It is well established that GHG emissions must be reduced by 50% to 80% by 2050 in order to limit global temperature increase to 2DGC. Achieving reductions of this magnitude in the transportation sector is a challenge and requires a multitude of policies and technology options. The research presented here analyzes three scenarios: changes in the perceived price of travel, land-use intensification, and increases in transit. Elasticity estimates are derived using an activity-based travel model for the state of California and broadly representative of the U.S. The VISION model is used to forecast changes in technology and fuel options that are currently forecast to occur in the U.S., providing a life cycle GHG forecast for the road transportation sector. Results suggest that aggressive policy action is needed, especially pricing policies, but also more on the technology side. Medium- and heavy-duty vehicles are in particular need of additional fuel or technology-based GHG reductions.

关键词：大气；环境保护；温室气体

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Cardiovascular disease outcomes have been associated with exposure to ambient particulate matter (PM) air pollution in many epidemiological studies. Experimental studies have revealed potential mechanisms behind the epidemiological results and many of these studies have revealed changes in the expression of important genes in key biological pathways with exposure to air pollution from fossil fuel combustion. Few epidemiological studies have examined this. We hypothesized that blood cell gene expression levels along biological pathways relevant to cardiovascular outcomes would be associated with traffic-related air pollutant exposures in elderly subjects with coronary artery disease. Available data were collected in a cohort panel study funded by the National Institutes of Health, National Institute of Environmental Health Sciences. Gene expression data were available for 43 subjects with up to 12 weekly repeated measures conducted in three of the four retirement communities in the Los Angeles Air basin where the exposure measurement work took place. Whole blood samples were collected weekly, RNA was isolated and then it was reversed transcribed into complementary DNA for subsequent gene expression analysis using the polymerase chain reaction method. Candidate genes (35) were selected a priori based on biological function and reported pollutant exposure effects. Exposure measurements were conducted in the indoor and outdoor environment of each community and included daily size-fractionated PM mass and PM organic chemical composition, including polycyclic aromatic hydrocarbons (PAH).

关键词：大气；威力污染物；基因表达

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No abstract available.

关键词：大气；空气过滤器；空气污染

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This report explores the characteristics, sources, and processes of submicrometer particles in northern California via integrated analyses of atmospheric observation data obtained during the Carbonaceous Aerosols and Radiative Effects Study (CARES) that took place in northern California in June 2010. We focus on reporting aerosol chemistry, physical properties, and diurnal and temporal variations at Cool (denoted as the T1 site of the project) at the foothills of the Sierra Nevada Mountains, where intense biogenic emissions are periodically mixed with urban outflow transported by daytime southwesterly winds from the Sacramento metropolitan area. During CARES, the average mass loading of submicrometer particles (PM1) was 3.0 ig m- 3, dominated by organics (80%) and sulfate (9.9%). The organic aerosol (OA) had a nominal formula of C1H1.38N0.004O0.44, thus an average organic mass-to-carbon (OM/OC) ratio of 1.70. Three OA types were identified by PMF analysis of the high resolution mass spectra: two different OOA components (90% of total organics) and a HOA (10%). The more oxidized MOOOA (O/C = 0.54) was identified as biogenically influenced SOA, while the less oxidized LOOOA (O/C = 0.42) corresponded to anthropogenically influenced SOA (e.g., from the Sacramento area). The HOA factor corresponded mainly to primary emissions from local traffic. On average, SOA (= MO-OOA + LO-OOA) accounted for 91% of the total OA mass and 72% of the PM1 mass observed at Cool. Twenty three periods of urban plumes from T0 (Sacramento) to T1 (Cool) were identified using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem).

关键词：大气；环境保护；有机气溶胶

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On May 22, 2013, the National Institute for Occupational Safety and Health (NIOSH) received a request for technical assistance from the shelter manager at a large homeless shelter in Dallas, Texas, linked to an ongoing tuberculosis outbreak. The request asked NIOSH to assess the heating, ventilation, and air-conditioning (HVAC) systems and make recommendations to improve overall environmental controls at the shelter. During an on-site evaluation of the homeless shelter in June 2013, we collected physical and ventilation measurements in all key areas of the facility. We focused on areas where shelter guests typically congregate or spend significant amounts of time. We recorded the make and model number of all air-handling units (AHUs) providing air to the facility, and visually inspected the units. When possible, we measured the air flow rate through supply diffusers and return grilles. The AHUs in place were state-of-the-art and were controlled by a modern building automation system. The ventilation systems were well maintained and functional during our visit, and all AHUs were equipped with proper filter configurations. Despite their excellent condition and maintenance, certain aspects of the ventilation systems' operation could potentially contribute to airborne disease transmission among shelter guests. During our visit, it appeared the AHUs were not providing adequate outdoor air to the occupied spaces under certain occupancy and environmental conditions, as is required by the Dallas Mechanical Code and ASHRAE standards. In addition to alleviating odors and maintaining occupant comfort, outdoor air serves to dilute infectious aerosols, such as Mycobacterium tuberculosis droplet nuclei that are responsible for TB transmission. Since the TB outbreak began, the shelter has taken numerous steps to improve administrative controls, particularly when it comes to identifying guests showing signs and symptoms of TB. We recommend additional improvements to the administrative and environmental controls at the shelter. From a ventilation standpoint, we suggest that all occupied spaces at the shelter complex be supplied adequate amounts of outdoor air, as prescribed by the Dallas Mechanical Code and ASHRAE standards.

