Grantee Research Project Results
Final 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: Human Models for Analysis of Pathways (H MAPs) Center
Center Director: Murphy, William L
Title: Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of Their Relative Toxicity
Investigators: Sioutas, Constantinos , Hinds, William C. , Schauer, James J. , Shafer, Martin M. , Fine, Philip M. , Geller, Michael , Zhu, Yifang
Institution: University of Southern California , University of Wisconsin - Madison , University of California - Los Angeles
Current Institution: University of Southern California , University of California - Los Angeles , University of Wisconsin - Madison
EPA Project Officer: Chung, Serena
Project Period: October 1, 2005 through September 30, 2010 (Extended to September 30, 2012)
RFA: Particulate Matter Research Centers (2004) RFA Text | Recipients Lists
Research Category: Human Health , 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 vary 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 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 of Long Beach- LA Port
- Collect concurrently samples for Projects 2-3
4. To assess the contributions of these outdoor sources to indoor exposure in support of Project 4
Summary/Accomplishments (Outputs/Outcomes):
Over the course of the rouhgly 6 yrs covered in this report, and in concert with our proposed scope of work, we carried out field sampling campaigns at the facilities of 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
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-f have been successfully completed and 8 manuscripts have bean already published,
As noted earlier, 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 same sampling campaign at the I-710, we investigated the volatility of ambient particles of 20, 40, 80 and 120 nm in diameter using a Tandem Differential Mobility Analyzer (TDMA) at two locations—close to the freeway (10 m) and approximately 150 m downwind. The smallest particles (20 nm) are largely volatile at both locations. Larger particles, e.g., (~40 nm) showed evidence of external mixing, with the non-volatile fraction increasing with particle size. Particle volatility increased with decreasing ambient temperature. The HDDVs contribute to relatively larger non-volatile particle number and volume fractions and greater external mixing than earlier observations at a pure light-duty gasoline vehicle freeway (Kuhn, et al., 2005c. Atmospheric Environment 39:7154–7166). 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 μm2cm−3 next to a freeway to ~100 μm2cm−3 at 100 m downwind of the freeway, and levels decline to 50–70 μm2cm−3 at urban background sites. Up to 51% and 30% of the total surface area corresponded to particles< 40 nm 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 to the per-mass toxicity of these particles. The presence of metals in the 18-32 nm 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 these can and should be characterized due to their likely 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) is reported in this study. 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. It 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 between the morning (traffic) and afternoon (photochemistry) periods in a typical urban site of LA
- Tandem DMA particle diameter/volatility measurements
- Chemical speciation of the above samples
- In Vitro collection of ultrafine PM
This 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 ~ 150 m 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. Ultrafine particles (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) particulate matter (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).
Los Angeles – Long Beach Port Studies
During our winter campaign (Arhami, et al., 2008), PM samples were collected concurrently at six sites for a 7-weeks period between February and May 2007. Four sites were set-up within the communities of Wilmington and Long Beach; one site was located at a background location near the harbors of the Los Angeles port; the sixth site, near downtown Los Angeles, was chosen to represent a typical urban area. Coarse (PM2.5-10), accumulation (PM0.25-2.5), and quasi-ultrafine (PM0.25) mode particles were collected at each site. Vehicular emissions from the nearby traffic were the most prominent anthropogenic sources of both quasi-ultrafine and accumulation mode PM in all port sites (except at the background site located upwind, where ship emissions were the dominant PM source). Overall, traffic sources were major contributors to the PM and organic matter mass, and prevailed over ship emissions and oil combustion even in the studied harbor community (Arhami, et al., 2008).
In collaboration with investigators from projects 2-3, 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. 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).
