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2007 Progress Report: Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of Their Relative Toxicity
EPA Grant Number: R832413C001Subproject: 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.
Institution: University of Southern California , University of Wisconsin
EPA Project Officer: Katz, Stacey
Project Period: October 1, 2005 through September 30, 2010
Project Period Covered by this Report: October 1, 2006 through September 30, 2007
Project Amount: Refer to main center abstract for funding details.
RFA: Particulate Matter Research Centers (2004)
Research Category: Particulate Matter
Description:
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:
- Physical and chemical properties of PM emitted from different PM sources.
- to determine emission rates of PM species vs size, from various source types.
- to evaluate how exposure to PM from various sources varies with respect to location, season, and particle size.
- in conjunction with Projects 2, 3 and 4 to assess the relative toxicity of PM sources by providing in vitro PM samples to the PIs of these projects
- Determine the characteristics of the volatile and non-volatile particle components of these sources. Provide volatile and non-volatile fractions for in vitro assessment in Projects 2- 4.
- Measure exposure gradients and intra-community variability of PM from complex, understudied sources such as airports and seaport activities.
- Several areas of Long Beach, the Los Angeles Port, Los Angeles International Airport (LAX), and receptor sites of the Los Angeles Basin (Riverside)
- Collect concurrently samples for analysis in Projects 2-3
- To assess the contributions of these outdoor sources to indoor exposure in support of Project 4
Over the course of the 9 months covered in this report, and in concert with our proposed scope of work, we completed field sampling campaigns at the I-710, carried out sampling at the facilities of USC (June 2006 - present), and we initiated our sampling campaign in Long Beach, CA..
Studies at the I-710
The I-710 freeway is a 26 m wide eight-lane highway connecting the ports complex of Long Beach and San Pedro to the shipping yards in East Los Angeles. For this reason, as much as 25% diesel traffic has been reported on this freeway (http://traffic-counts.dot.ca.gov). Total traffic counts on this freeway are also very high, with between 150,000-200,000 vehicles per day passing the sampling location. The sampling site was located in a paved property run by the Imperial Flood Control Yard in South Gate, CA. At the I-710 we pursued the following concurrent activities:
- High-volume filter collections of coarse, fine + ultrafine, and ultrafine PM;
- PAH and tracer concentrations and emission factors from the 710 and comparison to the Caldecott
- In Vitro collection of coarse, fine + ultrafine, and ultrafine PM to be used by Projects 2 and 3 of this center
- Tandem DMA particle diameter/volatility measurements
- Particle surface area measurements with TSI active PM surface monitor
- Ultrafine mass chemical composition measurement
Activities a-e were reported in the Year 1 report, and activity f the chemical composition work has now been completed. The project has now produced 3 manuscripts that are published, accepted or submitted for publication; they are listed below. In vitro PM samples have also been delivered to the investigators of Projects 2 and 3 at UCLA.
