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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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DOE OSTI2023

High-Reliability Systems and the Control of National Security Data and Information

High-reliability systems are characterized by catastrophic implications in the event of failure. These implications can include substantive damage to the environment, social order, and loss of life. Examples of high-reliability systems include nuclear submarines, nuclear reactors, the electric grid, and nuclear weapons. Due to the catastrophic implications of failure, there are heightened awareness and control mechanisms surrounding related data and information. However, defining the difference between data and information is often ambiguous across scholarly disciplines and in United States policy and legislation. For high-reliability systems, the implications of ambiguity between data and information may affect the security of United States interests and even cost lives. For security, data are raw facts or figures without context, while information is the compilation or articulation of data that forms context. Security depends on clarity in the differences between data and information and how to control them. Control is necessary to ensure that data and information are not unintentionally released to foreign governments, the public, or those without need-to-know. A primary concern in the practice of security is the control of data to avoid the unintended conversion to information. Intra-institutionally, this control is highly complex given the amalgam of legacy data systems and the numerous and constantly evolving nature of modern data systems that were not necessarily designed to be integrated. The complexity of this concern is augmented when institutions are part of interinstitutional collaborations or networks of public-private partnerships that share data and information. Additionally, institutions that share data as a function of policy and legislative action— particularly formally integrated data and information system infrastructures—may be at higher security risk. This paper will present an intra-institutional paradigm that utilizes and integrates concepts from numerous disciplines to frame a critical and underspecified practical issue in security—controlling for the unintended conversion of data to information.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2023

High-Reliability Systems and the Control of National Security Data and Information

High-reliability systems are characterized by catastrophic implications in the event of failure. These implications can include substantive damage to the environment, social order, and loss of life. Examples of high-reliability systems include nuclear submarines, nuclear reactors, the electric grid, and nuclear weapons. Due to the catastrophic implications of failure, there are heightened awareness and control mechanisms surrounding related data and information. However, defining the difference between data and information is often ambiguous across scholarly disciplines and in United States policy and legislation. For high-reliability systems, the implications of ambiguity between data and information may affect the security of United States interests and even cost lives. For security, data are raw facts or figures without context, while information is the compilation or articulation of data that forms context. Security depends on clarity in the differences between data and information and how to control them. Control is necessary to ensure that data and information are not unintentionally released to foreign governments, the public, or those without need-to-know. A primary concern in the practice of security is the control of data to avoid the unintended conversion to information. Intra-institutionally, this control is highly complex given the amalgam of legacy data systems and the numerous and constantly evolving nature of modern data systems that were not necessarily designed to be integrated. The complexity of this concern is augmented when institutions are part of inter-institutional collaborations or networks of public-private partnerships that share data and information. Additionally, institutions that share data as a function of policy and legislative action—particularly formally integrated data and information system infrastructures—may be at higher security risk. This paper will present an intra-institutional paradigm that utilizes and integrates concepts from numerous disciplines to frame a critical and underspecified practical issue in security—controlling for the unintended conversion of data to information.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2024

IRIS Reimagined: Advancements in Intelligent Runtime System for Task-Based Programming

Task-based programming models are gaining traction in scientific computing. IRIS is a portable runtime system that exploits multiple heterogeneous programming systems and can discover available resources and manage multiple diverse programming systems (e.g., CUDA, Hexagon, HIP, Level Zero, OpenCL, and OpenMP) simultaneously. It accounts for the constraints of task dependencies and provides customizable scheduling policies to map those tasks to heterogeneous devices. In this paper, we present new capabilities added to IRIS to improve its portability for heterogeneous programming, build-friendliness, and performance efficiency. The new additions include vendor-specific kernel support, a runtime system with a foreign function interface to eliminate writing wrapper or boilerplate code for heterogeneous kernels, an easy-to-use and configurable CMake-based build environment, automatic and efficient data transfers and orchestration, and the Hunter and DAGGER toolchains to evaluate IRIS’s task scheduling algorithms.

