Grantee Research Project Results

2008 Progress Report: PM Characterization and Exposure Assessment (Project 2)

EPA Grant Number: R832417C002
Subproject: this is subproject number 002 , established and managed by the Center Director under grant R832417
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for the Study of Childhood Asthma in the Urban Environment
Center Director: Hansel, Nadia
Title: PM Characterization and Exposure Assessment (Project 2)
Investigators: Geyh, Alison , Breysse, Patrick N.
Current Investigators: Geyh, Alison , Ondov, John M. , Breysse, Patrick N. , Rule, Ana , Han, Inkyu , Ramos-Bonilla, Juan , Datta, Saugatta , Chillrud, Steven
Institution: The Johns Hopkins University
Current Institution: The Johns Hopkins University , Kansas State University , Lamont Doherty Earth Observatory of Columbia University , University of Maryland - College Park
EPA Project Officer: Chung, Serena
Project Period: October 1, 2005 through September 30, 2010
Project Period Covered by this Report: October 1, 2007 through September 30,2008
RFA: Particulate Matter Research Centers (2004) RFA Text | Recipients Lists
Research Category: Human Health , Air

Objective:

The focus of Project 2 is the measurement of specific chemical components and physical characteristics of PM from different areas of the country in support of the Center focus, which is assessing characteristics of PM that determine toxicity. The goals of Project 2 are to collect bulk PM samples for use in biological assays and for detailed characterization including mass, inorganic ions, elemental carbon and organic compounds, specifically polycyclic aromatic hydrocarbons , elemental metals and their oxides, and sulfur isotope ratios. We will also collect information on the distribution of particle size. The objectives of Project 2 include: 1) the development of methods for collecting bulk ambient PM, and a system for characterizing the chemical and physical properties of ambient PM; 2) the identification of specific regional differences in PM characteristics that may contribute to differential biological responses demonstrated by in vitro and in vivo bioassay systems; 3) the assessment of the relationship between human exposure to PM_2.5 and biological response during high PM_2.5 exposure period and low PM_2.5 exposure periods. The goals and objectives have remained unchanged over this time period.

Approach:

We will collect bulk PM samples for bioassays and bulk and integrated samples for detailed characterization to include mass, inorganic ions, elemental carbon and organic compounds, specifically polycyclic aromatic hydrocarbons , elemental metals and their oxides, and sulfur isotope ratios. We will also evaluate PM characteristics in relation to particle size. We will use this matrix of information to characterize differences in PM composition and biological response by location. The objectives of Project 2 include: 1) developing new methods for collecting bulk PM for use in biological assays; 2) developing a portable system the characterization of chemical and physical properties of ambient PM; 3) identifying specific regional differences in PM characteristics that may contribute to differential biological responses in vitro and in vivo bioassay systems; and 4) assessing a relationship between human exposure to PM_2.5 and biological response during a high PM_2.5 exposure period and a low PM_2.5 exposure periods. By successfully completing this project, we anticpate providing a better understanding of how differences in physiochemical composition impact PM health effects.

Progress Summary:

I. Introduction

The rationale for this project is based on the conclusion that “[t]he diversity of PM characteristics and the array of possible health effects define a potentially large and complex matrix for investigation; in fact different features of particles might be relevant to different health outcomes” (NRC 2004) As a result we proposed to assess the specific chemical components and physical characteristics of particulate matter (PM) from samples taken in different areas of the country. These locations have been selected based on a gradient of estimated risks to health. Specifically, we proposed to develop a new method for collecting bulk PM for use in biological assays; to develop a portable system for the characterization of chemical and physical properties of ambient PM; and to identify specific regional differences in PM characteristics that may contribute to differential biological responses in in vitro and in vivo bioassay systems. This report will describe activities carried out by Project 2 (PI.Patrick Breysse) and the PM Characterization, Sampling and Analysis Core (PI Alison Geyh) since funding, giving emphasis to progress during the past year. The overall goal of developing a PM monitoring and collection approach and then deploying it at the sites identified through the Project 1 analyses has been accomplished.