Our I-710 study focused on particle characteristics next to the I-710 freeway. The I-710 has the highest ratio (up to 25%) of heavy-duty diesel vehicles in the Los Angeles highway network. Particle concentration measurements were accompanied by measurements of black carbon, elemental and organic carbon, and gaseous species (CO, CO2). Using the incremental increase of CO2 over the background to calculate the dilution ratio, this study makes it possible to compare particle concentrations measured next to the freeway to concentrations measured in roadway tunnels and in vehicle exhaust. In addition to the effect of the dilution ratio on the measured particle concentrations, multivariate linear regressions showed that light and heavy organic carbon concentrations are positively correlated with the particle volume in the nucleation and accumulation modes, respectively. Solar radiation was also positively correlated with the particle surface concentration and the particle volume in the accumulation (40-638 nm) mode, presumably as a result of secondary particle formation. The methods developed in this study may be used to decouple the effect of sampling position, meteorology, and fleet operation on particle concentrations in the proximity of freeways, roadway tunnels, and in street canyons. Moreover, we have found that adjustment for dilution ratios (DR) brings roadway, tunnel and in vehicle measurements very close for species such as particle number, mass, and black carbon concentrations (Ntziachristos et al, 2007)
During the I-710 sampling campaign we investigated the volatility of ambient particles of 20, 40, 80 and 120nm in diameter using a Tandem Differential Mobility Analyzer (TDMA) at two locations—close to the freeway (10m) and approximately 150m downwind. The smallest particles (20nm) are largely volatile at both locations. Larger particles, e.g., (~40nm) showed evidence of external mixing, with the non-volatile fraction increasing with particle size. Particle volatility increased with decreasing ambient temperature. The presence of heavy duty diesel vehicles contributes to a relatively larger non-volatile particle number and volume fractions and greater external mixing in comparison with earlier observations made at a pure light-duty gasoline vehicle freeway. Finally, the fraction of externally mixed soot particles decreased as the downwind distance increased from the I-710, due to atmospheric processes such as vapor adsorption and condensation as well as particle coagulation. (Biswas et al., 2007)
Particle surface area has recently been considered as a possible metric in an attempt to correlate particle characteristics with health effects. In order to provide input to such studies, two Nanoparticle Surface Area Monitors (NSAMs, TSI, Inc.) were deployed in different urban sites within Los Angeles, including the I-710, to measure the concentration levels and the diurnal profiles of the surface area of ambient particles. The NSAM’s principle of operation is based on the unipolar diffusion charging of particles. Results show that the particle surface concentration decreases from ~150 μm2/cm3 next to a freeway to ~100 μm2/cm3 at 100m downwind of the freeway, and levels decline to 50–70 μm2/cm3 at urban background sites. Up to 51% and 30% of the total surface area corresponded to particles <40nm next to the freeway and at an urban background site, respectively. The NSAM signal was well correlated with a reconstructed surface concentration based on the particle number size distribution measured with collocated Scanning Mobility Particle Sizers (SMPSs, TSI, Inc.). In addition, the mean surface diameter calculated by combination of the NSAM and the total particle number concentration measured by a Condensation Particle Counter (CPC, TSI, Inc.) was in reasonable agreement with the arithmetic combined with a CPC to derive high temporal resolution mean SMPS diameter, especially at the urban site. This study corroborates earlier findings on the application of diffusion chargers for ambient particle monitoring by demonstrating that they can be effectively used to monitor the particle surface concentration. (Ntziachristos et al, 2007b)
During the I-710 campaign, trace elements and metals in the ultrafine (0.18 μm) and accumulation (0.18–2.5 μm) particulate matter (PM) modes were measured in the winter season. Both ambient and concentrated size-segregated impactor samples were taken in order to collect enough mass for chemical analysis. Data at this location were compared to a site located 1 mile downwind of the freeway, which was reflective of urban background. The most abundant trace elements in the accumulation mode detected by inductively coupled plasma mass spectroscopy (ICPMS) were S (138 ng/m3), Na (129 ng/m3), and Fe (89 ng/m3) while S (35 ng/m3) and Fe (35 ng/m3) were the most abundant in the ultrafine mode. The concentrations of several trace elements, including Mg, Al, and Zn, and in particular Ca, Cu, and Pb, did not uniformly increase with size within fine PM, an indication that various roadway sources exist for these elements. Calculation of crustal enrichment factors for the two sites indicates that the freeway traffic contributed to enriched levels of ultrafine Cu, Ba, P and Fe and possibly Ca. Of particular interest is the elemental composition of the lowest size range (18-32 nm). These nanoparticles have a much higher fraction of Mg, Ca, Cr, Ni, Cu, Zn, Sr and Pb from all other size fractions. This finding may have significant implications for the per-mass toxicity of these particles. The presence of metals in the 18-32nm range reveals and important pathway for particle formation by means of condensation of supersaturated organic vapors on the surface of these stable nanoparticles. The results of this study show that trace elements constitute a small fraction of PM mass in the nanoparticle size range, but contain elements with potential importance to human health (Ntziachristos et al., 2007c).
