Plume to Global-scale Atmospheric Impacts of Aviation Emissions


Book Description

High-altitude emissions from current subsonic aviation or from potentially future supersonic aircraft modify the total column ozone, thus leading to either increases in tropospheric ozone or a decrease in stratospheric ozone, with the latter causing larger UV flux at the ground. Both changes affect human health and, in this thesis, I identify a column ozone-neutral altitude for subsonic and supersonic aviation. Adjoint models of CTMs have been developed to quantify receptor-oriented sensitivities of environmental metrics (e.g. population-weighted ozone exposure) to emissions. Adjoint modeling overcomes the numerical cost of source-oriented sensitivity analysis, as performed by forward models. However, adjoint models of atmospheric chemistry have historically been limited to the troposphere. In this thesis, I build upon previous work and extend the GEOS-Chem Adjoint to further include stratospheric processes, and then validate the sensitivities with multi-year scenarios. I then present adjoint-derived sensitivities to identify column ozone-neutral altitudes for subsonic and supersonic aviation, based on their respective emission characteristics. I find that the 12 - 15 km altitude band is approximately column ozone-neutral for aviation emissions. Neglecting the effects of plume-scale processes introduces a positive bias in the column ozone-neutral altitude that varies between 0.3 up to 1 km.




Atmospheric Effects of Aviation


Book Description

Aviation is an integral part of the global transportation network, and the number of flights worldwide is expected to grow rapidly in the coming decades. Yet, the effects that subsonic aircraft emissions may be having upon atmospheric composition and climate are not fully understood. To study such issues, NASA sponsors the Atmospheric Effects of Aviation Program (AEAP). The NRC Panel on Atmospheric Effects of Aviation is charged to evaluate AEAP, and in this report, the panel is focusing on the subsonic assessment (SASS) component of the program. This evaluation of SASS/AEAP was based on the report Atmospheric Effects of Subsonic Aircraft: Interim Assessment Report of the Advanced Sub-sonic Technology Program, on a strategic plan developed by SASS managers, and on other relevant documents.




Modeling Aircraft Contrails and Emission Plumes for Climate Impacts


Book Description

Aircraft emissions lead to contrails and change cloud coverage in the upper troposphere/lower stratosphere, but their quantitative impact on climate is highly uncertain. As environmental policy turns toward regulating anthropogenic climate change components, it will be necessary to improve quantification of the climate impacts of aviation. Toward this end, we present two models of aircraft emissions. The first model is a large eddy simulation (LES) with three-dimensional, eddy-resolving flow physics and ice deposition/sublimation microphysics. Modeled ice properties, cloud optical depths, and contrail width growth rates are consistent with observational field studies. A series of sensitivity cases shows the effect of various parameters over twenty minutes of simulation time. The analysis focuses on properties such as contrail optical depth and cross-sectional width that are relevant to climate impacts. Vertical wind shear is found to have the strongest effect on these properties through the kinematic spreading of the contrail. In cases with no shear, optical depth is most sensitive to aircraft type and ambient humidity. One model parameter, the effective emission index of ice crystals, is also found to affect optical depth. A subset of the LES cases is run for two hours of simulation time to approach the scale of dynamical time steps modeled by global climate simulations. These cases use more realistic ice microphysics, including sedimentation, and forced ambient turbulence, both of which are processes that control contrail development at late times. The second model is a simple, low cost parameterization of aircraft plume dynamics, intended to be used as a subgrid plume model (SPM) within large scale atmospheric simulations. The SPM provides basic plume cross-section time advancement that has been used as a dilution model within a coupled global atmosphere-ocean climate simulation to study the effects of aviation on air quality and climate. Comparison to the twenty-minute and two-hour LES results demonstrates that the SPM captures important plume development characteristics under the effect of vertical shear and atmospheric turbulence.




