Alternative ventilation strategies in U.S.offices:Comprehensive assessment and sensitivity analysis of energy saving potential

Mature technologies exist to reduce the heating,ventilation,and air-conditioning(HVAC) energy associated with ventilation and use ventilation proactively to save energy.This study investigated the energy use impacts in U.S.office buildings of multiple alternative ventilation strategies that combined:economizing,demand controlled ventilation(DCV),supply air temperature reset(SR),and/or a doubled ventilation rate.We used energy simulations in a Monte Carlo analysis,sampling 17 building inputs and varying locations to match the climate zone distribution of the U.S.office stock.Results indicated the possibility for significant savings compared to a baseline that ventilated constantly at a minimum rate in both a small office type with a constant air volume(CAV) HVAC system and a medium office type with a variable air volume(VAV) system.In 95%of instances,HVAC source energy savings were 5-25%in the small-CAV office(median:11%) and 6-42%in the medium-VAV office(median:27%).In the small-CAV office,DCV typically saved the most energy,usually from heating,and heating degree days and occupant density were decisive influences.In the medium-VAV office,economizing and SR were most important,DCV usually only had minor impacts,and zone temperature setpoints,along with climate indicators,were the critical influences.Other than infiltration,envelope characteristics did not strongly influence energy impacts.The untapped primary energy savings of alternative ventilation strategies over the 74%of U.S.office floorspace reasonably represented by our modeling was estimated at 36 TWh per year,with an annual value of U.S.$ 1.25 billion.     

Commentary: Landmark U.S. Supreme Court decision puts U.S. on likely path to regulating greenhouse gas emissions

In an April 2007 landmark decision that will have major implications for U.S.-based power utilities, the United States Supreme Court in Massachusetts v. Environmental Protection Agency (EPA) ruled that the U.S. Environmental Protection Agency has the authority to regulate greenhouse gas emissions, and that the EPA can avoid promulgating such regulations only if it determines that greenhouse gases do not contribute to climate change or if it provides some reasonable explanation as to why it cannot or will not exercise its discretion to determine whether they do. The Supreme Court also held that the petitioners, led by the state of Massachusetts, established “legal standing” to bring the action in federal court. While the ruling involved mobile sources of greenhouse gas emissions, many aspects of the ruling are likely to apply as well to stationary sources of emissions such as power plants.     

A time series analysis of U.S. metropolitan and non-metropolitan income divergence

This paper employs time series methods to analyze convergence across metropolitan and non-metropolitan regions during the 1969–2001 period. The results suggest that non-metropolitan regions are diverging from below the U.S. average income level, while metropolitan regions show mixed evidence of convergence. These summary results vary by geographic location and the size of the region, with medium-sized metropolitan regions showing the strongest tendencies to converge, while non-metropolitan areas with larger urban centers and small towns showed the strongest tendencies to diverge. Differences in human capital (as well as employment concentrations in farming and mining) appear to have influenced the relative performance of metropolitan and non-metropolitan regions during the last 30 years, suggesting a role for agglomeration economies in the observed trend toward divergence.

Report on eutrophication studies in the U.S.S.R.

Some results of eutrophication studies in the U.S.S.R. are briefly reviewed. It is shown that eutrophication has been spread into many water bodies in the U.S.S.R. Especially strong eutrophication and as its consequence heavy bloom of Cyanophita occur in Dnieper-impounding reservoirs. The problems of eutrophication prediction are briefly discussed. Preliminary work on the recovery of algal biomass from eutrophic water and its utilization are reported.     

Dynamic returns to scale and geography in U.S. banking

We observe spatial cost dependence among medium-sized and large U.S. banks (1998Q1–2020Q4). We contribute to the literature by accounting for this using an accessible dynamic spatial econometric cost model. For a movement along a bank's output expansion path, we calculate the cost returns that spillover to/from the bank. The noticeable impacts of the 2020 COVID pandemic are on the spillover cost returns and not the own returns. These spillover returns suggest the pandemic led to the smallest (largest) banks becoming suboptimally smaller (bigger). A number of banks with high-ranking spillover returns have geographically concentrated branches and/or specialize in particular activities.     