Miniskar, Narasinga Rao↗
NASA NTRS2012

Integrating NASA Satellite Data Into USDA World Agricultural Outlook Board Decision Making Environment To Improve Agricultural Estimates

The USDA World Agricultural Outlook Board (WAOB) is responsible for monitoring weather and climate impacts on domestic and foreign crop development. One of WAOB's primary goals is to determine the net cumulative effect of weather and climate anomalies on final crop yields. To this end, a broad array of information is consulted. The resulting agricultural weather assessments are published in the Weekly Weather and Crop Bulletin, to keep farmers, policy makers, and commercial agricultural interests informed of weather and climate impacts on agriculture. The goal of the current project is to improve WAOB estimates by integrating NASA satellite precipitation and soil moisture observations into WAOB's decision making environment. Precipitation (Level 3 gridded) is from the TRMM Multi-satellite Precipitation Analysis (TMPA). Soil moisture (Level 2 swath and Level 3 gridded) is generated by the Land Parameter Retrieval Model (LPRM) and operationally produced by the NASA Goddard Earth Sciences Data and Information Services Center (GBS DISC). A root zone soil moisture (RZSM) product is also generated, via assimilation of the Level 3 LPRM data by a land surface model (part of a related project). Data services to be available for these products include GeoTIFF, GDS (GrADS Data Server), WMS (Web Map Service), WCS (Web Coverage Service), and NASA Giovanni. Project benchmarking is based on retrospective analyses of WAOB analog year comparisons. The latter are between a given year and historical years with similar weather patterns and estimated crop yields. An analog index (AI) was developed to introduce a more rigorous, statistical approach for identifying analog years. Results thus far show that crop yield estimates derived from TMPA precipitation data are closer to measured yields than are estimates derived from surface-based precipitation measurements. Work is continuing to include LPRM surface soil moisture data and model-assimilated RZSM.

Teng, William↗
NASA NTRS1986

Physics through the 1990s: An overview

The volume details the interaction of physics and society, and presents a short summary of the progress in the major fields of physics and a summary of the other seven volumes of the Physics through the 1990s series, issues and recommended policy changes are described regarding funding, education, industry participation, small-group university research and large facility programs, government agency programs, and computer database needs. Three supplements report in detail on international issues in physics (the US position in the field, international cooperation and competition-especially on large projects, freedom for scientists, free flow of information, and education of foreign students), the education and supply of physicists (the changes in US physics education, employment and manpower, and demographics of the field), and the organization and support of physics (government, university, and industry research; facilities; national laboratories; and decision making). An executive summary contains recommendations for maintaining excellence in physics. A glossary of scientific terms is appended.

Source record↗
DOE OSTI2017

Co-benefits of global, domestic, and sectoral greenhouse gas mitigation for US air quality and human health in 2050

Policies to reduce greenhouse gas (GHG) emissions can bring ancillary benefits of improved air quality and reduced premature mortality, in addition to slowing climate change. Here we study the co-benefits of global and domestic GHG mitigation on US air quality and human health in 2050 at fine resolution using dynamical downscaling, and quantify for the first time the co-benefits from foreign GHG mitigation. Relative to a reference scenario, global GHG reductions in RCP4.5 avoid 16000 PM2.5-related all-cause deaths yr-1 (90% confidence interval, 11700-20300), and 8000 (3600-12400) O3-related respiratory deaths yr-1 in the US in 2050. Foreign GHG mitigation avoids 15% and 62% of PM2.5- and O3-related total avoided deaths, highlighting the importance of foreign GHG mitigation on US human health benefits. GHG mitigation in the US residential sector brings the largest co-benefits for PM2.5-related deaths (21% of total domestic co-benefits), and industry for O3 (17%). Monetized benefits, for avoided deaths from ozone, PM2.5, and heat stress from a related study, are $148 ($96-201) per ton CO2 at high valuation and $49 ($32-67) at low valuation, of which 36% are from foreign GHG reductions. These benefits likely exceed the marginal cost of GHG reductions in 2050. The US gains significantly greater co-benefits when coordinating GHG reductions with foreign countries. Similarly, previous studies estimating co-benefits locally or regionally may greatly underestimate the full co-benefits of coordinated global actions.

Zhang, Yuqiang (ORCID:0000000291617086)↗
DOE OSTI2021

Revisiting the Temporal Leontief Inverse: New Insights on the Analysis of Regional Technological Economic Change

The current availability of longer series of input-output tables, as well as the release of global input-output databases, has fostered a growing literature analyzing changes in the economic structure and their drivers. In this paper, we take advantage of these time-series by proposing a methodology designed to trace the contribution of different drivers of the change in interindustrial relationships over time. Based on the Temporal Leontief Inverse (TLI), the Extended TLI (ETLI) decomposes the economy-wide effects of changes in direct interindustrial links between years, isolating the impact of different determinants of economic (environmental, energy, etc.) spillovers according to the interests of the researcher. For example, one can explore how the multipliers of a particular industry were affected by changes in technology of other sectors and in the own sector; by changes in trade patterns in specific countries; by indirect changes in intraregional production chains in foreign nations; etc. The ETLI is illustrated by uncovering certain hidden effects not captured in a previous application of the original TLI to the Chicago region between 1980-1997.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2025

