Search

This paper presents an overall performance assessment of hybrid-electric medium-range transport aircraft, with the aim to evaluate the potential of such a propulsion technology towards the reduction in the environmental impact of aviation transport, in terms of both local air quality degradation in airport areas and climate change. The proposed approach presents distinct analyses of the environmental impact of transport aircraft, distinguishing climate-changing effects from local pollution effects so that the integration of hybrid-electric propulsion is carried out to face the two issues specifically. The proposed analysis, although of conceptual nature, presents a clear scenario in which, given the technological limitations of batteries, the use of hybrid-electric propulsion on medium-haul aircraft can only be useful to reduce local pollution. In contrast, other solutions are needed to mitigate the climate-changing impact. [ABSTRACT FROM AUTHOR]

Pollutant emissions from aircraft operations contribute to the degradation of air quality in and around airports. Meeting the ICAO's environmental certification standards regarding both gaseous and particulate aircraft engine emissions is one of the main challenges for air-transportation development over the coming years. To increase the accuracy of airport air pollution monitoring and prediction, advanced decision-making tools need to be developed. In this context, the present study aimed at demonstrating the modeling capabilities of an innovative methodology that accounts for the microscale evolution of aircraft emissions, both spatially and temporally. For this purpose, 3D high-resolution CFD simulations were carried out in the CAEPport configuration (medium-size mock airport) as defined by the Committee on Aviation Environmental Protection (CAEP/8) for local air-quality assessment. The modeled domain extends up to 8 km around the airport. A spatial resolution down to 1 m was used around buildings to refine the prediction of pollutant-emission concentrations. The model accounts for ambient meteorological conditions along with the background chemical composition. NOx emissions from main engines and auxiliary power units (APUs) were individually tracked along LTO trajectories with a time resolution down to 1 s. The impact of atmospheric stability was investigated in three cases, i.e., stable, neutral, and unstable. The results show NO2 dominating in apron areas due to the low power setting of main engines along APU contribution during extended parking. Conversely, a domination of NO emissions was observed at the runway threshold due to the high power setting of the main engines. Stable atmospheric conditions promoted higher NO and NO2 concentrations as compared to both neutral and unstable cases. The use of APUs contributed to higher concentrations of both NO and NO2 emissions and especially of NO2 in terminal areas. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) emission from various human activities has gained a great deal of attention due to their direct and indirect impacts on the atmosphere as well as human health. Despite the strong regulations and implementations driven by central government, i.e., top-down strategy, there still exists a certain gap between ultimate policy goals and actual effects of air quality implementations. For effective PM emission management, considering the local/provincial level of emission characteristic, i.e., bottom-up strategy should be also significant, because cities and provinces have different properties in industrial structure, geographical position, land use, and energy generation and usage. This study, therefore, has attempted to analyze the local PM emission inventory to discover reduction potential applying cluster analysis method as a case study for the Republic of Korea. As a result, five clustered groups that have similar emission features and common major emission sources among fugitive dust, energy production, non-industry, manufacturing industry, industrial process, road transport, non-road transport, waste, biomass burning, and other source were brought. The findings in this study implicate that further implementations for PM mitigation have to be understood the local-specific emission characteristics to effectively and efficiently address management policy, good practices, and budget planning/distribution. As future study, evaluating particular amounts of PM reduction potential and possible mitigation strategies covering both national derives and local/province situations are highly recommended. [ABSTRACT FROM AUTHOR]

This paper discusses how the efforts of authorities to limit the spread of COVID-19 have led to restrictions in people's mobility with significant impacts on air traffic operations worldwide. Zurich airport has experienced a drop of 91 per cent in aircraft movements from February to April 2020. The decrease in activity has led to a decrease in local emissions of 83 per cent for NOx, while NO2 concentrations at and around the airport decreased by only 50 per cent. Ultrafine particle numbers show similar values. The analysis further took into account the change in regional road traffic and the meteorology for comparable periods in 2019 and 2020, before and during the crisis. [ABSTRACT FROM AUTHOR]

