2009 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, 2008 through July 31,2009
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 among particulate matter (PM) sources, exposure, and toxicity within the constraints of the urban atmosphere. This project is an integral part of Projects 2, 3, and 4 because it serves as the field operation to collect PM samples for toxicity testing and for providing elevated levels of ambient PM for the animal exposure models described in these projects. Our major themes are:

  1. Assess the physical and chemical properties of PM emitted from different PM sources.
    • To determine the emission rates of PM species versus 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 relative toxicity by providing in vitro PM samples 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.
    • Areas ofLong Beach-LA Port
    • Concurrently collect samples for Projects 2 and 3
  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 at USC (July 2008 - present) and Long Beach.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.

Los Angeles – Long Beach Port Studies (in collaboration with Projects 2 and 3)

One of the major themes of Project 1 is the measurement of PM chemistry, toxicity, exposure gradients, and intra-community variability from complex, unstudied sources such as airports and port activities. The Los Angeles Ports complex consists of the Port of Long Beach and the Port of Los Angeles. Because of the high levels of PM emitted from many sources in the vicinity of these ports and their projected massive expansion, the Harbor area will be the focus of future government regulations.

In collaboration with investigators from Projects 2 and 3, we have also examined the ability of PM in that area to induce oxidative stress (Hu et al., 2008). The formation of reactive oxygen species (ROS) in cells exposed to particulate matter (PM) results in oxidative stress, which is an important mechanism associated with many adverse health effects caused by PM exposure. During our winter campaign in the LA-Long Beach port, two different types of assays were used to quantitatively measure the redox activity of PM: 1) in vitro exposure to rat alveolar macrophage (AM) cells using dichlorofluorescin diacetate (DCFH-DA) as the fluorescent probe (here referred to as macrophage ROS assay) and 2) consumption of dithiothreitol (DTT) in a cell-free system (DTT assay). Weekly coarse (PM10-2.5), accumulation (PM2.5-0.25), and quasi-ultrafine (quasi-UF, PM0.25) mode PM samples were collected at five sampling sites at Los Angeles-Long Beach Harbor and at one site near the University of Southern California campus (urban site). All PM samples were analyzed for organic carbon (total and water-soluble) and elemental carbon (OC and EC, respectively), organic species, inorganic ions, and total and water-soluble elements. Quasi-ultrafine mode particles showed the highest redox activities at all Long Beach sites (on both a per-mass and per-air volume basis). A significant association (R2 = 0.61) was observed between the two assays, indicating that macrophage ROS and DTT levels are affected by similar chemical driving forces. A relatively small spatial variation was observed for the DTT measurements across all size fractions and sites, whereas macrophage ROS levels showed more significant spatial variations across the three different particle size ranges and sites (coefficients of variation, or CVs, were 0.35, 0.24, and 0.53 for quasi-UF, accumulation, and coarse mode particles, respectively). Association between the main PM constituents and the redox activity was further investigated using multiple regression models. The results confirmed our earlier observations that OC (mostly from motor-vehicle emissions) is the most important component influencing the DTT consumption by PM samples. The variability of macrophage ROS was better explained by variations in OC concentrations and water-soluble vanadium (probably from ship emissions – bunker oil combustion) (Hu et al., 2008).

Quantification of organic molecular marker size distributions can provide information about the origin of carbonaceous PM. Organic molecular marker spatial variability studies are vital to more accurately determine population exposure to PM from various sources. A major part of our efforts in the Los Angeles-Long Beach study was to investigate the intra-community spatial variation of size-segregated PM (0-0.25 µm (quasi-ultrafine UF), 0.25-2.5 µm (accumulation ACC), and 2.5-10 µm (coarse C). Across all LA harbor sites, correlations were stronger for many compounds between UF and ACC size fractions, and weaker between concentrations in the C fraction and the corresponding UF and ACC fractions. These results indicate that the coarse PM organic compounds were emitted by different sources than those emitting small particles, such as combustion sources.

