METHODOLOGY FOR PREDICTING VEHICLE EMISSIONS ON MOTORWAYS AND THEIR IMPACT ON AIR-QUALITY IN THE NETHERLANDS

In 1989 the Road and Hydraulic Engineering Division of the Dutch Ministry of Transport and Public Works undertook to develop a system for predicting the concentration of air pollutants emitted by road vehicles travelling on motorways and for assessing the impact alternative routes have on air quality. The first stage of the development programme has recently been completed and has resulted in a methodology being devised that allows users to determine the average annual emission levels and concentrations of carbon monoxide, nitrogen oxides, total hydrocarbons, sulphur dioxide, aerosols, benzene, benzo[a]pyrene and lead. This system is now available in the form of a handbook, and development work is continuing on a software version. The calculation method used in the handbook version of the model assumes .hat a given stretch of road can be divided into individual sections, along which key traffic parameters, environmental factors and the condition of the road do not change significantly. Use of this version of the model allows calculations to be made of vehicle emissions and pollutant concentrations as a function of distance from the road under various weather and environmental conditions, as well as exposure levels at peripheral structures. Analyses can be performed both for individual road sections and complete stretches of motorway. The model also enables assessments to be made of the relative merits of a range of alternative routes.