H15-79: A congestion sensitive approach to modelling road networks for air quality management

Air Quality monitoring by Durham County Council has indicated that significant areas of the City of Durham are failing the national annual mean objective / EU limit value for nitrogen dioxide. In response to this an Air Quality Management Area was declared in May 2011. This research aims to establish an approach to modelling the Durham road network for air quality management, which enables the assessment of traffic management solutions that may create only subtle changes in the traffic flow regimes. Road network emissions have been calculated using standard factors taking into account details of vehicle fleet composition, traffic speeds and road type. Additionally, the use of microsimulation traffic modelling in conjunction with an instantaneous emissions model has been adopted to allow comparison between methodologies and enable congestion sensitive analysis of the impact of air quality management measures on the network. Findings from microscale modelling have revealed that the signalling of two key junctions and co-ordination with several adjacent junctions could reduce emissions in Durham, as well as improve journey times and total network delay. Furthermore, relationships between air pollution, health and deprivation potentially result in cost to both the public and the government in terms of increased mortality and morbidity; hence establishing links between them is justifiably important. Consequently, the effect of the proposed traffic scheme on environmental justice is discussed in relation to the spatial distribution of areas with poor air quality.