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Atmospheric chemistry

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Articles 91 - 120 of 208

Full-Text Articles in Chemistry

Emission Trends In Heavy-Duty Trucks In The South Coast Air Basin (Presentation), Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman Jan 2013

Emission Trends In Heavy-Duty Trucks In The South Coast Air Basin (Presentation), Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Heavy-Duty Truck Emissions In The South Coast Air Basin Of California, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman Jan 2013

Heavy-Duty Truck Emissions In The South Coast Air Basin Of California, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

California and Federal emissions regulations for 2007 and newer heavy-duty diesel engines require an order of magnitude reduction in particulate matter and oxides of nitrogen spurring the introduction of new aftertreatment systems. Since 2008 four emission measurement campaigns have been conducted at a Port of Los Angeles location and an inland weigh station in the South Coast Air Basin of California. Fuel specific oxides of nitrogen emissions at the Port have decreased 12% since 2010 while infrared opacity (a measure of particulate matter) remained low, showing no diesel particulate filter deterioration. The weigh station truck’s fuel specific oxides of nitrogen …


Ace-Fts Observations Of Pyrogenic Trace Species In Boreal Biomass Burning Plumes During Bortas, K. A. Tereszchuk, G. G. Abad, C. Clerbaux, J. Hadji-Lazaro, D. Hurtmans, P. F. Coheur, P. F. Bernath Jan 2013

Ace-Fts Observations Of Pyrogenic Trace Species In Boreal Biomass Burning Plumes During Bortas, K. A. Tereszchuk, G. G. Abad, C. Clerbaux, J. Hadji-Lazaro, D. Hurtmans, P. F. Coheur, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

To further our understanding of the effects of biomass burning emissions on atmospheric composition, the BORTAS campaign (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) was conducted on 12 July to 3 August 2011 during the boreal forest fire season in Canada. The simultaneous aerial, ground and satellite measurement campaign sought to record instances of boreal biomass burning to measure the tropospheric volume mixing ratios (VMRs) of short- and long-lived trace molecular species from biomass burning emissions. The goal was to investigate the connection between the composition and the distribution of these pyrogenic outflows and …


Emission Changes Resulting From The San Pedro Bay, California Ports Truck Retirement Program, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson Jan 2012

Emission Changes Resulting From The San Pedro Bay, California Ports Truck Retirement Program, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson

Fuel Efficiency Automobile Test Publications

Recent US EPA emissions regulations have resulted in lower emissions of particulate matter and oxides of nitrogen from heavy-duty diesel trucks. To accelerate fleet turnover the State of California in 2008 along with the Ports of Los Angeles and Long Beach (San Pedro Bay Ports) in 2006 passed regulations establishing timelines forcing the retirement of older diesel trucks. On-road emissions measurements of heavy-duty diesel trucks were collected over a three-year period, beginning in 2008, at a Port of Los Angeles location and an inland weigh station on the Riverside freeway (CA SR91). At the Port location the mean fleet age …


Multi-Species Remote Sensing Of Vehicle Emissions On Sherman Way In Van Nuys California, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson Jan 2012

Multi-Species Remote Sensing Of Vehicle Emissions On Sherman Way In Van Nuys California, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson

Fuel Efficiency Automobile Test Publications

As part of the 2010 Van Nuys tunnel study, researchers from the University of Denver measured on-road fuel-specific light-duty vehicle emissions from nearly 13,000 vehicles on Sherman Way (0.4 miles west of the tunnel) in Van Nuys, CA with its multi-species FEAT remote sensor a week ahead of the tunnel measurements. The remote sensing mean gram per kilogram carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx) measurements are 8.9% lower, 41%, and 24% higher than the tunnel measurements respectively. The remote sensing CO/NOx and HC/NOx mass ratios are 28% lower and 20% higher than …


Observation Of Sulfate Aerosols And So₂ From The Sarychev Volcanic Eruption Using Data From The Atmospheric Chemistry Experiment (Ace), D. Doeringer, A. Eldering, C. D. Boone, G. González Abad, P. F. Bernath Jan 2012

Observation Of Sulfate Aerosols And So₂ From The Sarychev Volcanic Eruption Using Data From The Atmospheric Chemistry Experiment (Ace), D. Doeringer, A. Eldering, C. D. Boone, G. González Abad, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

[1] Infrared spectra measured by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) on the SCISAT satellite were used to analyze the Sarychev volcanic aerosol after the eruption in June 2009. Evidence of the Sarychev eruptions was first detected in July 2009 from enhanced SO2 concentrations and atmospheric extinction. By February 2010, the atmosphere had returned to pre-Sarychev conditions. In July 2009, the volcanic plume was found between 8.5 km and 17.5 km in altitude at mid- and high latitudes (55°N–70°N). The first SO2 and sulfate aerosol retrievals carried out using the infrared solar occultation spectra recorded with …


Atmospheric Effects Of Energetic Particle Precipitation In The Arctic Winter 1978-1979 Revisted, L. A. Holt, C. E. Randall, V. L. Harvey, E. E. Remsberg, G. P. Stiller, B. Funke, P. F. Bernath, K. A. Walker Jan 2012

