Current Projects
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Environmental Impacts of Nanotechnology. Nanotechnology
brings the promise of improved medical imaging, thin display screens,
and clean energy. Although the growth of the nanotechnology industry
has been breathtakingly rapid, very little is known about the environmental
effects of manufactured nanomaterials. The overall objective of this
research is to conduct a cross-media assessment of the transport,
transformation, and fate of manufactured nanomaterials in atmospheric,
aquatic, and terrestrial environments. This video on YouTube describes the project in lay terms. We are also a key participant in the National Science Foundation-sponsored Center for the Environmental Impacts of Nanotechnology. |
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Measurement of Air Pollutant Emissions at the Neighborhood Scale. One of the largest uncertainties in our ability to manage air quality is the magnitude of emissions. Independent estimates have suggested that official inventories may be off by factors of 10 or more. We have developed a mobile platform, the Flux Laboratory for the Atmospheric Measurement of Emissions (FLAME), that uses eddy covariance to measure emissions of carbon dioxide, nitrogen oxides, volatile organic compounds, and fine particulate matter. So far, we have conducted field campaigns in a small Appalachian town dominated by coal transport near the corner of Kentucky, Ohio, and West Virginia; at 16 sites in Norfolk, Virginia; and at three schools in Roanoke, Virginia.
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Motor Vehicle Emissions. Vehicles
are the predominant source of many air pollutants in urban areas.
Exposure to vehicle emissions has been implicated in increased risk
of heart attack and genetic mutations in developing fetuses. We utilize
several approaches--a mobile laboratory, remote sensing, and tunnel
studies--to estimate emissions. We then apply dispersion and chemical-transport
models to predict their impact on local and regional air quality. |
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Air Quality Modeling. Three-dimensional chemical
transport models can be used to understand the relationships between
emissions, chemistry, and meteorology in producing certain concentrations
of pollutants. Models can also be used to optimize airshed management
strategies. Currently, we are working with local governments in the
Shenandoah Valley to help this area meet its air quality goals. |
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Air Pollution in Megacities. Mexico City is one of the most polluted
cities in the world and has been the focus of a case study on air pollution in megacities. During the MIRAGE field campaign in 2006, we measured polycyclic aromatic hydrocarbons (PAHs), with the intent of better characterizing their sources and transformations in the atmosphere. PAHs are important because of their potent mutagenicity and carcinogenicity. |
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Ammonia Emissions from Agriculture. Not only is ammonia a toxic gas, but it is also a key component of particle formation in the atmosphere. These particles endanger our health, degrade visibility, affect global climate change. Although agriculture is responsible for 90% of ammonia emissions, the understanding of such emissions is limited. The objective of this project is to quantify the emissions from cow manure during different stages of the storage and treatment process. The amount of nitrogen in the cows' diets will be manipulated in attempt to minimize ammonia emissions. |
Completed Projects
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Sustainable Mobility. Sustainable mobility is a concept intended to describe ways of moving people and goods around while eliminating the ensuing environmental damage caused by vehicles and infrastructure. In addition to consuming enormous amounts of resources and seriously degrading air quality, transportation also exacerbates many environmental and societal problems, such as water pollution, noise, erosion, and traffic. We have developed the Sustainable Mobility Lab to provide students and researchers with an interdisciplinary introduction to sustainable mobility. |
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Naphthalene Volatilization at a Phytoremediation Site. Phytoremediation
is used to enhance the removal of groundwater contaminants. We are
finding that trees enhance not only biodegradation and groundwater
transport, but also the volatilization of contaminants directly out
of the ground and into the atmosphere. Here, graduate student Claire
Booth pounds out her frustrations and installs a flux chamber at a
creosote-contaminated site in Tennessee. |
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PAH Exposure. In October 2002, we collaborated
with a team from the Harvard School of Public Health to measure exposure
to particles in diesel trucking terminals in Mexico City. We measured
PM2.5, particulate polycyclic aromatic hydrocarbons (PAHs), aerosol
active surface area, elemental and organic carbon, and detailed particle
speciation in loading dock areas and in delivery trucks driving throughout
the city. |
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Weekend Ozone Effect. Although emissions of ozone
precursors are typically lower on weekends, ozone concentrations are
higher on weekends in some urban areas. In this work, a combination
of data analysis, emission inventory development, and photochemical
modeling on multiple time scales shows how photochemical air pollution
responds to changes in precursor emissions on daily, weekly, and decadal
time scales. Changes in ozone sensitivity, combined with the increased
contribution of heavy-duty diesel trucks to the emission inventory
and correspondingly larger weekday-weekend difference in NOx emissions,
explains why the weekend ozone effect has spread throughout California
between 1980 and the present. |
Unsupported Projects
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Bullfighting. During a field campaign in Mexico
City in 2003, I tried my hand at bullfighting. I earned a nice bruise
and learned that I should stick to academic pursuits. |
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Sliced Bread: Even or Odd? While on a ski trip
in Colorado in 2002, I hypothesized that bags of bread contained
an even number of slices. Then, the buyer could make sandwiches and
not be left with an extra slice. At the City Market in Dillon, three
of us counted the number of slices in 10 randomly selected bags of
bread. Our preliminary results found that 60-70% of bags had an even
number of slices. |
Graduated Students
A dairy cow, whose manure is the source of ammonia emissions that we're studying, sniffs Jeff's shoulder while Sarah monitors the situation.
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Dwight checks the flow of a particle-measuring instrument inside the Aerodyne Mobile Laboratory during a field campaign in Mexico City.
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