Development of High-Resolution Motor Vehicle Emission Inventories for City-Wide Air Quality Impact Analysis in China

In recent years, large cities in China face severer air pollution due to motor vehicle emissions. Accurate high-resolution emission inventories are essential as they are commonly used in air quality dispersion modeling analysis to determine impacts from motor vehicle emissions and assess the effectiveness of control strategies. This paper presents a case study based on motor vehicle emissions in the City of Hangzhou, China. A method was developed to estimate the spatial and temporal distributions of motor vehicle emissions based on the best available database to the research team. The distributions of Vehicle Kilometers Traveled (VKT), vehicle age, type and technology classes operating on city streets were determined based on records obtained from various sources including on-scene video tapes, traffic count statistics, and Inspection and Maintenance (I/M) station database. The vehicle driving patterns were measured using the Global Positioning Satellite (GPS) technology. The International Vehicle Emission model (IVE) combined with Geographic Information System (GIS) was used to develop high-resolution spacial (1 km × 1 km) and temporal (hourly) emission inventories of CO, HC, NOx and PM10 from motor vehicles in Hangzhou in 2004. These high-resolution emission inventories in Hangzhou were used as inputs to the USEPA’s AERMOD model to simulate the concentration distributions caused by motor vehicle emissions. This paper details how to select the appropriate emission factor model, how to collect and analyze vehicle activity data, and allocate emissions spatially and temporally. The resulting vehicular emissions distributions and their effects on the urban air quality in the city are also discussed. INTRODUCTION With an annual vehicle fleet growth rate of more than 20% in Chinese major cities in recent years, China faces severer motor vehicle pollutions. The State Environmental Protection Administration of China (SEPA) has identified motor vehicles emissions as the major source of urban air pollution in China. In 2004, on-road vehicles were estimated to contribute over 50% of the nitrogen oxides (NOx) to large cities’ emission inventories. As a result, regulators and decision makers are being required to invest significant resources into managing and assessing roadway effects on air quality. To better quantify the impacts on air quality by on-road motor vehicles or assess the effectiveness of control strategies, accurate high-resolution emission inventories are needed as the inputs to air dispersion models. However, due to the limited database of motor vehicle activities (including VKT