Individual organic compounds such as hopanes and steranes (originating in lube oil) and selected polycyclic aromatic compounds (PAHs) (generated via combustion) found in particulate emissions from vehicles have proven useful in source apportionment of ambient particulate matter. Detailed information on the size-segregated (ultrafine and accumulation mode) chemical characteristics of organic particulate matter during the winter season originating from a pure gasoline traffic freeway (CA-110), and a mixed fleet freeway with the highest fraction of heavy-duty diesel vehicles in the state of California (I-710) can be compared. Hopanes and steranes as well as high molecular weight PAHs such as benzo(ghi)perylene (BgP) and coronene levels are found comparable near these freeways, while elemental carbon (EC) and lighter molecular weight PAHs are found much elevated near I-710 compared to CA-110. The roadway organic speciation data presented in this study was compared with the emission factors measured in the Caldecott tunnel, Berkeley CA (Phuleria et al., 2006) for light duty vehicles (LDVs) and heavy-duty vehicles (HDVs). Very good agreement is observed between CA-110 measurements and LDV emission factors (EFs) as well as I-710 measurements and corresponding reconstructed EFs from Caldecott tunnel for hopanes and steranes as well as heavier PAHs such as BgP and coronene. Our results, therefore, suggest that the emission factors for hopanes and steranes obtained in tunnel environments, where emissions are averaged over a large vehicle-fleet, enable reliable source apportionment of ambient particulate matter (PM), given the overall agreement between the roadway vs tunnel concentrations of these species (Phuleria et al, 2007).
In addition to the organic speciation study described in the previous paragraphs, trace organic species in the size-segregated ultrafine (<0.18 μm) and accumulation (0.18 – 2.5 μm) particulate matter (PM) modes were measured during the winter season next to the I-710. The ultrafine mode was further segregated into 4 size ranges (18-32 nm, 32-56 nm, 56-100 nm, and 100-180 nm) with a NanoMOUDI low-pressure cascade impactor sampler. Both ambient and concentrated size-segregated impactor samples were taken in order to collect enough mass for chemical analysis. Accumulation and size segregated ultrafine mode particles were analyzed by various methods to investigate their chemical composition. Particle acidity and its relationship with size were also investigated by the ratio of measured and required ammonium for neutralization with nitrate and sulfate. This is the first study to present size-segregated ambient organic species concentrations within the ultrafine mode. Nitrate and organic carbon were found to be the most abundant species in accumulation mode, while organic carbon dominates the ultrafine mode. Particle acidity and its relationship with particle size were also investigated by the ratio of measured and required ammonium concentration to neutralize sulfate and nitrate. UFP were much more acidic compared to the fully neutralized accumulation mode particles. Within the ultrafine mode, an increasing trend of acidity was observed with decreasing particle size, which may have implications for atmospheric chemistry and health effects. Good agreement was observed between the distributions of PAHs and hopanes/steranes presented herein and those from a dynamometer study. Thus, it may be plausible to estimate the concentration of organic tracers next to the freeway by averaging emission profiles of different vehicles and driving cycles measured on a dynamometer if the dilution factor (typically calculated based on CO2 concentrations) between dynamometer and the freeway is known or can be determined. (Ning et al., 2007).
Summer Campaign at USC
In order to investigate the temporal evolution of ambient ultrafine atmospheric aerosol, we recently conducted a summertime study at an urban background site in Los Angeles, California. The following activities occurred simultaneously during this study:
- High-volume filter collections of ultrafine PM
- Identification of distinct sources and formation mechanisms during the morning (traffic) and afternoon (photochemistry) periods in a typical urban site of LA
- Tandem DMA particle diameter/volatility measurements
- Chemical speciation
- Collection of ultrafine PM for in vitro analysis
The study was conducted at the University of Southern California’s Particle Instrumentation Unit (PIU) located on the University Park campus near downtown Los Angeles, California. Some additional data were obtained from a nearby monitoring site (described below). The study was conducted over 4 consecutive 5-day weeks from June 28 through July 27, 2006. Sampling was conducted on weekdays only. The PIU is located within ~150m of a routinely congested freeway (Interstate 110) and near construction and parking facilities. The temporal evolution of UFP tracers at “source” and “receptor” sites (Fine et al., 2004) has been reported as have chemical transformations in Lagrangian studies where fine aerosol were repeatedly observed as they moved downwind in the Los Angeles basin (Gard et al., 1998, Hughes et al., 2000, 2002). Here we focus on changes occurring at a traditional “source” site. Several different aerosol measurement techniques were used to characterize the physical and chemical properties of the aerosol.