Atmospheric Effects Of Energetic Particle Precipitation In The Arctic Winter 1978-1979 Revisted, L. A. Holt, C. E. Randall, V. L. Harvey, E. E. Remsberg, G. P. Stiller, B. Funke, P. F. Bernath, K. A. Walker

Chemistry & Biochemistry Faculty Publications

[1] The Limb Infrared Monitor of the Stratosphere (LIMS) measured polar stratospheric enhancements of NO2 mixing ratios due to energetic particle precipitation (EPP) in the Arctic winter of 1978–1979. Recently reprocessed LIMS data are compared to more recent measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) to place the LIMS measurements in the context of current observations. The amount of NOx (NO + NO2) entering the stratosphere that has been created by EPP in the mesosphere and lower thermosphere (EPP-NOx) has been quantified …


Climate Change: The Fork At The End Of Now, Micha Tomkiewicz Jan 2011

Climate Change: The Fork At The End Of Now, Micha Tomkiewicz

Publications and Research

There are many books on global warming written entirely from a layman's perspective, and there is a great deal of scientific literature on this subject. But few if any books attempt to bridge the science to those who lack a rigorous background in mathematics, physics and chemistry-but who may be working on careers in environmental science and policy. The new text is designed to introduce the field of global climate change from a scientific perspective-but written in a way that is accessible to students with some or little science background. It reviews the basic principles of climatic thermodynamics and atmospheric …


Ace-Fts Measurements Of Trace Species In The Characterization Of Biomass Burning Plumes, K. A. Tereszchuk, G. González Abad, C. Clerbaux, D. Hurtmans, P.-F. Coheur, P. F. Bernath Jan 2011

Ace-Fts Measurements Of Trace Species In The Characterization Of Biomass Burning Plumes, K. A. Tereszchuk, G. González Abad, C. Clerbaux, D. Hurtmans, P.-F. Coheur, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

To further our understanding of the effects of biomass burning emissions on atmospheric composition, we report measurements of trace species in biomass burning plumes made by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) instrument on the SCISAT-1 satellite. An extensive set of 15 molecules, C2H2, C2H6, CH3OH, CH4, CO, H2CO, HCN, HCOOH, HNO3, NO, NO2, N2O5, O-3, OCS and SF6 are used in our analysis. Even though most biomass burning smoke is typically confined to the …


Multi-Species On-Road Remote Sensing Of Vehicle Emissions In Van Nuys, California – August 2010, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman Jan 2010

Multi-Species On-Road Remote Sensing Of Vehicle Emissions In Van Nuys, California – August 2010, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Emission Measurements Of Reactive Nitrogen Compounds From Three California Cities, Gary A. Bishop, Allison Peddle, Donald H. Stedman Jan 2010

On-Road Emission Measurements Of Reactive Nitrogen Compounds From Three California Cities, Gary A. Bishop, Allison Peddle, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

The three California cities of San Jose, Fresno and West Los Angeles (wLA) were visited during March 2008 to collect on-road emission measurements of reactive nitrogen compounds from light-duty vehicles. At the San Jose and wLA sites comparison with historical measurements showed that emissions of carbon monoxide (CO), hydrocarbons (HC) and nitric oxide (NO) continue to decrease in the on-road fleet yet the ratio of nitrogen dioxide (NO2) to NO in new diesel vehicles appears to be under going large increases. A small fleet of 2007 diesel ambulances measured in Fresno was found to have more than 60% …


Correlation Of The Real-Time Particulate Matter Emissions Measurements Of A Esp Remote Sensing Device (Rsd) And A Dekati Electronic Tailpipe Sensor (Etaps) With Gravimetrically Measured Pm From A Total Exhaust Dilution Tunnel System, Mridul Gautam, Donald H. Stedman, Daniel K. Carder, Benjamin Shade, Nigel Clark, Gregory Thompson, Scott Wayne, Gary A. Bishop, Brent G. Schuchmann, Dan Pope, Niranjan Vescio, Gary Full, Peter Mcclintock, Drew Rau Jan 2010

Correlation Of The Real-Time Particulate Matter Emissions Measurements Of A Esp Remote Sensing Device (Rsd) And A Dekati Electronic Tailpipe Sensor (Etaps) With Gravimetrically Measured Pm From A Total Exhaust Dilution Tunnel System, Mridul Gautam, Donald H. Stedman, Daniel K. Carder, Benjamin Shade, Nigel Clark, Gregory Thompson, Scott Wayne, Gary A. Bishop, Brent G. Schuchmann, Dan Pope, Niranjan Vescio, Gary Full, Peter Mcclintock, Drew Rau

Fuel Efficiency Automobile Test Publications

No abstract provided.


Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 2, 2009, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman Jan 2010

Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 2, 2009, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 3, 2010, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman Jan 2010

Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 3, 2010, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Computer Simulation Of Ion-Induced Nucleation In The Presence Of Single Ions And Ion Pairs, Samuel Keasler Jan 2010

Computer Simulation Of Ion-Induced Nucleation In The Presence Of Single Ions And Ion Pairs, Samuel Keasler

LSU Doctoral Dissertations

Atmospheric aerosol particles play an important role in climate and human health. Despite their importance, the mechanisms of their formation are still poorly understood. Ion-induced nucleation may play a role in the process, but details are lacking about how the nucleation rate depends on the size, charge, and number of ions in the cluster. In order to better understand the role that ions might play in new particle formation, we have performed a series of AVUS-HR simulations of the water nucleation in the presence of both single ions and ion pairs. These simulations have shown that the location of the …


On-Road Motor Vehicle Emissions Including Nh3, So2 And No2, Donald H. Stedman, Gary A. Bishop, Allison Peddle Jan 2009

On-Road Motor Vehicle Emissions Including Nh3, So2 And No2, Donald H. Stedman, Gary A. Bishop, Allison Peddle

Fuel Efficiency Automobile Test Publications

No abstract provided.


Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 1, 2008, Gary A. Bishop, Nicolas E. Holubowitch, Donald H. Stedman Jan 2009

Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 1, 2008, Gary A. Bishop, Nicolas E. Holubowitch, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Motor Vehicle Emissions Including Ammonia, Sulfur Dioxide And Nitrogen Dioxide (Presentation), Donald H. Stedman, Gary A. Bishop, Allison Peddle Jan 2009

On-Road Motor Vehicle Emissions Including Ammonia, Sulfur Dioxide And Nitrogen Dioxide (Presentation), Donald H. Stedman, Gary A. Bishop, Allison Peddle

Fuel Efficiency Automobile Test Publications

No abstract provided.


Portable Emission Measurements Of Yellowstone Park Snowcoaches And Snowmobiles, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman, John D. Ray Jan 2009

Portable Emission Measurements Of Yellowstone Park Snowcoaches And Snowmobiles, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman, John D. Ray

Fuel Efficiency Automobile Test Publications

As part of the National Park Service’s Temporary Winter Use Plans Environmental Assessment, the University of Denver has been collecting in-use tailpipe emissions data from snowcoaches and snowmobiles in Yellowstone National Park. During the winter of 2006, using a portable emissions monitoring system, tailpipe data were collected from 10 snowcoaches and 2 four-stroke snowmobiles. These vehicles were operated over a standard route within the park, and the snowcoaches all carried identical passenger loads. These snowcoaches were newer in age with more advanced fuel management technology than those studied earlier, and average emissions were lower as a result (120, 1.7, and …


Signal To Noise Improvements In On-Road No, So2, And Nh3 Measurements Using A Multi-Component Classical Least Squares Fitting Approach (Presentation), Gary A. Bishop, Donald H. Stedman Jan 2008

Signal To Noise Improvements In On-Road No, So2, And Nh3 Measurements Using A Multi-Component Classical Least Squares Fitting Approach (Presentation), Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


A Decade Of On-Road Emissions Measurements, Gary A. Bishop, Donald H. Stedman Jan 2008

A Decade Of On-Road Emissions Measurements, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

A multi-year, on-road emission measurement program carried out in the cities of Chicago, IL, Denver, CO, Los Angeles, CA and Phoenix, AZ shows large, fuel specific tailpipe emissions reductions at all of the sites for carbon monoxide (CO), hydrocarbons (HC) and nitric oxide (NO). CO emissions decrease between 56% (Denver) and 71% (Chicago), HC emissions decrease between 27% (Phoenix) and 63% (Denver) and NO emissions have dropped between 48% (West LA) and 68% (Chicago). Three observed factors common to all of the sites are that the emission reductions are occurring in vehicles of all ages, that the influence of engine …


Calibrating Feat Instruments Without Gas Cylinders, Allison Peddle, Donald H. Stedman Jan 2008

Calibrating Feat Instruments Without Gas Cylinders, Allison Peddle, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 7, September 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman Jan 2007

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 7, September 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 6, January 2007, Gary A. Bishop, Donald H. Stedman Jan 2007

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 6, January 2007, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Portable Emission Measurements Of Snowcoaches And Snowmobiles In Yellowstone National Park, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman Jan 2007

Portable Emission Measurements Of Snowcoaches And Snowmobiles In Yellowstone National Park, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 6, November 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman Jan 2007

On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 6, November 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Fleet Vehicle Smoke Emissions As Measured By On-Road Remote Sensing Using Infrared Scattering: Years 1998 Through 2007, Jeffrey A. Caulfield, Gary A. Bishop, Donald H. Stedman Jan 2007

Fleet Vehicle Smoke Emissions As Measured By On-Road Remote Sensing Using Infrared Scattering: Years 1998 Through 2007, Jeffrey A. Caulfield, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


The Weekend Effect: The Science Suggests That We Are Embarking On An Expensive Policy Which Will Harm The Environment {Presentation}, Donald H. Stedman Jan 2006

The Weekend Effect: The Science Suggests That We Are Embarking On An Expensive Policy Which Will Harm The Environment {Presentation}, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 6, September 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2006

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 6, September 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 5, January 2005, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2006

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 5, January 2005, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.