Many European countries have adopted carbon dioxide–based (CO2-based) vehicle taxes to help reduce transportation sector emissions. The literature has shown that these policies reduce CO2 emissions but has not considered whether they affect emissions that harm local air quality. This paper analyzes whether CO2-based taxes have an unintended consequence of raising emissions of nitrogen oxides (NOx) and particulates, which harm local air quality. Using highly detailed data on European new vehicle registrations from 2002 through 2010, I estimate the effects of fuel costs and vehicle taxes on consumer vehicle choices. The CO2-based vehicle taxes reduce CO2 emissions but increase NOx and particulates emissions. The environmental harms from the NOx and particulates emissions roughly offset the benefits of the lower CO2 emissions. Because of the estimated substitution patterns, fuel-based CO2 taxes introduce milder trade-offs than do vehicle taxes. [ABSTRACT FROM AUTHOR]

The operation of aircraft auxiliary power units (APU) during ground time at airports causes emissions and noise and is not highly efficient. Instead, aircraft ground energy systems (AGES) provide technically feasible, economic viable and environmentally beneficial alternatives for providing electricity and preconditioned air to aircraft. This paper describes Zurich A irport's adopting a concept to install AGES for electricity and preconditioned air at all pier stands and fixed electrical system on open stands. The combination of a high technical serviceability, enforced local regulations and an attractive charging scheme has led to significant reductions of local and global emissions while providing cost savings to airlines. [ABSTRACT FROM AUTHOR]

Local air quality is a major concern for the population regularly exposed to high levels of air pollution. Due mainly to its aircraft engine activities during taxiing and take-off, the airport is often submitted to heterogeneous but important concentrations of NOx and Particulate Matter (PM). The study suggests an innovative approach to determining the air traffic impact on air quality at the scale of the airport, its runways, and its terminals, to be able to locate the persistent high-concentration spots, for example. The pollutant concentrations at 10 m resolution and 1 s time step are calculated in order to identify the most affected areas of an airport platform and their contributors. A real day of air traffic on a regional airport is simulated, using observations and aircraft trajectories data from radar streams. In order to estimate the aircraft emissions, the Air Transport Systems Evaluation Infrastructure (IESTA) is used. Regarding local air quality, IESTA relies on the non-hydrostatic meso-scale atmospheric model Meso-NH using its grid-nesting capabilities with three domains. The detailed cartography of the airport distinguishes between grassland, parking, and terminals, allowing the computation of exchanges of heat, water, and momentum between the different types of surfaces and the atmosphere as well as the interactions with the building using a drag force. The dynamic parameters like wind, temperature, turbulent kinetic energy, and pollutants concentration are computed at 10 m resolution over the 2 km - 4 km airport domain. The pollutants are considered in this preliminary study as passive tracers, without chemical reactions. This study aims at proving the feasibility of high-scale modelling over an airport with state-of-the-art physical models in order to better understand the repartition of pollutants over an airport, taking into account advection and turbulence in interactions with buildings and regional trends, emissions, Auxiliary Power Units (APU), taxiing, parking, take off. All these processes drive the model at each time step and are not averaged over one hour or more like in Gaussian or Lagrangian ones. This study is investigating the feasibility of high spatio-temporal air quality modelling for research purposes but not for operational forecasting. [ABSTRACT FROM AUTHOR]

In the EU-FP7 project APPRAISAL the current practice for integrated assessment modelling (IAM) of air quality in the EU was reviewed, limitations were identified and guidance for improvements was provided. In this article we present the guidance proposed by APPRAISAL. This guidance takes into account that a single IAM solution does not exist but that the different elements of the IAM methodology can be addressed in more or less detail taking into account the available data, the regional/local specificities, the financial resources and the actual purpose of the assessment. [ABSTRACT FROM AUTHOR]