Modeling Aircraft Contrails and Emission Plumes for Climate Impacts


Book Description

Aircraft emissions lead to contrails and change cloud coverage in the upper troposphere/lower stratosphere, but their quantitative impact on climate is highly uncertain. As environmental policy turns toward regulating anthropogenic climate change components, it will be necessary to improve quantification of the climate impacts of aviation. Toward this end, we present two models of aircraft emissions. The first model is a large eddy simulation (LES) with three-dimensional, eddy-resolving flow physics and ice deposition/sublimation microphysics. Modeled ice properties, cloud optical depths, and contrail width growth rates are consistent with observational field studies. A series of sensitivity cases shows the effect of various parameters over twenty minutes of simulation time. The analysis focuses on properties such as contrail optical depth and cross-sectional width that are relevant to climate impacts. Vertical wind shear is found to have the strongest effect on these properties through the kinematic spreading of the contrail. In cases with no shear, optical depth is most sensitive to aircraft type and ambient humidity. One model parameter, the effective emission index of ice crystals, is also found to affect optical depth. A subset of the LES cases is run for two hours of simulation time to approach the scale of dynamical time steps modeled by global climate simulations. These cases use more realistic ice microphysics, including sedimentation, and forced ambient turbulence, both of which are processes that control contrail development at late times. The second model is a simple, low cost parameterization of aircraft plume dynamics, intended to be used as a subgrid plume model (SPM) within large scale atmospheric simulations. The SPM provides basic plume cross-section time advancement that has been used as a dilution model within a coupled global atmosphere-ocean climate simulation to study the effects of aviation on air quality and climate. Comparison to the twenty-minute and two-hour LES results demonstrates that the SPM captures important plume development characteristics under the effect of vertical shear and atmospheric turbulence.







The Air Quality and Health Impacts of Aviation in Asia


Book Description

Aviation in Asia is growing more rapidly than other regions around the world. Adverse health impacts of aviation are linked to an increase in the concentration of particulate matter smaller than 2.5 [mu]m in diameter (PM2.5). This thesis aims to quantify the regional-scale health impacts of aviation in Asia by modeling the air quality in Asia and applying Concentration-Response Functions (CRFs) to the aviation-attributable PM2.5 perturbations. In order to quantify the perturbation to the ambient air quality due to aviation emissions, the Community Multiscale Air Quality (CMAQ) model---a regional-scale chemical transport model--utilized after its performance is evaluated in predicting ambient PM2.5 concentrations. Aviation emissions for 2006 are from the Aviation Environmental Design Tool (AEDT), and background emissions for 2006 are generated using a combination of four Asian and global emissions inventories. A domain average increase of approximately 15ng/m3 in annual PM2.5 is observed due to full flight aviation emissions, while Landing and Takeoff (LTO) cycle emissions account for an increase of approximately 0.75ng/m3. Calculations using two different CRFs used by the EPA and the WHO estimate the following amount of aviation-attributable premature mortalities in Asia: 9400 (using the EPA CRF) or 6400 (using the WHO CRF) in the full flight scenario, and 550 or 390 in the LTO cycle scenario. Finally, comparisons to the global-scale model simulation results show consistent spatial patterns of air quality perturbations, while the regional-scale model estimates approximately 1.4 times the number of mortalities obtained from corresponding global-scale studies.




Aviation and the Global Atmosphere


Book Description

This Intergovernmental Panel on Climate Change Special Report is the most comprehensive assessment available on the effects of aviation on the global atmosphere. The report considers all the gases and particles emitted by aircraft that modify the chemical properties of the atmosphere, leading to changes in radiative properties and climate change, and modification of the ozone layer, leading to changes in ultraviolet radiation reaching the Earth. This volume provides accurate, unbiased, policy-relevant information and is designed to serve the aviation industry and the expert and policymaking communities.




Global Sources of Local Pollution


Book Description

Recent advances in air pollution monitoring and modeling capabilities have made it possible to show that air pollution can be transported long distances and that adverse impacts of emitted pollutants cannot be confined to one country or even one continent. Pollutants from traffic, cooking stoves, and factories emitted half a world away can make the air we inhale today more hazardous for our health. The relative importance of this "imported" pollution is likely to increase, as emissions in developing countries grow, and air quality standards in industrial countries are tightened. Global Sources of Local Pollution examines the impact of the long-range transport of four key air pollutants (ozone, particulate matter, mercury, and persistent organic pollutants) on air quality and pollutant deposition in the United States. It also explores the environmental impacts of U.S. emissions on other parts of the world. The book recommends that the United States work with the international community to develop an integrated system for determining pollution sources and impacts and to design effective response strategies. This book will be useful to international, federal, state, and local policy makers responsible for understanding and managing air pollution and its impacts on human health and well-being.