Continuous and intermittent gas and aerosol measurements were made over 4 weeks with consistent daily meteorological conditions. Monthly averages of the data suggest the strong influence of commute traffic emissions on morning observations of ultrafine particle concentrations. By contrast, in the afternoon our measurements provide evidence of secondary photochemical reactions becoming the predominant formation mechanism of ultrafine aerosols. The ultrafine number concentration peak occurs in the early afternoon, before the maximum ozone concentration is observed. It is possible that the chemical mechanisms responsible for secondary organic aerosol formation evolve as atmospheric conditions change and/or secondary semi-volatile components of the aerosol re-volatilize due to the elevated peak temperatures observed (ca. 30-35°C) combined with the increased atmospheric dilution during that time. Measurements of the volatility of the ultrafine aerosol are consistent with this interpretation as overall volatility increases in the afternoon and there is less evidence of external mixing. (Moore et al., 2007)
During the same campaign, we focused on daily variation of ultrafine (< 180 nm in diameter) particle chemical characteristics. UFP were collected weekly for two 3-hr periods each day—one to capture the morning commute (06:00-09:00 PDT) (Pacific Daylight Time) and one to investigate photochemically-altered particles (13:00-16:00 PDT). Samples were analyzed for ionic compounds, metals, trace elements, elemental carbon, and organic carbon. In addition, measurements of individual organic species and their variation with time of day at the urban site were conducted. The relative abundances of alkanes, PAH, and hopanes in the morning denote a strong influence of commute traffic emissions on ultrafine particle concentrations. By contrast, afternoon concentrations of oxygenated organic acids and sulfate rose, while other species were diluted by increased mixing height or lost due to increasing temperature. These are clear indicators that secondary photochemical reactions are a major formation mechanism of ultrafine aerosols in the afternoon. The concentrations of organic species originating from vehicular emissions measured in this study compare favorably to those from freeway-adjacent measurements by using CO2 concentrations to adjust for dilution, demonstrating the effectiveness of this tool for relating sites affected by vehicular emissions. (Ning et al., 2007)
Intra-community Variability Studies
One of the major themes of Project 1 is the measurements of exposure gradients and intra-community variability of PM from complex, unstudied sources such as airports and port activities. We conducted a pilot study in the area of Long Beach, CA to investigate the intra-community spatial variation of PM impacted by numerous local and regional sources. Weekly size-segregated (<0.25 μm, 0.25-2.5 μm, and >2.5 μm) PM samples were collected. During each 1-week sampling cycle, data were collected concurrently at four sites within four miles of one another. Stagnant meteorological conditions created relatively higher OC and EC concentrations in the winter compared to the summer and fall sampling campaigns. Coefficients of divergence analyses for size-fractionated PM mass, organic and elemental carbon, sulfur, and 18 other metals and trace elements resulted in a wide range of spatial divergence. High spatial variability was observed in the <0.25 μm and 0.25-2.5 μm PM fractions for many elements associated with motor vehicle emissions. Relatively lower spatial divergence was observed in the coarse fraction, although road dust components were spatially diverse but highly correlated with each other. Mass and OC concentrations were homogenously distributed over the sampling sites. The potential of this size-fractionated dataset for source recognition is shown by identifying oil combustion sources and by distinguishing between primary sulfur and secondary sulfate contributions. This study shows that, although PM mass in different size fractions is spatially homogeneous within a community, the spatial distribution of some elemental components can be heterogeneous. Epidemiological studies using only PM mass concentrations from central sites may not accurately assess exposure to toxicologically-relevant PM components. (Krudysz et al., 2007).