In order to better understand and quantify intra-community variability in UFP concentrations in the complex area of the LA- Long Beach port, a dense network of 14 monitoring sites was set-up in Los Angeles in two clusters – San Pedro/Wilmington and West Long Beach – in communities surrounding the Ports of Los Angeles and Long Beach. The intra-urban variability observed in this study is comparable to and exceeds the inter-urban variability observed in a previous study in Los Angeles. UFP concentrations can vary considerably on short spatial scales in source-rich environments, which can strongly influence the accuracy of exposure assessments (Moore et al., 2008). In addition to the particle number concentration measurements described above, we conducted concurrent particle size distribution measurements in an effort to identify UFP sources and types in the LA – Long Beach port area, while providing data to investigate local scale effects of both photochemical and physical processes on UFP. Spatial heterogeneity exists between “background” and “source” sites especially for particles < 40 nm, while spatial homogeneity is observed between geographically close sites. In addition, variations in r-values as a function of particle size are not necessarily consistent with corresponding CODs values, indicating that using results from correlation analysis alone may not accurately assess spatial variability. This study is described in detail by Krudysz, et al. (2008).
Los Angeles Airport (LAX) Pilot Study
During this period, we also completed the data analysis and publication of our first pilot studies at LAX (see Westerdahl, et al., 2008). Air monitoring was performed in the vicinity of the Los Angeles International Airport (LAX) during the spring of 2006. The particle numbers at the upwind site were dominated by particles of approximately 90 nm diameter while downwind sites were dominated by particles peaking at approximately 10-to-15 nm. Additional data obtained from a study of UFP levels conducted subsequently by a co-author indicates that aircraft-generated UFP persist up to 900 meters from an LAX runway (Biswas, et al., 2005). Considered together, these observations suggest that airport operations are associated with elevated levels of UFP much further downwind in the neighboring community than would have been predicted by prior studies of UFP from roadway-traffic. Based on these results, we intend to conduct at a later time more detailed studies in that area, focusing this time on the collecting of ultrafine and accumulation mode particles for chemical and toxicological analysis in the same locations of the Westerdahl, et al. (2008) study.
Reconciling Emission Factors of PM Species Emitted by Vehicles in Freeways and Roadway Tunnel Environments
In addition to our tunnel-based emission factors for light and heavy duty vehicles, we estimated emission factors of various particle species from light and heavy duty vehicles (LDVs and HDVs, respectively), including organic and elemental carbon (OC and EC,), sulfate, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, trace metals, elements, and particle number (PN), based on roadway measurements (Ning, et al., 2008). Sampling campaigns were conducted at two different roadways: the CA-110 highway (where only gasoline-powered vehicles are allowed), and the I-710 freeway (where about 20% of the total number of vehicles are diesel-powered trucks). The PM emission factors determined in these roadways were compared to those reconstructed from recent source emission data from the Caldecott tunnel (Phuleria, et al., 2006), and those from previous tunnel and chassis dynamometer studies. Very good agreement between estimated and reconstructed emission factors was found. This suggests that PM speciated chemical data collected at roadsides can be used to calculate reliable emission factors for several important particulate species at other locations, characterized by a similar mix of on-road motor vehicles. 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). Based on these roadway measurements and average driving time, it appears that 33–45% of total UFP exposure for Los Angeles residents occurs due to time spent traveling in vehicles (Fruin, et al., 2008).
Physicochemical and toxicological properties of Particulate Matter from October 2007 Southern California wildfires (collaboration with Project 3 and Dr. Flemming Cassee)
Wood smoke is one of the important sources of PM whose chemistry and toxicity we proposed to investigate. On October 20, 2007, 23 large wildfires ranging from Santa Barbara County to the U.S.– Mexico border, burned more than 500,000 acres of land and destroyed over 1,500 homes with the largest mandatory evacuation (of over 900,000 people) in the state's history. During this period, we conducted measurements of various particle and gaseous pollutants such as CO, nitrogen oxides, O3, PM2.5 (particles with an aerodynamic diameter less that 2.5 µm) mass with its chemical constituents, and size fractionated particle number, measured at a site near the University of Southern California (USC). Detailed chemical and toxicological characteristics have been evaluated from the PM samples collected during the fire event, and compared to those after the October 2007 fire period (when outdoor PM2.5 is mostly impacted by the vehicular traffic emissions). We showed that concentration of water-soluble organic carbon (WSOC) and several organic tracers including levoglucosan were increased by 2-3 fold during the fire period. The per mass PM toxicity expressed in nmoles of DTT consumed per μg of PM and min was also higher for the samples collected during the wildfire episode compared to the PM samples impacted by traffic suggesting that wood smoke on a per PM mass basis is a significant source of PM that are redox active (Verma, et al., 2008).