For Greener Skies


Book Description

Each new generation of commercial aircraft produces less noise and fewer emissions per passenger-kilometer (or ton-kilometer of cargo) than the previous generation. However, the demand for air transportation services grows so quickly that total aircraft noise and emissions continue to increase. Meanwhile, federal, state, and local noise and air quality standards in the United States and overseas have become more stringent. It is becoming more difficult to reconcile public demand for inexpensive, easily accessible air transportation services with concurrent desires to reduce noise, improve local air quality, and protect the global environment against climate change and depletion of stratospheric ozone. This situation calls for federal leadership and strong action from industry and government. U.S. government, industry, and universities conduct research and develop technology that could help reduce aircraft noise and emissions-but only if the results are used to improve operational systems or standards. For example, the (now terminated) Advanced Subsonic Technology Program of the National Aeronautics and Space Administration (NASA) generally brought new technology only to the point where a system, subsystem model, or prototype was demonstrated or could be validated in a relevant environment. Completing the maturation process-by fielding affordable, proven, commercially available systems for installation on new or modified aircraft-was left to industry and generally took place only if industry had an economic or regulatory incentive to make the necessary investment. In response to this situation, the Federal Aviation Administration, NASA, and the Environmental Protection Agency, asked the Aeronautics and Space Engineering Board of the National Research Council to recommend research strategies and approaches that would further efforts to mitigate the environmental effects (i.e., noise and emissions) of aviation. The statement of task required the Committee on Aeronautics Research and Technology for Environmental Compatibility to assess whether existing research policies and programs are likely to foster the technological improvements needed to ensure that environmental constraints do not become a significant barrier to growth of the aviation sector.




Climate Change and Aviation


Book Description

'This is a timely, challenging and fascinating book on a topic of central importance to the success or otherwise of our climate change policies. It sets down a clear marker for what has to be done in the aviation sector.' Professor John Whitelegg, Stockholm Environment Institute, University of York, UK 'Climate Change and Aviation presents a clear picture of the transport sector's greatest challenge: how to reconcile aviation's immense popularity with its considerable environmental damage and its dependence on liquid hydrocarbon energy sources. This book avoids wishful thinking and takes the much harder, but more productive, path of considering difficult solutions that clash with short-term and short-sighted expectations about the unlimited growth potential for flying.' Professor Anthony Perl, Urban Studies Program, Simon Fraser University, Canada 'A convincing and timely collection that brings together an impressive range of expertise. The book integrates various perspectives into a powerful core argument - we must do something, and quickly, to tackle the impact of aviation on our environment. The authors recognise the political difficulties associated with promoting change but present constructive options for policy makers. Required reading, especially for transport ministers set on promoting the growth of air travel.' Professor Jon Shaw, Director of the Centre for Sustainable Transport, University of Plymouth, UK Trends such as the massive growth in availability of air travel and air freight are among those which have led to aviation becoming one of the fastest growing emitters of greenhouse gases. These trends have also caused a shift in expectations of how we do business, where we go on holiday, and what food and goods we can buy. For these reasons aviation is (and is set to stay) high up on global political, organizational and media agendas. This textbook is the first to attempt a comprehensive review of the topic, bringing together an international team of leading scientists. Starting with the science of the environmental issues, it moves on to cover drivers and trends of growth, socio-economics and politics, as well as mitigation options, the result being a broad yet detailed examination of the field. This is essential reading for undergraduate and postgraduate courses in transport, tourism, the environment, geography and beyond, while also being a valuable resource for professionals and policymakers seeking a clear understanding of this complex yet urgently pressing issue.