Indoor – Outdoor Exposure Characterization Studies (with Project 4)
In collaboration with investigators in Project 4, we measured hourly indoor and outdoor fine particulate matter (PM2.5), organic and elemental carbon (OC and EC, respectively), and particle number (PN), ozone (O3), carbon monoxide (CO), and nitrogen oxide (NOx) concentrations at two different retirement communities in the Los Angeles, CA, each during winter and summertime periods. This monitoring was part of a larger effort, the Cardiovascular Health and Air Pollution Study (CHAPS) which is also supported by the activities of Project 4. Overall, the magnitude of indoor and outdoor measurements was similar, probably because of the major influence of outdoor sources on indoor particle and gas levels. However, G2 showed a substantial increase in indoor OC, PN, and PM2.5 between 6:00 and 9:00 a.m., probably from cooking. The contributions of primary and secondary OC (SOA) to measured outdoor OC were estimated from collected OC and EC concentrations using EC as a tracer of primary combustion-generated OC (i.e., “EC tracer method”). The study average outdoor SOA accounted for 40% of outdoor particulate OC (40–45% in the summer and 32–40% in the winter). Air exchange rates (hr-1) and infiltration factors (Finf; dimensionless) at each site were also determined. Estimated Finf and measured particle concentrations were then used in a single compartment mass balance model to assess the contributions of indoor and/or outdoor sources to measured indoor OC, EC, PM2.5, and PN. The average percentage contributions of indoor SOA of outdoor origin to measured indoor OC were ~35% (during winter) and ~45% (during summer). On average, 36% - 44% of measured indoor OC was composed of outdoor-generated primary OC. contributions of outdoor-generated SOA and primary OC to indoor OC and to demonstrate their importance in indoor environments. The outcomes presented here will be used by CHAPS investigators to determine the relationship between cardiovascular outcomes and hourly retirement community exposures by each resident to PM2.5 of indoor and outdoor origin. (Polidori et al., 2007)
In the next year of our activities, we will continue our efforts to reconcile emission factors of size segregated PM species measured in freeway environments, roadway tunnels and dynamometer studies. Using the incremental increase of CO2 over the background as an indication of the dilution ratio of vehicle exhaust to ambient concentrations, we will attempt to relate organic tracers (hopanes steranes PAH) and trace metal concentrations measured in tunnels with those next to freeways. Reconciling these emission factors will have several important implications: it will affirms the robustness of emission factors derived in tunnel measurements; it will demonstrate the ability to derive reliable emission factors based solely on roadway measurements; and more importantly, it will allow us to predict within very reasonable uncertainly freeway exposures for most PM species if we have CO2 data available at the freeway.
We will also start a large sampling campaign in the are of Long Beach, CA to determine exposure gradients to PM. Weekly impactor and filter-based samples will be collected for analysis of spatial variability of chemical composition/toxicity with an emphasis on source locations in 7 sites of that area. These experiments focus on the Ports’ activities and will attempt to decouple their signatures from the local freeways and other industries. Two sets of Sioutas™ Impactors (PCIS) will be deployed in each of the 7 locations in shown in Map below. One will be loaded with Zefluor substrates and the other with quartz substrates with a quartz backup filter (0.25-0 μm). Particles will be collected in the following size ranges: 0 - 0.25 μm; 0.25 – 2.5 μm; 2.5 – 10 μm Samples will be collected at 10 LPM each week for a total of 6 weeks in the March- May period, and for another 6 weeks in the July – September period. The quartz substrates will be submitted for organic speciation analysis. Zefluor substrates will be split according to the amount of mass collected on each. Between ¼ and ½ will be sent to Dr. Schauer for ICP-MS, reactive oxygen species (ROS) and ion chromatography (IC) analysis. The remaining portion of each sample will be sent to Dr. Cho at UCLA for DTT and DHBA assays.
