2003 Progress Report: Characterization of the Chemical Composition of Atmospheric Ultrafine Particles

EPA Grant Number: R827354C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R827354
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Airborne PM - Rochester PM Center
Center Director: Oberd√∂rster, G√ľnter
Title: Characterization of the Chemical Composition of Atmospheric Ultrafine Particles
Investigators: Hopke, Philip K. , Prather, Kimberly A.
Current Investigators: Cass, Glen , Dillner, Ann , Hopke, Philip K. , Prather, Kimberly A.
Institution: Clarkson University , University of California - San Diego
Current Institution: Georgia Institute of Technology , Arizona State University - Main Campus , Clarkson University , University of California - Riverside
EPA Project Officer: Chung, Serena
Project Period: June 1, 1999 through May 31, 2005 (Extended to May 31, 2006)
Project Period Covered by this Report: June 1, 2003 through May 31, 2004
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air

Objective:

The objective of this research project is to provide improved understanding of the chemical and physical nature of the ultrafine ambient aerosol. There is relatively little data available that provides distinct information on particles in the size range less than 100 nm. Because of the relatively small amount of particle mass in this size range, sampling and chemical analysis is difficult. Such physical and chemical data, however, provide critical information to epidemiological and toxicological studies to help guide studies of the relationships of the ultrafine particles and adverse health effects. Initially the focus of this core has been on the development of effective methods to sample and analyze ultrafine particles. Now, these methods are being applied to characterize the ultrafine aerosol in a number of locations across the country to assess the variations that exist in the nature of the ultrafine particles.

This is one of the projects of the Rochester PM Center. The progress for the other projects is reported separately (see reports for R827354C002 through R827352C005).

Progress Summary:

Generation of Diesel Oil, Fuel, and Coated Elemental Carbon (EC) Particles

Methods have been developed to coat the EC particles generated by the PALAS generator that have been used as model aerosols in exposure studies. Ambient measurements have shown that the largest fraction of volatile organic carbon species in the atmosphere in urban locations is from vehicular (gas and diesel) fuel vapors. We have created a flow tube system that allows EC particles to be coated with varying amounts of vapor. The vapor can be a pure compound or mixtures such as fuels. We then measure the new size distributions with a scanning mobility particle sizing system (SMPS) to verify the particles have been coated. In initial experiments, we have noticed that when the particles become coated, their mobility diameters collapse to smaller sizes. We can also change the shape of the particles by changing the relative humidity to which they are exposed. These results could have implications when using these particles for exposure studies. We have also developed a method for dispersing oil droplets from used and new oil samples from diesel and gasoline vehicles. It has been shown that up to 95 percent of particles emitted from diesels are unburned lubricating oil. Thus, studying the health effects of these oil particles will have serious ramifications. Based on SMPS measurements, we are able to generate these particles over a wide range of sizes, from ultrafine (50 nm) up to several micrometers. We have noticed significant composition differences for used versus new oil samples. Again, performing exposure studies to these two different particle types should produce interesting results. We are providing the setup scheme to core 4 so they can make these particles for their exposure studies.

Characterization of Concentrated Ambient Particles (CAPs)

A comprehensive data analysis has been completed on the data sets collected in Rochester, NY, 2002; Boston, MA, 2003; Tuxedo Park, NY, 2003; and Chapel Hill, NC, 2003. Results were presented at the American Association for Aerosol Research (AAAR) PM meeting in Pittsburgh, PA, 2003, and the AAAR Fall meeting in Anaheim, CA, 2003. An article will be submitted for publication in the near future.

