Transport-related Activities Research Articles

Factors associated with physical fitness and disparities in population segments among older adults: A cross-sectional study.

This study aimed to investigate the factors associated with physical fitness and disparities in population segments among older adults, using data from the National Physical Fitness Surveilling Survey of China. A cross-sectional study. A total of 13524 older adults aged 60-79 years were involved in the study. Participants completed physical fitness assessments encompassing body fat percentage, lung capacity, high leg raise in place, grip strength, seated forward bending, 30-s sit-to-stand test, single-leg standing with eyes closed, and choice reaction time. A profile analysis model was constructed by feature extraction, label design and clustering using principal component analysis and k-prototypes. Factors associated with physical fitness were analyzed using ordered probit regression, and within-group differences were evaluated through the bootstrap method. The older adults were categorized into four clusters based on the clustering results (Cluster I: n=2728, Cluster II: n=6067, Cluster III: n=4189, Cluster IV: n=540). Significant positive associations were identified between moderate-to-vigorous transport-related activities =0.001, p<0.05), moderate-to-vigorous household chores ( =0.003, p<0.01), work-related physical activity ( =0.001, p<0.01), exercise ( =0.002, p<0.01) and physical fitness levels. Conversely, the number of illnesses ( =-0.089, p<0.01) and sedentary behavior ( =-0.002, p<0.05) were negatively associated with physical fitness. Inflection points were observed, indicating shifts from lower level to higher physical fitness levels as the volume of diverse moderate-to-vigorous physical activities increased. Disparities in factors associated with physical fitness were identified across the different clusters. The associations of household chores, transport-related activities, and work-related physical activity with physical fitness lacked robustness during heterogeneity processing. In contrast, exercise consistently demonstrated a facilitating role across all clusters. Furthermore, greater marginal effects on achieving higher physical fitness test scores were observed among individuals classified as inactive when engaging in more moderate-to-vigorous activities and exercise. The findings demonstrate that engagement in moderate-to-vigorous physical activities and exercise is associated with a significantly higher probability of achieving better physical fitness among older adults. Participating in physical activities and exercise should be encouraged based on population segments for precise and quantitative interventions to improve physical fitness.

Environmental impacts and scale-up efficiency of four carbon capture and storage scenarios

Capture, transportation, and permanent storage of CO2 is considered pivotal in reaching global net-zero emission targets. Conceptualization and deployment of carbon capture and storage (CCS) value chains require substantial resources with current CCS projects trailing behind expectations. To date few studies address the environmental impacts related to introducing CCS into existing value chains, and even fewer focus on the environmental efficiency of scaling-up CCS projects, despite the need for acceleration. Four scenarios were studied, resembling CCS projects at different capture capacities of 0.3, 1.5, 3.5 and 10 million tonnes of CO2 per year (mtpa) deployed within a Northern European region. Using attributional life cycle assessment, we demonstrate that permanent carbon storage today may furnish a 47–91% CO2 net-abatement potential depending on the CO2 source and geographical location of CCS projects. Despite limited operational data, results appear robust with general low uncertainty. Our environmental assessment show that capturing, conditioning and liquefaction account for the largest emission shares of the studied CCS value chains, ranging from 70 to 80%, which is heavily fluctuated by the carbon emission intensity of regional electricity production. Impacts related to permanent storage activities, such as offshore monitoring and well drilling are limited to less than 2% across all scenarios. Moreover, our study suggests that expanding the spatial geographical scope to accumulated 5000 km has a low influence on the efficiency of CCS value chains regardless of capture rate. Freshwater eutrophication shows the highest burden across the assessed environmental impact categories caused by the electricity production for capture processes. Lastly, we identify net-abatement improvement potential for post-combustion CCS projects at capturing capacities between 1.5 and 10 million tonnes per annum ranging from 10 to 20% for transport-related activities, and 60–68% for capturing processes when assuming net-zero energy scenarios.