Modeled infiltration rate distributions for U.S. housing

A set of 209 dwellings that represent 80% of U.S. housing stock is used to generate frequency distributions of residential infiltration rates. The set of homes is based on an analysis of the 1997 U.S. Department of Energy's Residential Energy Consumption Survey, which documents numerous housing characteristics including type, floor area, number of rooms, type of heating system, foundation type, and year of construction. The infiltration rate distributions are developed using the multizone network airflow model, CONTAM (CONTAMW 2.4 User Guide and Program Documentation, NISTIR 7251. National Institute of Standards and Technology.). In this work, 19 cities are selected to represent U.S. climatic conditions, and CONTAM simulations are performed for each of the 209 houses in these cities to calculate building air change rates for each hour over a year. Frequency distributions are then developed and presented nationally as well as based on house type and region. PRACTICAL IMPLICATIONS: These distributions will support indoor air quality, exposure, and energy analyses based on a truly representative collection of U.S. homes, which has previously not been possible. In addition, the methodology employed can be extended to other countries and other collections of buildings. For U.S.-specific analyses, these homes and their models, can be extended to include occupants, contaminant sources, and other building features to allow a wide range of studies to address other ventilation and indoor air quality issues.     

Free trade agreements and interregional labor migration: the case of the U.S. and Canada

This paper focuses on the different effects that trade policy have on distinctive regions within a country by modeling the subnational impact of the Free Trade Agreement between the U.S. and Canada using an applied general equilibrium model. This study incorporates interregional labor mobility into the model and, by comparing the new results to those measured in the absence of labor migration, shows the importance of allowing for interregional labor mobility when modeling at the subnational level the effects of nationality of internationally designed policies.A longer version of this paper was presented and received the 8Th Annual Charles M. Tiebout Prize at the Western Regional Science Association Annual Meetings, Tucson, Arizona, February 1994. I would like to thank Geoffrey Hewings, Earl Grinols, Werner Baer, Chris Horak, and three anonymous referees for useful comments. I gratefully acknowledge the support of the Economic Development Administration, U.S. Department of Commerce and the Canadian Embassy in the early stages of this research project. I am solely responsible for any remaining errors in this paper.     

Changing intra-metropolitan accessibility in the U.S.: Evidence from Atlanta

The U.S. federal government appears committed to the idea of performance measurement. The Intermodal Surface Transportation Efficiency Act (1991), provides an opportunity to change the focus of metropolitan transportation planning and policy from fostering mobility (more travel) increasing accessibility (greater potential for desired interaction), which is widely viewed as a desirable objective among planners and the general public. This paper does three things: (1) defines the concept and clarifies questions of measurement, (2) reviews the literature to identify importat issues associated with changing accessibility, including accessibility's relationship to land use and value, poverty and unemployment, race, energy use and air pollution, (3) reports results from a case study of change in gravity-accessibility to employment by automobile in Atlanta, between 1980 and 1990.Other authors have argued that accessibility has been increasing over time, as well as becoming more homogenous in U.S. metropolitan areas. Together these developments are thought to have reduced its policy importance. This case study illustrates that this was not entirely the case in Atlanta in the late 1980s. Overall accessibility declined at the end of the decade, rather than continuing its steady increase, and its influence on residential density at the tract level (the access-density gradient) also changed direction. However, accessibility's explanatory power did decline from 1980 to 1900 in Atlanta, as expected. It seems likely therefore that accessibility will continue to be valuable as an indicator of metropolitan transportation systems' performance, as well as allowing planners to better anticipate change and to be more aware of its consequences.     

Seasonal heat flux properties of an extensive green roof in a Midwestern U.S. climate

Green roofs, or vegetated roofs, can reduce heat flux magnitude through a building envelope as a result of insulation provided by the growing medium, shading from the plant canopy, and transpirational cooling provided by the plants. This study quantifies the thermal properties of an inverted 325 m² retro-fitted extensive green roof versus a traditional gravel ballasted inverted roof in a Midwestern U.S. climate characterized by hot, humid summers and cold, snowy winters. In autumn, green roof temperatures were consistently 5 °C lower than corresponding gravel roof temperatures. Even during chilly and moist conditions, the heat flux leaving the building was lower for the green roof than the gravel roof. Temperatures at the top of the insulation layer were more variable for both green roof and gravel roof on winter days with no snow cover than on days with snow cover. Variation in temperatures between roof types in spring was similar to those in autumn. Peak temperature differences between gravel and green roof were larger in summer than other seasons (sometimes by as much as 20 °C). Over the course of a year (September 2005-August 2006), maximum and minimum average monthly temperatures and heat fluxes were consistently more extreme for the gravel roof than the green roof.     

Thirty-three Years of Regulating Fire Protection at Commercial U.S. Nuclear Power Plants: Dousing the Flames of Controversy**

This article focuses on what have been, and may continue to be, the more controversial aspects of fires at commercial nuclear power plants regulated by the U.S. Nuclear Regulatory Commission. Examining what has transpired in fire protection regulation since the 1975 fire at Browns Ferry Unit 1, which first focused attention on the potential hazard of fire at commercial nuclear power plants, we offer a personal perspective as to whether or not the “the flames of controversy” have been “doused.” We show that significant progress has been made while speculating whether these “flames” may ever truly be extinguished, or only kept under control. No core damage accident has ever occurred at a commercial nuclear power plant due to fire.

