A program was initiated in June 2009 to evaluate the potential of porous organosilicate sorbents in the capture or neutralization of light gas threats. Of primary interest were targets identified by the TIC/TIM Task Force as priority threats. A number of approaches were taken for increasing binding capacity and reactivity in the sorbent materials: grafting of metalloporphyrins, incorporation of sites for metal coordination, and incorporation of acidic and basic groups. In addition, the impact of morphological considerations, such as pore size and organization, were evaluated. Target capture by the sorbents was evaluated using microbreakthrough testing completed at the Edgewood Chemical Biological Center. Development of relevant sorbent morphologies was also pursued. Overall, the sorbents show promise, with several offering improvements in target capture and retention over state-of-the-art materials.

关键词：大气；空气污染；空气净化

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Most climate scientists agree that humans are accelerating a change in the Earths climate through the emission of greenhouse gases (GHG). In response, governments and organizations in the United States at the state, regional, and local levels have been enacting policies aimed at reducing energy consumption and GHG emissions. These policies typically include an overall emissions reduction target for a city, a state, or an agency. To meet reduction targets, some agencies and organizations are developing plans and strategies that are often disaggregated by emissions sources. Transportation, surface transportation in particular, is one of the most significant sources of GHG emissions: About 29% of all U.S. GHG emissions are from transportation, and emissions are expected to increase, as can be seen in Figure 1. So far, the most common transportation-related response to reduce GHG emissions and promote energy security through reduced energy consumption has focused on four core strategies: reduce vehicle miles traveled (VMT), reduce carbon intensity of fuels, improve vehicle efficiency, and improve overall operational efficiency of the surface transportation system. Several of these strategies would require federal policy changes, namely advancements in vehicle technology and further regulation of fuel sources. However, transportation agencies at the state and local levels have more control over reducing VMT and improving the operational efficiency of the surface transportation system since they own, operate, and regulate much of the nations transportation system. Systematically incorporating GHG emissions into transportation planning and decision making can lead to successful strategies and plans for mitigation.

关键词：大气；温室气体；全球变暖

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The greenhouse gas (GHG) nitrous oxide (N2O) is produced by soil microorganisms. Nitrogen (N) inputs, soil moisture and carbon stimulate the production of this gas, which accounts for about one third of all GHGs from Californias agriculture sector. Nitrogen inputs, crop N removal, and cumulative N2O emissions were measured from spring 2011 to fall 2012 in three dairy forage production systems receiving liquid and solid manure, as well as synthetic N fertilizer. The annual N2O emissions ranged from 4.87.4 kg N2O-N (mass of N in the form of N2O) ha-1 from sites with sandy soil (>70% sand) and from 11.416.5 kg N2O-N ha-1 in clayey soils (>40% clay) and were comparable to those of similar systems in other regions (1.213.8 kg N loss as N2O) although the California systems received higher N inputs (694-1281 kg N ha-1) than those systems (150225 kg N ha-1). The periods of N2O release after irrigation events were longer (weeks) in a clayey than in sandy soils (days). Nitrous oxide fluxes up to 1.4 kg N2O-N ha-1 d-1 were recorded after large applications of synthetic N fertilizer (>100 kg N ha-1) whereas moderate additions of liquid manure and/or synthetic N fertilizer supplied together with the irrigation water resulted in lower, albeit consistent, N2O emissions of up to 100 g N2O-N ha-1 d-1. To lower N2O emission potential, applying N incrementally in moderate doses with the irrigation water according to crop N demand is recommended.

关键词：大气；空气污染；空气治理

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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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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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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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