Local air quality is a major concern for the population regularly exposed to high levels of air pollution. Due mainly to its aircraft engine activities during taxiing and take-off, the airport is often submitted to heterogeneous but important concentrations of NO x and Particulate Matter (PM). The study suggests an innovative approach to determining the air traffic impact on air quality at the scale of the airport, its runways, and its terminals, to be able to locate the persistent high-concentration spots, for example. The pollutant concentrations at 10 m resolution and 1 s time step are calculated in order to identify the most affected areas of an airport platform and their contributors. A real day of air traffic on a regional airport is simulated, using observations and aircraft trajectories data from radar streams. In order to estimate the aircraft emissions, the Air Transport Systems Evaluation Infrastructure (IESTA) is used. Regarding local air quality, IESTA relies on the non-hydrostatic meso-scale atmospheric model Meso-NH using its grid-nesting capabilities with three domains. The detailed cartography of the airport distinguishes between grassland, parking, and terminals, allowing the computation of exchanges of heat, water, and momentum between the different types of surfaces and the atmosphere as well as the interactions with the building using a drag force. The dynamic parameters like wind, temperature, turbulent kinetic energy, and pollutants concentration are computed at 10 m resolution over the 2 km × 4 km airport domain. The pollutants are considered in this preliminary study as passive tracers, without chemical reactions. This study aims at proving the feasibility of high-scale modelling over an airport with state-of-the-art physical models in order to better understand the repartition of pollutants over an airport, taking into account advection and turbulence in interactions with buildings and regional trends, emissions, Auxiliary Power Units (APU), taxiing, parking, take off. All these processes drive the model at each time step and are not averaged over one hour or more like in Gaussian or Lagrangian ones. This study is investigating the feasibility of high spatio-temporal air quality modelling for research purposes but not for operational forecasting.

The air quality impact of an airport due to both ground sources and air traffic emissions within the troposphere boundary layer is a relevant topic at a local scale, especially where the airport is surrounded by urbanized areas. The work analyses the emissions from the Amerigo Vespucci airport in Florence, Italy. The comparison between the present and the future layout of the airport, which is under project, is addressed, providing a possible tool to guide local air pollution prevention strategies within the framework of the strategic transport infrastructures development. The emission scenarios of the present and future airport layouts were estimated with EDMS 5.1.3, the software package issued by FAA (Federal Aviation Administration) which is an US-EPA (Environmental Protection Agency) preferred model for airport emissions evaluation. The total yearly emissions of NO X , CO, SO X , VOCs and PM 10 have been assessed, divided into the main phases of the LTO (landing and takeoff) cycle, provided for each aircraft. The results show that the takeoff phase is mainly responsible for NO X , SO X and PM 10 contributions. The AERMOD dispersion model was run over one year to evaluate the concentrations of those pollutants, modelled as chemically inert. The maximum concentrations occur close to the gate and the ground movement areas. However, the air quality standards ruled by Directive 50/2008/EU are never reached except for NO X , which shows an overall maximum of the annual average of about 40 μ g / m 3 , close to the standard for the vegetation health ( 50 μ g / m 3 ). [ABSTRACT FROM AUTHOR]

An aerofoil generates lift by transferring vertical momentum to the unperturbed flow. For an aerofoil of finite width, this effect is conventionally described through the generation of a pair of counter-rotating trailing vortices. For this paper we have modelled the swarm of vortices generated by an array of surface-mounted aerofoils and its effect on the distribution of a passive tracer released upwind of the array and show how such a tracer can be usefully lifted and dispersed. Using the notional trail of an exhaust plume emitted by an aircraft in its take-off roll at Heathrow, we show that some elements of the plume are lifted by tens of metres by the distance of the perimeter fence. Such an array might be of value in abating surface concentrations near any distributed surface source of pollution, e.g., a road, runway or landfill site - or perhaps in suppressing ground frosts. [ABSTRACT FROM AUTHOR]

Autonomous vehicles (AVs) are pointed out as the technology that will reshape the concept of mobility, with significant implications for the economy, the environment, and society. This fact will bring new challenge to cities urban planning. Research to anticipate the AVs impacts, maximizing their benefits and reduce trade-offs are currently crucial. This work investigates the potential challenges and benefits of gradually replace internal combustion engine human driven vehicles with different penetration rates of AVs - 10%, 30%, 50%, 70%, 90%, and 100% - in urban roads of different characteristics, either in terms of traffic singularities or volumes, and its related implications on air quality. For that purpose, two urban areas with distinct features, Porto and Aveiro, were selected as case studies, and a modelling setup composed of a traffic model, an emission model, and a local air quality model was applied. The results revealed that the AVs benefits are directly linked with the urban design and the road characteristics. In the Aveiro case study, the AVs promoted positive changes with average reductions in daily NOx emissions (compared with the baseline scenario, without AVs) ranging between −2.1% (for C10%) and −7.7% (for C100%). In line with the emissions impacts, positive effects were found on air quality, with average reductions of NO 2 concentrations up to −4% (for C100%). In Porto urban area, slight differences in NOx emissions were obtained (<2%), which implied no changes in the air quality levels. The distinct impact of AVs in the study areas is mostly explained by the traffic light coordination system and directional split distributions in the main roads. These results provide valuable insights to support decision-makers in the definition of strategies that allow the integration of these new emerging technologies in the road infrastructure, considering the features of the urban design, traffic profile and road characteristics. [Display omitted] • Benefits and challenges of autonomous vehicles (AVs) on air quality were assessed. • A traffic model, an emission model, and a local air quality model was applied. • AVs benefits are directly linked to urban morphology and road characteristics. • The results can support decision-makers in the definition of future mobility strategies. [ABSTRACT FROM AUTHOR]

