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Peng Z.,Beijing Institute of Technology | Ge Y.,Beijing Institute of Technology | Tan J.,Beijing Institute of Technology | Fu M.,Tsinghua University | And 5 more authors.
Ocean Engineering

Seven ships were tested using portable emission measurement system. Particles from three ships were sampled using quartz-filters and analyzed using Thermal/Optical Carbon Analyzer and GC-MS. The emission factors of CO, HC, NOx and PM are 11.00-84.60 g/kg, 22.75-98.88 g/kg, 0.72-5.83 g/kg and 0.15-9.53 g/kg, respectively. In most cases, the ships emit larger quantity of pollutants during cruising. For particle number, the majority is formed in the nucleation mode. The nucleation mode and the accumulation mode from ships during maneuvering increase by 2.63 and 3.52 times respectively, compared with those from ships during cruising. Particle mass is dominated by the accumulation mode and the coarse mode. Analysis of the samples shows that OC is the major composition of carbonaceous particle, whose mass fraction is 0.52-0.88. The emission factors of OC and EC are 0.29-1.44 g/kg and 0.04-0.64 g/kg, respectively. Most of the particle-phase PAHs are medium molecular weight PAHs, while high molecular weight PAHs are seldom observed. © 2016 Elsevier Ltd. All rights reserved. Source

Wang X.,Cornell University | Westerdahl D.,Cornell University | Hu J.,Chinese Research Academy of Environmental Sciences | Wu Y.,Tsinghua University | And 3 more authors.
Atmospheric Environment

Nitrogen oxides (NOx) and black carbon (BC) emission factors (EF) of 440 on-road diesel trucks were determined by conducting on-road chasing studies in Beijing and Chongqing, China, in the winter 2010. NOx and BC EF distributions are reported. The median NOx EFs for trucks sampled on level roads in Chongqing and Beijing are 40.0 and 47.4g kg-fuel-1, respectively. The median BC EFs are 1.1 and 0.4g kg-fuel-1in Chongqing and Beijing, respectively. In addition, a clear downward trend of BC EFs of on-road diesel trucks sampled in Beijing since 2008 is observed. Moreover, Beijing-registered trucks had the lowest BC EFs among the entire sample. These observations appear to reflect the effectiveness of emission standard and fuel quality standard implemented in Beijing (China IV) and nationwide (China III) in reducing BC (and likely overall particulate matter) emission. However, NOx EFs for Beijing-registered trucks did not show lower value than those from other regions. Unlike black carbon, there is no clear correlation between emission controls and NOx emissions from the sampled on-road trucks. Further analysis shows that trucks with high BC EFs do not usually have high NOx EFs, and vice versa, indicating that the current emission standards implemented in Beijing and nationwide have only limited impact on NOx emissions control. Therefore, effective multi-pollutant control strategies and in-use compliance programs are imperative to reduce the overall emissions from the transportation sector. © 2011 Elsevier Ltd. Source

Huo H.,Tsinghua University | Yao Z.,Beijing Technology and Business University | Yao Z.,Tsinghua University | Zhang Y.,Tsinghua University | And 4 more authors.
Atmospheric Environment

This paper is the second in a series of three papers aimed at understanding the emissions of vehicles in China by conducting on-board emission measurements. This paper focuses on light-duty gasoline vehicles. In this study, we measured 57 light-duty gasoline vehicles (LDGVs) in three Chinese mega-cites (Beijing, Guangzhou, and Shenzhen), covering Euro 0 through Euro IV technologies, and generated CO, HC, and NOx emission factors and deterioration rates for each vehicle technology. The results show that the vehicle emission standards have played a significant role in reducing vehicle emission levels in China. The vehicle emission factors are reduced by 47-81%, 53-64%, 46-71%, and 78-82% for each phase from Euro I to Euro IV. Euro 0 vehicles have a considerably high emission level, which is hundreds of times larger than that of Euro IV vehicles. Three old taxis and four other Euro I and Euro II LDGVs are also identified as super emitters with equivalent emission levels to Euro 0 vehicles. Of the measured fleet, 23% super emitters were estimated to contribute 50-80% to total emissions. Besides vehicle emission standards, measures for restricting super emitters are equally important to reduce vehicle emissions. This study is intended to improve the understanding of the vehicle emission levels in China, but some key issues such as emission deterioration rates are yet to be addressed with the presence of a sufficient amount of vehicle emission measurements. © 2011 Elsevier Ltd. Source

Zhou L.,Jinan University | Zhou L.,Chinese Academy of science | Zhou L.,California Air Resources Board | Wang B.-G.,Jinan University | Tang D.-G.,Vehicle Emission Control Center
Huanjing Kexue/Environmental Science

Through an analysis of the characteristics of diesel vehicle emissions and motor vehicle emissions inventories, this paper examines the impact of heavy-duty diesel vehicles on air quality in China as well as issues related to the control of their emissions. Heavy-duty diesel vehicles emit large amounts of nitrogen oxides and particulate matter. Nitrogen oxides is one of the important precursors for the formation of secondary particles and ozone in the atmosphere, causing regional haze. Diesel particulate matter is a major toxic air pollutant with adverse effect on human health, and in particular, the ultrafine particles in 30-100 nm size range can pose great health risks because of its extremely small sizes. Motor vehicles have become a major source of air pollution in many metropolitan areas and city cluster in China, and among them the heavy-duty diesel vehicles are a dominant contributor of nitrogen oxides and particulate matter emissions. Hence, controlling heavy-duty diesel vehicle emissions should be a key component of an effective air quality management plan, and a number of issues related to heavy-duty diesel vehicle emissions need to be addressed. Source

Huo H.,Tsinghua University | Zhang Q.,Tsinghua University | He K.,Tsinghua University | Yao Z.,Beijing Technology and Business University | And 5 more authors.
Environmental Pollution

We propose a method to simulate vehicle emissions in Chinese cities of different sizes and development stages. Twenty two cities are examined in this study. The target year is 2007. Among the cities, the vehicle emission factors were remarkably different (the highest is 50-90% higher than the lowest) owing to their distinct local features and vehicle technology levels, and the major contributors to total vehicle emissions were also different. A substantial increase in vehicle emissions is foreseeable unless stronger measures are implemented because the benefit of current policies can be quickly offset by the vehicle growth. Major efforts should be focused on all cities, especially developing cities where the requirements are lenient. This work aims a better understanding of vehicle emissions in all types of Chinese cities. The proposed method could benefit national emission inventory studies in improving accuracy and help in designing national and local policies for vehicle emission control. © 2010 Published by Elsevier Ltd. Source

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