Associations between the same compounds in different size fractions across all sites were performed to gain insight into the types of sources influencing the study sites. The results showed clear differences between size fractions, with stronger correlations within UF and ACC size fractions, compared to the C fraction. Differences between correlations within UF and ACC size fractions, specifically between steranes and n-alkanes, imply that steranes in the UF fraction are emitted from specific sources that may be different from the sources emitting n-alkanes. In the ACC particles, similar sources emit both hopanes and n-alkanes, and aging or atmospheric transformation of aerosols is responsible for the higher correlations. Organic compounds quantified in this study are more suitable for identification of sources that emit particles in the UF and ACC than C size fractions.

Strong correlations across all sites were observed between steranes in the UF and the ACC size fractions, and they were attributed to motor vehicle emissions. High correlations between some PAHs in the UF and ACC size fractions were indicative of emissions from poor spark-ignition combustion in gasoline-powered vehicles and incomplete combustion of gasoline derived from light duty gasoline vehicles. Ratio-ratio plots were used to investigate the relative influence of similar sources on the molecular marker concentrations. Compounds in all three size fractions were shown to be impacted by two sources with unique emission rates. Steranes associated with EC partition preferentially into the ACC fractions, indicating motor oil emissions as the main PM source, while EC not associated with motor oil, perhaps diesel vehicle tailpipe emissions, is found preferentially in the freshly emitted UF particles. This source hypothesis was further corroborated by the much higher EC/OC ratios in the UF compared to the ACC and C size fractions, whereas steranes were shown to be comparable in both the ACC and UF particles.

Spatial variability was assessed by comparing the same compounds from different sites within each size fraction. The COD values for organic species did not differ appreciably between size fractions or between compound classes, but comparatively high spatial divergence was observed for most species. The molecular tracers were more heterogeneous than OC but comparable to EC. Numerous sources contribute to OC concentrations, resulting in relatively low spatial divergence, whereas EC, like the molecular tracers, originates mostly from traffic sources, which are more local and thus increase its spatial variability. The large variation in spatial distribution of organic compounds and particle sizes presented in this paper (COD = 0.0 - 0.7) suggests that it might be difficult to characterize a community-average concentration for the molecular marker compounds with only one monitoring station or a single particle size. Resolving the spatial variability of PM chemical components will require longer sampling times and a denser network of samplers capable of distinguishing exposure in different microenvironments (Krudysz et al., 2009)

A Chemical Mass Balance (CMB) model was applied to speciated chemical measurements of quasi-ultrafine and fine particulate matter from seven different sites. Winter measurements were obtained during a 7-week period between March and May, 2007, and summer measurements corresponded to a 6-week period between July and September, 2007. Four of the sites were located within the communities of Wilmington and Long Beach, two sites were located at a background area in the harbor of Los Angeles and Long Beach, and one site was located further downwind, near downtown Los Angeles, representing urban downtown LA, influenced mostly by traffic sources. The samples were analyzed for OC and EC content, organic species, inorganic ions, and water-soluble and total elements. The sources included in the CMB model were light-duty vehicles (LDV), heavy-duty vehicles (HDV), road dust (RD), biomass burning, and ship emissions. The model predictions of the LDV and HDV source contributions accounted, on average, for 83% of total fine OC in winter and for 70% in summer, whereas ship emissions’ contribution was lower than 5% of total OC at all sites. In the quasi-ultrafine mode, the vehicular sources accounted for 118% in winter and 103% in summer. Spatial variation of source contributions was not very pronounced, with the exception of some specific sites. In terms of total fine PM, vehicular sources together with road dust explain up to 54% of the mass, whereas the ship contribution is less than 5% of total fine PM mass. Our results clearly indicate that, although ship emissions can be significant, PM emissions in the area of the largest U.S. harbor are dominated by vehicular sources (Minguillon et al., 2008). It should be noted, however, that although ship emissions accounted for only 5% of the overall PM mass, they had a higher association with PM toxicity, as measured by the ROS assay (Hu et al., 2008), than any other PM source in the area, so their impact on public health should not be discounted.