Abstract: Particulate matter (PM) emissions, and the associated human health risks, are likely to continue increasing in urban environments of developing countries like Abidjan (Ivory Cost). This study evaluated the potential of leaves of several herbaceous and tree species as bioindicators of urban particulate matter pollution, and its variation over different land use classes, in a tropical area. Four species well distributed (presence frequencies >90%) over all land use classes, easy to harvest and whose leaves are wide enough to be easily scanned were selected, i.e.: Amaranthus spinosus (Amaranthaceae), Eleusine indica (Poaceae), Panicum maximum (Poaceae) and Ficus benjamina (Moraceae). Leaf sampling of these species was carried out at 3 distances from the road and at 3 height levels. Traffic density was also noted and finally biomagnetic parameters of these leaves were determined. Results showed that Saturation Isothermal Remanent Magnetization (SIRM) of leaves was at least 4 times higher (27.5×10−6 A) in the vicinity of main roads and industrial areas than in parks and residential areas. The main potential sources of PM pollution were motor vehicles and industries. The slightly hairy leaves of the herbaceous plant A. spinosus and the waxy leaves of the tree F. benjamina showed the highest SIRM (25×10−6 A). Leaf SIRM increased with distance to road (R2 >0.40) and declined with sampling height (R2 =0.17). The distance between 0 and 5m from the road seemed to be the most vulnerable in terms of PM pollution. This study has showed that leaf SIRM of herbaceous and tree species can be used to assess PM exposure in tropical urban environments. [Copyright &y& Elsevier]

This paper presents a comparison of modelled and measured annual mean NO2 concentrations around Zürich airport. Modelled concentrations were derived from the LASAT Lagrangian model for the airport and from a Gaussian plume model for the Zürich canton. The measured annual mean NO2 concentrations were monitored at stations within the airport. The modelled airport NO2 concentrations fell below 1 μg/m3 beyond 3 km from the airport's sources. The correlation between measured and modelled concentrations depended on the dominating source. Concentrations for road vehicle dominated sources were underestimated by the model, whereas concentrations from aircraft dominated sources tended to be overestimated. [ABSTRACT FROM AUTHOR]

In regulatory and public health contexts the long-term average pollutant concentration in the vicinity of a source is frequently of interest. Well-developed modelling tools such as AERMOD and ADMS are able to generate time-series air quality estimates of considerable accuracy, applying an up-to-date understanding of atmospheric boundary layer behaviour. However, such models incur a significant computational cost with runtimes of hours to days. These approaches are often acceptable when considering a single industrial complex, but for widespread policy analyses the computational cost rapidly becomes intractable. In this paper we present some mathematical techniques and algorithmic approaches that can make air quality estimates several orders of magnitude faster. We show that, for long-term average concentrations, lateral dispersion need not be accounted for explicitly. This is applied to a simple reference case of a ground-level point source in a neutral boundary layer. A scaling law is also developed for the area in exceedance of a regulatory limit value. [Copyright &y& Elsevier]

Meeting the demand for increased mobility, airports are adapting their infrastructure, but face the challenge of controlling their emissions in the light of the EU air quality standards. A possible way out is a joint and combined approach where the various aviation industry partners (airports, airlines, manufacturers and service providers) team up to develop and implement comprehensive mitigation programmes. Such programmes could include technological, regulatory, operational and economic measures alike. [ABSTRACT FROM AUTHOR]