Characteristics And Control Strategies Of Vehicle Emissions In Typical Cities Of China

The surge of the vehicle population has caused the abatement of vehicleemissions becomes one of the most important concerns for air pollution control inChina. Pressure from the substantial growth of vehicle population makes it urgent tocharacterize vehicle emissions and develop effective control strategies for better airquality.This study collects laboratory measurement results for1634vehicles by usingchassis dynamometers and on-road measurement results for263vehicles by usingportable emission measurement systems (PEMS). Emission factors are characterizedby emission control level, traffic pattern, and other operating conditions and vehicleemission factor models for China’s typical cities are developed. A multi-yearinventory of vehicle emissions in Beijing is developed based on the trends incity-level traffic demand. Uncertainties in vehicle factors and total vehicle emissionsare quantitatively characterized based on a Monte Carlo stotastic simulation method.Traffic flow data on Macao’s typical roads are also collected and characterized, toestablish hourly profiles of vehicle volume, vehicle category, average speed andvehicle age. Hense, this study establishes a link-based emissions inventory foron-road vehicles in Macao during2010with high resolution for vehicle technologygroup meshed in a temporal and spatial framework.The results indicate that NOXemission factors of heavy-duty diesel vehicles(HDDVs) are not improved with their emission standards. Abatement of NOXemissions from HDDVs remains a significant challenge for vehicle emissionscontrols in the future. For example, average NOXemission factors for diesel buses inBeijing complying with emission standards from the Euro II to the Euro IV are allapproximately12g/km. Proper natural gas and diesel hybrid bus technologies canmitigate on-road NOXemissions more effectively than the Euro V diesel engine.Multi-scale integration techniques of traffic flow and vehicle emissions aredeveloped based on the micro-trips generated from the PEMS data. This studyobserves very strong correlations between average speed and relative CO2emissionfactors for light-duty passenger vehicle categories with R-squares (R2) nearly0.9,except for the gasoline hybrid cars. The operation of on-board air conditioning systems would greatly increase real-world CO2emissions of all urban bus categories.The impacts on CO2emissions for urban buses from air conditioning usage are moresignificant compared to those from increased loading mass.Total emissions of CO, THC, NOXand PM2.5from Beijing’s on-road vehicles in2010are estimated505kt,58.7kt,74.1kt and2.62kt, respectively. Owing to a seriesof stringent emission controls, total vehicle emissions for those major air pollutantswere significantly reduced by58%,59%,31%and62%, respectively. Thecomprehensive emission control scenario containing the implementation of morestringent emission standards, the aggressive scrappage of older vehicles, and therestrictive policies for car purchase and driving, the penetration of alternative fueltechnologies could mitigate vehicle emissions by74%of CO,68%of THC,56%ofNOXand72%for Beijing in2020compare to2010levels. The link-based emissioninventory for on-road vehicles in Macao indicates strongly correlations betweenemission intensity and traffic flow in the temporal and spatial patterns. Our simulatedresults indicate that vehicle NOXemissions are the major local source of urbanambient NO2. As for the exceedance of NO2concentration is significant in the MacaoPeninsula, substantial efforts are needed using a combination of control measures forreducing vehicle NOXemissions. This study can help with policy-makers as theypursue future vehicle emission control in China.