Health Studies – collectively with Project 2 :The Role of Oxidative Stress in the Susceptibility to PM-Induced Adverse Health Effects
During this period covered by this report, we have assisted the investigators of project 2 to conduct exposures of genetically susceptible (apoE-deficient) mice to well characterized (physically and chemically) fine and ultrafine CAPs. Following up on the results of the Campbell et al (2008) study, we have further explored the evidence that the brain may also constitute a site adversely effected by the environmental presence of airborne particulate matter by examining the association between exposure to PM and adverse CNS effects in apolipoprotein E knockout (ApoE-/-) mice exposed to two levels of concentrated ultrafine particulate matter in central Los Angeles (USC) using our concentrators. The study provided clear evidence of aberrant immune activation in the brains of exposed animals as judged by a dose-related increase in nuclear translocation of two key transcription factors, NF-kB and AP-1. In order to determine the mechanism by which these events occurred, levels of several MAP kinases involved in activation of these transcription factors were assayed by Western blotting. The results suggest that the signaling pathway by which these transcription factors are activated involves the activation of JNK (Kleinman, et al., 2008).
Development of high collection efficiency electrostatic precipitator for in vitro cell exposure to concentrated ambient particulate matter (PM)- Projects 2-3
In several discussions with ESAC members (Drs. Flagan, McMurry, Russell and Cassee) over the past year and during our previous meetings, we entertained the idea of utilizing electrostatic precipitation for on-line collections of PM for toxicity studies. To that end, we developed a new sampling system to collect ambient particles for in-vitro studies (Sillanpaa, et al., 2008). The in-vitro electrostatic collector consists of two units: a Versatile Aerosol Concentration Enrichment System (VACES) and a new design of electrostatic precipitator (ESP). This system allows for shorter sampling durations, which benefits cells that might not be viable after prolonged exposure to the sampling environment. Shorter time interval sampling also enables discovery of possible relationships between health effects and time of day or short-term source emissions. The main advantage of in-vitro electrostatic collector is that it collects >95% of particles - regardless of particle type or diameter - directly to a target area, on which a cell culture can be placed. The unique design implements two metal needles to facilitate a corona discharge, resulting in high particle charging efficiency with little ozone production. These advantages make the in-vitro electrostatic collector a viable in-vitro cell exposure technique.
Novel Zero-Ozone Unipolar Charging of Ultra-fine Aerosol Particles using Carbon Fiber Ionizers
Expanding further our technology and use of ESPs for in vitro PM collections, we replaced the unipolar corona discharge charger of our ESP with a simple and novel unipolar charger using carbon fiber ionizers (Han, et al., 2008). This charger was developed to effectively charge ultra-fine aerosol particles without the generation of ozone. The newly developed unipolar charger using carbon fiber ionizers can charge ultra-fine particles at least as effectively as currently available unipolar chargers, but with the major advantage of negligible ozone generation, a highly desirable feature if the charged particles are to be used for chemical or biological analysis. (Han et al., 2008)
Health Studies with Project 3: Chemical Reactivity of Particulate Matter Sources, and Modification of Chemical and Cellular Properties of PM-Associated Components by the Particle Matrix
In a collaborative study with investigators from projects 3 and 4, we have collected using our VACES fine and ultrafine PM in the area of Riverside and in one of the retirements homes of the subjects of the study in Project 4, to assist our colleagues in their efforts to develop an analytical procedure to detect electrophiles that can be applied to the study of air pollution samples, using the active site of the thiol enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (EC 1.2.1.12) as the target nucleophile.
Health Studies with Project 4: Oxidative Stress Reponses to PM Exposure in Elderly Individuals with Coronary Heart Disease
In collaboration with investigators in Project 4, we explored the association between circulating biomarkers of inflammation, antioxidant activity, and platelet activation with primary combustion and secondary aerosols among the study subjects of that project. Our results suggest traffic emission sources of primary OC and quasi-ultrafine particles lead to increases systemic inflammation and platelet activation, and decreases in antioxidant enzyme activity in elderly people with coronary artery disease (Delfino, et al., 2008).
