2010 Progress Report: Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of Their Relative Toxicity

EPA Grant Number: R832413C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R832413
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Southern California Particle Center
Center Director: Froines, John R.
Title: Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of Their Relative Toxicity
Investigators: Sioutas, Constantinos , Schauer, James J.
Current Investigators: Sioutas, Constantinos , Fine, Philip M. , Geller, Michael , Hinds, William C. , Schauer, James J. , Shafer, Martin M. , Zhu, Yifang
Institution: University of Southern California , University of Wisconsin
Current Institution: University of Southern California , University of California - Los Angeles , University of Wisconsin
EPA Project Officer: Chung, Serena
Project Period: October 1, 2005 through September 30, 2010 (Extended to September 30, 2012)
Project Period Covered by this Report: August 1, 2009 through July 31,2010
RFA: Particulate Matter Research Centers (2004) RFA Text |  Recipients Lists
Research Category: Health Effects , Air

Objective:

The primary objective of Project 1 is to examine the relationships between PM sources, exposure, and toxicity within the constraints of the urban atmosphere. This project is an integral part of Projects 2, 3 and 4,by serving as the field operations to collect PM samples for toxicity testing and for providing elevated levels of ambient PM for animal exposure models described in these projects. Our major themes are:

  1. Physical and chemical properties of PM emitted from different PM sources.
    • To determine their emission rates of PM species vs size
    • To evaluate how exposure to PM from these sources varies with respect to location, season, and particle size
    • In conjunction with Projects 2, 3 and 4, to assess their relative toxicity by providing in vitro PMsamples to the PIs of these projects
  2. Determine the characteristics of the volatile and non-volatile particle components of these sources. Also provide in vitro samples to Projects 2 and 3.
  3. Measure exposure gradients and intra-community variability of PM from complex, unstudied sources such as airports and port activities.
    • Collect concurrently samples for Projects 2 and 3
    • Areas of Long Beach-LA Port
  4. To assess the contributions of these outdoor sources to indoor exposure in support of Project 4.

Progress Summary:

Over the course of the months covered in this report, and in concert with our proposed scope of work, we carried out field sampling campaigns at the facilities of the University of Southern California (USC). We completed our data analysis and submitted several manuscripts for publication from our collaborative efforts with Projects 2, 3 and 4. Results from these studies and their linkages to Projects 2-4 are described in the following paragraphs.

Our Ning Z, et al., paper published in Environmental Science & Technology 2007;41(17):6000-6006) identified clearly two distinctly different time periods in the summertime at USC; one impacted by vehicular emissions and the other by secondary formation processes. To characterize the redox activity profiles of atmospheric aerosols from primary (traffic) and secondary photochemical sources, ambient quasi-ultrafine particles were collected near downtown Los Angeles in two different time periods – morning (6:00–9:00 PDT) and afternoon (11:00–14:00 PDT) in the summer of 2008. Detailed chemical analysis of the collected samples, including water-soluble elements, inorganic ions, organic species and water soluble organic carbon (WSOC), was conducted and redox activity of the samples was measured by two different assays: the dithiothreitol (DTT) and the macrophage reactive oxygen species (ROS) assays. Tracers of secondary photochemical reactions, such as sulfate and organic acids were higher (2.1 ± 0.6 ) times for sulfate, and up to 3 times for the organic acids) in the afternoon period. 

WSOC also was elevated by 2.5 ± 0.9 times in the afternoon period due to photo-oxidation of primary particles during atmospheric aging. Redox activity measured by the DTT assay was considerably higher for the samples collected during the afternoon; on the other hand, diurnal trends in the ROS-based activity were not consistent between the morning and afternoon periods. We showed (Verma, et al., 2009) that aged particles in LA exhibited greater DTT activity and increased endogenous ROS as compared to fresh ultrafine particles. Figure 1 shows the DTT (left) and ROS (right) measured for morning (fresh) and afternoon (aged) particles. 

A linear regression between redox activity and various PM chemical constituents showed that the DTT assay was highly correlated with WSOC (R2 = 0.80), while ROS activity was associated mostly with water soluble transition metals (Vanadium, Nickel and Cadmium; R2 > 0.70). The DTT and ROS assays, which are based on the generation of different oxidizing species by chemical PM constituents, provide important information for elucidating the health risks related to PM exposure from different sources. Thus, both primary and secondary particles possess high redox activity; however, photochemical transformations of primary emissions with atmospheric aging enhance the toxicological potency of primary particles in terms of generating oxidative stress and leading to subsequent damage in cells. (More details can be found in Verma V, Ning Z, Cho AK, Schauer JJ, Shafer MM, Sioutas C. Redox activity of urban ultrafine particles from primary and secondary sources. Atmospheric Environment 2009;43:6360-6368.)

