densely built up terrain (partly or completely closed front of buildings, street canyons) the supplementary modulel PROKAS_B is available. PROKAS_B bases on the result of dispersion calculations with the microscale flow - and dispersion model MISKAM for typified building structures.
- On the basis of a local dispersion statistics PROKAS_V and PROKAS_B calculate the statistical parameters of the air pollutant time series (annual mean and 98%) in a way, suitable for comparison with the limit values of the EU Air Quality Directives.
- Import interface is available for MOBILEV, for ARCINFO, IMMI and VISUM under preparation.
- PROKAS_V and PROKAS_B are capable to run on a PC with WINDOWS 2000, XP and 7.
In case of a partially or totally closed (street canyon) front of buidlings adjacent to the road the background concentration is calculated by PROKAS_V. For the calculation of the additional street concentration the supplementary module PROKAS_B is available. PROKAS_B bases on the result of dispersion calculations with the microscale flow - and dispersion model MISKAM for typified building structures. It calculates for example the annual mean and the 98-percentile of the traffic induced air pollutant concentrations in a height of 1.5 m and in 1 m distance to the nearest building. The superposition of the background concentration by the surrounding net of roads and the additional street concentration is done time correlated, it is not done via a parametrization.
The typified building scheme differenciates between street canyon as adjacent buildings on one or both sides of the road with different ratios of (height of the buildings)/(width of the canyon) and different ratios of (gaps between the buildings)/(length of the road section).
The dimensionsless concentrations c* were taken from wind tunnel measurements with idealized building structures and calculations with the numerical model MISKAM. Validations were executed using the results of field measurements in Hannover, Karlsruhe and Dresden. The correlation between the calculated and the monitored concentrations is satisfying.
- PROKAS_E calculates traffic induced emissions of relevant pollutant substances for complext road networks considering emission factor tables.
- The emission factor tables ar defined an the basis of the 'Handbuch für Emissionsfaktoren des Straßenverkehrs' (HBEFA 3.1, INFRAS (2010).