In the Eastern Seaboard Intermodal Transportation Applications Center at Hampton University, we started an investigation of the air pollutants around heavily-travelled roadways, shipping channels, airports, and railroads with the purpose of obtaining real time measurements of pollutant concentrations and relating them to real-time weather and traffic information. In the first two cycles of our research program, we built a mobile unit containing a NOx and an ozone analyzer, and a weather station to provide simultaneous measurements of wind speed, wind direction, temperature, and solar intensity with the concentration measurements. The measured NO2 concentrations were compared to the predictions of CALINE4. Considering the effects of PM2.5 on public health and the 2008 US Census Bureau report, which showed that around 16% of American households live within 100 m of a highway having four or more lanes, an instrument for the measurements of PM10 and PM2.5 were added to our measurement capabilities for the current research cycle.

关键词：大气；气体健康；空气污染

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Department of Energy Technical Standard 1027 categorizes DOE facilities by the off-site radiation dose consequence resulting from a design basis accident, using this postulated event to determine if a facility is considered to be a radiological facility or a nuclear facility. The accident scenario used in this type of assessment is an uncontrolled release of the entire radioactive material inventory within the facility, using standard assumptions on air plume dispersion, uptake of radionuclides, distance to receptor, and other parameters that are consistent for all DOE facilities. Thus, the primary input on determining off-site dose in this assessment is the quantity of radioactive material within the facility. Controlling and tracking this inventory becomes the principal method of managing a facility's hazard categorization. A radiological facility is considered to pose very little risk to the public, while nuclear facilities have increasing amounts of controls required in their processes due to the increasing hazards of their operations and increasing radioactive material inventories. The dose threshold between a radiological facility and a Hazard Category 3 nuclear facility is a 10 rem dose to an individual located 30 meters from the facility. Prior to 2011, the amount of radioactive material inventory that would correspond to this 10 rem dose was 8.4 grams of plutonium-239 or equivalent material. Facilities track their radioactive material inventory relative to the threshold quantities of nuclides used in that facility, using a gsum of fractionsh method.

关键词：大气；大气污染；放射性元素

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The United Nations Intergovernmental Panel on Climate Change (IPCC) has stated that the warming of the climate system is unequivocal, as is now evident from observed increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level. In the coming decades, it is expected that these changes will result in regional climate impacts, including, but not limited to, permafrost thawing, increased tropical cyclone intensity, shifting tropical storm tracks, and an increase in the frequency of heat waves and heavy precipitation. As a result of these findings, concern is growing both in the United States and abroad (47) that these changes will have serious adverse impacts on transportation and civil infrastructure systems unless agencies take proactive steps to mitigate these issues.

关键词：大气；气候变化；空气质量

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The objective of this project was to investigate the complex fracture of ice and understand its role within larger ice sheet simulations and global climate change. This objective was achieved by developing novel physics based models for ice, novel numerical tools to enable the modeling of the physics and by collaboration with the ice community experts. Fracture of ice is important in several fields of which the most visible and certainly the most significant is global warming. This has recently received international attention due to the collapse of some significant ice shelves. Ice fracture, however, is also important in other areas including oil and gas exploration and production within ice-infested waters, materials science research and length scales in ice, and microbiology. At the present time, ice fracture is not explicitly considered within ice sheet models due in part to large computational costs associated with the accurate modeling of this complex phenomena. However, fracture not only plays an extremely important role in regional behavior but also influences ice dynamics over much larger zones in ways that are currently not well understood. Dramatic illustrations of fracture-induced phenomena most notably include the recent collapse of ice shelves in Antarctica (e.g. partial collapse of the Wilkins shelf in March of 2008 and the diminishing extent of the Larsen B shelf from 1998 to 2002).

关键词：大气；气候变化；全球变暖

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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；空气治理；空气污染

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Exposure assessments of open burn pits are often complicated by a lack of sampling equipment and resources. This research investigated the hypothesis of carbon dioxide (CO2) as a viable surrogate for particulate matter with diameter 8804; 2.5m (PM2.5). Large-scale solid waste combustion tests resulted in linear trends between mean PM2.5 and CO2 (R2 = 0.964 - 0.989). This pilot study demonstrates the feasibility of using CO2 as a surrogate of PM2.5 concentration as CO2 sensors potentially provide a cost-effective solution for monitoring in lieu of expensive PM instruments. It also indicates the potential reduction in particulate matter when using batch-feeding practices with burn boxes (versus open burning).

