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2007 Progress Report: Ultrafine Particles on and Near Freeways
EPA Grant Number: R832413C005Subproject: 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.
Current Investigators: Hinds, William C. , Cho, Arthur K. , Froines, John R. , Kleinman, Michael T.
Institution: University of California - Los Angeles
Current Institution: University of California - Los Angeles , University of Southern California
EPA Project Officer: Katz, Stacey
Project Period: October 1, 2005 through September 30, 2010
Project Period Covered by this Report: October 1, 2006 through September 30, 2007
RFA: Particulate Matter Research Centers (2004)
Research Category: Particulate Matter
Description:
Objective:To determine the relative contributions of gaseous and particle components of ambient air samples to oxidative stress related health effects.
Progress Summary:Project 5 consists of three subprojects that either directly or indirectly seek to clarify uncertainties in the chemical and biological assays used by SCPC. Subproject 1 will obtain a large simultaneous sample of both particulate and gas phase contaminants from the same volume of air. Both phases will be used for the full slate of bioassays and detailed chemical analysis. Samples will be taken at three locations with a different mix of fresh , aged, and photochemically produced contaminants: an urban site, a freeway site or on-freeway, and an urban receptor site. Subproject 2 will provide concentrator capability for the Southern California Particle Center investigators and their projects. Subproject 3 will use the concentrator to obtain particle samples at UCLA that will be analyzed by our DTT redox activity assay immediately after collection and after a series of aging and freeze-thaw cycles. The objective is to determine the effect of age and freeze-thaw cycles on redox activity of the samples as measured by the DTT assay.
Subproject 1
Simultaneous sampling of particles and vapors for assays
We have setup the sampling system in the animal exposure trailer at the UC Riverside agricultural facility in Riverside, CA. We have completed the first multi-day sampling run. We collected particles on Teflon coated glass fiber filters and gas phase contaminants onto XAD resin at 226 Lpm through a PM2.5 inlet for six days at approximately five hours per day for a total sample volume of approximately 410 m3. Two replications of this multi-day sampling will be conducted. Filters and XAD resin are stored on-site in a refrigerator and periodically transferred to UC Irvine for freezer storage. A portion of the XAD resin will be sent to Professor Kumagai in Japan for analysis by his assay. Thus far neither gas phase or particle phase samples have been analyzed or assayed. The next set of samples will also include simultaneously collected concentrator plus impinger samples. This process will be repeated twice for each of three sampling sites, a freeway site, and urban site, and a receptor (photochemical) site.
The activity on this subproject has led to a collaborative effort between Mike Kleinman, Bill Hinds, and Art Cho for a more comprehensive sampling scheme. We have prepared and submitted a proposal to the 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 will provide 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.
Subproject 2
Concentrator testing, modification, and deployment
Our three channel Sioutas aerosol concentrator is being tested and modified to make it more portable and easier to use. The refrigeration unit has been mounted on a platform truck and the other components on a second platform truck. A drain with a valve has been installed at the bottom of the humidifier tank. The large rotary vane pump is housed in a noise control box on wheels. The second platform truck has a detachable vertical frame section to support the condenser columns, virtual impactors (concentrators), a control panel, and associated tubing. This arrangement allows easy transportation in a van or small truck.
The inlet to the saturator now floats so that it maintains a precisely controlled gap between the airflow entering the saturator and the water surface. The gap can be adjusted without stopping the air flow or shutting down the system. The control panel houses two pressure gauges, two flow control rotameters, and a differential temperature controller. The latter maintains a constant (within +/- 0.2 °C) differential temperature between the incoming air and the exiting humidified air. The control panel also has mounts for an impinger, filter holder, and personal sampling pumps.
We have added a thermometer to continuously measure water temperature in the saturator. This facilitates determining when the whole system has reached thermal equilibrium. It will also aid in debugging conditions where we have incomplete saturation. We have achieved the theoretical concentration factor of 20:1 when using only one of the three condensation columns. However we are only able to achieve approximately a concentration factor of 10:1, under conditions where the theoretical concentration factor is 20:1, when we are using all three columns. Incomplete saturation may affect the lower size limit that can be concentrated.
Subproject 3
Redox Decay Study
This subproject seeks to systematically determine the extent to which redox activity of a sample of CAPs diminishes as a result of storage and/or freeze/thaw cycling. Our observations suggest this may be happening and other investigators have observed such changes. When our concentrator is fully operational and validated, six eight-hour concentrator/impinger samples will be collected above the Center for Health Sciences loading dock, through a window in the analytical laboratory. At the conclusion of sampling a portion will be immediately assayed by the DTT assay and the remainder split with a portion stored in a refrigerator and the rest stored in a freezer (-4 °C). Over the next six weeks DTT assays will be performed on samples with various storage and freeze/thaw histories. All tests will be conducted in triplicate. Once a consistent decay can be demonstrated, we will define and test conditions or treatments that minimize loss of DTT activity.
CARB study: Cardiovascular Health Effects of Fine and Ultrafine Particles during Freeway Travel
In a related project, funded by 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 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.
As outlined above we will take the particle and gas phase samples for subproject 1 at three locations. All current assays will be conducted on the samples and the results compared with the results from the animal studies. The chemical and physical analyses will be used in interpreting the results.
We will continue debugging and using the concentrator until we are confident we can get reliable and reproducible results with it. We expect this phase to be completed in the next few months. Once we reach that stage we will use our concentrator to take samples for the redox decay study and other studies.
We expect to complete the initial 16 subjects for our CARB freeway study by the end of May 2007. We have requested additional funding for additional subjects and if successful we will run three or four additional subjects. This will improve statistical power.
Journal Articles on this Report: 2 Displayed | Download in RIS Format
| Other subproject views: | All 6 publications | 2 publications in selected types | All 2 journal articles |
| Other center views: | All 94 publications | 48 publications in selected types | All 47 journal articles |
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Zhu Y, Eiguren-Fernandez A, Hinds WC, Miguel AH. In-cabin commuter exposure to ultrafine particles on Los Angeles freeways. Environmental Science & Technology 2007;41(7):2138-2145. |
R832413 (2008) R832413C005 (2007) R832413C005 (2008) R827352 (Final) |
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Zhu Y, Fung DC, Kennedy N, Hinds WC, Eiguren-Fernandez A. Measurements of ultrafine particles and other vehicular pollutants inside a mobile exposure system on Los Angeles freeways. Journal of the Air & Waste Management Association 2008;58(3):424-434. |
R832413 (2007) R832413 (2008) R832413C005 (2007) R832413C005 (2008) |
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Progress and Final Reports:
2006 Progress Report
Original Abstract
2008 Progress Report
Main Center Abstract and Reports:
R832413 Southern California Particle Center
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R832413C001 Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of Their Relative Toxicity
R832413C002 Project 2: The Role of Oxidative Stress in PM-induced Adverse Health Effects
R832413C003 The Chemical Properties of PM and their Toxicological Implications
R832413C004 Oxidative Stress Responses to PM Exposure in Elderly Individuals With Coronary Heart Disease
R832413C005 Ultrafine Particles on and Near Freeways