II. Protocol development and testing of the Hopkins Sequential Cyclone Sampler (HSCS)

As reported previously, the cyclone system has been re-designed over the first two years to include a commercially available PM-10 inlet instead of a cyclone. The second stage cyclone was retained, and designed to collect inhalable coarse particles (<10 μm and >2.5 μm). When tested with a challenge aerosol, a D₅₀ cut size of 2.33 mm was obtained at a flow rate of 1000 L/min. The third stage is a commercially available cyclone with a D₅₀ cut-size of 0.3 mm tested at the same flow rate for collection of PM <2.5 μm and >0.3 μm.

During the past year, Project 2 has been working with a commercial manufacturing company, Hi-Q Environmental Products Company, to produce the systems that have now been deployed in the field. There have been significant delays in the manufacturing process of the first two complete systems, which resulted in delays in the testing the systems in Baltimore and their ultimate deployment to the field.

Protocols and procedures for leak testing the system and flow calibration were developed. After deployment in Seattle and Sacramento, temperature and noise reduction strategies were required before sampling in Phoenix due to the unique characteristics of the Phoenix site, which was located in a residential area – less than 15 feet away from neighboring houses – and where temperatures can reach 120 ºF during summer. After completing the field effort in Sacramento both HSCS systems were shipped to Baltimore to perform these tests. To achieve noise reduction, the inside of the HSCS cabinet was lined with a sound dampening material; sound pressure level testing showed a significant reduction when standing 10 cm in front of the HSCS with the door closed (Figure 1)

To reduce cabinet temperature, two strategies were tested: an insulating material was installed inside of the cabinet; and a reflective material was wrapped around the outside of the cabinet. Neither resulted in a significant temperature decrease inside the cabinet, and the insulating material was suspected of retaining heat generated by the pump. Therefore, none of the temperature control strategies was implemented. Continuous monitoring inside the cabinets, both in Baltimore and Phoenix, showed temperatures of 130 F or lower, well below the 200 F maximum recommended by the manufacturer.

While noise and temperature reduction were being tested in Baltimore, the system ran for 3 weeks in order to collect Baltimore bulk PM.

A manuscript describing the characterization and testing of the sequential cyclone system has been prepared, as well as a Report of Invention (ROI) entitled "Hopkins Sequential Cyclone System for the Collection of Bulk Particulate Matter" to Johns Hopkins Technology Transfer (JHTT). A provisional application for a patent was filed on March 6, 2008.

III. PM Monitoring

PM Monitoring and locations: Monitoring locations identified by Project 1 are found in Table 1.

We plan to monitor the nine sampling sites. Given the timeline and the budgeted resources. we anticipate that we will be able to complete monitoring for at least 7 out of the nine sampling locations with Allegheny PA included. Beginning April, 2007 the Project 2 team began the process of contacting state and county environmental agencies to discuss potential monitoring locations and to beginning scheduling monitoring dates. To date, agencies in the following five counties/states have been contacted: King County WA, Sacramento CA. Maricopa AZ, Hennepin MN, and Harris TX. Contact was facilitated through a letter sent by EPA to the state and local air quality agencies introducing the project and stating EPA support. To date monitoring has been conducted in three counties with a fourth scheduled for September 2009.

King County, WA: Monitoring in King County, WA was carried out from October 25 to December 1, 2007. The location within King County was an air quality monitoring site maintained by the Department of Ecology Air Quality Program (John Williamson and Doug Knowlton). It is located on Beacon Hill in Seattle, WA, a centrally located hilltop surrounded by urban development that was identified by the local agencies as representative of urban PM in the county. In addition, the monitoring station at this location was large enough to house and had adequate power to run the equipment listed in Table 2.

Sacramento County, CA: Monitoring in Sacramento County was carried out January 12 – March 13, 2008. Sacramento Metropolitan Air Quality Management District (SMAQMD -John Ching and Ken Lashbrook) identified one site in the City of Folsom that was adequately powered and had enough space to house Project 2 equipment. The City of Folsom is approximately 20 miles east of Sacramento and is impacted by air quality from the City of Sacramento. The monitoring site was located behind City Hall away from busy roads and freeways. SMAQMD required proof against legal liability in the form of a Hold Harmless agreement before monitoring could be conducted. Negotiation between the University and SMAQMD required several months and were finalized January 2008.