Motor vehicle emissions are the dominant sources of particulate matter (PM) in urban cities, and numerous studies have linked vehicular exhaust particles to adverse health effects, including premature deaths. Understanding the health and toxicological effects of PM emitted for traffic sources has been a major thrust area of our center. To that end, we tested three light-duty passenger vehicles in five configurations in a chassis dynamometer study to determine the chemical and oxidative potential of the particulate exhaust emissions. The first vehicle was a diesel Honda with a three-stage oxidation system. Its main catalyst was replaced with a diesel particulate filter (DPF) and tested as a second configuration. The second vehicle was a gasoline-powered Toyota Corolla with a three-way catalytic converter. The last vehicle was an older Volkswagen Golf, tested using petro-diesel in its original configuration, and biodiesel with an oxidation catalyst as an alternative configuration. PM was collected on filters and subsequently analyzed using various chemical and toxicological assays. The production of reactive oxygen species (ROS), quantified by the dithiothreitol (DTT) and macrophage-ROS assays, was used to measure the PM-induced oxidative potential. The results showed that the Golf vehicle in both configurations had the highest emissions of organic species (PAHs, hopanes, steranes, and organic acids). The DPF-equipped diesel Accord car emitted PM with the lowest amounts of organic species and the lowest oxidative potential. Correlation analyses showed that soluble Fe is strongly associated with particulate ROS activity (R = 0.99), while PAHs and hopanes were highly associated with DTT consumption rates (R = 0.94 and 0.91, respectively). In particular, tracers of lube oil emissions, namely Zn, P, Ca, and hopanes, were strongly correlated with distance-based DTT consumption rates (R = 0.96, 0.92, 0.83, and 0.91, respectively), suggesting that incomplete combustion of lube oil might be important driving factors of the overall PM-induced oxidative stress. In summary, our results showed that the Golf vehicle (in both petro-diesel and biodiesel) emitted the most redox potent exhaust per km driven and also had the highest emissions of organic species (PAHs, hopanes, steranes, and organic acids). The biodiesel vehicle had elevated emissions of several organic acids due to incomplete combustion, although they did not seem to affect the oxidative properties of the emitted PM. The DPF-equipped Accord diesel car, by comparison, was effective in reducing overall PAHs and PM mass, and had the least potent emissions measured by both DTT and ROS assays. Thus, to reduce the emissions of carcinogenic aromatics, the use of advance after-treatment technologies and/or cleaner fuel may be a better remedy than the use of biodiesel. (More details can be found in Cheung K, Ntziachristos L, Tzamkiozis T, Schauer JJ, Samaras Z, Sioutas C. Emissions of particulate metal and organic species from gasoline, diesel and biodiesel passenger vehicles and their relation to oxidative potential. Aerosol Science and Technology 2010;44(7):500-513.)

Following up and expanding upon the activities of this study, which included, through separate European Union funding, collaborations from the Helmholtz Institute in Germany and the Aristotle University of Thessaloniki (Greece), PM samples from the exhaust of these different vehicles were collected by a versatile aerosol concentration enrichment system (VACES). Water-borne PM samples were collected with this technique, thus retaining the original physicochemical characteristics of aerosol particles. PM samples originated from a gasoline Euro 3 car and two diesel cars complying with the Euro 2 and Euro 4 standards, respectively. The Euro 2 diesel car operated consecutively on fossil diesel and biodiesel. The Euro 4 car also was retrofitted with a diesel particle filter. In total, five vehicle configurations and an equal number of samples were examined. Each sample was intratracheal instilled to 10 mice at two different dose levels (50 μl and 100 μl).

The mice were analyzed 24 hours after instillation for acute lung inflammation by bronchoalveolar lavage and also for hematological changes. Results showed that a moderate but still significant inflammatory response is induced by PM samples, depending on the vehicle. Several organic and inorganic species, including benz(a)anthracene, chrysene, Mn, Fe, Cu, and heavy PAHs, as well as the reactive oxygen species content of the PM suspensions are correlated to the observed responses. The study develops conceptual dose-response functions for the different vehicle configurations. These demonstrate that inflammatory response is not directly proportional to the mass dose level of the administered PM and that the relative toxicity potency depends on the dosage level. (More details are available in Tzamkiozis T, Stoeger T, Cheung K, Ntziachristos L, Sioutas C, Samaras Z. Monitoring the inflammatory potential of exhaust particles from passenger cars in mice. Inhalation Toxicology 2010;22(Suppl 2):59-69.)

