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Abstract Megacities in emerging markets are a relatively new phenomenon. The size of these cities combined with the high growth rates provides substantial sustainability challenges. Urban freight transport (UFT) contributes to these challenges. Despite its relatively low share as part of total traffic, the negative impact of UFT is disproportionate. Improving the sustainability in this context is inevitable in the light of further prospected urbanization. To study this topic, a theoretical framework is developed which is subsequently applied on literature. This allows characterizing the UFT system in a city. Such a framework is currently lacking. The framework is developed around the components of a UFT system (demand, supply and context) and the factors influencing these components. Factors include the different supply chains (demand), vehicles used (supply) and traffic measures (context). It is applied to analyze the UFT system in megacities in emerging markets. Results show that demand in different supply chains is fragmented as well as the transport. Uncontrolled sprawl and the existence of an informal economy further contribute to the complexity to regulate UFT. Based hereupon, we discuss efforts to move to more sustainable UFT in this context.

Growing concern over emissions from increased airport operations has resulted in a need to assess the impact of aviation related activities on local air quality in and around airports, and to develop strategies to mitigate these effects. One such strategy being investigated is the use of alternative fuels in aircraft engines and auxiliary power units (APUs) as a means to diversify fuel supplies and reduce emissions. This paper summarizes the results of a study to characterize the emissions of an APU, a small gas turbine engine, burning conventional Jet A-1, a fully synthetic jet fuel, and other alternative fuels with varying compositions. Gas phase emissions were measured at the engine exit plane while PM emissions were recorded at the exit plane as well as 10 m downstream of the engine. Five percent reduction in NO(x) emissions and 5-10% reduction in CO emissions were observed for the alternative fuels. Significant reductions in PM emissions at the engine exit plane were achieved with the alternative fuels. However, as the exhaust plume expanded and cooled, organic species were found to condense on the PM. This increase in organic PM elevated the PM mass but had little impact on PM number.

Many households in Cameroon live in energy poverty. Thus, energy usage and energy efficiency have become increasingly important in Cameroon. An important step towards improving building energy efficiency is knowledge about household energy appliances. In Cameroon, the construction sector is mostly informal, presenting huge challenges for stakeholders including clients or dwelling owners to establish quality factors of household energy appliances for use in various building projects. Furthermore, studies about household energy appliances are scarce. The aim of this study is to investigate household energy appliances in relation to energy efficiency in dwellings. To achieve this aim, 15 dwellings in the political capital Yaounde of Cameroon were surveyed. Given the wider nature of building energy efficiency and the limited research materials about the same, the scope was limited to typology of household energy appliances, typical dwellings’ characteristics and energy consumption pattern. Some factors that have influence on energy consumption/pattern such as occupants’ daily activities were also considered. Although this study is still in its preliminary stages, the findings reported here can be useful in conducting detail research in the future.

The need for achieving efficient and sustainable use of water resources is pressing, however, this often requires better understanding of the potential of water conservation, taking into account the impact on return flows, and the costs in relation to sectoral benefits. Using modelling and limited observational data we explore the costs and potential water savings of 24 combinations of water conservation measures in the Rufiji basin, Tanzania. We compare these costs with estimates of the value such water savings could generate from water use in three important economic sectors; agriculture, energy and downstream ecosystems with high tourism potential. The cost of water conservation measures (median: 0.07 USD m−3) is found to be: higher than the value of most uses of water for agriculture (growing crops in expanded irrigation sites) and the median value for hydropower generation (from a new mega dam currently under construction); and lower than the ecosystem value. Nevertheless, under our modelling assumptions, the volume of additional water required to supply planned irrigation expansion in the basin could be reduced by 1.5 BCM using water conservation methods that would be financially viable, given the value of competing uses of water. Water savings of this magnitude would reduce potential trade-offs between use of water for hydropower and ecosystem services, by allowing peak environmental flow releases even in dry years, and without reducing firm energy generation. This methodology is transferable and relevant for producing realistic assessments of the financial incentives for long-term sustainable water use in agriculture, given incentives for other uses. With most reservoirs now being built for multiple purposes improved understanding of trade-offs between different sectors and functions is needed.

