Grantee Research Project Results

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.

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.

 

* 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.

 

 

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