Vehicle emissions calculation for urban roads based on the Macroscopic Fundamental Diagram method and real-time traffic information

ABSTRACT Vehicle emissions calculation methods mostly use ownership information or annual road monitoring data as the activity level to calculate air pollutant emissions, but it is hard to reflect either the emissions intensity under different conditions or the spatiotemporal characteristics in various sections based on such approaches. This paper presents a method based on the Macroscopic Fundamental Diagram and real-time traffic data to calculate vehicle emissions, which could reflect the operation conditions and emission characteristics of vehicles. Following the ‘Technical Guide for the Compiling of Road Vehicle Air Pollutant Emissions Inventories’, the emissions of three roads with different lane numbers and road grades in Beijing were estimated and verified using this method. Compared with monitoring data, the average deviations of the traffic flow on the Fifth Expressway, Jingfu National Highway, and Jingzhou Provincial Highway were ？25.5%, ？26.5%, and ？13.4%, respectively, and the average deviations of nitrogen oxides emissions were ？27.7%, ？12.9%, and ？12%, respectively. This method showed good application potentials to construct the emissions inventory applied to the block-scale model and analyze the spatiotemporal distribution characteristics of motor vehicle emissions in urban areas. Graphical abstrac