Maricopa County, AZ: Monitoring in Maricopa County was carried out June 1 – July 20, 2008. Maricopa County Air Quality Department (MCAQD –Ben Davis) and the Arizona Department of Environmental Quality (AZDEQ – Raymond Redman) were both responsible for helping us to identify an appropriate monitoring site. On December 21, 2008 Drs. Ana Rule and Alison Geyh traveled to Phoenix to explore potential monitoring locations. The site selected was located in a residential neighborhood not directly impacted by busy road, freeways or other specific sources. The site was a residential housing lot, which contained one small trailer housing MCAQD equipment. The MCAQD provided a second trailer with power specifically to house Project 2 equipment.

Hennepin County, MN: Contacts with the MN Pollution Control Agency (MNPCA) (Rick Strassman) began April 2008. At the end of May 2008, Dr. Patrick Breysse traveled to Minneapolis to explore potential monitoring locations. Dr. Breysse could not identify any possible monitoring locations within Hennepin County, as all sites in this county are roof top and support only one or two instruments. Two options were offered. The first option was a trailer that could be provided by MNPCA in a park in Hennepin County. Project 2 would be responsible for providing power. The cost to provide power was estimated at between $10,000 and $15,000, and to take several weeks or months to establish. The second option was a monitoring site located at a small airport catering to private aircraft in a county adjacent to Hennepin, Anoka County. The airport has an average of 2-3 small aircraft per day. The site is 4 miles north of the Hennepin border, has adequate power and space to house Project 2 equipment and is available immediately. An analysis of the correlation between PM_2.5 concentrations measured at all locations within and surrounding Hennepin County showed the correlation to be 0.92. After discussions with Project 1 and the Center PI, Project 2 has accepted the offer of the site at the Anoka airport. We anticipate monitoring will begin at this location the middle of September 2008.

Harris County TX: Preliminary discussions have begun with the Texas Commission of Environmental Quality (Kristin Bourdon). We have been offered space at the Deer Park monitoring station which is the STN site in Houston and anticipate the beginning of the field effort for February 2009.

Table 1 summarizes the status of the field monitoring effort.

Table 1. Monitoring Schedule
Order	County	Start Date	End Date
1	King, WA*	October 25, 2007	December 1, 2007
2	Sacramento CA*	January 12, 2008*	March 13, 2008
3	Maricopa AZ*	June 1, 2008	July 20, 2008
4	Hennepin MN**	September 15, 2008	October 30, 2008
5	Harris TX	February 1, 2008	April 30, 2008
6	Allegheny PA	June 1, 2009	July 15, 2009
7	Jefferson KY	TBD	TBD
8	Kings NY	TBD	TBD
9	Pinellas FL	TBD	TBD

* Completed

**Scheduled

TBD – to be decided

Establishing a site: At each location, the equipment listed in Table 2 is deployed. This set of instruments was prepared and tested for field use during the first two years and the feasibility of using a van for deployment was assessed, leading to the present approach of moving the equipment from site to site. To establish the site, a team of three people spend between 5 – 7 10-hour days setting up equipment, building inlets and calibrating instruments. Once established, the site is managed by one member of Project 2 who visits the site each day to conduct a daily site check or a weekly data download. At the end of the monitoring period, two members of Project 2 dismantle the site and ship the equipmentto the next location.