Taking holistic actions to improve urban air quality is central to reducing the health risks associated with urbanisation, yet local evidence-based and institutional frameworks to achieve this are still challenging especially in many low-and middle-income countries (LMICs). This paper develops and applies an integrated systemic approach to explore the state of air quality management in Nairobi, Kenya; as an LMIC exemplar city. The urban diagnostics approach developed assesses current particulate matter air pollution in Nairobi; quantifies anthropogenic emissions for the years 2015 and 2020 and projects scenarios of impacts of actions and inactions to 2030. This was combined with a review of grey literature on air quality policies, urban development and interviews with key stakeholders. The analysis suggests that commendable progress has been made to improve air quality in Nairobi but continuing hazardous levels of air pollution still require concerted policy efforts. Data available for numerical simulations have low spatial resolution and are generated from global emission inventories that can miss or misrepresent local emission sources. The current air quality data gap that needs to be addressed are highlighted. Strong political support is required to ensure that current air quality improvement approaches are evidence based to achieve long-term sustainability goals.

Children empowerment should be a core component of any responsible tourism initiatives and their involvement and support is required to achieving the Sustainable Development Goals (SDGs). Drawing o...

Abstract Most of the world’s energy consumption is greatly dependent on fossil fuel, which is exhaustible and is being used extensively due to continuous escalation in the world’s population and development. This valuable resource needs to be conserved and its alternatives need to be explored. In this perspective, dissemination and utilisation of renewables such as solar energy has gained worldwide momentum since the onset of oil crises of 1970s. Moreover, burning of fuels is the principal cause of air pollution, and possibly environmental warming. Saudi Arabia, being blessed with a fairly high level of solar radiation, is a suitable candidate for deployment of solar photo-voltaic (PV) panels for power generation during crisis. Literature indicates that commercial/residential buildings in Saudi Arabia consume an estimated 10–45% of the total electrical energy generated/consumed. In the present study, hourly mean solar radiation data for the period 1986–1993 recorded at the solar radiation and meteorological monitoring station, Dhahran (26° 32′ N, 50° 13′ E), Saudi Arabia, have been analyzed to investigate the potential of utilizing hybrid (PV+diesel) power systems to meet the load requirements of a typical commercial building (with an annual electrical energy demand of 620,000 kWh). The monthly average daily solar global irradiation for Dhahran ranges from 3.61 to 7.96 kWh/m 2 . The hybrid systems considered in the present analysis consist of different combinations of PV panels/modules (different array sizes) supplemented with a battery storage unit and diesel back-up. The study shows that with a combination of 3700 m 2 PV together with 12 h of battery storage, the diesel back-up system has to provide 6% of the load demand. However, in the absence of a battery bank, about 56% of the load needs to be provided by the diesel system.

Traditional top-down strategies to reduce climate-change-related risks have often failed to produce tangible results in vulnerable urban areas of the Global South. Approaches based on the co-production of adaptation solutions between diverse stakeholders offer promising alternative strategies. This contribution draws on our experiences in growing informal and low-income urban areas in two Latin American cities, Medell�n (Colombia) and Puebla (Mexico). These communities lack adequate access to clean water and are exposed to risks related to increasingly frequent high-intensity rainfall events, making water management a key consideration for risk reduction. However, the factors driving insufficient water access and the perceptions of risks vary in each location, demonstrating the need for context-specific solutions. We explore how increasing community agency and co-creating knowledge for risk management between diverse stakeholders at a range of geographical scales can contribute to redressing existing social and environmental injustices, by identifying, implementing, and scaling up technically appropriate and culturally sustainable solutions aimed at reducing climate-change-related risks.