A total cost of ownership analysis of zero emission powertrain solutions for the heavy goods vehicle sector

Transport-related activities represented 34% of the total carbon emissions in the UK in 2022 and heavy-duty vehicles (HGVs) accounted for one-fifth of the road transport greenhouse gas (GHG) emissions. Currently, battery electric vehicles (BEVs) and hydrogen fuel cell electric vehicles (FCEVs) are considered as suitable replacements for diesel fleets. However, these technologies continue to face techno-economic barriers, creating uncertainty for fleet operators wanting to transition away from diesel-powered internal combustion engine vehicles (ICEVs). This paper assesses the performance and cost competitiveness of BEV and FCEV powertrain solutions in the hard-to-abate HGV sector. The study evaluates the impact of battery degradation and a carbon tax on the cost of owning the vehicles. An integrated total cost of ownership (TCO) model, which includes these factors for the first time, is developed to study a large retailer's HGV fleet operating in the UK. The modelling framework compares the capital expenditures (CAPEX) and operating expenses (OPEX) of alternative technologies against ICEVs. The TCO of BEVs and FCEVs are 11% to 33% and 37% to 78% higher than ICEVs; respectively. Despite these differences, by adopting a longer lifetime for the vehicle it can effectively narrow the cost gap. Alternatively, cost parity with ICEVs could be achieved if BEV battery cost reduces by 56% or if FCEV fuel cell cost reduces by 60%. Besides, the pivot point for hydrogen price is determined at £2.5 per kg. The findings suggest that BEV is closer to market as its TCO value is becoming competitive, whereas FCEV provides a more viable solution than BEV for long-haul applications due to shorter refuelling time and lower load capacity penalties. Furthermore, degradation of performance in lithium-ion batteries is found to have a minor impact on TCO if battery replacement is not required. However, critical component replacement and warranty can influence commercial viability. Given the high costs, we propose financial incentives and vehicle tax reforms to reduce costs of critical components that will encourage the roll-out of zero emission HGVs.

Assessing environmental sustainability in top Middle East travel destinations: insights on the multifaceted roles of air transport amidst other energy indicators.

The Middle Eastern region is well-known for its flourishing tourism industry as the aviation sector contributes over US$213 billion to the regional GDP while air transport-related activities account for over 3.3 million jobs. Howbeit, the environmental impacts of this flourishing industry remain questionable. Hence, this study examines the tourism-emissions nexus in the Middle Eastern region from the perspective of air transportation while underscoring the multifaceted roles of major indicators like globalization, income, and energy use in the region. The empirical analysis of data spanning from 1975 to 2018 was conducted with advanced panel data analytical approach using the CS-ARDL technique. The sample selection was guided by available statistics on international tourist arrivals from the United Nations World Tourism Organization (UNWTO 2020), with a focus on the case of the five leading travel destinations in the region including Saudi Arabia, the United Arab Emirates (UAE), Egypt, Oman, and Qatar. The robustness of the evaluated outputs was checked after which result-based policy suggestions were enunciated for authorities and other regional stakeholders. The analysis indicated that air transportation although boosting tourism has constituted significant detrimental environmental impacts on the reviewed destinations with an estimated long-run elasticity of ∼1.03. Additionally, while the trio of globalization, energy utilization, and income expansion exacerbate environmental degradation, the lowest carbon-triggering magnitude was observed from the regional income expansion. Thus, while the aviation sector facilitates the growing quest to diversify from a primary sector-based economy (mainly resources exploitation) to other prospective service industries like tourism, the study posits the need for authorities to put measures in place to address the environmental side effect of air transportation.

Expanding the VBN theory on succeeding the transportation demand management policies

The growth of the car fleet has caused many problems, such as environmental problems, uncontrolled energy consumption, and traffic congestion. To resolve the issues caused by transport-related activities, transportation planners should implement policies that reduce car use and move forward to sustainable transportation. The prerequisite of the efficiency of the policies that reduce car use is the acceptance of them by the entire community members. Previously a few studies have tested individuals’ environmental attitudes using the Value-Belief-Norm (VBN) theory. This research aims to analyze and examine car use reduction policy using a comprehensive VBN and Norm-Activation-model (NAM) theories to consider more variables and provide a model with more analytical capability. To address this issue, 500 questionnaires were filled by travelers’ in Tehran, Iran, in the restricted traffic area to describe their behavior. The result shows that the biospheric value significantly affects car use reduction policy, associated with considerable environmental concerns. Besides, it was found that a high ascription of responsibility (A.R.) appeared as the strongest predictor of the policy. The findings have represented initial support for the VBN theory and revealed that the theory could explain the car use reduction policy’s Intention, according to Tehran’s respondents’ environmental behavior. This study’s findings can assist policymakers in adopting appropriate policies to reduce car use based on environmental advantages and could target biospheric values and ascription of responsibilities.