美国州立公园体系的发展、特征与评估

美国州立公园与国家公园相比,更强调满足州内居民就近户外休闲游憩需求的功能,这使得其在美国整体公共户外休闲空间体系中占据特殊的位置。在中国第一次全面地研究了美国州立公园体系的发展、特征及与国家公园体系的关系,特别是以部分州为例研究了美国州立公园的分类、质量评估、可达性与空间分布评估等关键问题。研究认为,州立公园的意义在于既缓解了美国国家公园面临的巨大旅游游憩压力,也满足了大众户外休闲游憩的需求。这值得中国在目前构建国家公园与自然保护地体系的同时予以借鉴。最后基于中国的实际需求与挑战,探讨了在省域/区域层次加强构建地方公园、保护地和游憩地体系建设的必要性与途径。     

Pharmaceuticals and personal care products in archived U.S. biosolids from the 2001 EPA national sewage sludge survey

In response to the U.S. National Academies' call for a better assessment of chemical pollutants contained in the approximately 7 million dry tons of digested municipal sludge produced annually in the United States, the mean concentration of 72 pharmaceuticals and personal care products (PPCP) were determined in 110 biosolids samples collected by the U.S. Environmental Protection Agency (EPA) in its 2001 National Sewage Sludge Survey. Composite samples of archived biosolids, collected at 94 U.S. wastewater treatment plants from 32 states and the District of Columbia, were analyzed by liquid chromatography tandem mass spectrometry using EPA Method 1694. Thirty-eight (54%) of the 72 analytes were detected in at least one composite sample at concentrations ranging from 0.002 to 48 mg kg⁻¹ dry weight. Triclocarban and triclosan were the most abundant analytes with mean concentrations of 36 ± 8 and 12.6 ± 3.8 mg kg⁻¹ (n = 5), respectively, accounting for 65% of the total PPCP mass found. The loading to U.S. soils from nationwide biosolids recycling was estimated at 210-250 metric tons per year for the sum of the 72 PPCPs investigated. The results of this nationwide reconnaissance of PPCPs in archived U.S. biosolids mirror in contaminant occurrences, frequencies and concentrations, those reported by the U.S. EPA for samples collected in 2006/2007. This demonstrates that PPCP releases in U.S. biosolids have been ongoing for many years and the most abundant PPCPs appear to show limited fluctuations in mass over time when assessed on a nationwide basis. The here demonstrated use of five mega composite samples holds promise for conducting cost-effective, routine monitoring on a regional and national basis.     

Fuel loads in U.S. Cities

Sources of burnable material within U.S. cities are analyzed. Based on a detailed evaluation of construction practices, storage of burnable contents, building function and layout, and density of buildings in city districts, we derive urban fuel load densities in terms of land use type and geographic location. Residential building fuel loads vary regionally from 123 to 150 kg m^–2; non-residential building classes have loads from 39 to 273 kg m^–2. The results indicate that average U.S. urban area fuel loads range from 14 to 21 kg m^–2.     

Explaining Progress in Climate Adaptation Planning Across 156 U.S. Municipalities

Problem, research strategy, and findings: Cities are increasingly experiencing the effects of climate change and taking steps to adapt to current and future natural hazard risks. Research on these efforts has identified numerous barriers to climate adaptation planning, but has not yet systematically evaluated the relative importance of different constraints for a large number of diverse cities. We draw on responses from 156 U.S. cities that participated in a 2011 global survey on local adaptation planning, 60% of which are planning for climate change. We use logistic regression analysis to assess the significance of 13 indicators measuring political leadership, fiscal and administrative resources, ability to obtain and communicate climate information, and state policies in predicting the status of adaptation planning. In keeping with the literature, we find that greater local elected officials’ commitment, higher municipal expenditures per capita, and an awareness that the climate is already changing are associated with cities engaging in adaptation planning. The presence of state policies on climate adaptation is surprisingly not a statistically significant predictor, suggesting that current policies are not yet strong enough to increase local adaptation planning. However, the model's sampling bias toward larger and more environmentally progressive cities may mask the predictive power of state policies and other indicators.

Takeaway for practice: State governments have an opportunity to increase local political commitment by integrating requirements for climate-risk evaluations into existing funding streams and investment plans. Regional planning entities also can help overcome the lack of local fiscal capacity and political support by facilitating the exchange of information, pooling and channeling resources, and providing technical assistance to local planners.     