Oxidative Potential of Semi-Volatile and Non Volatile Particulate Matter (PM) (collaboration with Project 3 and Dr. Flemming Cassee, RIVM)

Ambient organic particles, especially those emitted from vehicular sources, are complex mixtures of numerous semi-volatile species (organics, nitrates, and sulfates) and nonvolatile species (metals, EC). The semi-volatile compounds, depending on their vapor pressures, may be present in gas and/or particle phases. Semi-volatile organic compounds, such as polycyclic aromatic hydrocarbons (PAHs) and their derivatives, are known to possess genotoxic and carcinogenic characteristics. The comparative toxicity of the semi-volatile versus the non-volatile fractions of PM has been one of the major themes of Project 1. This research topic becomes even more crucial in light of the new state of California emission standards to become effective in 2010. With the promulgation of stringent PM mass based emission standards (US 2007, 2010; EURO IV, V), new advanced emission control technologies are being inducted into the current fleet. Although these after-treatment devices are remarkably efficient in controlling solid particles, they have varied success in removing potentially dangerous semi-volatile species. These semi-volatile species, after passing through the control devices, may nucleate to form fresh particles or condense onto existing particles under favorable dilution and temperature conditions. The primary objective of our first investigation, which was funded jointly by CARB, was to measure the oxidative potential of these distinct PM fractions from heavy vehicles operating with and without various emissions control technologies. This study is a prelude to subsequent studies, currently under way, focusing on ambient aerosols. Apart from assessing the potency of semivolatile species to induce oxidative stress, the results reported here will be useful in assessing the efficacy of these control technologies and in establishing future needs for additional measures to control these PM species.

Vehicles were tested on a chassis dynamometer under three driving conditions: cruise, transient urban dynamometer driving schedule (UDDS), and idle. The consumption rate of dithiothreitol (DTT), one of the surrogate measures of OP, was determined for PM samples collected at ambient and elevated temperatures (thermally denuded of semi-volatile species). Control devices reduced the OP expressed per vehicle distance traveled by 60-98%. The oxidative potential per unit mass of PM, however, was highest for vehicles with uncatalyzed after-treatment filter traps, followed by vehicles using a combination of catalyzed filters. Significant reduction in OP (by 50-100%) was observed for thermally denuded PM from vehicles with retrofitted technologies (PM with significant semi-volatile fraction), while particles emitted by the baseline vehicle, operating without any after-treatment (with insignificant semi-volatile fraction), did not demonstrate any measurable changes in oxidative activity. This suggests that the semivolatile fraction of particles is far more oxidative in nature than refractory particles—a conclusion further supported by previous tunnel and ambient studies demonstrating a clear and significant decline in PM oxidative activity with increasing atmospheric dilution (Figure 1 below) Correlation analysis performed between all the species showed that OP is moderately associated (R=0.76) with organic carbon (OC) and strongly associated (R=0.94) with water soluble organic carbon (WSOC). This work is described in detail by Biswas et al. (2009).

Figure 1 Health Studies – collectively with Projects 2 and 3: The Adjuvant Effect of Ambient Particulate Matter Is Closely Reflected by the Particulate Oxidant Potential

During the period covered by this report, we have assisted the investigators of Projects 2 and 3 in an exposure study involving the development of a murine intranasal sensitization model that utilizes a precise amount of size-fractionated ambient PM collected by our particle concentrators in the Southern California Particle Center to determine how these concentrated particulates may contribute to an adjuvant effect through intranasal administration in a murine OVA sensitization model (Li et al., 2003). This model allows the comparison of ultrafine particles (UFP) with an aerodynamic diameter less than 0.18 μm with that of a mixed atmosphere of sub-2.5 μm particles, which for this report will be designated as F/UFP. The endpoints that were used to evaluate the adjuvant effect of ambient PM included the assessment of nasal and pulmonary inflammation as a measurement of OVA-specific IgG1 and IgE in the blood. We also used morphometric analysis of mucosubstances and eosinophils to show that the allergic sensitization leads to an allergic inflammatory response in both upper and lower airways. Finally, we also measured the production of IL-5 and IL-13 as signature cytokines for Th2 allergic inflammatory responses. We showed that the enhanced in vivo adjuvant effects of the concentrated ambient UFP correlate with a higher in vitro oxidant potential and higher content of redox-cycling organic chemicals. UFP, having a higher per PM mass PAH content and higher oxidant potential, enhanced OVA sensitization more readily than fine particles. This is manifested as enhanced allergic inflammation upon secondary OVA challenge, leading to eosinophilic inflammation and mucoid hyperplasia starting at the nasal turbinates all the way down to the small pulmonary airways. The thiol antioxidant N-acetyl cysteine was capable of suppressing some of these sensitization events. In conclusion, the adjuvant effects of ambient UFP are determined by their oxidant potential, which likely plays a role in changing the redox equilibrium in the mucosal immune system (Li et al., 2009).