Table 2. Summary of PM Sampling
Continuous PM Monitoring Instruments			Integrated PM Sampling Instruments
Type	Analyte (units)	Sampling Frequency	Type	Analyte	Collection Frequency	No. samples per sampling period
TSI Aerosol Particle Sizer	<0.5 - 20 um (particle counts/cm³)	every 15 min	Hopkins Sequential Cyclone System	coarse PM	integrated over entire site monitoring period	1
TSI Aerosol Particle Sizer	<0.5 - 20 um (particle counts/cm³)	every 15 min	Hopkins Sequential Cyclone System	fine PM	integrated over entire site monitoring period	1
TSI Scanning Mobility Particle Analyzer	17.9 - 881.7 nm (particle counts/cm³)	every 15 min	Harvard Impactor (Telfon filters)	PM₁₀	7 days	2
TSI Scanning Mobility Particle Analyzer	17.9 - 881.7 nm (particle counts/cm³)	every 15 min	Harvard Impactor (Telfon filters)	PM_2.5	7 days	2
Echochem PAS2000	un-differentiated particle-bound PAHs (ng/m³)	every 5 min	PMASS (quartz fiber filters)	PM2.5	7 days	4
Magee Scientific Aethalometer	black carbon (ng/m³)	every 5 min
Thermo Environmental SPA 5020	particulate sulfate (ug/m³)	every 15 min

Yields for bulk PM collected from deployment of the HSCS are reported in Table 3.

Table 3. Bulk PM mass results
Site	Dates	Coarse PM (mg)	Fine (mg)
Seattle	Nov 2007	89	705
Sacramento	Feb / Mar 2008	111	397
Baltimore	Apr / May 2008	325	1551
Phoenix	Jun / Jul 2008	1181	1510

IV. Data Management

Data sets reporting concentration data from the continuous instruments listed in Table 2 are currently being processed by two member of Project 2. Data management activities are summarized below.

Data storage: Downloaded data are stored on a network drive at JHU-SPH server. Once the data are stored in the network drive, the files are not altered. The files are also backup onto another server, and to a DVD.

Data management procedure and documentation: Data cleaning and processing have begun on data sets from King and Sacramento Counties. Weekly raw data files for each instrument are manually reviewed for completeness. The weekly raw data files are imported into EXCEL. Any identified problems are highlighted and logged. The weekly files for each instrument are collapsed into a composite data set for the entire monitoring period. Flagging codes are being developed which will reflect common problems across all instruments and specific problems unique to each instrument. An additional level of quality assurance is provided by culling and validating the raw data based on daily operating status as recorded in the monitoring site log book and daily checklists. Raw data in the EXCEL files are uploaded into SAS for further cleaning. In this stage, observations predating the official start-up time for the specific monitoring site are removed from database. Repetitive observations, such as two or more identical observations for each time point, are flagged. Additionally, negative observations, possible outliers (> 99^th percentiles), and missing observations are flagged. These flags are summarized into an EXCEL file. All data management procedures are documented in a separate WORD file.

V. PM Characterization

Table 3 presents the analysis plan for the integrated PM samples collected at each location. Sample analysis has begun. All samples have been evaluated for mass and a mass concentration determined from samples collected by the Harvard Impactor and PMASS. Protocol development has begun for the analysis of soluble and insoluble metals from the same sample in the Geyh laboratory at JHSPH. Bulk coarse and fine PM from King County, Sacramento County and Baltimore, as well as PM_2.5 samples collected on quartz filters from Sacramento, have been delivered to the laboratory of Dr. Steven Chillrud for Pt-group elements and PAH characterization (see below).

Table 3. Sample Analysis Plan

Type	Mass	Inorganic Ions	Soluble Metals	Insoluble Metals	Elemental carbon	Pt-Group Elements	PAHs	Oxidation States
HI - PM10	P_#	P_#	P_#	P_#		P
HI - PM2.5	P_#	P_#	P_#	P_#		P
PMASS - PM2.5					P		P
PM Bulk Coarse	P	P	P	P	P	P	P	P
PM Bulk Fine	P	P	P	P	P	P	P	P

Pt - Group Element and PAH Analysis (Work conducted at LDEO-CU: Steven Chillrud, James Ross and Beizhan Yan)

In the past year, we have purchased an isotopically enriched platinum spike from Oak Ridge National Laboratory, prepared it, and verified that it agrees with our other Pt standard (High Purity Standards, Charleston SC). We have used high resolution (M/delta M ~ 4000) to determine that the optimal isotopes for Rh and Pd (respectively 103 and 105) were not interfered with by polyatomic species. And we have carried out multiple digests of 5 mg of reference material BCR-723 (tunnel dust), using the microwave/aqua regia/cation exchange method developed previously, to verify that we can measure Rh and Pd in this low sample mass. In the past few months we have encountered a recurring problem with the Pt blank. At present we are trouble-shooting our procedure in order to identify the source of the problem. Once this problem is resolved, we will be ready to determine PGE's in bulk and filter samples collected at each location.