Our Ning, et al. (Environmental Science & Technology 2007;41(17):6000-6006) paper identified clearly two distinctly different time periods in the summertime at USC; once 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 was also 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-fuelled 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. Particulate matter (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 EU 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 are 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 was also 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 ten 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 (see more details 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. Submitted for publication to Inhalation Toxicology, June 2010).
In our Dahger, et al. (2011) study, we compare the chemical and oxidative characteristics of concentration-enriched PM2.5 samples simultaneously collected by a filter, a Nano-Micro-Orifice Uniform Deposition Impactor, and a BioSampler. Gravimetric measurements showed considerable agreement in particulate matter (PM) collection efficiency for all three samplers. Accordingly, samples from the three collectors exhibited similar chemical compositions. The mass fractions of their inorganic ions, labile and nonlabile, were comparable. Moreover, the organic carbon (OC) content of the BioSampler slurry was similar to that of the filter, while water-soluble OC levels of the filter and impactor samples were close to a 100% agreement. Lastly, linear regression analyses demonstrated that the water-soluble elements existed in similar proportions for the filter and impactor samples. Their respective total components were also in very good agreement. By contrast, the recoverable elements from the BioSampler slurry, determined by high-resolution magnetic sector inductively coupled plasma mass spectrometry, were in good agreement with the water-soluble elements of the filter and impactor samples but not their corresponding total components. In spite of the overall agreement among the samples on their chemical composition, findings from a macrophage reactive oxygen species (ROS), a dithiothreitol (DTT), and a dihydroxybenzoate (DHBA) assay revealed that the oxidative potential of aqueous extracts of the filter and impactor substrates was similar yet substantially lower than that of the BioSampler slurry. However, filtering of the BioSampler slurry, i.e., removal of insoluble PM components, attenuated its ROS activity to about the same level as that of the water extracts of the filter and impactor samples. These findings first indicate that insoluble PM species are potentially redox active, and second that particle collection by the BioSampler, which circumvents the need for PM extraction, constitutes a viable alter- native for collecting concentrated particles for characterization of the oxidative properties of PM.
Lastly a novel sampling system was developed to provide concentrated vapor phase only semi-volatile organic species for in-vivo exposure studies (Pakbin, et al., 2011). The system consists of two units: particles (including their semi-volatile component) are first concentrated by means of the Versatile Aerosol Concentration Enrichment System (VACES), and subsequently drawn through a heating section, in which semi-volatile particle-bound components partition to the gas phase, while non-volatile particles are removed by a quartz filter placed after the heater. The vapors are then cooled to ambient temperatures, without producing nano-particles by nucleation, and can be readily used for exposure studies. Laboratory tests were carried out at various heater temperatures using ammonium sulfate, adipic acid and glutaric acid to investigate the occurrence of nucleation in the cooling section. Subsequently the system was tested in the field with concentrated particle and vapor samples taken upstream of the heater, immediately downstream of the filter, and after the cooling section. Chemical analysis of particle and vapor phases upstream and downstream of the system was conducted for selected polycyclic aromatic hydrocarbons (PAHs), and showed very good PAH recovery. These tests indicate that the modified VACES-heater-filter (VHF) system can provide concentrated PM (including their semi-volatile compounds) and PM-bound semi-volatile species purely in the vapor phase for inhalation exposure studies separately, a feature that makes this system an attractive approach for toxicity studies, particularly in light of the increasing interest in health effects of exposures to multi-pollutant atmospheres.
