This report is the sixteenth volume in the series Acute Exposure Guideline Levels for Selected Airborne Chemicals. In the Bhopal disaster of 1984, approximately 2,000 residents living near a chemical plant were killed and 20,000 more suffered irreversible damage to their eyes and lungs following accidental release of methyl isocyanate. The toll was particularly high because the community had little idea what chemicals were being used at the plant, how dangerous they might be, or what steps to take in an emergency. This tragedy served to focus international attention on the need for governments to identify hazardous substances and to assist local communities in planning how to deal with emergency exposures.

关键词：大气；化学物质；空气污染

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Carbon storage and flux estimates for the two national forests in Alaska are provided using inventory data from permanent plots established in 19952003 and remeasured in 20042010. Estimates of change are reported separately for growth, sapling recruitment, harvest, mortality, snag recruitment, salvage, snag falldown, and decay. Although overall aboveground carbon mass in live trees did not change in the Tongass National Forest, the Chugach National Forest showed a 4.5 percent increase. For the Tongass National Forest, results differed substantially for managed and unmanaged forest: managed lands had higher per-acre rates of sequestration through growth and recruitment, and carbon stores per acre that were higher for decomposing downed wood, and lower for live trees and snags. The species composition of carbon stores is changing on managed lands, with a carbon mass loss for yellow-cedar but increases for red alder and Sitka spruce. On unmanaged lands, the Chugach National forest had carbon mass increases in Sitka spruce and white spruce, and the Tongass National Forest had increases in western redcedar and red alder.

关键词：大气；碳通量；森林公园

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The goal of the project is to build up a modeling tool to quantify soil greenhouse gases (GHG) emitted from agricultural production in California (CA) under current climate, soil and management conditions. We conducted (1) field data collection and analysis, (2) model calibration, validation and comparison tests, (3) regional simulation, and (4) tool development to help ARB with greenhouse gas inventory and mitigation studies. As nitrous oxide (N2O) is the major greenhouse gas for CA agricultural production, we focused our analyses on N2O emissions.

关键词：大气；温室气体；排放标准

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Reducing the environmental impact of facilities and operations has become an important function for many organizations. In many cases, such as utility and fuel use, reducing these impacts can also be coupled to financial savings. The Kansas Department of Transportation (KDOT) has determined that conducting an energy and CO2 audit of its building and vehicle fleets will aid in assessing KDOT energy use, prepare for any future regulations regarding CO2 emissions, and help identify areas for increased savings through reduced use of commercial resources (primarily energy and fuel). Phase 1 of this project established baseline carbon and energy data from three major sources: the total energy embodied in the construction, operation and repair of KDOT-owned buildings, the total energy embodied in KDOT use of utilities (electricity,  water and natural gas) and the energy expended in the operation of KDOT’s vehicle fleet and other associated equipment.

关键词：大气；碳排放；燃料

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In this review, we summarize the literature from the warm deserts of North America and consider leaf (Anet), soil (Rs), and plant community (aboveground net primary productivity; ANPP) studies from the Mojave, Sonoran, and Chihuahuan Deserts to determine if common trends exist across measurement scales that can be utilized to effectively manage the warm deserts. Furthermore, we investigate the potential management strategies that may increase carbon sequestration or minimize carbon losses in this region. We begin by describing the warm deserts in the southwestern United States and consider climate change projections for this region. We then examine how climate change may affect NEE and carbon sequestration.

关键词：大气；碳存储；空气管理

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This project was motivated by the continuing need to improve ambient air quality. As of December 2012, more than 74 million Americans live in areas that violate the National Ambient Air Quality Standard for fine particulate matter (or PM2.5). Organic aerosol often contributes between 30 and 60% of ambient fine particulate matter. However, the sources of ambient organic aerosols are not well understood and state-of-the-art chemical transport models often underpredict the measured organic aerosol concentrations by a factor of 2 or more. Better understanding of the sources of organic aerosols may be needed for the development of effective control strategies. This report describes results from a three-phase test program that characterized the emissions from on-road gasoline vehicles, on-road diesel vehicles, and small off-road engines. The overarching goal of the project was to investigate the atmospheric transformations of mobile source emissions to better quantify their contribution to ambient PM levels in other words to link tailpipe to ambient. This was done by characterizing the tailpipe emissions from in-use sources and by investigating the atmospheric evolution of the emissions using dilution tunnels and smog chambers.