Critical minerals lists for low-carbon transitions: Reviewing their structure, objectives, and limitations

Critical minerals lists have flourished in the past decade, in particular linked to the importance of critical minerals for low-carbon transitions. We identified 27 critical minerals or materials lists across 15 countries and the European Union (EU). These lists are designed to attract public and private attention and investments to secure both domestic and foreign supplies. This review article fills a gap in the existing literature by analyzing the ways in which these lists are defined and utilized by countries engaged in a mineral rush. We focus our attention on three categories of minerals – battery minerals, platinum-group metals (PGMs), and rare earth elements (REEs) that are particularly important to energy transitions. We situate this research in the broader legal and administrative developments that have driven critical minerals policies in the past decade. We provide an in-depth analysis of the commonalities and variations in the raw materials included in these lists, and identify six core limitations of critical minerals lists: (1) unclear links between criticality assessments and mineral prioritization (2) failure to account for the full mineral value-chain; (3) limited strategic alignment between allied nations; (4) limited flexibility in dynamic environments (5) limited consideration for recycling and by-product sourcing; and (6) reliance on incomplete reserve and resource data.

Battery minerals↗
DOE OSTI2017

A Study of China s Explosive Growth in the Plug-in Electric Vehicle Market

The year 2015 marks a turning point in China s plug-in electric vehicle (PEV) or new energy vehicle (NEV) industry, with an explosive growth in both productions and sales, following the gloomy period of 2009-2012. The PEV production in 2015 reached a record level of nearly 380,000 units, a 352 % increase from 2014, making China the largest PEV market in the world. For the potential implications on energy and the environment, it is worth studying the driving forces of China s PEV market and understanding its future trajectory and dynamics. The key findings of this report are listed in the following. Though controversial, the government monetary incentives have played a significant role to impel China to be the largest light PEV (191,100 units) market in the world. Chinese vehicle buyers appear more price sensitive on PEVs. Inexpensive low-cost micro electric vehicles are the most popular vehicle model in China s PEV market (38.9 % of the PEV market in 2015). In contrast, the premium or luxury vehicles are more popular in the gasoline vehicle segment. In fact, China is expected to be the largest premium car market in 2016. The PEV sales growth is primarily possible because of the young domestic private-owned auto manufacturers, which are mostly located in south China. Top-tier conventional vehicle automakers in China appear to be less proactive in the PEV market, based on market shares. This is in clear contrast to the U.S. market, where major automakers are generally the primary players in the PEV market. The PEVs produced by the domestic automakers are concentrated in the low-end market segment, while the high-end vehicle segment is dominated by the foreign brands. At present, the substantial market growth and government subsidies afford the domestic entrants to quickly gain profits in the low-end segment. The PEV consumers in China are very sensitive to the vehicle price, thus prefer the PEVs with cheaper prices after government subsidies, and care less about the driving quality and comfort. In contrast, most PEV consumers in the United States (U.S.) have higher incomes, view the PEVs as a high-status symbol, and care less about the vehicle prices, and therefore welcome the premium PEVs more in the U.S. The PEV financial subsidies by the Chinese government are divided into three stages based on the strategic directions and policies. In 2009 2012, government incentives concentrated on the public fleet vehicles, while excluding the individual consumers from the subsidies in most cities. In 2013 2015, comprehensive central/local government incentives were extended to all vehicle purchasers including the individual buyers in most cities, which was conducive to the phenomenal growth of the PEV sales. For years 2016 to 2020, monetary incentives are being phased out and will be substituted by other non-monetary incentives (such as the standards for Chinese Cooperate Average Fuel Consumption and New Energy Vehicle Credits) for the sustainable development of the PEV market. The PEV subsidy fraud has drawn attention by the central government, which prompts the government to be more prudent about monetary incentives. With the advantage of high acceptance in the PEV market and integrated EV charging infrastructure, the region with better economic development brings a more aggressive PEV roll-out plan to the municipalities who are more willing to solve the local urban pollution while keeping the automotive market in sustainable growth. On the one hand, the local automakers are offered abundant subsidies from the Chinese government to those who intend to help the Chinese automotive industry seize the industrial upgrading opportunity to transform its manufacturing sector, and they have taken most shares of the PEV market. On the other hand, facing the trade barriers, the foreign automakers have dominated the premium PEV sales in China, although their total market shares in the PEV market are much less than the domestic automakers. In diverse selectable alternative fuel vehicle technologies, China has put its focus on the PEV technologies for the technological modernization in the automotive industry; the research and development in fuel cell vehicle technologies in China is less competitive compared with other countries such as Japan and the U.S. With the demand of batteries from the PEV automakers, the Chinese EV battery industry is aggressively expanding. It has risks in excessive production capacity, and faces the challenges from the competitors from Japan and South Korea.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Energy & Environmental Research Center (EERC)–U.S. Department of Energy (DOE) Joint Program on Research and Development for Fossil Energy-Related Resources