Journal Articles on this Report : 85 Displayed | Download in RIS Format
| Other subproject views: | All 87 publications | 85 publications in selected types | All 85 journal articles |
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| Other center views: | All 241 publications | 157 publications in selected types | All 157 journal articles |
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Araujo JA, Barajas B, Kleinman M, Wang X, Bennett BJ, Gong KW, Navab M, Harkema J, Sioutas C, Lusis AJ, Nel AE. Ambient particulate pollutants in the ultrafine range promote early atherosclerosis and systemic oxidative stress. Circulation Research 2008;102(5):589-596. |
R832413 (2008) R832413 (2009) R832413 (2010) R832413 (Final) R832413C001 (2008) R832413C001 (Final) R832413C002 (2007) R832413C002 (2008) R832413C002 (2009) R832413C002 (Final) R832413C003 (Final) |
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Arellanes C, Paulson SE, Fine PM, Sioutas C. Exceeding of Henry's law by hydrogen peroxide associated with urban aerosols. Environmental Science & Technology 2006;40(16):4859-4866. |
R832413 (Final) R832413C001 (Final) R827352 (Final) |
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Arhami M, Kuhn T, Fine PM, Defino RJ, Sioutas C. Effects of sampling artifacts and operating parameters on the performance of a semicontinuous particulate elemental carbon/organic carbon monitor. Environmental Science & Technology 2006;40(3):945-954. |
R832413C001 (Final) R827352 (Final) |
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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) R832413 (Final) R832413C001 (2009) R832413C001 (Final) R832413C004 (2009) R832413C004 (2010) R832413C004 (Final) |
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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) R832413 (2009) R832413 (Final) R832413C001 (2009) R832413C001 (Final) |
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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) R832413C001 (2009) R832413C001 (Final) R832413C004 (2009) R832413C004 (2010) R832413C004 (Final) |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R832413C002 (2008) R832413C003 (2008) R832413C003 (2009) |
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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) R832413 (2009) R832413 (Final) R832413C001 (2006) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
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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) R832413C001 (2009) R832413C001 (Final) R832413C003 (2009) R832413C003 (2010) R832413C003 (Final) |
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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) R832413C001 (2009) R832413C001 (Final) |
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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) R832413C001 (2009) R832413C001 (Final) |
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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) |
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Daher N, Ning Z, Cho AK, Shafer M, Schauer JJ, Sioutas C. Comparison of the chemical and oxidative characteristics of particulate matter (PM) collected by different methods:filters, impactors, and biosamplers. Aerosol Science and Technology 2011;45(11):1294-1304. |
R832413 (Final) R832413C001 (Final) R832413C003 (Final) |
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Delfino RJ, Staimer N, Gillen D, Tjoa T, Sioutas C, Fung K, George SC, Kleinman MT. Personal and ambient air pollution is associated with increased exhaled nitric oxide in children with asthma. Environmental Health Perspectives 2006;114(11):1736-1743. |
R832413 (Final) R832413C001 (Final) |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R832413C004 (2007) R832413C004 (2008) R832413C004 (2009) R832413C004 (2010) R832413C004 (Final) |
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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) R832413C001 (Final) R832413C004 (2009) R832413C004 (2010) R832413C004 (Final) |
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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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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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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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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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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) |
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Doherty SP, Prophete C, Maciejczyk P, Salnikow K, Gould T, Larson T, Koenig J, Jaques P, Sioutas C, Zelikoff JT, Lippmann M, Cohen MD. Detection of changes in alveolar macrophage iron status induced by select PM2.5-associated components using iron-response protein binding activity. Inhalation Toxicology 2007;19(6-7):553-562. |
R832413 (Final) R832413C001 (Final) R827351 (Final) R827352 (Final) R827355 (2004) R827355 (Final) |
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Fine PM, Sioutas C, Solomon PA. Secondary particulate matter in the United States: insights from the Particulate Matter Supersites Program and related studies. Journal of the Air & Waste Management Association 2008;58(2):234-253. |
R832413 (2008) R832413 (Final) R832413C001 (Final) |
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Fruin SA, Hudda N, Sioutas C, Delfino RJ. Predictive model for vehicle air exchange rates based on a large, representative sample. Environmental Science & Technology 2011;45(8):3569-3575. |
R832413 (Final) R832413C001 (Final) |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
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Geller MD, Ntziachristos L, Mamakos A, Samaras Z, Schmitz DA, Froines JR, Sioutas C. Physicochemical and redox characteristics of particulate matter (PM) emitted from gasoline and diesel passenger cars. Atmospheric Environment 2006;40(36):6988-7004. |