Impacts of urban form on integrated energy demands of buildings and transport at the community level: A comparison and analysis from an empirical study

• Combining research on building energy demands with transport energy consumption is performed. • CO 2 emissions from buildings are around four times higher than transport-related activities. • Multinomial logistic modelling was applied to evaluate travel mode selection. • Travel time and distance have statistically significant relationships with transport mode choices. Buildings and transport are key sources of energy consumption in cities. However, most previous studies have investigated energy consumption separately, and have not explored them in combination. This study investigates the energy consumption of both buildings and transport activities, with the city of Wuhan in China being used as a case study. Three categories: travel patterns, participants’ evaluations on travelling, and socioeconomic characteristics, are analysed. The findings have shown that buildings produce approximately four times more CO 2 emissions than transport activities, with annual CO 2 emissions from residential buildings being higher than those produced by public buildings in well-developed areas. Mode-choice modelling revealed that travel time and distance play critical roles in determining transit modes. For example, a traveller is 1.44 times more likely to choose a transit option than walking if the trip distance increases by one kilometre. Moreover, driving decisions are heavily influenced by monthly household income, car ownership, comfort level and self-assessments of congestion. The simultaneous study of the carbon emissions of both buildings and transport can help urban policymakers, planners, and designers to avoid unintended outcomes of one-sided strategies to reduce urban CO 2 emissions.

Patterns of physical activity and sedentary behavior and their associated factors among nondisabled stroke survivors

ObjectivesTo investigate the levels of physical activity and sedentary behavior, and the factors associated with these, in middle-aged and elderly stroke survivors who had no limitations to their physical activity. Study design and main outcome measuresWe analyzed physical activity and sedentary behavior patterns using data from 12,986 community-dwelling adults aged ≥50 years without activity limitation: 377 stroke survivors, 531 ischemic heart disease (IHD) survivors, and 12,078 healthy controls in the Korean National Health and Nutrition Examination Survey. The prevalence and associated factors of compliance to aerobic activity guidelines and prolonged sedentary time were investigated using complex-sample statistics. ResultsStroke survivors spent less time in transport-related activities and walking than healthy controls. Stroke survivors, despite having no restriction in daily and social activities, had lower rates of compliance with aerobic activity guidelines (32.4%) and a higher prevalence of long sedentary time (56.6%) than IHD survivors (aerobic activity, 36.3%; sedentary behavior, 55.1%) and healthy controls (aerobic activity, 42.4%; sedentary behavior, 46.2%). Stroke survivors with hypertension were less likely to engage in recommended aerobic activity. Higher levels of education were positively associated with both aerobic activity compliance and long sedentary time. Although older age was associated with long sedentary time, stroke survivors with hypercholesterolemia and those who were married and living with their spouses were less likely to have a long sedentary time. ConclusionsNondisabled stroke survivors tended to spend less time in aerobic activity and more time in sedentary behavior than IHD survivors and healthy controls, and environmental factors had a considerable impact on their levels of physical activity and sedentary behavior.

Transition of mobility in companies – A semi-systematic literature review and bibliographic analysis on corporate mobility and its management