关键词：大气；空气污染；燃料控制

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Previous work by us and others demonstrates induction of a systemic pro-inflammatory and pro-coagulant state in response to inhalation of environmental particulate matter. Our work demonstrated PM exposure activated platelets to a enhanced state of reactivity and suggested this could be a key factor in adverse cardiovascular events. This project evaluated pulmonary inflammation and systemic inflammatory and platelet responses to fine and ultrafine (PM2.5) ambient particulate matter collected from an urban (Sacramento) and rural (Davis) location. The objective of these experiments was to determine whether prior chelation of transition metals with deferoxamine mesylate (DFM) or binding of bacterial source endotoxin by polymyxin B reduced pulmonary and systemic responses to PM2.5. We hypothesized those inflammatory responses to a more transition metal rich urban source PM2.5 would be inhibited more by metal chelation while rural source PM2.5 would be more affected by endotoxin binding. Adult mice were given intratracheal instillations of collected PM2.5 and pulmonary pathology, systemic cytokine concentrations, and platelet activation were evaluated 24 hours later. To better assess contributions of aromatic hydrocarbons, oxidants or pro-inflammatory responses to biologically active material like endotoxin, we used laser capture microscopy to probe specific anatomic locations in lung for gene responses associated with each of these components.

关键词：大气；环境污染；健康

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According to the NRC and the USGCRP, changes in the earth's climate--including higher temperatures, changes in precipitation, rising sea levels, and increases in the severity and frequency of severe weather events--are under way and expected to grow more severe over time. These impacts present significant risks to the nation's energy infrastructure. Economic losses arising from weather-related events--including floods, droughts, and storms--have been large and are increasing, according to USGCRP. Adaptation--an adjustment to natural or human systems in response to actual or expected climate change--is a risk-management strategy to help protect vulnerable sectors and communities that might be affected by climate change. GAO was asked to examine the vulnerability of the nation's energy infrastructure to climate change impacts. This report examines: (1) what is known about potential impacts of climate change on U.S. energy infrastructure; (2) measures that can reduce climate-related risks and adapt energy infrastructure to climate change; and (3) the role of the federal government in adapting energy infrastructure and adaptation steps selected federal entities have taken. GAO reviewed climate change assessments; analyzed relevant studies and agency documents; and interviewed federal agency officials and industry stakeholders, including energy companies at four sites that have implemented adaptive measures.

关键词：大气；能源；气候变化

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This project was an initial effort to investigate the feasibility of an instrument combining real-time atmospheric particle composition measurements using an ATOFMS (Atmospheric Time-Of-Flight Mass Spectrometer) such as those performed by Prathers group at the University of California, San Diego (UCSD) with multi-wavelength scattering measurements of the type investigated by Sorensen et al., of Kansas State University (KSU). In this Phase I effort we proposed to investigate near-angle scattering and the possibility of integration of a multi-wavelength scattering instrument into the UCSD ATOFMS. After an initial optical design and calculations, we discovered issues with the theory of measurement and with mechanical integration. Evidence emerged that the method of multi-wavelength scattering is only efficacious for spherical particles, while most atmospheric particles are non-spherical fractal aggregates. We also determined that the integration of the detector into existing ATOFMS instruments would be severely limited by volume constraints, and additional volume would require prohibitive additional pumping compared with the existing ATOFMS systems. Based on this evidence, we decided not to pursue a Phase II effort.

关键词：大气；光子；气溶胶

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关键词：氨氧化古菌；CANON；生物膜；活性污泥；丰度；多样性

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