R832413 (Final) R832413C001 (Final) R827352 (Final) |
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Geller M, Biswas S, Sioutas C. Determination of particle effective density in urban environments with a differential mobility analyzer and aerosol particle mass analyzer. Aerosol Science and Technology 2006;40(9):709-723. |
R832413C001 (Final) R827352 (Final) |
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Gerlofs-Nijland ME, Totlandsdal AI, Kilinc E, Boere AJ, Fokkens PH, Leseman DL, Sioutas C, Schwarze PE, Spronk HM, Hadoke PW, Miller MR, Cassee FR. Pulmonary and cardiovascular effects of traffic-related particulate matter:4-week exposure of rats to roadside and diesel engine exhaust particles. Inhalation Toxicology 2010;22(14):1162-1173. |
R832413 (Final) R832413C001 (Final) |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R827352 (Final) |
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Gong KW, Zhao W, Li N, Barajas B, Kleinman M, Sioutas C, Horvath S, Lusis AJ, Nel A, Araujo JA. Air-pollutant chemicals and oxidized lipids exhibit genome-wide synergistic effects on endothelial cells. Genome Biology 2007;8(7):R149 (13 pp.). |
R832413 (2008) R832413 (2009) R832413 (Final) R832413C001 (2008) R832413C001 (Final) R832413C002 (2007) R832413C002 (2008) R832413C002 (Final) |
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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) |
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Han B, Hudda N, Ning Z, Sioutas C. Enhanced unipolar charging of concentration-enriched particles using water-based condensational growth. Journal of Aerosol Science 2008;39(9):770-784. |
R832413 (2009) R832413 (Final) R832413C001 (2008) R832413C001 (Final) |
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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) |
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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) |
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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) |
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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) |
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Hudda N, Cheung K, Moore KF, Sioutas C. Inter-community variability in total particle number concentrations in the eastern Los Angeles air basin. Atmospheric Chemistry and Physics 2010;10(23):11385-11399. |
R832413 (Final) R832413C001 (Final) |
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Kim YH, Sioutas C, Fine P, Shing KS. Effect of albumin on physical characteristics of drug particles produced by supercritical fluid technology. Powder Technology 2008;182(3):354-363. |
R832413C001 (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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) 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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R831952 (Final) |
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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) R832413 (Final) R832413C001 (2007) R832413C001 (Final) R832413C003 (2007) R832157 (2007) R832157 (Final) |
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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) |
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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 2009;9(3):1061-1075. |
R832413 (2008) R832413 (2009) R832413 (Final) R832413C001 (2009) R832413C001 (Final) R832157 (Final) |
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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) |
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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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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) |
Exit Exit Exit |
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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) |
Exit Exit Exit |
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Majestic BJ, Schauer JJ, Shafer MM, Turner JR, Fine PM, Singh M, Sioutas C. Development of a wet-chemical method for the speciation of iron in atmospheric aerosols. Environmental Science & Technology 2006;40(7):2346-2351. |
R832413C001 (Final) R827352 (Final) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit |
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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) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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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) |
Exit Exit |
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Morgan TE, Davis DA, Iwata N, Tanner JA, Snyder D, Ning Z, Kam W, Hsu YT, Winkler JW, Chen JC, Petasis NA, Baudry M, Sioutas C, Finch CE. Glutamatergic neurons in rodent models respond to nanoscale particulate urban air pollutants in vivo and in vitro. Environmental Health Perspectives 2011;119(7):1003-1009. |
R832413 (Final) R832413C001 (Final) |
Exit |
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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) |
Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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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) |
Exit Exit Exit |
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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) |
Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2006) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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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 and Fibre Toxicology 2007;4:5 (12 pp.). |