Advancement measures and negative externalities of the current transport system have been extensively researched but significant changes concerning greenhouse gas (GHG) emission reduction is yet to be achieved. The expected mobility changes, triggered by the introduction of electric mobility, sharing concepts, modern vehicle concepts, new planning approaches and future autonomous vehicle concepts open up new options for an improved efficiency in the corporate mobility sector. The purpose of this article is to review literature between 2016 and mid-2020 on all transport-related activities of corporations and critically review research conclusions and their implication to determine research gaps for potential alternative ways of system transition. This is achieved by a semi-systematic review of international scientific journals and conference papers independently from their research field with a set of a-priori defined terms on corporate mobility and logistics. The article concludes with a summary of major research motivations and outcomes to the mobility transition in companies and identified research gaps with potential added value to the transport system. The review reveals that the major objective of analysed articles is the zero-emission future. An examination of new mobility solutions, technologies, and their potential impact is ongoing. The potentials to design future systems and ways of system transition have yet to be sufficiently examined. The relevant question is how mobility management in corporations could be upgraded. The integration into companies’ strategic management and inter-company mobility concepts could be potential fields. These findings are important for policymakers and mobility managers to jointly work on the zero-emission future.

Are Physical Activities Associated With Perceived Stress? The Evidence From the China Health and Nutrition Survey.

Psychological stress is a negative affective state. The association between physical activity and psychological stress was commonly reported in previous researches. Few published studies with large sample sizes have explored such an association in Chinese population. The current research aims to assess the association between perceived stress and physical activity preferences, as well as the association between risk of high perceived stress and physical activity behaviors (e.g., sports-, transport-, occupational-related physical activity, sedentary activities and time in bed). The data were collected from the China Health and Nutrition Survey (CHNS) in 2015. Generalized linear models and logistic regression models were used to explore the association between perceived stress and physical activity. In total, 11,066 participants were included in the current analysis. For physical activity preferences, we found that “like” preference of all six mentioned domains of activities contributed to lower perceived stress (i.e., lower perceived stress scale −14 score, all β < 0 and p < 0.05). For physical activity behaviors, the results indicated that none/low intensity physical activity behaviors (e.g., sports-, occupational- related, sedentary) were associated with risk of high perceived stress, except that low intensity of transport-related activities seemed to be protective from high stress. However, the association between intensity of physical activity behaviors and perceived stress was not simply the higher the better. High intensity of all these physical activity behaviors was also associated with high perceived stress. Our findings suggest that positive preferences and moderate physical activity behaviors were associated with low perceived stress. The findings herein highlight the effect of regulating physical activity on perceived stress, as well as inform potential strategies to reduce psychological stress.

Calculating carbon emissions from personal travelling: insights from a top-down analysis of key calculators.

Personal travelling unfavourably contributes to the emissions of greenhouse gases, which adversely causes long-term damage to the climate. In order to reduce the associated negative impacts of such activities on the environment, there is a wide consensus that enhancements and innovations in the efficiency of vehicles will not be enough, but behavioural changes are needed. For this, individuals should be able to measure their travel-related carbon emissions, and such emissions could be determined by using personal carbon footprint calculators, which proliferated during the previous decade. However, various research questions related to such calculators are yet to be answered in published literature. As such, this paper investigates how key transport-based calculators account for emissions from personal transport-related activities following a top-down analysis. In this endeavour, ten such calculators are investigated through a set of formulated research questions to analyse their scope, calculation approach used, transparency, consistency of results, communication methods utilized and platform differences. Results revealed that the calculators have varying granularity, have limited transparency, provide significantly inconsistent results in some cases and are not fully engaging end users. Based on limitations identified, recommendations have been proposed through a taxonomy to guide policy-makers towards improving such tools.

Pre-schoolers' transport imaginaries: Moving towards sustainable futures?

Being on the move is part of children's everyday life in cities. However, little is known about how young children experience transport systems or their aspirations for mobility in cities. In this paper, we explore pre-schoolers' experiences with the mobile world and show their affinity with different transport modes and hopes for their current transport system. We draw on a participatory research project that engaged children in class discussions, a tile-based city building exercise and neighbourhood walks. Findings suggest that although the voices of children aged 3–5 years are absent in mobility or transport debates, children are fascinated by mobility and transport related activities and services. Pre-schoolers from Dunedin, New Zealand, though recognising a predominantly motorised transport system, also showed creative or alternative modes making their way into their own transport systems. In this paper we argue that children should be introduced to and experience alternative modes of transport in the early years to allow for more imaginary transport geographies creating greater support for more sustainable, liveable urban environments for all ages.