Dr. Beizhan Yan, an organic geochemist specializing in the analysis of trace organic compounds including PAHs and their compound-specific stable isotope ratios, has joined Dr. Chillrud’s group starting September 2007. Dr. Yan is responsible for the analysis and interpretation of results for PAHs within the bulk and filter based PM samples. Dr. Yan is also interested in developing new methods for resolving specific compounds within the “unresolved complex mixture” of hydrocarbons related to fuel combustion. Dr. Yan has begun analysis for PAHs of the bulk and PM_2.5 quartz filter samples.

Oxidation States and Coordination Chemistry (Work conducted at the Brookhaven National Lab (BNL): Saugata Datta (GCSU) and Steve Chillrud (LDEO))

During this last year, the BNL has awarded Project 2 investigators three additional time slots on the National Synchrotron Light Source: November 2007 (5 days Beamline X11A), March 2008 (4 days; Beamline X23A), July 2008 (5 days; Beamline X23B). The purpose of the November visit was to establish the best media for sample support. Previous experiments had suggested the quartz filters would be ideal. In response PM_2.5 samples collected on quartz filters were included in the sample collection field protocol. Filters loaded with a PM mass estimated to be reflective of the mass loading for actual samples were evaluated. Filters were analyzed singly and in stacks to increase the total mass presented to the beam. The mass on a single filter was found to be too low for detection of the elements of interest (Fe, V, Mn, Cr, Ni). Significant interference was found from the quartz itself when the filters were stacked. A new sample support method was developed. The new method is a polyethylene frame designed to the dimensions of the beam. The new holder was developed to minimize the mass need for analysis of the bulk PM. The new sample holder was evaluated during the March 2008 visit using SRM 1648 and BCR 723. In addition, bulk PM from Baltimore as analyzed for Fe and Ni oxidation states. Baltimore samples were also analyzed to evaluate the impact of different in storage conditions on oxidations states (Air/RT vs. Argon/ 4 C). During the July 2008 visit coarse and fine bulk PM from King, Sacramento, and Maricopa Counties and Baltimore were evaluated for Ni, V, Mn, Cr, and Fe.

Delivery of bulk PM to Project 3. Bulk fine PM from King county, Sacramento county and Baltimore has been delivered to Project 3.

Expected Results:

We anticipate that the results of this project will inform PM air quality regulations, suggesting new PM exposure metrics that can be used to modify existing air monitoring networks. Project investigators are well qualified to conduct this research and this project leverages support from a wide range of funded projects, including data from existing air quality databases and resources from a previously EPA funded PM Supersite.

Future Activities:

Journal Articles:

No journal articles submitted with this report: View all 13 publications for this subproject

Supplemental Keywords:

air pollution, PM10, mobile sources, Bulk particle collection, cyclone, exhaled breath condensate, markers of inflammation, RFA, Health, PHYSICAL ASPECTS, Scientific Discipline, Air, particulate matter, Health Risk Assessment, Epidemiology, Risk Assessments, Physical Processes, atmospheric particulate matter, acute cardiovascular effects, long term exposure, atmospheric particles, airway disease, exposure, ambient particle health effects, human exposure, ultrafine particulate matter, atmospheric aerosol particles, aersol particles, particulate matter components, cardiovascular disease

Relevant Websites:

www.jhsph.edu/particulate_matter

Progress and Final Reports:

Original Abstract

Main Center Abstract and Reports:

R832417 Center for the Study of Childhood Asthma in the Urban Environment

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R832417C001 Estimation of the Risks to Human Health of PM and PM Components
R832417C002 PM Characterization and Exposure Assessment (Project 2)
R832417C003 Biological Assessment of the Toxicity of PM and PM Components

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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.