R832413 (2008) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R832413C003 (2008) R832413C003 (2010) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2006) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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Pakbin P, Ning Z, Eiguren-Fernandez A, Sioutas C. Modification of the Versatile Aerosol Concentration Enrichment System (VACES) for conducting inhalation exposures to semi-volatile vapor phase pollutants. Journal of Aerosol Science 2011;42(9):555-566. |
R832413 (Final) R832413C001 (Final) |
Exit Exit Exit |
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Phuleria HC, Geller MD, Fine PM, Sioutas C. Size-resolved emissions of organic tracers from light-and heavy-duty vehicles measured in a California roadway tunnel. Environmental Science & Technology 2006;40(13):4109-4118. |
R832413C001 (Final) R827352 (Final) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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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. |
R832413 (2008) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit |
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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 2008;8(5):1277-1291. |
R832413 (2007) R832413 (2008) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit |
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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) |
Exit Exit |
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Prophete C, Maciejczyk P, Salnikow K, Gould T, Larson T, Koenig J, Jaques P, Sioutas C, Lippmann M, Cohen M. Effects of select PM-associated metals on alveolar macrophage phosphorylated ERK1 and-2 and iNOS expression during ongoing alteration in iron homeostasis. Journal of Toxicology and Environmental Health, Part A:Current Issues 2006;69(10):935-951. |
R832413C001 (Final) R827351 (Final) R827351C008 (Final) R827351C010 (Final) R827352 (Final) R827352C014 (Final) R827355 (Final) R827355C008 (Final) |
Exit |
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Sardar SB, Geller MD, Sioutas C, Solomon PA. Development and evaluation of a high-volume dichotomous sampler for chemical speciation of coarse and fine particles. Journal of Aerosol Science 2006;37(11):1455-1466. |
R832413C001 (Final) R827352 (Final) |
Exit Exit Exit |
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Shinyashiki M, Rodriguez CE, Di Stefano EW, Sioutas C, Delfino RJ, Kumagai Y, Froines JR, Cho AK. On the interaction between glyceraldehyde-3-phosphate dehydrogenase and airborne particles:evidence for electrophilic species. Atmospheric Environment 2008;42(3):517-529. |
R832413 (2008) R832413 (2009) R832413 (Final) R832413C001 (2008) R832413C001 (Final) R832413C003 (2007) R832413C003 (2008) R832413C003 (2010) R832413C003 (Final) R832413C004 (2009) R832413C004 (2010) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) |
Exit Exit Exit |
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Snyder DC, Dallmann TR, Schauer JJ, Holloway T, Kleeman MJ, Geller MD, Sioutas C. Direct observation of the break-up of a nocturnal inversion layer using elemental mercury as a tracer. Geophysical Research Letters 2008;35(17):L17812. |
R832413 (2008) R832413 (2009) R832413 (Final) R832413C001 (2008) R832413C001 (Final) |
Exit Exit |
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Solomon PA, Sioutas C. Continuous and semicontinuous monitoring techniques for particulate matter mass and chemical components:a synthesis of findings from EPA's Particulate Matter Supersites Program and related studies. Journal of the Air & Waste Management Association 2008;58(2):164-195. |
R832413 (2008) R832413 (Final) R832413C001 (Final) |
Exit Exit |
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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. |
R832413 (Final) R832413C001 (Final) |
Exit |
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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) |
Exit Exit Exit |
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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) |
Exit Exit Exit |
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Verma V, Shafer MM, Schauer JJ, Sioutas C. Contribution of transition metals in the reactive oxygen species activity of PM emissions from retrofitted heavy-duty vehicles. Atmospheric Environment 2010;44(39):5165-5173. |
R832413 (Final) R832413C001 (Final) |
Exit Exit Exit |
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Verma V, Pakbin P, Cheung KL, Cho AK, Schauer JJ, Shafer MM, Kleinman MT, Sioutas C. Physicochemical and oxidative characteristics of semi-volatile components of quasi-ultrafine particles in an urban atmosphere. Atmospheric Environment 2011;45(4):1025-1033. |
R832413 (Final) R832413C001 (Final) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R827352 (Final) R831861 (2005) |
Exit Exit Exit |
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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) R832413 (Final) R832413C001 (2007) R832413C001 (Final) R827352 (Final) R831952 (2005) R831952 (Final) |
Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R832413C002 (2006) R832413C002 (2008) R827352 (Final) R827352C002 (Final) R827352C014 (Final) |
Exit Exit Exit |
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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) R832413 (2009) R832413 (Final) R832413C001 (2007) R832413C001 (2008) R832413C001 (Final) R827352 (Final) |
Exit Exit Exit |
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, particulates, atmospheric particulate matter, chemical characteristics, human health effects, PM 2.5, toxicology, airway disease, cardiovascular vulnerability, airborne particulate matter, air pollution, human exposure, vascular dysfunction, cardiovascular disease, human health riskRelevant Websites:
Progress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R832413 Human Models for Analysis of Pathways (H MAPs) 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
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.