Academic Appointments

  • Lecturer, Civil and Environmental Engineering

2023-24 Courses

All Publications

  • Fine organic aerosols collected in a humid, rural location (Great Smoky Mountains, Tennessee, USA): Chemical and temporal characteristics ATMOSPHERIC ENVIRONMENT Yu, L. E., Shulman, M. L., Kopperud, R., Hildemann, L. M. 2005; 39 (33): 6037-6050
  • Characterization of organic compounds collected during Southeastern Aerosol and Visibility Study: Water-soluble organic species ENVIRONMENTAL SCIENCE & TECHNOLOGY Yu, L. E., Shulman, M. L., Kopperud, R., Hildemann, L. M. 2005; 39 (3): 707-715


    As part of the Southeastern Aerosol and Visibility Study (SEAVS), water-soluble organic species (WSOS) in fine aerosols collected from July 15 to August 25, 1995, at the Great Smoky Mountain National Park, Tennessee (USA), were chemically classified into seven groups, with concentrations ranging from around 1 to >200 ng/m3. Dicarboxylic acids represented the dominant identified compound class, and succinic acid was the most abundant dicarboxylic acid. The trends in data suggest that most WSOS collected in the SEAVS samples were mainly generated from secondary photochemical reactions, especially during the first (cleaner) half of the sampling campaign. High relative humidity at the sampling site resulted in substantial water uptake by the aerosols, which may have enhanced the levels of succinic acid by reducing its rate of photooxidation. Concurrent trends in malic and malonic acid concentrations suggest these were generated from the oxidation of succinic acid. Consistent with the conversion of 3-hydroxypropanoic acid to malonic acid, it appears that 4-hydroxybutanoic acid served as a major precursor contributing to high levels of succinic acid in the daytime. Nocturnal WSOS generally followed the trend of diurnal WSOS, but they exhibited different chemical compositions and lower concentrations, unlike what has been reported for an urban site. A nocturnal-to-diurnal ratio of succinic acid larger than 0.25 may indicate an atmosphere dominated by photochemical reactions, rather than by primary emissions.

    View details for DOI 10.1021/es0489700

    View details for Web of Science ID 000226712600015

    View details for PubMedID 15757330

  • Outdoor versus indoor contributions to indoor particulate matter (PM) determined by mass balance methods 4th Colloquium on PM and Human Health Kopperud, R. J., Ferro, A. R., Hildemann, L. M. AIR & WASTE MANAGEMENT ASSOC. 2004: 1188–96


    This study compares an indoor-outdoor air-exchange mass balance model (IO model) with a chemical mass balance (CMB) model. The models were used to determine the contribution of outdoor sources and indoor resuspension activities to indoor particulate matter (PM) concentrations. Simultaneous indoor and outdoor measurements of PM concentration, chemical composition, and air-exchange rate were made for five consecutive days at a single-family residence using particle counters, nephelometers, and filter samples of integrated PM with an aerodynamic diameter of less than or equal to 2.5 microm (PM2.5) and PM with an aerodynamic diameter of less than or equal to 5 microm (PM5). Chemical compositions were determined by inductively coupled plasma mass-spectrometry. During three high-activity days, prescribed activities, such as cleaning and walking, were conducted over a period of 4-6 hr. For the remaining two days, indoor activities were minimal. Indoor sources accounted for 60-89% of the PM2.5 and more than 90% of the PM5 for the high-activity days. For the minimal-activity days, indoor sources accounted for 27-47% of PM2.5 and 44-60% of the PM5. Good agreement was found between the two mass balance methods. Indoor PM2.5 originating outdoors averaged 53% of outdoor concentrations.

    View details for Web of Science ID 000223701500016

    View details for PubMedID 15468671

  • Elevated personal exposure to particulate matter from human activities in a residence 9th International Conference on Indoor Air Quality and Climate (Indoor Air 2002) Ferro, A. R., Kopperud, R. J., Hildemann, L. M. NATURE PUBLISHING GROUP. 2004: S34–S40


    Continuous laser particle counters collocated with time-integrated filter samplers were used to measure personal, indoor, and outdoor particulate matter (PM) concentrations for a variety of prescribed human activities during a 5-day experimental period in a home in Redwood City, CA, USA. The mean daytime personal exposures to PM(2.5) and PM(5) during prescribed activities were 6 and 17 times, respectively, as high as the pre-activity indoor background concentration. Activities that resulted in the highest exposures of PM(2.5), PM(5), and PM(10) were those that disturbed dust reservoirs on furniture and textiles, such as dry dusting, folding clothes and blankets, and making a bed. The vigor of activity and type of flooring were also important factors for dust resuspension. Personal exposures to PM(2.5) and PM(5) were 1.4 and 1.6 times, respectively, as high as the indoor concentration as measured by a stationary monitor. The ratio of personal exposure to the indoor concentration was a function of both particle size and the distance of the human activity from the stationary indoor monitor. The results demonstrate that a wide variety of indoor human resuspension activities increase human exposure to PM and contribute to the "personal cloud" effect.

    View details for DOI 10.1038/sj.jea.7500356

    View details for Web of Science ID 000221128900005

    View details for PubMedID 15118743

  • Source strengths for indoor human activities that resuspend particulate matter ENVIRONMENTAL SCIENCE & TECHNOLOGY Ferro, A. R., Kopperud, R. J., Hildemann, L. M. 2004; 38 (6): 1759-1764


    A mathematical model was applied to continuous indoor and outdoor particulate matter (PM) measurements to estimate source strengths for a variety of prescribed human activities that resuspend house dust in the home. Activities included folding blankets, folding clothes, dry dusting, making a bed, dancing on a rug, dancing on a wood floor, vacuuming, and walking around and sitting on upholstered furniture. Although most of the resuspended particle mass from these activities was larger than 5 microm in diameter, the resuspension of PM2.5 and PM5 was substantial, with source strengths ranging from 0.03 to 0.5 mg min(-1) for PM2.5 and from 0.1 to 1.4 mg min(-1) for PM5. Source strengths for PM > 5 microm could not be quantified due to instrument limitations. The source strengths were found to be a function of the number of persons performing the activity, the vigor of the activity, the type of activity, and the type of flooring.

    View details for DOI 10.1021/es0263893

    View details for Web of Science ID 000220193900025

    View details for PubMedID 15074686