关键词：大气；健康危害；大气污染

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The Health Hazard Evaluation Program received a request from employees at a medical office building. They were concerned about indoor environmental quality and exposure to sewer gas, specifically hydrogen sulfide. The medical office building was a four-story, concrete masonry office building constructed in the 1960s that had been renovated twice; the three main floors were converted into offices and exam rooms. The building was surrounded by manholes that had been identified as sources of odors. The building was within 30 feet of a 24-inch trunk line that carried sewage from approximately 60% of the surrounding area toward the wastewater treatment facility. Most of the building's current plumbing was the original cast iron waste and vent piping, which can become brittle and crack with age. We visited the facility in April 2013 and measured hydrogen sulfide, carbon dioxide, temperature, and humidity levels throughout the building. We also inspected the building's heating, ventilation, and air-conditioning system. We did not detect hydrogen sulfide in the building. We found that carbon dioxide concentrations generally increased when moving further away from the supply air discharge point on each floor; outdoor air supplied to each floor was not uniformly distributed. Temperature and humidity were within ANSI/ASHRAE recommended levels. We found problems with duct dampers, heat pumps, and the computerized control system, and determined that air flowed from the restrooms into the hallways. We found odor sources within and near the building such as dry drain traps and manholes.

关键词：大气；空气污染；室内环境

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The U.S. Environmental Protection Agency (EPA) developed a year 2007 air quality modeling platform in support of the Tier 3 Motor Vehicle Emission and Fuel Standards. The air quality modeling platform consists of all of the emissions inventories, ancillary files needed for emissions modeling, and the meteorological, initial condition, and boundary condition files needed to run the air quality model. This platform uses all Criteria Air Pollutants (CAPs) and a select set of Hazardous Air Pollutants (HAPs). This document focuses on the emissions modeling components of the 2007 platform, including the emission inventories and the ancillary data and the approaches used to transform emission inventories for use in air quality modeling.

关键词：大气；机动车；燃料

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There is increasing evidence that improved health outcomes may be a significant co-benefit of land use plans and transport policies that increase active transport (or active travel)--walking, biking or other physical activity for the purpose of transportation--as they reduce greenhouse gas emissions (GHGs). A greater understanding of these benefits may broaden the constituency for regional planning that supports local and national GHG reduction goals. In this study, California's activity-based travel demand model (ABM) is applied to (1) demonstrate how this new generation of travel models can be used to produce the active travel data (age and sex distributions) required by comparative risk assessment models to estimate health outcomes for alternative land use and transport plans and to (2) identify the magnitude of change in active travel that may be possible from land use, transit, and vehicle pricing policies for California and its five major regions for a future 2035 time horizon. The results of this study suggest that distance-based vehicle pricing may increase walking by about 10% and biking by about 17%, and concurrently GHG from VMT may be reduced by about 16%. Transit expansion and supportive development patterns may increase active travel by about 2% to 3% for both walk and bike modes while also reducing VMT by about 4% on average. The combination of all three policies may increase time spent walking by about 13% and biking by about 19%, and reduce VMT by about 19%.

关键词：大气；温室气体；空气污染

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The Health Hazard Evaluation Program received a request from the manager of a federal government office complex. Employees were concerned about health problems including cancer, gallbladder problems, and chronic obstructive pulmonary disease. Some employees believed their health problems were associated with contamination of the buildings, soil, and groundwater from an adjoining weapons component manufacturing agency. The entire complex consisted of 13 buildings with the largest structure at the site containing over 1 million square feet across three floors. This structure contained two main areas: (1) Buildings 1 and 2 (office and warehouse space where most of the complex's employees worked) and (2) the weapons component agency. A floor-to-ceiling fire wall physically separated Buildings 1 and 2 from the weapons component agency. We reviewed environmental sampling records, did a visual inspection of Building 1 and 2 ventilation systems, spoke with employees about their health. We also tested former and current employees with sarcoidosis (an inflammatory disease that is nearly identical to chronic beryllium disease) for sensitization to beryllium, which was used for weapons manufacturing. Our evaluation found (1) no reports of employee overexposures to volatile organic compounds, polychlorinated biphenyls, beryllium or other metals, solvents, formaldehyde, or radon; (2) no evidence of beryllium sensitization among 22 persons tested; and (3) no cancer excess or abnormal pattern of disease. We noted that (1) Buildings 1 and 2 have separate ventilation systems from the weapons component agency and (2) potentially contaminated exhaust air from the weapons component agency was unlikely to enter the outdoor air intake(s) for Building 1 and 2. We recommended the employer encourage employees to learn about their personal cancer risk factors and educate employees on what they can do to reduce their risk for cancer. We also advised the employer to stop all investigations of cancer incidence and routine air and surface wipe sampling for chemicals.

关键词：大气；空气污染；健康

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Between September 18th and October 13th, 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 field testing of a local exhaust ventilation system (LEV) on a Roadtec RX600e cold milling machine. The tests included ten days of air sampling across seven different highway construction sites in Indiana. At each site, full-shift personal breathing zone samples for respirable crystalline silica were collected from the operator and ground man during the course of normal employee work activities of asphalt pavement milling.

关键词：职业暴露；空气污染影响；二氧化硅

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