BLACK MALE UNEMPLOyMENT IN U.S. METROPOLITAN AREAS: THE ROLE OF BLACK CENTRAL CITy SEGREGATION AND JOB DECENTRALIZATION*

Housing segregation has been suggested as an important cause of high unemployment among black Americans, because segregation restricts the black population to living in those central city areas which are losing jobs. Previous studies have not offered a conclusive test of this hypothesis, as they present conflicting findings and have a number of methodological difficulties. Using regression analyses on data from U.S. SMSAs, it is shown that the differential in unemployment rates between blacks and whites in U. S. SMSAs (and particularly SMSAs outside the South) is substantially influenced both by segregation patterns restricting blacks to the central city and by job decentralization. This black/while unemployment differential and the overall unemployment rate in an area determine the level of black unemployment in the area. Thus, central city segregation and job decentralization have important indirect effects on the black unemployment rates of U. S. metropolitan areas.     

Benefits and costs of improved IEQ in U.S. offices

This study estimates some of the benefits and costs of implementing scenarios that improve indoor environmental quality (IEQ) in the stock of U.S. office buildings. The scenarios include increasing ventilation rates when they are below 10 or 15 l/s per person, adding outdoor air economizers and controls when absent, eliminating winter indoor temperatures >23°C, and reducing dampness and mold problems. The estimated benefits of the scenarios analyzed are substantial in magnitude, including increased work performance, reduced Sick Building Syndrome symptoms, reduced absence, and improved thermal comfort for millions of office workers. The combined potential annual economic benefit of a set of nonoverlapping scenarios is approximately $20 billion. While the quantitative estimates have a high uncertainty, the opportunity for substantial benefits is clear. Some IEQ improvement measures will save energy while improving health or productivity, and implementing these measures should be the highest priority. PRACTICAL IMPLICATIONS: Owners, designers, and operators of office buildings have an opportunity to improve IEQ, health, work performance, and comfort of building occupants and to obtain economic benefits by improving IEQ. These benefits can be achieved with simultaneous energy savings or with only small increases in energy costs.     

Clean-energy policies and electricity sector carbon emissions in the U.S. states

State governments in the United States have enacted various clean-energy policies to decarbonize electric utilities, diversify energy supplies, and stimulate economic development. With a panel data set for 48 continental states from 1990 to 2008, fixed-effect panel regressions are estimated to test the impacts of clean-energy policies on total carbon emissions, electricity consumption, and carbon intensity. The results indicate that supply-side policy tools, such as RPS and EERS, are negatively correlated with carbon intensity in the electricity sector. More aggressive policies are needed to reduce total carbon emissions.     

美国大气污染控制装置市场的分析(Ⅲ)

2.2.2.2电除尘器销售额增长速度缓慢,市场发展速度适中在八十年代中,电除尘器市场的增长速度比较缓慢,其销售额从1981年的1.15亿美元,增加到1986年的3.96亿美元,6年间增加了两倍多。到1986年,在所有大气污染控制装置中,电除尘器的销售额仅次于袋滤器,居第二位。自本世纪初电除尘器应用于工业以来,在电除尘器的理     

从供需角度分析美国住房保障

文章介绍了美国从20世纪30年代至今针对中低收入阶层的住房保障政策,并通过供给和需求两个角度来分析美国在不同阶段采取不同住房保障模式的历史原因。结合中国现状指出美国住房保障对中国的借鉴意义。     

Prospects for walkable, mixed-income neighborhoods: insights from U.S. developers

In the U.S. today, there is a significant danger that walkable communities are becoming unaffordable to low and even moderate-income residents. This paper reports on the results of a survey of affordable housing developers that was conducted to provide a better understanding of what kinds of strategies could be used to substantially increase the prevalence of walkable, mixed-income neighborhoods from the point of view of developers. Thirty-four developers from around the U.S. were interviewed by telephone in November and December, 2010. Five themes emerged from the survey: the need for financing and access to capital and subsidy; the need for reform of financial regulation; the need for reform of land use regulation; the need for incentives; and the need for better communication and networking. Responses to the survey underscored the frustrations affordable housing developers are having with development more generally, and how those frustrations are amplified when trying to locate affordable housing in walkable, mixed-income neighborhoods. The paper concludes by suggesting strategies that could be employed to help promote walkable, mixed-income neighborhoods, beyond the obvious need for better access to capital: support for research that focuses on the benefits of mixed-income neighborhoods; documentation and illumination of best practices; and the fostering of communication and partnerships among a diverse set of advocates.