Future Activities:

Our SCPC PI, Dr. John Froines, requested a formal 18 month no-cost extension for the California Particle Center, the grant for which is due to expire on September 30, 2010. If approved, a no-cost extension will extend the performance period of this award through March 31, 2012. Eighteen months is being requested to ensure the completion of the current projects. The 18-month research plan consists of a continuance and completion of our five current projects.

For Project 1: Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of their RelativeToxicity (Sioutas, Schauer), we will complete the following research activities:

  1. Complete chemical and toxicity analyses of UFP from traffic vs. photochemical processes. We already have completed in vitro experiments and now we will use separate but identical in all other aspects PM sample collections for in vivo exposures of transgenic mice via intranasal instillations.
  2. Collect Ultrafine PM at ambient, 50, 100, 220 deg C to conduct chemical and toxicological (DTT, ROS, etc.) characterization. The main idea here is to characterize the physico-chemical and oxidative characteristics of the semi-volatile and non-volatile fractions of atmospheric aerosols. We will use a thermodenuder (TD) for shifting to shift the gas-particle partitioning of semi-volatile components of these aerosols. The oxidative potential of collected particles will be measured by means of the DTT (dithiothreitol) assay. Detailed chemical analyses of the collected PM samples, including total and water soluble organic carbon, elemental carbon, water soluble elements, inorganic ions and PAHs (polycyclic aromatic hydrocarbons), will be conducted to quantify the volatility behavior of different PM species, and also to investigate their correlation with the effect on measured oxidative potential.
  3. Compare the chemical and toxicological characteristics of size fractionated PM collected using three different sampling methodologies: a) Filters, b) Impactors (NanoMOUDI to capture PM> 0.018um), and c) Biosamplers. We seek to identify similarities and determine how differences in chemical characteristics of PM sampled by these three different methodologies will affect toxicity measurements both in vitro and in vivo.
  4. Following recommendation of our ESAC, develop a methodology to effectively separate the accumulation mode particles (100nm-2.5μm) from ultrafine particles (<100nm), which allows for a directcomparison of the in vivo exposure studies on different modes of particles. We will carry out an intensive investigation on the diffusion batteries with different flow rates and pore size configurations.< br/>
    We will make the following modification to the VACES shown in Figure 2; the concentrated PM2.5 flow exiting the VACES will go through a screen type diffusion battery prior to entering the inhalation exposure chambers, as shown in the figure. The purpose of the diffusion battery is to remove ultrafine PM from the concentrated air sample prior to entering the inhalation chamber.

    Figure 2. Diffusion Battery- Removal of Ultrafine PM



    The design of the screen type diffusion battery (Figure 2) will be based on the formerly commercially available model by TSI (Model 376060). Briefly the concentrated aerosol will pass at 1.5 lpm through a series of stainless steel screens that are 47 mm in diameter.

  5. Moreover we will modify our VACES technology to conduct inhalation exposures to vapor phase SVOC without the PM component. To that end, animal exposures to vapor-gas phase semivolatile organic compounds (SVOC) only, separated from the PM phase, will be conducted using the experimental set up shown in Figure 3. To accomplish separation of particles from their SVOC component and supply the SVOC into the chamber for inhalation studies, the aerosol mixture leaving the VACES concentrator will pass through the same thermodenuder technology made by Dekati, described earlier, with one modification; the carbon denuder of the device will be removed so that SVOC vapors that volatilize from PM are not removed from the air sample