Aerosol time-of-flight mass spectrometry (ATOFMS) was employed to characterize individual concentrated ultrafine and fine particles from several high volume particle concentrators. Particles were sampled by ATOFMS and a variety of other aerosol analysis instruments from the input and output of the fine/coarse concentrator located at the U.S. Environmental Protection Agency (EPA) facility in North Carolina. No change was evident in the composition of particles exiting the coarse concentrator. In contrast, experimental results from the UF concentrator characterization studies show that particles undergo chemical transformations in direct analogy to fog processing during the concentration enrichment processes at a supersaturation ratio of 3.0 or lower. In comparison to direct (non-concentrated) ambient sampling, enhancement in the fractions of elemental carbon coated organic carbon and/or organic carbon type particles and significant depletion in the fraction of elemental carbon type ultrafine particles were observed in the concentrated particles.

An increase in the number fraction of aromatic and polycyclic aromatic hydrocarbon type particles was also observed in both ultrafine and fine modes. Such changes are attributed to the chemical conversion and deposition/coating of gaseous components (e.g. water-soluble organic compounds) on the pre-existing ultrafine and fine particles during the particle concentration enrichment process, which involves high supersaturation ratios, condensation, desolvation, and evaporation for particle growth and size restoration. The occurrence of aqueous phase sulfur chemistry inside the particle concentrator in Rochester was indicated by the formation of hydroxymethanesulfonate, which was most likely due to the enhanced partitioning of gaseous SO2 into the diluted water droplets. Because the toxicity of particles is likely to be related to their chemical composition and the saturation conditions in these concentrators are higher than that of the human body, subsequent influence on health effects as a result of the change in particle chemical composition caused by these particle concentrators needs to be further explored.

Particle-Bound Reactive Oxidative Species

Reactive oxygen species (ROS), a term used to collectively describe oxygen-containing species with strong oxidizing ability, include molecules like hydrogen peroxide (H2O2), ions like the hypochlorite ion (OCl-) and the superoxide anion (O2-), and radicals like the hydroxyl (OH) radical. One of the hypotheses for the adverse health effects of airborne particulate matter is the effects of ROS, formed by metals acting as catalysts for Fenton reactions, at concentrations that cause inflammation and lead to systemic dysfunctions. ROS are present, however, in the atmosphere associated with respirable particles to which we are exposed. It is the purpose of this study to determine the concentration of ROS in the background atmosphere, carried by atmospheric particles.

This study determined the concentrations of particle-bound ROS in ambient particles at Rubidoux, CA, and Flushing, NY. We did not deal with threats or health effects. This study was a straightforward effort to look at the routine concentrations of ROS in particulate matter. It also explored the diurnal variations in the ROS concentrations at these two sites and the factors affecting the diurnal variations, with a special emphasis on the relation between ROS concentration and the photochemical activity. The ozone concentration was taken as the index of intensity of photochemical activity.

A Micro-Orifice Uniform Deposit Impactor (MOUDI) and a Nano-MOUDI were used to sample particles at 3-hour intervals and collect them on 47-mm polycarbonate membrane filters. The ROS in the particles were then extracted and reacted with dichlorofluorescin horseradish peroxidase (DCFH2-HRP) reagent. The particle-size range sampled and analyzed for ROS ranged over three orders of magnitude from 18 μm to 0.01 μm. The study in Rubidoux, CA, was conducted in July 2003; the study in Flushing, NY, was conducted from the January 12 to February 5, 2004.

In Rubidoux, CA, which is on the eastern side of the Los Angeles basin, it was found that average nighttime concentrations were comparable to the average daytime concentrations. The daytime concentrations ranged from (6.11 ± 1.39) x 10-7M/m3 during the early afternoon sampling interval between 12-3 p.m., and (5.96 ± 1.16) x 10-7M/m3 during the late afternoon sampling interval between 4-7 p.m., to (5.70 ± 0.96) x 10-7M/m3 during the early morning sampling interval of 8-11 a.m. The average nighttime concentrations were found to be (5.19 ± 0.83) x 10-7M/m3. The intensity of photochemical reaction was found to be a moderate factor affecting the formation of ROS.

