David C. Snyder

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Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionmenttechniques. The secondary organic aerosol (SOA) mass is estimated by elemental carbon and carbon monoxide(More)
Primary and secondary sources contributing to atmospheric organic aerosol during the months of July and August were quantitatively assessed in three North American urban areas: Cleveland, Ohio, and Detroit, Michigan, in the Midwest region and Riverside, California, in the Los Angeles Air Basin. Organic molecular marker species unique to primary aerosol(More)
Gaseous elemental mercury (GEM), particulate mercury (PHg) and reactive gaseous mercury (RGM) were measured every other hour at a rural location in south central Wisconsin (Devil's Lake State Park, WI, USA) between April 2003 and March 2004, and at a predominantly downwind urban site in southeastern Wisconsin (Milwaukee, WI, USA) between June 2004 and May(More)
Two months of treatment with rifampin-pyrazinamide (RZ) and 9 months of treatment with isoniazid are both recommended for treatment of latent tuberculosis infection in adults without human immunodeficiency virus infection, but the relative cost-effectiveness of these 2 treatments is unknown. We used a Markov model to conduct a cost-effectiveness analysis to(More)
Speciated measurements of atmospheric mercury plumes were obtained at an industrially impacted residential area of East St. Louis, IL. These plumes were found to result in extremely high mercury concentrations at ground level that were composed of a wide distribution of mercury species. Ground level concentrations as high as 235 ng m(-3) for elemental(More)
Here we present a new open-source software package designed to facilitate the analysis of atmospheric data, with emphasis on data mining applications applied to single-particle mass spectrometry data from aerosol particles. The software package, Enchilada (Environmental Chemistry through Intelligent Atmospheric Data Analysis), is designed to seamlessly(More)
BACKGROUND Before 2003, almost all dialysis access procedures performed at the G.V. Montgomery Veterans' Affairs Medical Center were arteriovenous grafts. In mid-2003, it was decided to place fistulas in most patients. This study compared the patency rates and frequency of interventions to maintain function between the 2 procedures. METHODS Patency rates(More)
Organic aerosol measurements with high temporal resolution can differentiate primary organic carbon (POC) from secondary organic carbon (SOC) and can be used to distinguish morning rush hour traffic emissions and subsequent photo-oxidation. In the current study, five hour filter samples were collected during the Summer Study for Organic Aerosols at(More)
Carbonaceous atmospheric particulate matter (PM25) collected in the midwestern United States revealed that soot emissions from incomplete coal combustion were important sources of several organic molecular markers used in source apportionment studies. Despite not constituting a major source of organic carbon in the PM25, coal soot was an important source of(More)