Development of a high collection efficiency electrostatic precipitator for in vitro cell exposure to concentrated ambient particulate matter (PM)--projects 2-3 collaborations with the US EPA and RIVM

In year 2 we embarked on series of investigations to develop novel technologies for direct cell exposure to ambient PM in the real world form. Recent studies have shown that the charging efficiencies of corona discharge for nano and submicron aerosol particles have been improved by means of growing the particles via condensation of super-saturated volatile species to micro-sized droplets and charging them in the corona charger, followed by drying them to their original sizes while maintaining the high number of charges (Suh et al., 2005; Kim et al., 2006; Choi and Kim, 2007). These studies are using corona chargers that generate high concentrations of O3 and also use organic solvents and the growth medium.

To that end, a novel particle sampling methodology developed recently by our group (Han et al., 2008, J. Aerosol Sci., 39, 770-784) has been extended in Year 3 to collect atmospheric particles in electrostatic precipitators (ESPs) for chemical and biological-toxicological analysis. Particles are grown to super-micron droplets via condensation of ultrapure deionized water and concentrated by virtual impaction in the versatile aerosol concentration enrichment system (VACES). The grown droplets are charged in a carbon fiber charger (shown in Figure 2) with negligible ozone generation, and diffusion-dried to their original particle size, while preserving their acquired charges.

Figure 2. Carbon fiber ionizer

The charged particles are subsequently collected on suitable substrates in two different ESP prototypes, which can then be used for further chemical and toxicological analysis. To minimize possible chemical reactions between sampled particles and ions generated in the corona region, the previously developed carbon fiber charger was modified by separating the charging zone from the ionization zone. By combining this novel charger with the VACES, we achieved a higher number of elementary charges per particle (more than 50) and high particle removal efficiency (more than 90%) in the ESP, while preserving the chemical composition of the sampled atmospheric aerosols. Uniform particle deposition, which is an essential feature for cell exposures to PM, was accomplished on the ESP substrate designed for biological PM analysis (Han et al., 2008 a, b; Han et al., 2009 a, b). Two versions of this ESP sampler are being currently developed for the US EPA and RIVM.

Health Studies – collectively with Project 4: contributions of outdoor sources to indoor exposure in retiree communities, in support of the panel studies of Project 4

The research in Project 4 was driven by the view that the time series associations between cardiovascular effects and PM may be due to airway deposition of airborne ultrafine particles and traffic-related pollutant components, followed by an increase in thrombogenic and inflammatory activity in the blood, inducing adverse effects on cardiovascular function. There have been no other studies to our knowledge conducted in California among vulnerable individuals on the acute cardiovascular health effects of exposures near subject residences to size-fractionated particles and to particle characteristics linked to general air pollutant sources and components. We conducted a comprehensive exposure assessment study and PM monitoring effort for a repeated measures panel study aimed at evaluating acute cardiovascular health effects of exposure to ultrafine PM. This project is largely to supplement the exposure assessment for an NIH, NIEHS funded study (grant no. ES-012243) entitled "Ultrafine Particulate Matter & Cardiorespiratory Health." Indoor and outdoor air pollution monitors were deployed under the proposed exposure assessment effort to provide continuous air pollutant concentrations, as well as data on PM composition and redox activity. Modeling efforts specific to this proposal include PM source characterization and additional repeated measures statistical analyses of the relationship between health outcomes and supplemental air pollutant measurements. In collaboration with our colleagues in Project 4, we followed 64 nonsmoking elderly individuals with coronary artery disease (CAD) living in four retirement homes in the Los Angeles Air Basin of California. Each subject was to be followed for a total of 12 weeks in two 6-week seasonal periods (warm and cold). Each Friday, blood samples were obtained for biomarkers of inflammation including plasma interleukin-6 (IL-6), tumor necrosis factor-α and its receptor (sTNF-RII), and C-reactive protein (CRP). We also measured a biomarker of platelet activation, soluble platelet selectin (sP-selectin). Biomarkers of erythrocyte antioxidant activity included glutathione peroxidase-1 and superoxide dismutase. Over 10 days, we also monitored subjects’ cardiovascular function with ambulatory electrocardiographs and ambulatory blood pressure monitors.