Journal Articles on this Report : 11 Displayed | Download in RIS Format

Other subproject views: All 87 publications 85 publications in selected types All 85 journal articles
Other center views: All 241 publications 157 publications in selected types All 157 journal articles
Type Citation Sub Project Document Sources
Journal Article Cheung KL, Ntziachristos L, Tzamkiozis T, Schauer JJ, Samaras Z, Moore KF, Sioutas C. Emissions of particulate trace elements, metals and organic species from gasoline, diesel, and biodiesel passenger vehicles and their relation to oxidative potential. Aerosol Science and Technology 2010;44(7):500-513. R832413 (Final)
R832413C001 (2010)
R832413C001 (Final)
  • Full-text: Taylor&Francis-Full Text HTML
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  • Journal Article Delfino RJ, Staimer N, Tjoa T, Arhami M, Polidori A, Gillen DL, Kleinman MT, Schauer JJ, Sioutas C. Association of biomarkers of systemic inflammation with organic components and source tracers in quasi-ultrafine particles. Environmental Health Perspectives 2010;118(6):756-762. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
    R832413C004 (2010)
    R832413C004 (Final)
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  • Journal Article Delfino RJ, Tjoa T, Gillen DL, Staimer N, Polidori A, Arhami M, Jamner L, Sioutas C, Longhurst J. Traffic-related air pollution and blood pressure in elderly subjects with coronary artery disease. Epidemiology 2010;21(3):396-404. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (2010)
    R832413C001 (Final)
    R832413C004 (2010)
    R832413C004 (Final)
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  • Journal Article Delfino RJ, Staimer N, Tjoa T, Arhami M, Polidori A, Gillen DL, George SC, Shafer MM, Schauer JJ, Sioutas C. Associations of primary and secondary organic aerosols with airway and systemic inflammation in an elderly panel cohort. Epidemiology 2010;21(6):892-902. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
    R832413C004 (2010)
    R832413C004 (Final)
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  • Journal Article Delfino RJ, Gillen DL, Tjoa T, Staimer N, Polidori A, Arhami M, Sioutas C, Longhurst J. Electrocardiographic ST-segment depression and exposure to traffic-related aerosols in elderly subjects with coronary artery disease. Environmental Health Perspectives 2011;119(2):196-202. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
    R832413C004 (2010)
    R832413C004 (Final)
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  • Journal Article Li N, Harkema JR, Lewandowski RP, Wang M, Bramble LA, Gookin GR, Ning Z, Kleinman MT, Sioutas C, Nel AE. Ambient ultrafine particles provide a strong adjuvant effect in the secondary immune response:implication for traffic-related asthma flares. American Journal of Physiology 2010;299(3):L374-L383. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
    R832413C002 (2010)
    R832413C002 (Final)
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  • Journal Article Li R, Ning Z, Majumdar R, Cui J, Takabe W, Jen N, Sioutas C, Hsiai T. Ultrafine particles from diesel vehicle emissions at different driving cycles induce differential vascular pro-inflammatory responses:implication of chemical components and NF-κB signaling. Particle and Fibre Toxicology 2010;7:6. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
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  • Journal Article Li R, Ning Z, Cui J, Yu F, Sioutas C, Hsiai T. Diesel exhaust particles modulate vascular endothelial cell permeability:implication of ZO-1 expression. Toxicology Letters 2010;197(3):163-168. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
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  • Journal Article Ngo MA, Pinkerton KE, Freeland S, Geller M, Ham W, Cliff S, Hopkins LE, Kleeman MJ, Kodavanti UP, Meharg E, Plummer L, Recendez JJ, Schenker MB, Sioutas C, Smiley-Jewell S, Haas C, Gutstein J, Wexler AS. Airborne particles in the San Joaquin Valley may affect human health. California Agriculture 2010;64(1):12-16. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
    R826246 (Final)
    R832414 (2010)
    R832414C003 (2010)
    R832414C003 (Final)
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  • Journal Article Ning Z, Sioutas C. Atmospheric processes influencing aerosols generated by combustion and the inference of their impact on public exposure:a review. Aerosol and Air Quality Research 2010;10(1):43-58. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
  • Full-text: Aerosol and Air Quality Research-Full Text PDF
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  • Journal Article Verma V, Ning Z, Cho AK, Schauer JJ, Shafer MM, Sioutas C. Redox activity of urban quasi-ultrafine particles from primary and secondary sources. Atmospheric Environment 2009;43(40):6360-6368. R832413 (Final)
    R832413C001 (2010)
    R832413C001 (Final)
    R832413C003 (Final)
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  • Supplemental Keywords:

    PM, sources, toxicity, apportionment, ultrafine, semi-volatile;, RFA, Health, Scientific Discipline, Air, particulate matter, Health Risk Assessment, Risk Assessments, Biochemistry, Ecology and Ecosystems, atmospheric particulate matter, particulates, human health effects, PM 2.5, chemical characteristics, toxicology, airway disease, airborne particulate matter, cardiovascular vulnerability, air pollution, human exposure, vascular dysfunction, cardiovascular disease, human health risk

    Relevant Websites:

    http://www.usc.edu/aerosol Exit

    Progress and Final Reports:

    Original Abstract
  • 2006 Progress Report
  • 2007 Progress Report
  • 2008 Progress Report
  • 2009 Progress Report
  • 2011
  • Final Report

  • Main Center Abstract and Reports:

    R832413    Southern California Particle Center

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R832413C001 Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of Their Relative Toxicity
    R832413C002 Project 2: The Role of Oxidative Stress in PM-induced Adverse Health Effects
    R832413C003 The Chemical Properties of PM and their Toxicological Implications
    R832413C004 Oxidative Stress Responses to PM Exposure in Elderly Individuals With Coronary Heart Disease
    R832413C005 Ultrafine Particles on and Near Freeways