Impact of rainfall on travel time and fuel usage for Greater Mumbai city

Climate change can severely affect the rainfall pattern of a city and thus impact transport related activities. Travel time and mileage are an important transport parameter that may significantly be affected by rainfall. Objective of the study was to estimate the difference in travel time and fuel consumption for rainfall and non-rainfall days for Greater Mumbai. The study analyzed the impact of different intensities of rainfall on travel time and mileage for two roads of Greater Mumbai. A survey was carried out to collect data on the chosen transport parameter at different rainfall intensity. Rainfall intensity was categorized based on Indian meteorological department’s standards. The results shows that travel time and fuel consumption are influenced by intensity of rainfall. Due to rainfall, there is an increase in travel time by 8-140% for both the roads studied. Also, travel time during evening peak hours is ~10% higher than morning peak hours.

A model for reduction of transport-related CO2 emissions by optimizing industrial waste treatment facility location

One of the objectives of industrial waste management is to reduce the amount of waste and to ensure its reuse in a way that allows notable improvement of resource efficiency. Location of a waste treatment plant is a strategic issue that require careful logistics system planning. The aim of this article is to create a model for solving the locationallocation problem of waste (i..e. secondary raw materials) treatment facilities, taking into account the territorial distribution, the type, and the quantity of secondary raw materials, the distance between waste-generating industries, as well as the CO 2 emissions from transport of secondary raw materials. The basic principle for defining a mathematical model is minimization of CO emissions from transport-related activities; 2 for this reason, modeling is based on the p median model that has been modified and put within the context of industrial waste management, including CO emissions from 2 transport. The location model is based on common industrial waste streams and CO 2 emissions from vehicles commonly used to transport secondary raw materials from generators to facilities. The verification of the model was performed through a case study that included the region of southeast Serbia. It confirmed usefullness of the proposed model for deciding on optimal locations for new industrial waste treatment plants.

‘Eco-Hauling’ principles to reduce carbon emissions and the costs of earthmoving - A case study

Mitigating emissions of carbon dioxide and other greenhouse gases is critical if we are to meet the increasing threats posed by global warming. Previous studies have shown conclusively that a substantial part of all carbon dioxide emissions comes from transportation, and that Eco-Driving principles based upon strategic, tactical, and operational decisions have the potential to reduce these emissions. However, these well-established principles have been neglected within the construction industry despite the large number of transport-related activities that attend most construction projects. This paper therefore aims to increase awareness and understanding within the industry of the potential reductions of both carbon dioxide emissions and the costs of earthmoving activities that could be achieved through the use of Eco-Driving principles. A new concept labeled ‘Eco-Hauling’, which extends the Eco-Driving concept to earthmoving, is proposed. A case study of a road project has been conducted and used to demonstrate the new concept. Discrete-event simulation is used to support the data analysis as it enables modeling of the dynamic interactions between equipment and activities of multiple different construction scenarios. The presented findings show that a combination of decisions taken from the proposed Eco-Hauling concept can enable earthmoving contractors to substantially reduce carbon dioxide emissions and costs while maintaining productivity. This study has implications for the general advancement of Eco-Driving theory, as well as for project management as it sets out a viable approach for reducing greenhouse gas emissions in construction projects.

Assessment of sedentary behaviors and transport-related activities by questionnaire: a validation study.

