2010 Progress Report: Ultrafine Particles on and Near Freeways

EPA Grant Number: R832413C005
Subproject: this is subproject number 005 , 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: Ultrafine Particles on and Near Freeways
Investigators: Hinds, William C. , Cho, Arthur K. , Froines, John R. , Kleinman, Michael T.
Current Investigators: Hinds, William C. , Cho, Arthur K. , Froines, John R. , Kleinman, Michael T. , Zhu, Yifang
Institution: University of California - Los Angeles , University of Southern California
Current Institution: University of California - Los Angeles
EPA Project Officer: Chung, Serena
Project Period: October 1, 2005 through September 30, 2010 (Extended to September 30, 2012)
Project Period Covered by this Report: August 1, 2009 through July 31,2010
RFA: Particulate Matter Research Centers (2004) RFA Text |  Recipients Lists
Research Category: Health Effects , Air

Objective:

The objectives of Project 5 are to: (1) determine the relative contributions of gaseous and particle components of ambient air samples to oxidative stress related health effects and (2) evaluate environmental factors that might affect the accuracy of the chemical and biological assays used by the Southern California Particle Center (SCPC). Subproject 2 includes efforts that either directly or indirectly seek to improve our ability to assess health risk of air pollution by chemical and biological assays, such as sample handling.

Progress Summary:

a. Project Summary/Accomplishments

In Subproject 1 we have nearly completed taking the large simultaneous samples of both particulate and gas phase contaminants from the same volume of air. Both phases were used for the full slate of bioassays and detailed chemical analysis. Samples were taken at three different locations having a different mix of fresh, aged, and photochemically produced contaminants: a freeway adjacent site, an urban site and a receptor site. Most of the assays of these samples have been completed and are reported in the progress report for Project 3 (see the report for R832413C003). Subproject 2 previously included an evaluation of the aerosol concentrator for use with these assays. That investigation is now complete. Planning has started for an evaluation of the effect of ambient NO2 concentration on bioassays.

b. Discussion of Progress

Simultaneous sampling of particles and vapors for assays

At each location we collected particles on Teflon coated glass fiber filters and gas phase contaminants onto XAD resin at 226 Lpm through a PM2.5 inlet to collect a total sample volume of approximately 400 – 600 m3. This was repeated up to two more times. Filters and XAD resin were stored onsite in a refrigerator and periodically transferred to University of California (UC)-Irvine for freezer storage and then transferred to UCLA for analysis. Results thus far for these gas phase and particle phase samples are given in the progress report for Project 3 (see the report for R832413C003). Composite sample volumes were 399, 423, and 415 m3 for the three replicate samples for the first campaign; 232, 245, and 339 m3 for the second campaign; and 488, 488, and 488 m3 for the third. The first set of samples was taken at the animal exposure trailer at the UC-Riverside agricultural facility in Riverside, CA. Riverside is a receptor site with a significant photochemical component. Samples were taken for 5.5 hours/day for 6 days and this was repeated three times. A portion of the XAD resin was sent to Professor Kumagai in Japan for analysis by his assay. The second set of samples, also done in triplicate, were taken at an urban site with freeway influence, next to the University of Southern California (USC) and near the 110 freeway. Samples were taken continuously for 48 hours. The third site is adjacent to and downwind of the 405 freeway. Sampling was conducted during 12 daylight hours for three consecutive days in March, May and June of 2009. Thus far, we are able to conclude that the particle phase shows higher redox activity than the vapor phase, but the vapor phase showed higher electrophilic content than the particle phase.

An outgrowth of the activity on this subproject led to a collaborative effort between Mike Kleinman, Bill Hinds, and Art Cho for a more comprehensive sampling scheme. We prepared and submitted a proposal to the Air Quality Management District (AQMD) Asthma Consortium for funding to conduct simultaneous sampling for (1) animal exposure (direct with a concentrator); (2) the full battery of chemical and biological assays (samples taken with the concentrator plus impinger); (3) detailed physical characterization including number concentration, size distribution, PM2.5 mass concentration, elemental carbon, particle bound PAHs; and (4) filter and XAD resin samples for detailed chemical analysis of the gas phase and particle phase. This provides a direct comparison of in-vivo response, chemical and bioassay response for gas and particle phases and detailed physical and chemical analysis from simultaneous, collocated samplers. Results are given in Mike Kleinman's section of the progress report.

Real-time DTT assay evaluation

A feasibility evaluation was undertaken to determine if a Particle Into Liquid Sampler (PILS) could be used as a real-time DTT assay monitor. We concluded that the sensitivity was marginal and that there were significant cost and practical problems with this approach.

Concentrator testing, modification, and deployment

As described in previous progress reports, we made many modifications to our concentrator to make it more portable, easier to use, more reliable, and produce a more stable output. In all cases, we found some particle size dependence for the enrichment factor with the greatest enrichment factors in the 20-25 nm particle size range. Best results were obtained using only one channel at a time.

Redox decay study

The subproject to determine the effects of storage and freeze/thaw cycling on redox activity has been discontinued because the limitation of the concentrator to one channel prevents obtaining a large enough sample quickly enough to conduct the planned tests.