The EERC teamed with the DOE National Energy Technology Laboratory to conduct complementary research and development under the Joint Program on Research and Development for Fossil Energy-Related Resources (Cooperative Agreement No. DE-FC26-08NT43291). This 10-year program merged two previous 10-year agreements—DE-FC26-98FT40320 and DE-FC26-98FT40321—into a single follow-on agreement. The Fossil Energy cooperative agreement between DOE and the EERC was initiated in 1983 when the EERC was defederalized. This dynamic 35-year partnership has evolved to further research in areas that address DOE Office of Fossil Energy program goals while serving the missions and exploiting the strengths of both organizations through this agreement and a new 5-year Fossil Energy-Related Resources cooperative agreement established in 2015. As the 10-year program has ended, the purpose of this report is to summarize the activity and significant outcomes that were accomplished by the EERC. This program is an excellent model for research, development, demonstration, and commercialization partnerships between government, industry, and the applied science and engineering communities to bring cutting-edge science closer to commercial application. The overarching goal was to support DOE Fossil Energy goals by advancing the scientific knowledge and technical development essential to ensuring future sustainable supplies of affordable energy and clean water, protecting and restoring the environment, and reducing dependence on foreign energy sources, thereby increasing U.S. energy security. The strategic objective was to advance continued use of domestic fossil fuels as a mainstay of U.S. energy production by making fossil energy systems nonpolluting and more efficient, capturing and sequestering greenhouse gases, and integrating the use of fossil and renewable energy sources into the energy mix. The research achievements from this partnership have exceeded the goals and objectives by contributing substantially to the development of science-based energy and environmental policy, educational foundations for science and technology, and commercialization and international marketing of energy technologies. The program comprised 75 individual projects, which included basic/applied fossil energy research projects involving no cost share and development, demonstration, and commercialization projects (many derived from applied research projects) that included nonfederal cost share of approximately 40% (the contractually required minimum level of cumulative nonfederal cost share was 29%). In all, 32,798,698 of federal funding was leveraged with industry cash and in-kind cost share of 21,697,129 from 80 nonfederal partners for a total of 54,495,827 of funded research that 1) advanced the development of unconventional tight oil resources in the Bakken Formation; 2) demonstrated the application of CO 2 Storage and EOR in tight oil formations; 3) developed advanced carbon capture technology; 4) addressed key application and infrastructure concerns for commercial deployment of CO 2 ; 5) demonstrated innovative, integrated water management strategies for energy development projects; 6) developed novel pollution control technologies for mercury and hazardous air pollutants; and 7) performed world-class outreach and dissemination of research results to industry partners and other stakeholders. These outcomes speak to the valuable return on the substantial investment in this program.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Best Practices for NPT Transit Matching

Transit matching is the process for relating or matching reports of shipments and receipts submitted to the International Atomic Energy Agency (IAEA). Transit matching is a component used by the IAEA in drawing safeguards conclusions and performing investigative analysis. Transit matching is part of IAEA safeguards activities and the State evaluation process, and it is included in the annual Safeguards Implementation Report (SIR). Annually, the IAEA currently receives reports of ~900,000 nuclear material transactions, of which ~500,000 are for domestic and foreign transfers. Of these the IAEA software can automatically match (i.e., machine match) about 95% of the domestic transfers and 25% of the foreign transfers. Given the increasing demands upon IAEA resources, it is highly desirable for the machine-matching process to match as many transfers as possible. Researchers at Oak Ridge National Laboratory (ORNL) have conducted an investigation funded by the National Nuclear Security Administration through the Next Generation Safeguards Initiative to identify opportunities to strengthen IAEA transit matching. Successful matching, and more specifically machine matching, is contingent on quality data from the reporting States. In February 2016, ORNL hosted representatives from three States, the IAEA, and Euratom to share results from past studies and to discuss the processes, policies, and procedures associated with State reporting for transit matching. Drawing on each entity's experience and knowledge, ORNL developed a best practices document to be shared with the international safeguards community to strengthen transit matching. This paper shares the recommendations that resulted from this strategic meeting and the next steps being taken to strengthen transit matching.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2020

What Factors Drive the Changes in Water Withdrawals in the U.S. Agriculture and Food Manufacturing Industries between 1995 and 2010?