BackgroundComprehensive assessment of sedentary behavior (SB) and physical activity (PA), including transport-related activities (TRA), is required to design innovative PA promotion strategies. There are few validated instruments that simultaneously assess the different components of human movement according to their context of practice (e.g. work, transport, leisure). We examined test-retest reliability and validity of the Sedentary, Transportation and Activity Questionnaire (STAQ), a newly developed questionnaire dedicated to assessing context-specific SB, TRA and PA.MethodsNinety six subjects (51 women) kept a contextualized activity-logbook and wore a hip accelerometer (Actigraph GT3X + TM) for a 7-day or 14-day period, at the end of which they completed the STAQ. Activity-energy expenditure was measured in a subgroup of 45 subjects using the double labeled water (DLW) method. Test-retest reliability was assessed using intra-class-coefficients (ICC) in a subgroup of 32 subjects who filled the questionnaire twice one month apart. Accelerometry was annotated using the logbook to obtain total and context-specific objective estimates of SB. Spearman correlations, Bland-Altman plots and ICC were used to analyze validity with logbook, accelerometry and DLW data validity criteria.ResultsTest-retest reliability was fair for total sitting time (ICC = 0.52), good to excellent for work sitting time (ICC = 0.71), transport-related walking (ICC = 0.61) and car use (ICC = 0.67), and leisure screen-related SB (ICC = 0.64-0.79), but poor for total sitting time during leisure and transport-related contexts. For validity, compared to accelerometry, significant correlations were found for STAQ estimates of total (r = 0.54) and context-specific sitting times with stronger correlations for work sitting time (r = 0.88), and screen times (TV/DVD viewing: r = 0.46; other screens: r = 0.42) than for transport (r = 0.35) or leisure-related sitting-times (r = 0.19). Compared to contextualized logbook, STAQ estimates of TRA was higher for car (r = 0.65) than for active transport (r = 0.41). The questionnaire generally overestimated work- and leisure-related SB and sitting times, while it underestimated total and transport-related sitting times.ConclusionsThe STAQ showed acceptable reliability and a good ranking validity for assessment of context-specific SB and TRA. This instrument appears as a useful tool to study SB, TRA and PA in context in adults.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3412-3) contains supplementary material, which is available to authorized users.

Estimated Greenhouse Gases Emissions from Mobile and Stationary Sources in the Limestone and Basalt Rock Mining in Thailand

Mineral processing can become more environmentally sustainable by integrating practices that reduce all environmental impact of mining operations. Along with pollution problems, global climate change is presently one of the most important environment concerns. This research aimed to identify all potential sources and also compare the net emissions of greenhouse gases (GHGs) from the limestone and basalt rock mining operations in Thailand. Limestone (Plant I) and basalt (Plant II) rock mining located in the central and the northeast of Thailand were selected as research case studies. The results indicated that the total amount of GHGs emitted from limestone mining operation were approximately 1,457.61 and 1,753.73 tCO2-eq in 2014 and 2015, respectively. Estimated GHGs intensity ranged between 18.83 to 22.36 kgCO2-eq/tonne of rock product. Similarly, over 2014 to 2015, the range of total GHGs emissions from basalt rock mining was about 1,467.27 to 1,670.18 tCO2-eq. Interestingly, estimated GHGs intensity of basalt mining was roughly two times greater than limestone rock mining (31.85 to 35.72 kgCO2-eq/tonne of product). By scope, direct emission from transport-related activities in both limestone and basalt rock mining was by far the largest source of emissions (45-62%) compared to indirect emission from purchased grid-electricity (34-40%). Some GHGs mitigation options and also challenges ahead for archiving environmental sustainability in the mining industry in Thailand were further raised.

THE MODERN TRENDS OF INFRASTRUCTURE DEVELOPMENT

Purpose – is to summarise and present the development of theoretical foundations of the process of integration of the national industrial infrastructure system based on logistic transformations. Methodology of research. Theoretical and methodological basis of the study are research works of domestic and foreign scholars on the integration of social and economic systems. The article used the dialectical method of cognition, as well as the following methods: a systematic and structural analysis, logical generalization – the study of the formation of scientific positions and forming the methodological foundations of the development of production infrastructure. Results. Implemented theoretical and methodological substantiation of the implementation of transformational changes infrastructural capacity in the context of sustainable development of the regional economic system. The transformation of the infrastructure capacity in the region is defined as a process of deep changes in the quantitative and qualitative characteristics of the Multisectoral infrastructure complex on the principles of sustainable development in the direction of achieving the optimum, tailored to the needs of the regional parameters of its operation, taking into account global trends and inherited experience. The authors constructed a conceptual framework based on the transformation of infrastructure transformation sector. Transport related activities have many impacts on the environment. The most important effects are contribution to climate change, to local air pollution, to noise levels, to biodiversity loss and natural resources depletion. Practical value. These findings have practical value in the development of regional strategies and programs of development in the context of the European integration vector.

Physical Activity Level and Associated Factors Among Higher Secondary School Students in Banke, Nepal: A Cross-Sectional Study.