Supplemental air pollutant measurements funded under this contract included concurrent hourly indoor and outdoor concentrations of PM2.5 mass and PM2.5 elemental and organic carbon (EC-OC), and pollutant gases (NO2, NOx, and CO). At outdoor sites only, we measured hourly black carbon (BC) and ozone (O3). Additional data from the NIH-funded study included hourly indoor and outdoor particle number (PN) concentrations (dominated by ultrafine PM), and size fractionated PM (quasi-ultrafine mode < 0.25 µm, accumulation mode 0.25-2.5 µm, and coarse mode 2.5-10 µm). Using this and other data, we also estimated primary and secondary organic carbon (OCpri, SOC), and indoor EC, OCpri, SOC, and PN of outdoor origin. In collaboration with colleagues in Project 3, we also conducted in vitro testing to assess redox activity in concentrated fine (PM2.5) and ultrafine (PM0.15) particle suspensions collected at indoor and outdoor sites with biosamplers (Di Stefano et al., 2009).

The relationship of 10-day ambulatory cardiovascular outcomes and 12-weekly systemic (blood) biomarkers of inflammation and erythrocyte antioxidant activity to indoor and outdoor concentrations of EC, total OC (and OCpri, SOC fractions), PM2.5 mass, PN, and criteria pollutant gases, and to redox activity of PM using in vitro bioassay results was analyzed by investigators in Project 4. Data were analyzed with mixed effects models adjusted for potential confounders. The analysis of biomarkers revealed that primary combustion markers (EC-BC, OCpri, CO, NOx-NO2) were positively associated with inflammatory biomarkers and platelet activation and inversely associated with erythrocyte antioxidant enzymes (N=578). PN and quasi-ultrafine PM were more strongly associated than PM0.25-2.5. Biomarker associations were stronger during cooler periods when only OCpri, PN, and NOx were higher, suggesting that pollutant components and/or nanoparticles that increase during colder weather and air stagnation are important. We found weaker associations for sTNF-RII and CRP among subjects taking the anti-cholesterol drug, statin, that is known to reduce systemic inflammation and oxidative stress, and weaker associations for sP-selectin among subjects taking the platelet aggregation inhibitor, clopidogrel. Associations were stronger for indoor exposures to EC and PN of outdoor origin than uncharacterized indoor exposures, suggesting that outdoor air pollution was important. We found positive associations of hourly ambulatory systolic and diastolic blood pressure with exposure to PM2.5, BC, EC, OC, PN, CO, and NOx. The strongest association was for OC, especially the estimated fossil fuel combustion fraction (OCpri). (Delfino et al., 2009a; 2009b).

Our exposure assessment work provided a comprehensive view of indoor and outdoor exposure relations. We found that vehicular sources showed the highest contribution among the apportioned sources for both indoor and outdoor particles at all sites. The contribution of mobile sources to indoor levels was similar to their corresponding outdoor estimates, thus illustrating the significance of these sources on indoor PM concentrations (Arhami et al., 2009c). Linear mixed effects models and Spearman’s correlation coefficients were used to elucidate the relationships among size segregated PM levels, their particle components, and gaseous co-pollutants. Seasonal and spatial differences in the concentrations of all measured species were evaluated at all sites based on p-values for product terms. Outdoor quasi-UF and, to a lesser extent, accumulation mode particles were the two fractions that best correlated with outdoor concentrations of CO, NO2, NOx (during both phases of the study), and O3 (only during the warmer months). Outdoor and indoor concentrations of CO, NO2, and NOx were more positively correlated to personal quasi-UF particles (R = 0.20 to 0.36; average regression slopes = 0.36 to 2.41) than larger size fractions. In spite of these findings, it seems unlikely that these gaseous co-pollutants could confound epidemiologic associations between quasi-UF particles and adverse health effects. Overall, measured gaseous co-pollutants were weak surrogates of personal exposure to accumulation mode PM, at least for subjects with similar exposure profiles and living in similar urban locations. Indoor sources were not significant contributors to personal exposure to accumulation and quasi UF PM, which is predominantly influenced by primary emitted pollutants produced/emitted outdoors (Arhami et al., 2009b).

