Why did US air pollution decline after 1970?

US economic growth and air pollution were decoupled after 1970. Possible explanations include regulation, oil price shocks, technology and income growth. This paper uses VAR analysis to show that the 1970 Clean Air Act (CAA) may have actually increased pollution in the short run but led to accelerated improvements in abatement technology. Gross domestic product and consumption growth had little direct effect while oil price increases caused small but significant emissions reductions. Recursive simulation shows that overall, the CAA, by accelerating improvements in abatement technology, reduced total emissions as of 1998 to 46% of what they would have been.      

Environmental participation in the U.S. sulfur allowance auctions

The 1990 Clean Air Act established a sulfur emissions-trading program among utilities. This was the first large scale adoption of this type of emissions-trading program and the program’s success has attracted international attention. An interesting aspect of this program is that in addition to trades among the polluting firms and brokers or investors, individuals and groups have been participants, buying allowances to retire them and reduce sulfur emissions. This provides a relatively unique way to examine the “willingness to pay” for further reductions of sulfur emissions. I examine environmental participation in the sulfur allowances market, focusing on the Environmental Protection Agency (EPA) allowance auctions which have been conducted annually since 1993. The existence of groups purchasing these allowances in order to retire them suggests that the overall cap on sulfur emissions may be higher than the optimal emissions level. The marginal benefits from the first ton of emissions reduction appear to be significantly larger than marginal abatement costs. Total spending to retire sulfur emissions allowances, while small in relation to the total market, is sizeable in terms of the alternate purchases these groups and individuals could have made.      

Air China Signs Deal to Buy 23 Airbus Passenger Jets

Air China has signed a deal to buy 23 Airbus A320 passenger planes.[第一段]     

Beyond Adoption of Travel Technology: Its Application to Unplanned Travel Behaviors

The ultimate goal of information distribution for a destination marketer is to stimulate travelers to make a purchase decision. Today, travel information can be obtained by travel technology, which enables travelers to exploit on-the-move information. Navigation services for travel technology are being more broadly used across the globe by providing a wide range of en route information. This study evaluates the effects of travel information disseminated by navigation services on unplanned behaviors during trips. The results of the study illustrate that travelers who use navigation during trips are more likely to be involved in unplanned activities and, hence, will have an increase in unplanned travel expenditures. Destination marketers can partner with travel technology providers to encourage better travel experiences for tourists and generate more travel revenues for the tourism industry.     

Air passenger duties as strategic tourism taxation

There has been a recent debate on the rationale and economic impacts of air passenger duties (APDs) linked to puzzling empirical results on this topic. We argue that an approach from strategic tourism taxation can improve our understanding of these results. APD set by origin countries of tourists can be viewed as an instrument for extracting economic rents that would otherwise be retained by tourism destinations. A theoretical model of strategic taxation between an origin and two destinations is developed to illustrate this idea. We find that countries' strategies may end up with winners and losers, or with all parties facing welfare losses. The game outcome depends on countries' market shares of profits and the substitutability between tourism services provided by different destinations. The findings suggest that the economic impacts of APDs recently evaluated in the literature might be biased because of the omission of other countries' potential tax reactions.     

Causality in direct air services and tourism demand

Unlike income or relative prices, air transport attributes and tourism demand on a given route can be endogenous. Using instrumental variables, this study attempted to account for the circular causality in estimating the effect of direct air service on tourism demand. Although we found evidence of endogeneity, the nature of the circular causation is context-specific; while direct air service can be regarded as an exogenous variable in one direction, it can have an endogenous relationship on the other. Findings emphasise the need to explicate information about the network nature of transportation and its endogenous relations with tourism.     

Carbon footprint of tourism in Barcelona

This study evaluates the carbon footprint (CF) of Barcelona tourist activity taking into account the above 30 million visitors who visit the city every year. This study analyzes the main sources of emissions considering direct (Scope 1) and indirect emissions (Scope 2 and 3) as a consequence of energy use. This research has been carried out in close collaboration with Barcelona City Council and in the context of the new Strategic Tourism Plan for Barcelona city. The impacts of arrival and departure transport, accommodation, leisure and professional activities and Intra-urban transport from Barcelona city were all included. The total CF of Barcelona tourist activity is about 9.6MtCO₂eq/year, which represents an emission of 96.9 kg CO₂eq/visitor·day. The main source of emissions is arrival and departure transport (95.6%), and particularly aviation. These results show that if substantial reductions in CO₂ emissions are to be achieved, initiatives strategically focused on transport and also accommodation are necessary.     

一种动态交通导航的寻优模型研究与仿真

针对目前的车辆路径算法不能满足动态导航的要求,提出了一种用于动态交通导航的优中手优模型。该模型定义了出行时间、路径风险性和路径适宜度等三大指标,并以三大指标的目标函数作为适应度因子,通过遗传算法寻找最优路径。仿真实验表明,诙模型能够根据不同的指标提供多种最优出行方案,并动态计算最优路径,满足车辆动态导航的要求。     

The effects of deregulation, changed customer requirements and new technology on the organisation and spatial patterns of the air freight sector in Europe

Customer requirements, new technologies and the deregulation and liberalisation measures of the last 15 years have had a significant influence on market structures in air freight transport in Europe. The study examines the sector using the concept of global production networks. It describes the reorganisation in various dimensions. Firstly, there is the development from single air freight forwarders to global networks of firms. Secondly, we find a reorganisation of inter-company relations. Thirdly, airlines around the world organise their air traffic as a hub system. This lends added importance to the selected hub airport, and puts pressure on them to enlarge. As spatial consequences there is greater competition among international airports.     

Continuum modeling approach to the spatial analysis of air quality and housing location choice

Today, air pollution is a great issue, and the transport sector is an important emission source. In this study, we present an integrated land use, transport, and environment model in which transport-related pollutants are assumed to influence people's housing location choices, and a continuum modeling approach is applied. The pollutants generated by the transport sector are dispersed by the wind and they affect air quality. The air quality changes people's housing choices, which in turn changes their travel behavior. We assume that the road users are continuously distributed over the city, that the road network is relatively dense, and that this network can be approximated as a continuum. The total demand is categorized into several classes, and the modeled region contains several subdistricts. People who live in different subdistricts or who belong to different classes of commuters are assumed to have different perceptions of travel time, air quality, and the housing provision–demand relationship. The finite element method and the Newton–Raphson algorithm are adopted to solve this problem, and a numerical valuation is given to illustrate the effectiveness and efficiency of the proposed model.