This study was carried out to assess physical activity level and identify associated factors among higher secondary school students in Banke district, Nepal. A school-based, cross-sectional descriptive study was conducted among 405 students studying in grades 11 and 12 in 7 higher secondary schools selected randomly. A self-administered questionnaire based on the International Physical Activity Questionnaire was used to measure physical activity level. Only 5% of students were found to be inactive, and domestic and transport-related activities were major contributors to total physical activity score. No significant difference existed for total physical activity and domain-specific and activity-specific scores across different age groups when males and females were tested separately. Being male (P = .046), lower economic status (P = .026), living at a distance of less than 30 minutes (P = .007), walking/cycling to school (P < .001), and studying in government school (P < .001) were associated with increased physical activity scores on multivariate logistic regression analysis. Routine activities such as transport and household chores contributed greatly to total physical activity among students. This study highlights the need for physical activity promotion interventions at school addressing the associated factors and a need for greater focus on leisure-time physical activities.

Single-Till Versus Dual-Till Regulation of Airports

Most airports operate under public ownership, while some are privatized and economically regulated. Only a few airports are privately owned and experience little or no ex-ante regulation of airport charges. On the other hand, airports nowadays earn as much revenue from transport-related activities as from commercially-oriented business activities. Taken together, these two observations lead to a natural question: How to optimally integrate profits derived from commercial activities into the regulation of airport infrastructure charges? This question is addressed in this paper. We discuss basic issues that are relevant for the design of regulatory regimes for airports and how these issues can be tackled by using airport profits derived from commercial activities for infrastructure cost recovery. The main insights are summarized at the end of each section and then are further summarized in the conclusions section.

Global model simulations of the impact of ocean-going ships on aerosols, clouds, and the radiation budget

Abstract. International shipping contributes significantly to the fuel consumption of all transport related activities. Specific emissions of pollutants such as sulfur dioxide (SO2) per kg of fuel emitted are higher than for road transport or aviation. Besides gaseous pollutants, ships also emit various types of particulate matter. The aerosol impacts the Earth's radiation budget directly by scattering and absorbing the solar and thermal radiation and indirectly by changing cloud properties. Here we use ECHAM5/MESSy1-MADE, a global climate model with detailed aerosol and cloud microphysics to study the climate impacts of international shipping. The simulations show that emissions from ships significantly increase the cloud droplet number concentration of low marine water clouds by up to 5% to 30% depending on the ship emission inventory and the geographic region. Whereas the cloud liquid water content remains nearly unchanged in these simulations, effective radii of cloud droplets decrease, leading to cloud optical thickness increase of up to 5–10%. The sensitivity of the results is estimated by using three different emission inventories for present-day conditions. The sensitivity analysis reveals that shipping contributes to 2.3% to 3.6% of the total sulfate burden and 0.4% to 1.4% to the total black carbon burden in the year 2000 on the global mean. In addition to changes in aerosol chemical composition, shipping increases the aerosol number concentration, e.g. up to 25% in the size range of the accumulation mode (typically &gt;0.1 μm) over the Atlantic. The total aerosol optical thickness over the Indian Ocean, the Gulf of Mexico and the Northeastern Pacific increases by up to 8–10% depending on the emission inventory. Changes in aerosol optical thickness caused by shipping induced modification of aerosol particle number concentration and chemical composition lead to a change in the shortwave radiation budget at the top of the atmosphere (ToA) under clear-sky condition of about −0.014 W/m² to −0.038 W/m² for a global annual average. The corresponding all-sky direct aerosol forcing ranges between −0.011 W/m² and −0.013 W/m². The indirect aerosol effect of ships on climate is found to be far larger than previously estimated. An indirect radiative effect of −0.19 W/m² to −0.60 W/m² (a change in the atmospheric shortwave radiative flux at ToA) is calculated here, contributing 17% to 39% of the total indirect effect of anthropogenic aerosols. This contribution is high because ship emissions are released in regions with frequent low marine clouds in an otherwise clean environment. In addition, the potential impact of particulate matter on the radiation budget is larger over the dark ocean surface than over polluted regions over land.