Climate change and increasing world population will directly impact the global food supply chain linkages. In the United States, agricultural production requires less irrigated water than before but it still accounts for a third of total water withdrawals. To better understand the evolution of its water use, we perform a structural decomposition analysis of water withdrawals across eight different crops and six livestock categories and differentiate the trends over 1995–2005 vs 2005–2010 to account for the role of the economic crisis in the second period. Based on USGS data, the results show that both periods experienced an overall decline in water withdrawals in the production of all crops except oilseeds. This trend is driven by a decrease in water intensity, reflecting greater efficiency of irrigation systems, and by reduced local per capita income in the second period. However, increased foreign demand for water-intensive sectors like oilseeds from NAFTA and Asian partners mitigated the decline. Results indicate also a decreasing water use in livestock production partially due to a shift from red to white meat consumption in the country. Arguably, recent tariff wars and border closures have greatly reduced the virtual water embodied in American exports.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2026

Foreign Entity of Concern Requirements in the One Big Beautiful Bill Act

The One Big Beautiful Bill Act (OBBB), enacted July 4, 2025, makes billions of dollars in federal energy tax credits conditional on supply chain independence from China and other foreign entities of concern. The OBBB simultaneously creates powerful economic incentives to reshore energy supply chains to the United States and allied nations. Through such incentives, the OBBB elevates digital assurance and supply chain verification from voluntary best practices into critical capabilities for demonstrating tax credit eligibility. The OBBB uses tax credit eligibility requirements to simultaneously address national security concerns regarding foreign supply chain dependencies and incentivize domestic energy manufacturing. This brief details how organizations should operationalize these requirements through baseline compliance audits, interim documentation systems, supply chain diversification strategies, and long-term institutional integration of digital assurance capabilities that turn compliance burdens into competitive advantages

29 - ENERGY PLANNING, POLICY AND ECONOMY↗
DOE OSTI2023

A Clean Energy Korea by 2035

The current global energy crisis has massive implications for the people and economy of South Korea (Korea), where at least 90% of energy use depends on foreign fossil fuels. Clean electricity accounts for only 39% of total generation, with electricity demand expected to increase 30% by 2035. This study shows that Korea can achieve 80% clean electricity by 2035 by capitalizing on rapid technological improvements and decreasing costs of solar, wind, and battery technology. Doing so would slightly lower electricity supply costs, significantly reduce dependence on imported natural gas and coal, and dramatically cut power sector emissions. Further, this study finds that Korea’s power grid under a clean energy scenario will maintain reliability without coal generation or new natural gas plants. To realize these significant economic, environmental, and energy security benefits, policies such as an 80% clean electricity standard by 2035 and corresponding renewable energy deployment goals are required.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1999

The Conference Proceedings of the 1999 Air Transport Research Group (ATRG) of the WCTR Society

In this paper, we develop a model with which allows us to measure not only the changes in equilibrium outcomes and welfare consequences of liberalizing a bilateral air transport agreement, but also the distribution of the gains and losses to carriers and consumers of each bilateral country and those of the third foreign countries. Our model also allows to measure the effects of changes in a bilateral agreement on the amount of traffic diversion between the direct bilateral routes and the indirect routes via a third country. We also provide an extension of our model to a case of oligopoly market outcome (Coumot Nash equilibrium). In our model, quality aspects are treated in the framework of hedonic price theory by specifying the quality-adjusted price (quantity) as a multiplication of the observed price (quantity) by the reciprocal quality index function (the quality index function). Numerical simulations were conducted to measure the effects of changing the following major policy levers in a bilateral air transport agreement: 1) Removing price regulation while retaining frequency and entry restrictions; 2) Removing price and entry regulation while retaining frequency restrictions; 3) Removing frequency regulations while retaining price and entry regulations; 4) Removing frequency and entry regulations while retaining price regulation; 5) Removing price and frequency regulations while retaining entry restriction; and 6) Removing all price, frequency and entry regulations (de facto, open skies).