A major implication of the exposure assessment findings is that even if people (particularly the elderly, retired population of our study) generally spend most of their time indoors, a major portion of the PM to which they are exposed comes from outdoor mobile sources. In the epidemiologic analysis, we found that traffic-related air pollutants near the home are associated with increased systemic inflammation, increased platelet activation, and decreased erythrocyte antioxidant enzyme activity, which may partly account for air pollutant-related increases in systemic inflammation and thrombosis. Differences in association by period and particle size suggest components of quasi-ultrafine particles are important.

Future Activities:

In the next year, we will continue our efforts toward the completion of the following activities:

  • Our Ning Z. et al, Environmental Science and Technology, 41(17),6000-6006, 2007 paper identified clearly two distinctly different time periods in the summertime at USC: one impacted by vehicular emissions and the other by secondary formation processes. In year 4, we will conduct high volume collections (order of 20-30 mg) of ultrafine and accumulation mode PM during these two periods at USC for in vitro toxicological analysis, thus coupling the chemical work previously performed byour group with toxicological outcomes. These samples (impacted by traffic sources vs. photochemical secondary reactions) will be used by investigators in Projects 2 and 3. Specifically, samples will be submitted for toxicological analysis to the group of Dr. Nel; a small subset of the same samples will also submitted to Dr. Cho’s lab at UCLA for complementary analysis of redox properties of these particles (DTT, DHBA assays). Moreover, these samples will be analyzed for ionic compounds, metals, trace elements, elemental carbon, and organic carbon and reactive oxygen species (ROS), measured at the University of Wisconsin-Madison. In addition, measurements of individual organic species and their variation with time of day at the urban site will be conducted.The main goal of this part of our activities will be to investigate the two time periods with representative characteristics (AM vs. PM, primary vs. secondary PM) and to investigate the correlation of various redox activities with the chemical constituents of these particles. We anticipate several publications to be produced in Year 4 from this work.
  • Heavy and light duty vehicle emissions are the major contributors of ambient PM in urban environments. These combustion-generated aerosols contain both non-volatile and semi-volatile components. Semi-volatile compounds shift between gas and particle phases depending on the vapor pressure, ambient temperature, and atmospheric dilution. Moreover, the volatile organic compounds (VOCs) are active in photochemical reactions and contribute to secondary organic aerosol (SOA) formation, altering the physical and chemical properties of urban particulate matter. Our studies have shown that the semi-volatile PM fraction of vehicular exhaust is responsible for the majority of the overall redox activity of the emitted PM.
  • In a follow-up study to that conducted in dynamometer facilities, ultra-fine particles will be analyzed with differentiation to their non-volatile and semi-volatile components at a site close to University of Southern California (USC) in downtown Los Angeles. A thermodenuder will be used to shift the gas-particle partitioning of the semi-volatile component of these aerosols. The thermodenuder consists of a heating section in which the aerosols are heated to 250ºC, followed by a cooling section, equipped with a charcoal denuder that adsorbs semivolatile vapors that might otherwise have re-condensed on the cooled particles. In our field tests, the volatility of PM will be investigated in the 50-220ºC temperature range.Detailed chemical and toxicological characteristics of PM samples collected before and after the thermodenuder, including water-soluble organic carbon, inorganic elements, and organic compounds, as well as measurements of reactive oxygen species and redox activity, will be evaluated and compared. A qualitative analysis correlating the redox activity profiles with the chemical components present in non-volatile and semi-volatile fractions of PM will be conducted to evaluate the relative contribution of semi-volatile species to overall PM toxicity.
  • We will continue to support the animal exposure activities related to Project 2.
  • We will continue to support the exposure assessment activities related to Project 4.Specifically, because we have already completed our exposure analysis and source apportionment of UF PM in the retiree communities, we will work with Dr. Delfino and his group to link the observed cardiovascular health outcomes to these sources. This will be accomplished byusing the contributions of each source in the UF PM of each community and season asan input parameter to explain the health endpoints, including the production of pro-inflammatory biomarkers.