A similar trend in diurnal variations was observed at Flushing, NY, although the magnitudes of total average concentrations was almost an order of a magnitude less than the corresponding values at Rubidoux. The diurnal trends in Flushing, NY, were more pronounced. The average daytime concentrations were found to range from (10.7 ± 0.887) x 10-8 M/m3 during the early afternoon sampling interval between 12-3 p.m., and (9.41 ± 1.22) x 10-8 M/m3 during the late afternoon sampling interval between 4-7 p.m., to (9.19 ± 0.88) x 10-8 M/m3 during the early morning sampling interval of 8-11 a.m. The average nighttime concentrations were found to be (8.45 ± 1.29) x 10-8 M/m3. Again, as in Rubidoux, the average nighttime concentrations were found to be comparable to the average daytime concentrations. These results suggest the possibility that the nitrate radical is playing an important role in ROS formation at night relative to the hydroxyl radical in the presence of sunlight. These results suggest a need for greater interest in nighttime nitrate radical chemistry.


Journal Articles on this Report : 7 Displayed | Download in RIS Format

Other subproject views: All 30 publications 30 publications in selected types All 29 journal articles
Other center views: All 104 publications 98 publications in selected types All 90 journal articles
Type Citation Sub Project Document Sources
Journal Article Jeong C-H, Hopke PK, Chalupa D, Utell M. Characteristics of nucleation and growth events of ultrafine particles measured in Rochester, NY. Environmental Science & Technology 2004;38(7):1933-1940. R827354 (Final)
R827354C001 (2003)
R827354C001 (Final)
R827354C003 (Final)
R832415 (2010)
R832415 (2011)
R832415 (Final)
R832415C003 (2011)
  • Abstract from PubMed
  • Full-text: ACS-Full Text HTML
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  • Abstract: ACS-Abstract
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  • Other: ACS-Full Text PDF
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  • Journal Article Jeong C-H, Lee D-W, Kim E, Hopke PK. Measurement of real-time PM2.5 mass, sulfate, and carbonaceous aerosols at the multiple monitoring sites. Atmospheric Environment 2004;38(31):5247-5256. R827354 (Final)
    R827354C001 (2003)
    R827354C001 (Final)
    R832415 (2010)
    R832415 (2011)
    R832415 (Final)
  • Full-text: ScienceDirect-Full Text HTML
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  • Abstract: ScienceDirect-Abstract
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  • Other: ScienceDirect-Full Text PDF
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  • Journal Article Jeong C-H, Hopke PK, Kim E, Lee D-W. The comparison between thermal-optical transmittance elemental carbon and Aethalometer black carbon measured at multiple monitoring sites. Atmospheric Environment 2004;38(31):5193-5204. R827354 (Final)
    R827354C001 (2003)
    R827354C001 (Final)
    R832415 (2010)
    R832415 (2011)
    R832415 (Final)
  • Full-text: ScienceDirect-Full Text HTML
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  • Abstract: ScienceDirect-Abstract
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  • Other: ScienceDirect-Full Text PDF
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  • Journal Article Moffet RC, Shields LG, Berntsen J, Devlin RB, Prather KA. Characterization of an ambient coarse particle concentrator used for human exposure studies: aerosol size distributions, chemical composition, and concentration enrichment. Aerosol Science and Technology 2004;38(11):1123-1137. R827354 (Final)
    R827354C001 (2003)
    R827354C001 (Final)
    R832415 (2010)
    R832415 (2011)
    R832415 (Final)
  • Full-text: IngentaConnect-Full Text PDF
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  • Abstract: IngentaConnect-Abstract
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  • Journal Article Su Y, Sipin MF, Furutani H, Prather KA. Development and characterization of an aerosol time-of-flight mass spectrometer with increased detection efficiency. Analytical Chemistry 2004;76(3):712-719. R827354 (Final)
    R827354C001 (2003)
    R827354C001 (Final)
    R832415 (2010)
    R832415 (2011)
    R832415 (Final)
  • Abstract from PubMed
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  • Abstract: ACS-Abstract
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  • Journal Article Su Y, Sipin MF, Prather KA, Gelein RM, Lunts A, Oberdorster G. ATOFMS characterization of individual model aerosol particles used for exposure studies. Aerosol Science and Technology 2005;39(5):400-407. R827354 (Final)
    R827354C001 (2003)
    R827354C001 (Final)
    R827354C004 (Final)
    R832415 (2010)
    R832415 (2011)
    R832415 (Final)
    R832415C004 (2011)
  • Full-text: Taylor & Francis-Full Text PDF
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  • Abstract: Taylor & Francis-Abstract
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  • Journal Article Venkatachari P, Hopke PK, Grover BD, Eatough DJ. Measurement of particle-bound reactive oxygen species in rubidoux aerosols. Journal of Atmospheric Chemistry 2005;50(1):49-58. R827354 (Final)
    R827354C001 (2003)
    R827354C001 (Final)
    R832415 (2010)
    R832415 (2011)
    R832415 (Final)
  • Abstract: SpringerLink-Abstract
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  • Other: Environmental Expert-Full Text PDF
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  • Supplemental Keywords:

    pollution prevention, urban air pollution, atmosphere, metals, air, health, waste, atmospheric sciences, biochemistry, children’s health, environmental chemistry, epidemiology, genetics, virology, molecular biology, health risk assessment, risk assessments, incineration, combustion, combustion engines, air toxics, tropospheric ozone, PM2.5, particulates, ultrafine particles, particulate matter, particle exposure, particle size, aerosol, aerosols, ambient air, ambient air monitoring, ambient air quality, animal model, atmospheric, cardiopulmonary, cardiopulmonary responses, cardiovascular disease, cardiovascular vulnerability, coronary artery disease, cytokine production, fine particles, human exposure, human health, human health effects, environmental health effects, inhalation toxicology, lead, lung, lung inflammation, metals, morbidity, mortality, pathophysiological mechanisms, pulmonary, pulmonary disease, stratospheric ozone, sensitive populations, susceptible populations,, RFA, Health, Scientific Discipline, Air, Geographic Area, particulate matter, Environmental Chemistry, Health Risk Assessment, Epidemiology, State, Risk Assessments, Biochemistry, ambient air quality, particle size, particulates, sensitive populations, cardiopulmonary responses, fine particles, human health effects, morbidity, ambient air monitoring, chemical characteristics, pulmonary disease, susceptible populations, epidemelogy, environmental health effects, particle exposure, nano differential mobility analyzer, human exposure, particulate exposure, chemical kinetics, Texas (TX), PM, mortality, urban environment, aerosols, ultrafine particles, chemical speciation sampling

    Relevant Websites:

    http://www2.envmed.rochester.edu/envmed/PMC/ Exit

    Progress and Final Reports:

    Original Abstract
  • 1999 Progress Report
  • 2000 Progress Report
  • 2001 Progress Report
  • 2002 Progress Report
  • 2004 Progress Report
  • Final Report

  • Main Center Abstract and Reports:

    R827354    Airborne PM - Rochester PM Center

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827354C001 Characterization of the Chemical Composition of Atmospheric Ultrafine Particles
    R827354C002 Inflammatory Responses and Cardiovascular Risk Factors in Susceptible Populations
    R827354C003 Clinical Studies of Ultrafine Particle Exposure in Susceptible Human Subjects
    R827354C004 Animal Models: Dosimetry, and Pulmonary and Cardiovascular Events
    R827354C005 Ultrafine Particle Cell Interactions: Molecular Mechanisms Leading to Altered Gene Expression
    R827354C006 Development of an Electrodynamic Quadrupole Aerosol Concentrator
    R827354C007 Kinetics of Clearance and Relocation of Insoluble Ultrafine Iridium Particles From the Rat Lung Epithelium to Extrapulmonary Organs and Tissues (Pilot Project)
    R827354C008 Ultrafine Oil Aerosol Generation for Inhalation Studies