This project, CRC E-90-2b, was conducted by Southwest Research Institute (SwRI) in order to assess the impact of E10+ blends on MIL illumination and exhaust emissions compliance. The original objectives of this study were to: (1) Document the change in fuel trim and other engine parameters as vehicles operate on a range of ethanol fuels under real-world conditions. (2) Determine if the MIL would illuminate and/or diagnostic trouble codes (DTCs) would be set on potentially sensitive vehicles when exposed to E15 and/or E20. (3) Determine if a vehicle with an illuminated MIL induced by E15 or E20 still meets its emission category target, using a standard cold-start FTP-75 test.

关键词：大气；燃料气体；废气排放

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One of the primary objectives of the Atmospheric Radiation Measurement (ARM) Programs second ARM Mobile Facility (AMF2) is to obtain reliable measurements of radiation (solar, surface, and atmospheric), cloud, and atmospheric properties from ocean-going vessels. To ensure that these climatic measurements are representative and accurate, many AMF2 instrument systems are designed to collect data in a zenith orientation. A pillar of the AMF2 strategy in this effort is the use of a stable platform. The purpose of the platform is to (1) mitigate vessel motion for instruments that require a truly vertical orientation and keep them pointed in the zenith direction and (2) allow for accurate positioning for viewing or shading of the sensors from direct sunlight. Of the numerous ARM instruments that require a zenith orientation, perhaps the most important are the vertically pointing cloud radars, for which vertical motion is a critical parameter.

关键词：大气；气体检测；气候模型

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Increases in the abundance of methane (CH4) in the Earth's atmosphere are responsible for significant radiative forcing of climate change (Forster et al., 2007; Wuebbles and Hayhoe, 2002). Since 1750, a 2.5 fold increase in atmospheric CH4 contributed 0.5 W/m2 to direct radiative forcing and an additional 0.2 W/m2 indirectly through changes in atmospheric chemistry. Next to water and carbon dioxide (CO2), methane is the most abundant greenhouse gas in the troposphere. Additionally, CH4 is significantly more effective as a greenhouse gas on a per molecule basis than is CO2, and increasing atmospheric CH4 has been second only to CO2 in radiative forcing (Forster et al., 2007). The chemical reactivity of CH4 is important to both tropospheric and stratospheric chemistry. Along with carbon monoxide, methane helps control the amount of the hydroxyl radical (OH) in the troposphere where oxidation of CH4 by OH leads to the formation of formaldehyde, carbon monoxide, and ozone.

关键词：大气；甲烷；空气排放

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In April 2012, National Institute for Occupational Safety and Health (NIOSH) researchers and the Silica/Milling-Machines Partnership coordinated by the National Asphalt Pavement Association (NAPA) conducted laboratory testing of a local exhaust ventilation (LEV) system on a Roadtec RX600e cold milling machine. The testing was conducted indoors at the Roadtec manufacturing facility in Chattanooga, Tennessee. All tests were conducted on a stationary milling machine with the cutter drum and conveyor belts moving, but without any reclaimed asphalt pavement (RAP) moving through the system. Smoke and tracer gas were used as surrogates for silica dust to evaluate capture efficiencies of the dust emission-control system in the cutter drum housing of the machine. Smoke was used as an initial qualitative test to visually check for leaks. Sulfur Hexafluoride (SF(6)) was used to quantitatively evaluate capture efficiency of tracer gas released in the cutter drum housing of the machine. Two independent analytical instruments were used to measure the resulting SF(6) concentrations in the LEV exhaust duct, an Innova AirTech Instruments 1412 Photoacoustic field gas-monitor and a Miran SapphIRe infrared spectrometer. Capture efficiency tests were conducted at a single flow rate on the Roadtec cold milling machine. The mean capture efficiency from the Innova AirTech Instruments 1412 Photoacoustic field gas-monitor and Miran SapphIRe data were 98% and 99%, respectively. The lower 95% confidence limits were 97% for both the Innova AirTech Instruments 1412 Photoacoustic field gas-monitor and Miran SapphIRe results. Additional testing during actual milling activities is recommended to document capture efficiency under true field conditions. The testing reported here only evaluated capture efficiency within the cutter drum housing. Other potential dust release locations on the machine such as the transition between the primary and secondary conveyor and the top of the secondary conveyor were not evaluated during this testing but could contribute to silica exposures during actual field operation.

关键词：大气；气体流通；空气健康

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Interest in estimating the air pollutant emissions that occur during highway project construction is increasing. This paper describes a construction emissions modeling framework with companion calculation methodologies. On the basis of bid data and field data collected from a range of highway construction projects, the modeling framework builds linkages between material quantities, equipment in-use hours, and pollutant emissions. The data calculation and processing methodologies can assist project analysts in creating emissions estimates across various construction operations at early environmental assessment stages when, typically, limited data are available for characterizing equipment activity for the future project A hypothetical freeway-widening case study was used to demonstrate the application of the modeling framework and calculation methodologies. The example illustrates the framework's ability to disaggregate emissions by construction operation; in the case analysis, hours of equipment use and emissions were greatest during roadway excavation and foundation work. Project analysts can also vary individual equipment characteristics that affect emissions, such as tier group (emissions certification standards), horsepower rating, equipment deterioration, and other factors in construction emissions analyses. For example, the emissions reduction benefits of shifting the equipment fleet to more stringent (Tier 4) emissions standards, especially as a strategy for reducing particulate emissions, can be quantified.

