Jensen, S.S., Becker, T., Ketzel, M., Løfstrøm, P., Olesen, H.R., Lorentz, H. (2010): OMLHighway within the framework of SELMAGIS. Final Report. National Environmental Research Institute, Aarhus University, Denmark, 26 p, NERI Technical Report No. 771.
In 2007 the first phase of the OML-Highway project was conducted by the National Environmental Research Institute (NERI) at Aarhus University to outline the overall specifications for a new user-friendly Danish highway air pollution model as a tool for environmental impact assessment and mapping of air quality along highways.
Within this report the implementation of OML-Highway into SELMAGIS is described and potential model applications are outlined.
Based on the results of Berkowicz et al. (2007), the Danish Road Directorate decided to develop the OML-Highway as a user-friendly Danish highway air pollution model coupled with a geographical information system (GIS). The challenge within the project was the implementation of a complex workflow of inputs to the OML-Highway model into a GIS program.
It was the intention to use the capabilities of GIS to create required inputs for a given road network and to use the possibilities of GIS for visualisation of model results.
With SELMAGIS the German company Ingenieurbüro Lohmeyer is offering a system for air pollution modelling and visualisation. The program has a unique user interface to work with different dispersion models and is based on ArcGIS™, where it is implemented as an extension.
In the OML-Highway GIS-extension an emission model and a dispersion model are implemented.
The emission module of the Operational Street Pollution Model (OSPM) is integrated into the OML-Highway. NERI has developed the OSPM model. The emission module is based on the COPERT 4 methodology.
The OML-Highway model is a local Gaussian air pollution model based on boundary layer scaling, which estimates dispersion from point sources and area sources. It has a meteorological pre-processor, which applies Monin-Obukhov similarity theory using synoptic, sonic and radio-sonde data to calculate the required turbulent parameters (Berger et al., 2010). The OML-Highway model may also be used with meteorological input data that alone are based on synoptic data and this feature has been implemented into the OML-Highway in SELMAGIS. The OML-Highway model is used to calculate the air pollution concentration at receptor point level.
The new Danish Highway Air Pollution Model has a number of potential application areas.
Environmental Impact Assessment – to improve information about air pollution as part of legal requirements to assess environmental impacts for new major highway constructions or alteration of existing highways.
EU Ambient Air Quality Limit Values – to be able to assess current or future air quality levels along highways in relation to European Union air quality limit values that have been implemented in Danish legislation.
Systematic Mapping of Air Quality and Human Exposure – to provide overview of the current and future state of air quality and human exposure along a large road network to identify hot spots and areas that merit further analysis and assessment of mitigating measures.
“What-If” Scenario Analysis – to predict future air quality levels under different scenario assumptions e.g. construction of noise barriers, changed traffic volumes and emission factors.
Ranking of Road Investments based on Cost-benefit Analysis – a potential spin-off in a long-term perspective is to provide inputs to cost-benefit analysis of road investments although it is not within the scope of the proposed new highway model at present. The OML-Highway model could be extended to include external costs of air pollution.
Full report in PDF-format (1,94 MB).