Journal Articles on this Report : 22 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 Arhami M, Polidori A, Delfino RJ, Tjoa T, Sioutas C. Associations between personal, indoor, and residential outdoor pollutant concentrations:implications for exposure assessment to size-fractionated particulate matter. Journal of the Air & Waste Management Association 2009;59(4):392-404. R832413 (2009)
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  • Journal Article Arhami M, Sillanpaa M, Hu S, Olson MR, Schauer JJ, Sioutas C. Size-segregated inorganic and organic components of PM in the communities of the Los Angeles harbor. Aerosol Science and Technology 2009;43(2):145-160. R832413 (2008)
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  • Journal Article Arhami M, Minguillon MC, Polidori A, Schauer JJ, Delfino RJ, Sioutas C. Organic compound characterization and source apportionment of indoor and outdoor quasi-ultrafine particulate matter in retirement homes of the Los Angeles Basin. Indoor Air 2010;20(1):17-30. R832413 (2009)
    R832413 (Final)
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  • Journal Article Biswas S, Verma V, Schauer JJ, Cassee FR, Cho AK, Sioutas C. Oxidative potential of semi-volatile and non volatile particulate matter (PM) from heavy-duty vehicles retrofitted with emission control technologies. Environmental Science & Technology 2009;43(10):3905-3912. R832413 (2009)
    R832413 (Final)
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  • Journal Article Campbell A, Araujo JA, Li H, Sioutas C, Kleinman M. Particulate matter induced enhancement of inflammatory markers in the brains of apolipoprotein E knockout mice. Journal of Nanoscience and Nanotechnology 2009;9(8):5099-5104. R832413 (2009)
    R832413 (Final)
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  • Journal Article Cheung KL, Polidori A, Ntziachristos L, Tzamkiozis T, Samaras Z, Cassee FR, Gerlofs M, Sioutas C. Chemical characteristics and oxidative potential of particulate matter emissions from gasoline, diesel, and biodiesel cars. Environmental Science & Technology 2009;43(16):6334-6340. R832413 (2009)
    R832413 (Final)
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  • Journal Article Delfino RJ, Staimer N, Tjoa T, Gillen DL, Polidori A, Arhami M, Kleinman MT, Vaziri ND, Longhurst J, Sioutas C. Air pollution exposures and circulating biomarkers of effect in a susceptible population: clues to potential causal component mixtures and mechanisms. Environmental Health Perspectives 2009;117(8):1232-1238. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
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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)
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  • Journal Article DiStefano E, Eiguren-Fernandez A, Delfino RJ, Sioutas C, Froines JR, Cho AK. Determination of metal-based hydroxyl radical generating capacity of ambient and diesel exhaust particles. Inhalation Toxicology 2009;21(9):731-738. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
    R832413C003 (2009)
    R832413C003 (2010)
    R832413C004 (2010)
  • Abstract from PubMed
  • Abstract: Taylor and Francis-Abstract
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  • Journal Article Han B, Kim H-J, Kim Y-J, Sioutas C. Unipolar charging of fine and ultra-fine particles using carbon fiber ionizers. Aerosol Science and Technology 2008;42(10):793-800. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
  • Full-text: Taylor&Francis-Full Text HTML
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  • Abstract: Taylor&Francis-Abstract
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  • Other: Taylor&Francis-Full Text PDF
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  • Journal Article Han B, Hudda N, Ning Z, Kim H-J, Kim Y-J, Sioutas C. A novel bipolar charger for submicron aerosol particles using carbon fiber ionizers. Journal of Aerosol Science 2009;40(4):285-294. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (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 Han B, Hudda N, Ning Z, Kim Y-J, Sioutas C. Efficient collection of atmospheric aerosols with a particle concentrator-electrostatic precipitator sampler. Aerosol Science and Technology 2009;43(8):757-766. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
  • Full-text: Taylor&Francis-Full Text HTML
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  • Abstract: Taylor&Francis-Abstract
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  • Other: Taylor&Francis-Full Text PDF
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  • Journal Article Hsu A, Mendez L, Shah J, Sioutas C, Kleinman M, Campbell A. Nanoparticles in air pollution and innate immune responses within the CNS. International Journal of Neuroprotection and Neuroregeneration 2007;3(2):107-113. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