Various PM and gaseous co pollutants measurements will be conducted near-continuously in these sites. These will include the coarse PM TEOM, Ultrafine BAM, SMPS-CPC, APS, CPC, DataRAM, Diffusion Chargers (NSAM), Photoelectric Aerosol Sensors (PAS), Sunset Labs EC-OC Monitors, Q-Trak, Ozone monitor, NOx analyzers. Unique hourly data for PM mass in coarse, fine and ultrafine modes in each site will help us identify correlation trends with time of day, day of week, wind direction, wind speed, and regulatory pollutants as a first step to identify the impact of specific sources such as a point source (wind direction and criteria pollutants), mobile sources (time of day and day of week and criteria pollutants), resuspension of off-road soil. For each of these sampling locations, correlation coefficients will be determined between coarse , fine and ultrafine particle concentrations and the concentrations of gaseous precursors, wind speed and direction. Using the PAS, NSAM, EC-OC Sunset Lab Monitors we will determine associations between PAS and the EC - OC signal (for all the 4 OC volatility fractions measured by the monitor). We will also use the slope of the PAS vs NSAM (a diffusion charger) data to identify differences in chemical composition of PM over different time periods (e.g., traffic vs photochemistry vs nighttime vs fog-marine layer periods) of day and different seasons. The CPC Particle Number (PN) data in 10-12 sites of that area will allow us determine the much needed spatial variability of UFP number concentrations. we will also investigate the effect of season and time of day on that variability and explore the idea of particle numbers (PN) in each site being the sum of an urban background superimposed by the contribution of local sources. Using the SMPS – APS data we will determine the spatial correlations of PM as a function of particle size. We will investigate the hypotheses that the spatial variability (measured by the correlation coefficient (r) as well as the coefficient of divergence, COD) among various sites increases with increasing particle size. We examine seasonality in these patterns and values of r and COD for PM in the 10 nm – 700 nm range.
Lastly, we will make efforts to coordinate our measurements in the LAX airport area with a large study sponsored by Los Angeles World Airports that is scheduled to commence in area starting early 2008. Assuming that this schedule will be met, we will conduct an intensive 20 weeks study, starting in winter of 2008 at LAX. Our proposed involvement is summarized as follows:
We will place our collocated Sioutas ™ Personal Cascade Impactor Samplers (Sioutas™ PCIS SKC Inc., Eighty Four, PA) in their site and collect size fractionated PM (< 0.25; 0.25 - 2.5 and 2.5 - 10 μm) in each of their locations around LAX and the nearby communities (about 7 sites total). In each oftheir sites, we will collect oneweekly compositedset of samples for n=3 weeks. We will analyze these samples (3 size fractions x 2-3 per site x 7-8 sites) for:trace elements and metals, organic species and reactive oxygen species (ROS). The idea behind this analyses will be to identify possible tracers for airplane emissions, to also determine the contribution of mobile and other sources in the same areas and to see how they all affect the toxicity of PM.
