Data, Methods, and Applications of Traffic Source Prediction

2018 ◽  
pp. 105-120
Author(s):  
Chengcheng Wang ◽  
Pu Wang
Keyword(s):  
Traffic Source

scholarly journals Particle size distribution and particle mass measurements at urban, near-city and rural level in the Copenhagen area and Southern Sweden

2003 ◽  
Vol 3 (6) ◽  
pp. 5513-5546 ◽  
Author(s):  
M. Ketzel ◽  
P. Wåhlin ◽  
A. Kristensson ◽  
E. Swietlicki ◽  
R. Berkowicz ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Number ◽  
Size Range ◽  
Urban Background ◽  
Total Particle ◽  
Urban Level ◽  
20 Nm ◽  
Traffic Source

Abstract. Particle size distribution (size-range 3–900 nm) and PM10 was measured simultaneously at an urban background station in Copenhagen, a near-city background and a rural location during a period in September-November 2002. The study investigates the contribution from urban versus regional sources of particle number and mass concentration. The total particle number (ToN) and NOx are well correlated at the urban and near-city level and show a distinct diurnal variation, indicating the common traffic source. The average ToN at the three stations differs by a factor of 3. The observed concentrations are 2500 # cm−3, 4500 # cm−3 and 7700 # cm−3 at rural, near-city and urban level, respectively. PM10 and total particle volume (ToV) are well correlated between the three different stations and show similar concentration levels, in average within 30% relative difference, indicating a common source from long-range transport that dominates the concentrations at all locations. Measures to reduce the local urban emissions of NOx and ToN are likely to affect both the street level and urban background concentrations, while for PM10 and ToV only measurable effects at the street level are probable. Taking into account the supposed stronger health effects of ultrafine particles reduction measures should address particle number emissions. The traffic source contributes strongest in the 10–200 nm particle size range. The maximum of the size distribution shifts from about 20–30 nm at kerbside to 50–60 nm at rural level. We also observe particle formation events in the 3–20 nm size range at rural location in the afternoon hours, mainly under conditions with low concentrations of pre-existing aerosol particles. The maximum in the size distribution of the "traffic contribution" seems to be shifted to about 28 nm in the urban location compared to 22 nm at kerbside. Assuming NOx as an inert tracer on urban scale let us estimate that ToN at urban level is reduced by 15–30% compared to kerbside. Particle removal processes, e.g. deposition and coagulation, which are most efficient for smallest particle sizes (<20 nm) and condensational growth are likely mechanisms for the loss of particle number and the shift in particle size.

scholarly journals Measurements of traffic dominated pollutant emissions in a Chinese megacity

2020 ◽  
Author(s):  
Freya A. Squires ◽  
Eiko Nemitz ◽  
Ben Langford ◽  
Oliver Wild ◽  
Will S. Drysdale ◽  
...  
Keyword(s):  
Central Area ◽  
Pollutant Emissions ◽  
Emission Rates ◽  
Emissions Inventory ◽  
Direct Measurements ◽  
Benzene Toluene ◽  
Emissions Inventories ◽  
Additional Influence ◽  
The City ◽  
Traffic Source

Abstract. Direct measurements of NOx, CO and aromatic VOC (benzene, toluene, C2-benzenes and C3-benzenes) flux were made for a central area of Beijing using the eddy covariance technique. Measurements were made during two intensive field campaigns in central Beijing as part of the Air Pollution and Human Health (APHH) project, the first in November–December 2016 and the second during May–June 2017, to contrast winter and summertime emission rates. There was little difference in the magnitude of NOx flux between the two seasons (mean NOx flux was 4.41 mg m−2 h−1 in the winter compared to 3.55 mg m−2 h−1 in the summer). CO showed greater seasonal variation with mean CO flux in the winter campaign (34.7 mg m−2 h−1) being over twice that of the summer campaign (15.2 mg m−2 h−1). Larger emissions of aromatic VOCs in summer were attributed to increased evaporation due to higher temperatures. The largest fluxes in NOx and CO generally occurred during the morning and evening rush hour periods indicating a major traffic source with high midday emissions of CO indicating an additional influence from cooking fuel. Measured NOx and CO fluxes were then compared to the MEIC 2013 emissions inventory which was found to significantly overestimate emissions for this region, providing evidence that proxy-based emissions inventories have positive biases in urban centres. This first set of pollutant fluxes measured in Beijing provides an important benchmark of emissions from the city which can help to inform and evaluate current emissions inventories.

Users' perceptions of blog functions: educational vs personal use

2014 ◽  
Vol 48 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Hsiu-Ping Yueh ◽  
Weijane Lin ◽  
Tzuyi Lu
Keyword(s):  
College Students ◽  
Information Exchange ◽  
Design Methodology ◽  
Content Type ◽  
Specific Focus ◽  
Field Practice ◽  
Detailed Evaluation ◽  
Personal Use ◽  
Educational Blogging ◽  
Traffic Source

Purpose – This paper aims to understand how users' perceptions of the different functions of blogs vary in educational use and personal use, and further to explore whether experience with blogs has an influence on differences in perceptions of blog functions. Design/methodology/approach – To empirically determine whether the blog functions were suitable for educational and personal use, a blog system with numerous functions was constructed for users to evaluate. In total, 48 college students were recruited to participate in the study. The participants navigated this system and then filled in a questionnaire to give their opinions on the functions of both educational blogs and personal blogs. Findings – The findings of this study indicate that of the 26 blog functions, perceptions of 20 of the functions differed significantly between educational and personal use. Moreover, the results showed that only two blog functions, backup and traffic source, were influenced by both blog experience and blog usage. Originality/value – This study distinguishes itself from the previous studies on blogging systems in its specific focus on functionality with detailed evaluation under different purposes of contexts. Practical suggestions are accordingly made for practitioners to choose when and which functions to use under different circumstances to enhance the interaction and information exchange between users in the field practice of educational blogging.

A multiservice user descriptive traffic source model

1996 ◽  
Vol 44 (10) ◽  
pp. 1243-1246 ◽  
Author(s):  
M.E. Anagnostou ◽  
J.-A. Sanchez-P. ◽  
I.S. Venieris
Keyword(s):  
Source Model ◽  
Traffic Source

Identifying Internet background radiation traffic based on traffic source distribution

2015 ◽  
Vol 21 (2) ◽  
pp. 107-120 ◽  
Author(s):  
Ruoyu Wang ◽  
Zhen Liu ◽  
Ming Tao ◽  
Ling Zhang
Keyword(s):  
Background Radiation ◽  
Source Distribution ◽  
Traffic Source
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