  • Abstract: ResearchGate-Abstract
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  • Journal Article Hu S, Polidori A, Arhami M, Shafer MM, Schauer JJ, Cho A, Sioutas C. Redox activity and chemical speciation of size fractioned PM in the communities of the Los Angeles-Long Beach harbor. Atmospheric Chemistry and Physics 2008;8(21):6439-6451. R832413 (2008)
    R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
    R832413C003 (2010)
    R832413C003 (Final)
  • Full-text: ACP-Full Text PDF
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  • Abstract: ACP-Abstract
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  • Journal Article Krudysz MA, Dutton SJ, Brinkman GL, Hannigan MP, Fine PM, Sioutas C, Froines JR. Intra-community spatial variation of size-fractionated organic compounds in Long Beach, California. Air Quality, Atmosphere & Health 2009;2(2):69-88. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
    R832157 (Final)
  • Full-text: Springer-Full Text PDF
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  • Abstract: Springer-Abstract & Full Text HTML
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  • Journal Article Krudysz M, Moore K, Geller M, Sioutas C, Froines J. Intra-community spatial variability of particulate matter size distributions in Southern California/Los Angeles. Atmospheric Chemistry and Physics 2009;9(3):1061-1075. R832413 (2008)
    R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
    R832157 (Final)
  • Full-text: ACP-Full Text PDF
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  • Abstract: ACP-Abstract
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  • Journal Article Li N, Wang M, Bramble LA, Schmitz DA, Schauer JJ, Sioutas C, Harkema JR, Nel AE. The adjuvant effect of ambient particulate matter is closely reflected by the particulate oxidant potential. Environmental Health Perspectives 2009;117(7):1116-1123. R832413 (2009)
    R832413 (2010)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
    R832413C002 (2009)
    R832413C002 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: EHP-Full Text PDF
  • Abstract: EHP-Abstract and Full Text HTML
  • Journal Article Minguillon MC, Arhami M, Schauer JJ, Sioutas C. Seasonal and spatial variations of sources of fine and quasi-ultrafine particulate matter in neighborhoods near the Los Angeles-Long Beach harbor. Atmospheric Environment 2008;42(32):7317-7328. R832413 (2008)
    R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (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 Moore K, Krudysz M, Pakbin P, Hudda N, Sioutas C. Intra-community variability in total particle number concentrations in the San Pedro harbor area (Los Angeles, California). Aerosol Science and Technology 2009;43(6):587-603. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
    R832157 (Final)
  • Full-text: Taylor&Francis-Full-text PDF
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  • Abstract: Taylor&Francis-Abstract & Full-text HTML
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  • Journal Article Ning Z, Sillanpaa M, Pakbin P, Sioutas C. Field evaluation of a new particle concentrator-electrostatic precipitator system for measuring chemical and toxicological properties of particulate matter. Particle and Fibre Technology 2008;5:15. R832413 (2008)
    R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: PFT-Full Text HTML
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  • Abstract: PFT-Abstract
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  • Other: PFT-Full Text PDF
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  • Journal Article Polidori A, Cheung KL, Arhami M, Delfino RJ, Schauer JJ, Sioutas C. Relationships between size-fractionated indoor and outdoor trace elements at four retirement communities in southern California. Atmospheric Chemistry and Physics 2009;9(14):4521-4536. R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
    R832413C004 (2009)
    R832413C004 (2010)
    R832413C004 (Final)
    R833743 (Final)
  • Full-text: ACP-Full Text PDF
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  • Abstract: ACP-Abstract
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  • Journal Article Verma V, Polidori A, Schauer JJ, Shafer MM, Cassee FR, Sioutas C. Physicochemical and toxicological profiles of particulate matter in Los Angeles during the October 2007 Southern California wildfires. Environmental Science & Technology 2009;43(3):954-960. R832413 (2008)
    R832413 (2009)
    R832413 (Final)
    R832413C001 (2009)
    R832413C001 (Final)
  • 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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  • 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

    Progress and Final Reports:

    Original Abstract
  • 2006 Progress Report
  • 2007 Progress Report
  • 2008 Progress Report
  • 2010 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