Journal Articles on this Report: 27 Displayed | Download in RIS Format
| Other subproject views: | All 36 publications | 35 publications in selected types | All 34 journal articles |
| Other center views: | All 94 publications | 48 publications in selected types | All 47 journal articles |
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Ayres JG, Borm P, Cassee FR, Castranova V, Donaldson K, Ghio A, Harrison RM, Hider R, Kelly F, Kooter IM, Marano F, Maynard RL, Mudway I, Nel A, Sioutas C, Smith S, Baeza-Squiban A, Cho A, Duggan S, Froines J. Evaluating the toxicity of airborne particulate matter and nanoparticles by measuring oxidative stress potential—a workshop report and consensus statement. Inhalation Toxicology 2008;20(1):75-99. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) R832413C002 (2008) R832413C003 (2008) |
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Biswas S, Ntziachristos L, Moore KF, Sioutas C. Particle volatility in the vicinity of a freeway with heavy-duty diesel traffic. Atmospheric Environment 2007;41(16):3479-3493. |
R832413 (2008) R832413C001 (2006) R832413C001 (2007) R832413C001 (2008) |
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Delfino RJ, Staimer N, Tjoa T, Polidori A, Arhami M, Gillen DL, Kleinman MT, Vaziri ND, Longhurst J, Zaldivar F, Sioutas C. Circulating biomarkers of inflammation, antioxidant activity, and platelet activation are associated with primary combustion aerosols in subjects with coronary artery disease. Environmental Health Perspectives 2008;116(7):898-906. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) R832413C004 (2007) R832413C004 (2008) |
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Delfino RJ, Staimer N, Tjoa T, Gillen D, Kleinman MT, Sioutas C, Cooper D. Personal and ambient air pollution exposures and lung function decrements in children with asthma. Environmental Health Perspectives 2008;116(4):550-558. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Fruin S, Westerdahl D, Sax T, Sioutas C, Fine PM. Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los Angeles. Atmospheric Environment 2008;42(2):207-219. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Gong Jr. H, Linn WS, Clark KW, Anderson KR, Sioutas C, Alexis NE, Cascio WE, Devlin RB. Exposures of healthy and asthmatic volunteers to concentrated ambient ultrafine particles in Los Angeles. Inhalation Toxicology 2008;20(6):533-545. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) R827352 (Final) |
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Kleinman MT, Sioutas C, Froines JR, Fanning E, Hamade A, Mendez L, Meacher D, Oldham M. Inhalation of concentrated ambient particulate matter near a heavily trafficked road stimulates antigen-induced airway responses in mice. Inhalation Toxicology 2007;19(Suppl 1):117-126. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) R832413C003 (2007) R827352 (Final) |
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Kleinman MT, Araujo JA, Nel A, Sioutas C, Campbell A, Cong PQ, Li H, Bondy SC. Inhaled ultrafine particulate matter affects CNS inflammatory processes and may act via MAP kinase signaling pathways. Toxicology Letters 2008;178(2):127-130. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Krudysz MA, Froines JR, Fine PM, Sioutas C. Intra-community spatial variation of size-fractionated PM mass, OC, EC, and trace elements in the Long Beach, CA area. Atmospheric Environment 2008;42(21):5374-5389. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C003 (2007) R832157 (2007) |
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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 Discussions 2008;8(3):9641-9672. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) R832413C003 (2007) R832413C003 (2008) |
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Majestic BJ, Schauer JJ, Shafer MM, Fine PM, Singh M, Sioutas C. Trace metal analysis of atmospheric particulate matter:a comparison of personal and ambient samplers. Journal of Environmental Engineering and Science 2008;7(4):289-298. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Moore KF, Ning Z, Ntziachristos L, Schauer JJ, Sioutas C. Daily variation in the properties of urban ultrafine aerosol—Part I: Physical characterization and volatility. Atmospheric Environment 2007;41(38):8633-8646. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Ning Z, Moore KF, Polidori A, Sioutas C. Field validation of the new miniature Versatile Aerosol Concentration Enrichment System (mVACES). Aerosol Science and Technology 2006;40(12):1098-1110. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Ning Z, Geller MD, Moore KF, Sheesley R, Schauer JJ, Sioutas C. Daily variation in chemical characteristics of urban ultrafine aerosols and inference of their sources. Environmental Science & Technology 2007;41(17):6000-6006. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Ning Z, Polidori A, Schauer JJ, Sioutas C. Emission factors of PM species based on freeway measurements and comparison with tunnel and dynamometer studies. Atmospheric Environment 2008;42(13):3099-3114. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Ntziachristos L, Polidori A, Phuleria H, Geller MD, Sioutas C. Application of a diffusion charger for the measurement of particle surface concentration in different environments. Aerosol Science and Technology 2007;41(6):571-580. |