关键词：大气；空气排放；空气污染

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The basic principles of the U.S. Environmental Protection Agencys (EPA) Traceability Protocol for the Assay and Certification of Gaseous Calibration Standards (EPA, 1997) were developed jointly by EPA, the National Bureau of Standards (now National Institute of Standards and Technology (NIST)), and specialty gas producers over 30 years ago. At the time, commercially-prepared calibration gases were perceived as being too inaccurate and too unstable for use in calibrations and audits of continuous source emission monitors and ambient air quality monitors. The protocol was developed to improve their quality by establishing their traceability to NIST Standard Reference Materials (SRMs) and to provide reasonably priced products. This protocol established the gas metrological procedures for measurement and certification of these calibration gases for EPA's Acid Rain Program under 40 Code of Federal Regulations (CFR) Part 75, for the Ambient Air Quality Monitoring Program under 40 CFR Part 58, and for the Source Testing Program under 40 CFR Parts 60, 61, and 68. EPA required monitoring organizations implementing these programs (the regulated community) to use EPA Protocol Gases as their calibration gases. EPA revised the protocol to establish detailed statistical procedures for estimating the total uncertainty of these gases. EPA's Acid Rain Program developed acceptance criteria for the uncertainty estimate.

关键词：大气；气体成分；大气 保护

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The Special Analytical Studies Group at the 222-S Laboratory (222-S) examined the particulate recovered from a series of samples from the annular space of tank 241-AY-102 (AY-102) using solid phase characterization (SPC) methods. These include scanning electron microscopy (SEM) using the ASPEX1 scanning electron microscope, X-ray diffraction (XRD) using the Rigaku2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information. Gary A. Cooke conducted the SEM analysis, John Pestovich performed the XRD analysis, and Dr. Heinz Huber performed the PLM examination. The results and conclusion of these analyses are presented here.

关键词：大气；空气污染；颗粒物

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Increased demands for cleaner burning energy, coupled with the relatively recent technological advances in accessing unconventional hydrocarbon-rich geologic formations, have led to an intense effort to find and extract natural gas from various underground sources around the country. One of these sources, the Marcellus Shale, located in the Allegheny Plateau, is currently undergoing extensive drilling and production. The technology used to extract gas in the Marcellus Shale is known as hydraulic fracturing and has garnered much attention because of its use of large amounts of fresh water, its use of proprietary fluids for the hydraulic-fracturing process, its potential to release contaminants into the environment, and its potential effect on water resources. Nonetheless, development of natural gas extraction wells in the Marcellus Shale is only part of the overall natural gas story in this area of Pennsylvania. Conventional natural gas wells, which sometimes use the same technique, are commonly located in the same general area as the Marcellus Shale and are frequently developed in clusters across the landscape. The combined effects of these two natural gas extraction methods create potentially serious patterns of disturbance on the landscape. This document quantifies the landscape changes and consequences of natural gas extraction for Somerset County and Westmoreland County in Pennsylvania between 2004 and 2010. Patterns of landscape disturbance related to natural gas extraction activities were collected and digitized using National Agriculture Imagery Program (NAIP) imagery for 2004, 2005/2006, 2008, and 2010. The disturbance patterns were then used to measure changes in land cover and land use using the National Land Cover Database (NLCD) of 2001. A series of landscape metrics is also used to quantify these changes and is included in this publication.

关键词：大气；天然气开采；能源利用

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In 1963, the Atomic Energy Commission (AEC), predecessor to the US Department of Energy (DOE), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range (NAFR)). Operation Roller Coaster consisted of four tests in which chemical explosions were detonated in the presence of nuclear devices to assess the dispersal of radionuclides and evaluate the effectiveness of storage structures to contain the ejected radionuclides. These tests resulted in dispersal of plutonium over the ground surface downwind of the test ground zero. Three tests, Clean Slate 1, 2, and 3, were conducted on the TTR in Cactus Flat; the fourth, Double Tracks, was conducted in Stonewall Flat on the NTTR. DOE is working to clean up and close all four sites. Substantial cleaned up has been accomplished at Double Tracks and Clean Slate 1. Cleanup of Clean Slate 2 and 3 is on the DOE planning horizon for some time in the next several years.

关键词：大气；空气检测；气候变化

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In response to the Energy Independence and Security Act (Public Law 110-40, 2007), the U.S. Geological Survey (USGS) conducted a national assessment of potential geologic storage resources for carbon dioxide (CO2). Storage of CO2 in subsurface saline formations is one important method to reduce greenhouse gas emissions and curb global climate change (Benson and Cook, 2005). The assessment methodology describes the probabilistic model developed to calculate potential storage resources in subsurface saline formations. This report documents both the methodology updates and the details of methodology implementation and is meant to supplement the Brennan and others (2010) methodology and the national assessment final reports. The final reports will include (1) an assessment results report with all output results, a description of the assessment, and analysis; (2) an assessment summary report; and (3) an assessment data report, which will include data inputs and outputs, assessment forms, resource allocations, and figures.

关键词：大气；二氧化碳存储；温室气体

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