Zhang, Anming↗
DOE OSTI2015

Time allocations across collaborations of academic scientists and their impact on efforts to commercialize novel technologies: is more always better?

We investigate how time spent in different collaborative research arrangements by academic scientists affect their propensity of involvement in the commercialization of novel, university‐originated technologies. Three common collaborative strategies used by academic scientists: (1) internal (within the research group or within the home university) research collaboration; (2) cosmopolitan research collaboration (with scientists in other US or foreign universities); or (3) university–industry research collaboration are assessed. Drawing on the concepts of cognitive and spatial distance, the empirical findings suggest that only one internal research collaboration strategy has a significant impact on the propensity of academic scientists to engage in the commercialization of novel technologies with a private firm; however, this relationship is inverse U shaped. More importantly, academic scientists adopting a university–industry collaboration strategy and spending more research time in such an arrangement have a significantly stronger propensity for being involved in technology commercialization with a private firm; however, this relationship is inverse U shaped as well. We discuss the managerial and policy implications of the findings.

Libaers, Dirk↗
DOE OSTI2024

BESSIE: Battery & Energy Storage Supply Chain Analysis, Mitigation Deployment, and Tools

Battery energy storage systems (BESS) and their associated power electronic interfaces are key components to delivering clean and more resilient energy, providing much-needed fast-ramping, emergency discharge, generation, and operations support to the electric grid. These services have grown to be invaluable over the past ten years and will soon be an irreplaceable element of energy delivery. The Idaho National Laboratory (INL) strives to address these challenges through a strategic approach to supply chain risk assessment and mitigation for BESS and related digital energy equipment through the BESSIE project under the Center for Securing Digital Energy Technology. Recognizing that decreasing dependence on a foreign supply chain will take significant time and investment, BESSIE’s focus is strategically addressing battery supply chain risks by pairing short-term steps to operate securely through today’s risks with long-term steps to shape the supply chain over the coming years.

25 ENERGY STORAGE↗
DOE OSTI2016

Co-benefits of global and regional greenhouse gas mitigation for US air quality in 2050

Policies to mitigate greenhouse gas (GHG) emissions will not only slow climate change but can also have ancillary benefits of improved air quality. Here we examine the co-benefits of both global and regional GHG mitigation for US air quality in 2050 at fine resolution, using dynamical downscaling methods, building on a previous global co-benefits study (West et al., 2013). The co-benefits for US air quality are quantified via two mechanisms: through reductions in co-emitted air pollutants from the same sources and by slowing climate change and its influence on air quality, following West et al. (2013). Additionally, we separate the total co-benefits into contributions from domestic GHG mitigation vs. mitigation in foreign countries. We use the Weather Research and Forecasting (WRF) model to dynamically downscale future global climate to the regional scale and the Sparse Matrix Operator Kernel Emissions (SMOKE) program to directly process global anthropogenic emissions to the regional domain, and we provide dynamical boundary conditions from global simulations to the regional Community Multi-scale Air Quality (CMAQ) model. The total co-benefits of global GHG mitigation from the RCP4.5 scenario compared with its reference are estimated to be higher in the eastern US (ranging from 0.6 to 1.0 µg m -3 ) than the west (0–0.4 µg m -3 ) for fine particulate matter (PM 2.5 ), with an average of 0.47 µg m -3 over the US; for O 3 , the total co-benefits are more uniform at 2–5 ppb, with a US average of 3.55 ppb. Comparing the two mechanisms of co-benefits, we find that reductions in co-emitted air pollutants have a much greater influence on both PM 2.5 (96 % of the total co-benefits) and O 3 (89 % of the total) than the second co-benefits mechanism via slowing climate change, consistent with West et al. (2013). GHG mitigation from foreign countries contributes more to the US O 3 reduction (76 % of the total) than that from domestic GHG mitigation only (24 %), highlighting the importance of global methane reductions and the intercontinental transport of air pollutants. For PM 2.5 , the benefits of domestic GHG control are greater (74 % of total). Since foreign contributions to co-benefits can be substantial, with foreign O 3 benefits much larger than those from domestic reductions, previous studies that focus on local or regional co-benefits may greatly underestimate the total co-benefits of global GHG reductions. We conclude that the US can gain significantly greater domestic air quality co-benefits by engaging with other nations to control GHGs.

54 ENVIRONMENTAL SCIENCES↗