R832413 (2008) R832413C001 (2006) R832413C001 (2007) R832413C001 (2008) |
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Ntziachristos L, Ning Z, Geller MD, Sheesley RJ, Schauer JJ, Sioutas C. Fine, ultrafine and nanoparticle trace element compositions near a major freeway with a high heavy-duty diesel fraction. Atmospheric Environment 2007;41(27):5684-5696. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Ntziachristos L, Ning Z, Geller MD, Sioutas C. Particle concentration and characteristics near a major freeway with heavy-duty diesel traffic. Environmental Science & Technology 2007;41(7):2223-2230. |
R832413 (2008) R832413C001 (2006) R832413C001 (2007) R832413C001 (2008) |
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Ntziachristos L, Froines JR, Cho AK, Sioutas C. Relationship between redox activity and chemical speciation of size-fractionated particulate matter. Particle & Fibre Toxicology 2007;4(June):5. |
R832413 (2008) R832413C001 (2007) |
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Phuleria HC, Sheesley RJ, Schauer JJ, Fine PM, Sioutas C. Roadside measurements of size-segregated particulate organic compounds near gasoline and diesel-dominated freeways in Los Angeles, CA. Atmospheric Environment 2007;41(22):4653-4671. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Polidori A, Arhami M, Sioutas C, Delfino RJ,Allen R. Indoor/outdoor relationships, trends, and carbonaceous content of fine particulate matter in retirement homes of the Los Angeles Basin. Journal of the Air & Waste Management Association 2007;57(3):366–379. |
R832413C001 (2007) |
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Polidori A, Hu S, Biswas S, Delfino RJ, Sioutas C. Real-time characterization of particle-bound polycyclic aromatic hydrocarbons in ambient aerosols and from motor-vehicle exhaust. Atmospheric Chemistry and Physics Discussions 2008;8(5):1277-1291. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Sillanpaa M, Geller MD, Phuleria HC, Sioutas C. High collection efficiency electrostatic precipitator for in vitro cell exposure to concentrated ambient particulate matter (PM). Journal of Aerosol Science 2008;39(4):335-347. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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Westerdahl D, Fruin SA, Fine PL, Sioutas C. The Los Angeles International Airport as a source of ultrafine particles and other pollutants to nearby communities. Atmospheric Environment 2008;42(13):3143-3155. |
R832413 (2007) R832413 (2008) R832413C001 (2007) R831861 (2005) |
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Wold LE, Simkhovich BZ, Kleinman MT, Nordlie MA, Dow JS, Sioutas C, Kloner RA. In vivo and in vitro models to test the hypothesis of particle-induced effects on cardiac function and arrhythmias. Cardiovascular Toxicology 2006;6(1):69-78. |
R832413 (2008) R832413C001 (2007) R827352 (Final) |
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Xia T, Kovochich M, Brant J, Hotze M, Sempf J, Oberley T, Sioutas C, Yeh JI, Wiesner MR, Nel AE. Comparison of the abilities of ambient and manufactured nanoparticles to induce cellular toxicity according to an oxidative stress paradigm. Nano Letters 2006;6(8):1794-1807. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) R832413C002 (2006) R832413C002 (2008) R827352 (Final) R827352C002 (Final) R827352C014 (Final) |
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Yacobi NR, Phuleria HC, Demaio L, Liang CH, Peng C-A, Sioutas C, Borok Z, Kim K-J, Crandall ED. Nanoparticle effects on rat alveolar epithelial cell monolayer barrier properties. Toxicology in Vitro 2007;21(8):1373-1381. |
R832413 (2008) R832413C001 (2007) R832413C001 (2008) |
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PM, sources, toxicity, apportionment, ultrafine, semi-volatile,
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Air, Scientific Discipline, Health, RFA, Risk Assessments, Health Risk Assessment, Biochemistry, particulate matter, Ecology and Ecosystems, cardiovascular disease, cardiovascular vulnerability, chemical characteristics, human health risk, oxidative stress, human health effects, particulates, PM 2.5, toxicology, air pollution, airway disease, atmospheric particulate matter, vascular dysfunction, airborne particulate matter
Relevant Websites:
Progress and Final Reports:
2006 Progress Report
Original Abstract
2008 Progress 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