CARB study: Cardiovascular health effects of fine and ultrafine particles during freeway travel

In a related project, funded by the California Air Resources Board (CARB), we have developed an instrumented van for human exposure to freeway air while traveling on a freeway. EPA and SCPC contributed to this project through partial salary support for Dr. Yifang Zhu. The study seeks to evaluate short-term measures of exposure and response by measuring heart rate variability, and 26 cytokines and other blood factors before, after, and 20 hours after a 2-hour exposure to freeway or filtered air. The van includes a HEPA air filtration system, a two-person exposure chamber, a vibration isolation table, nine near real-time instruments, and a battery power supply. Instruments include a CPC, SMPS, aethelometer, particle-bound PAH, PM10, PM2.5, NOx, CO2, CO, temperature, relative humidity, and GPS. The van has and will benefit the SCPC for the projects described in this report. We have completed all exposure runs for all 19 subjects.

Average total particle number concentration measured by a condensation particle counter (CPC) of unfiltered air observed inside the enclosure was 77,800 and 107,500 particles/cm3 on the I-405 and the I-710 freeway, respectively. The highest 1-minute averaged particle number concentration was 730,000 particles/cm3 on the I-710 freeway. Bimodal size distributions were typical for both freeways with the first mode around 12–20 nm and the second mode around 50–100 nm. BC and particle-bound PAH concentrations were more than two times greater on the I-710 than on the I-405 freeway. Ultrafine particles represented from 36 to 76% of total particle number concentrations on I-405, and 56% to 84% on I-710. A peak in average particle number concentration of 125,000 particles/cm3 was associated with a traffic speed of 40 to 50 mph. Most health endpoints did not vary significantly by freeway or filter condition. Atrial ectopic beat incidence during and after exposure, however, decreased 20% on average with filtered versus unfiltered air (P<0.05). Between-freeway differences were non-significant, but individual responses related more strongly to count (P=0.01) than to mass (P=0.07). N-terminal pro B-type natriuretic peptide (NT pro-BNP) and vascular endothelial growth factor (VEGF) decreased 30% on average in filtered compared to unfiltered air (P<0.05). Effects appeared to relate to the ultrafine particulate fraction, in that particle count was strongly correlated with arrhythmia incidence, while PM2.5 and PM10 mass concentrations were not significantly correlated with arrhythmia incidence. Rigorous double-blind conditions and filtered-air controls in this study, rule out other traffic-related stresses or pollutant gases as causes of the PM-associated cardiovascular effects. The final report on this project has been submitted and accepted by CARB. Further heart rate variability (HRV) analysis is continuing using a new, more sophisticated, nonlinear analytical method.

Future Activities:

As outlined above, and as time permits, we will continue to take large volume samples for particle and gas phase contaminants at urban and freeway sites. All current assays will be conducted on the samples and the chemical and physical analyses will be used in interpreting the results. The new activity, a retrospective assessment of the influence of ambient NO2 concentrations on our large volume particle/vapor samples used for reactive oxygen species (ROS) assays.  High concentrations of NO2 could reduce the ROS potential of vapor phase samples. We will start with the determination of average NO2 concentrations at the location and time of each of the large volume samples. We will analyze these data for statistical association. If there is evidence of an effect, we will take samples with and without a NO2 scrubber.


Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other subproject views: All 34 publications 13 publications in selected types All 13 journal articles
Other center views: All 241 publications 157 publications in selected types All 157 journal articles
Type Citation Sub Project Document Sources
Journal Article Eiguren-Fernandez A, Shinyashiki M, Schmitz DA, DiStefano E, Hinds W, Kumagai Y, Cho AK, Froines JR. Redox and electrophilic properties of vapor-and particle-phase components of ambient aerosols. Environmental Research 2010;110(3):207-212. R832413 (Final)
R832413C003 (2010)
R832413C003 (Final)
R832413C005 (2010)
R832413C005 (Final)
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  • Journal Article Fung DC, Zhang QF, Hinds WC, Zhy YF. Particle concentration on freeways: affecting factors and a simple model development. Aerosol and Air Quality Research 2013;13(6):1693-1701. R832413C005 (2010)
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  • Journal Article Iwamoto N, Nishiyama A, Eiguren-Fernandez A, Hinds W, Kumagai Y, Froines JR, Cho AK, Shinyashiki M. Biochemical and cellular effects of electrophiles present in ambient air samples. Atmospheric Environment 2010;44(12):1483-1489. R832413 (Final)
    R832413C003 (2010)
    R832413C003 (Final)
    R832413C005 (2010)
    R832413C005 (Final)
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  • Supplemental Keywords:

    RFA, Health, Scientific Discipline, Air, particulate matter, Environmental Chemistry, Health Risk Assessment, Risk Assessments, Ecological Risk Assessment, Ecology and Ecosystems, cardiopulmonary responses, chemical characteristics, human health effects, toxicology, cardiovascular vulnerability, airborne particulate matter, chemical composition, biological mechanisms, biological mechanism , traffic related particulate matter, human exposure, mobile sources, ambient particle health effects, ultrafine particulate matter, respiratory impact, PM, cardiotoxicity, cardiovascular disease, human health risk

    Progress and Final Reports:

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

  • Main Center Abstract and Reports:

    R832413    Southern California Particle Center

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