关键词：大气；空气污染；空气监控

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The U.S. Consumer Product Safety Commission (CPSC) and others are concerned about the hazard of acute residential carbon monoxide (CO) exposures from portable gasoline powered generators that can result in death or serious adverse health effects in exposed individuals. CPSC databases contain records of 755 deaths from CO poisoning associated with consumer use of generators in the period of 1999 through 2011, with nearly three-quarters of those occurring between 2005 and 2011. The majority of these incidents occur during power outages, or when a generator is used to provide power to a structure that is not wired for electrical power. Typically, these deaths occur when consumers use a generator in an enclosed or partially enclosed space or outdoors near an open door, window or vent. While avoiding the operation of such generators in or near a home is expected to reduce indoor CO exposures significantly, it may not be realistic to expect such usage to be eliminated completely. Another means of reducing these exposures would be to decrease the amount of CO emitted from these devices. In order to support life-safety based analyses of potential CO emission limits, a computer simulation study was conducted to evaluate indoor CO exposures as a function of generator source location and CO emission rate. These simulations employed the multizone airflow and contaminant transport model CONTAM, which was applied to a collection of 87 single-family, detached dwellings that are representative of the U.S. housing stock for that housing type. A total of almost one hundred thousand individual 24-hour simulations were conducted. This report presents the simulation results in terms of the maximum levels of carboxyhemoglobin that would be experienced by occupants in the occupied portions of the dwellings as a function of CO emission rate for different indoor source locations.

关键词：大气；一氧化碳泄露；室内空气健康

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The welding process results in the formation of high concentrations of nano-sized particles loaded with toxic metals such as hexavalent chromium (Cr6+), nickel (Ni), and manganese (Mn). Welding fumes pose serious health risks to welders because fumes can cause respiratory and neurological ailments as well as cancer. Tightened occupational standards require an exposure reduction of at least 90% that is not satisfied by current control technologies. There is also potential public concern about the environmental risks associated with the release of welding fumes into ambient air. The overall objective of this demonstration was to develop an innovative silica precursor technology that can limit the oxidation of chromium by quenching oxygen species and coating metal particles in welding fumes with a thin, amorphous silica layer. An additional objective was to assess the benefit of increased particle size distribution. The demonstration verified the feasibility and practicality of implementing silica precursor technology into DOD welding operations. Silica precursor technology was demonstrated to be an effective means of controlling metal emissions in welding fumes. The two-fold approach of limiting oxidation potential and coating metal particles with an amorphous silica layer goes beyond previous control technologies by addressing all the toxic metals, regardless of their oxidation state. This project demonstrated, through both a laboratory study and field tests, the benefits of adding silica precursor during the welding process.

关键词：大气；空气污染；空气健康

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The U.S. Geological Survey Branch of Quality Systems operates the Precipitation Chemistry Quality Assurance project (PCQA) to provide independent, external quality-assurance for the National Atmospheric Deposition Program (NADP). NADP is composed of five monitoring networks that measure the chemical composition of precipitation and ambient air. PCQA and the NADP Program Office completed five short-term studies to investigate the effects of equipment performance with respect to the National Trends Network (NTN) and Mercury Deposition Network (MDN) data quality: sample evaporation from NTN collectors; sample volume and mercury loss from MDN collectors; mercury adsorption to MDN collector glassware, grid-type precipitation sensors for precipitation collectors, and the effects of an NTN collector wind shield on sample catch efficiency.

关键词：大气；大气治理；空气健康

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In-cylinder blending of gasoline and diesel fuels to achieve low-temperature reactivity controlled compression ignition (RCCI) can reduce NOx and PM emissions while maintaining or improving brake thermal efficiency compared to conventional diesel combustion (CDC). Moreover, dual-fueling is able to achieve these benefits by tailoring combustion reactivity over a wider range of engine operation than is possible with a single fuel. However, the currently demonstrated range of stable RCCI combustion just covers a portion of the engine speed-load range required in several light-duty drive cycles. This means that engines must switch from RCCI to CDC when speed and load fall outside of the stable RCCI range. In this study we investigated the potential impact of RCCI on the engine-out exhaust temperature and emissions of a multimode RCCI-enabled vehicle operating over two urban and two highway driving cycles. To implement our simulations, we employed experimental RCCI/CDC engine maps combined with a standard mid-size, automatic transmission, passenger vehicle configuration details in the Autonomie vehicle simulation platform. Our results include both detailed transient and cycle-averaged engine exhaust temperature and emissions. We note the potential implications of the modified exhaust properties on catalytic emissions control and utilization of waste heat recovery on future RCCI-enabled vehicles.

关键词：大气；废气排放；空气污染

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