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EPA Home > Region 5 > Air > Correspondence


October 9, 1998

Robert Hodanbosi
Chief, Division of Air Pollution Control
Ohio Environmental Protection Agency
1600 Watermark Drive
P.O. Box 1049
Columbus, Ohio 43216-1049

Dear Mr. Hodanbosi:

Thank you for your timely submittal of the PM 2.5 Monitoring Network Design for Ohio. As you know, the deployment of a PM 2.5 monitoring network is a critical component in the implementation of the PM 2.5 National Ambient Air Quality Standard (NAAQS). The ambient data from this network will drive an array of regulatory decisions, ranging from designating areas as attainment or nonattainment, to developing cost-effective control programs, and tracking the progress of such programs.

Thank you for your commitment to establish 51 PM 2.5 monitoring sites in Ohio by the end of Calendar Year 1999. I am pleased that of these, you intend to deploy 38 sites by the end of Calendar Year 1998. This is in accordance with the timetable for monitor deployment set up by the Office of Air Quality Planning and Standards (OAQPS).

I am pleased that several of your proposed PM 2.5 sites will be collocated with ozone monitors. Only one of your proposed PM 2.5 sites, however, will be collocated with meteorologic monitoring equipment(AIRS # 39-095-0081). I suggest that you consider enhancing your PM 2.5 network by collecting wind direction data at several sites. I am confident that ultimately these data will prove to be useful in and necessary for establishing control strategies for both PM 2.5 and ozone.

Your PM 2.5 monitoring network will be among the largest networks in the country. Deploying a network of this size in the time frame established by OAQPS is, in and of itself, a daunting task. This task may be further confounded, however, by the number of State and Local Agencies that are participating in the PM 2.5 monitoring program. Installation and operation of the sites will be performed by monitoring personnel of nine local air agencies and five district offices, none of whom have significant


experience in PM 2.5 monitoring. In order to assure credible and comparable data for all of Ohio, I urge you to develop unified
standard operating procedures and training protocols for all field personnel. In addition to streamlining both administrative planning and preparations, this approach will be more amenable to the analysis of all PM 2.5 filters for Ohio in two centralized weighing laboratories within the State. I understand that a PM 2.5 filter weighing facility at the Hamilton County Department of Environmental Services Laboratory in Cincinnati will be operational by December 1998 and will initially serve all of Ohio, and that plans are being formulated for establishing a second such facility in Columbus. This laboratory will not begin construction, however, until after the Columbus Air Laboratory is relocated some time this fall. I am confident that with unified standard operating, chain of custody and quality control procedures implemented for all participating agencies that the Hamilton County Laboratory will be able to provide credible and comparable data for all of Ohio in a timely fashion. I am also pleased that you have arranged for backup filter weighing operation at Ohio University at Athens, OH.

You have identified a new site located in the Price Hill area of Cincinnati as a Special Purpose Monitor (SPM). This site will be a population-oriented neighborhood scale site. While the United States Environmental Protection Agency (USEPA) has provided States with the flexibility to exempt SPM data from regulatory use for the first two complete calendar years of operation of the SPM, data from any monitoring site that satisfies all applicable 40 CFR Part 58 requirements and continues to collect data beyond this time frame would then be generally eligible for comparisons to the NAAQS.

Although SPM data will be exempt from regulatory use during the 2-year moratorium, I would like to emphasize that SPM data will be considered during the annual network review. Depending on PM 2.5 concentrations measured at this site, the site may be upgraded to a State and Local Air Monitoring Station (SLAMS) during the annual network review. Regardless of site status in 1999, all population-oriented Federal Reference Monitor sites that sample at least once in six days and produce three years of data with 75% data capture are eligible for comparison to the NAAQS.

I will approve the Price Hill site to operate as SPM for one calendar year. This site should be operated following all the guidelines for SLAMS. At the time the first annual network review is conducted, the Region will evaluate whether or not the site should be upgraded to SLAMS.

I have some concerns about three sites in your network which you have identified as middle scale source impact sites. These sites are all in the Cleveland Metropolitan Statistical Area and are the Research Oil site (AIRS # 39-035-0013), the Harvard Yard site (AIRS # 39-035-0065),and the G.T. Craig site (AIRS # 39-035-0060). You have indicated that although these sites still have


significant population around them, data from these sites will be used for comparison only to the daily PM 2.5 NAAQS.
While the PM 2.5 NAAQS allows for population-oriented hot spot impact sites to be eligible for comparison only to the 24-hour NAAQS, this standard is intended to supplement the annual PM 2.5 standard by providing additional protection at this small spatial scale. A violation of the annual PM 2.5 NAAQS at localized hot spot and other areas of small spatial scale may not be indicative of a greater area-wide problem which would initiate the need for an area-wide implementation strategy.

I will approve these sites to operate as middle scale sites for one calendar year. During Fiscal Year 1999, these sites will be evaluated by Regional staff in order to verify the spatial scales. Your assistance in obtaining PM 2.5 emissions data and preliminary modeling results as well as population density information for these sites will be greatly appreciated. These supporting data will permit the Region to evaluate the eligibility of the PM 2.5 data from these sites for comparison only to the 24-hour NAAQS.

As there are little historical PM 2.5 monitoring data available, this design represents a very good first attempt at what will be a dynamic process. As data are collected and as newer monitoring technologies become available, it may be useful or necessary to redefine the network so that it continues to provide information essential to describe ambient PM 2.5 concentrations as well as to assist in developing control strategies for PM 2.5. In addition, budget constraints and changes in implementation goals arising from the Agency’s response to the National Academy of Science’s review of the PM 2.5 NAAQS monitoring program may lead to reevaluation of monitoring strategies and ultimately to changes in network design.

I am pleased to conditionally approve your PM 2.5 monitoring network pending Regional site evaluations and approval of the FY 99 budget. I am looking forward to receiving your annual revised PM 2.5 monitoring network description by July 1, 1999, as required by 40 CFR 58.26. In addition, my staff will continue to work closely with your staff to develop a PM 2.5 speciation network that will assist in characterizing the fine particle aerosol of Ohio, and ultimately provide the basis for the development of control strategies. The first draft of the speciation plan is due to the Regional Office by March 1, 1999, and the final draft should be incorporated into the annual revised PM 2.5 monitoring network.

I appreciate your continued high level of commitment to the coordination of the PM 2.5 monitoring program in Ohio. I consider the implementation of the PM 2.5 network, as I’m sure you do, to be a critical priority.


If you have any questions or comments, please feel free to contact me or have your staff contact Maryann Suero, of my staff, at (312) 886-9077.

Sincerely yours,


Stephen Rothblatt, Acting Director
Air and Radiation Division

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This Information Last Modified On: 09/18/2008 03:58 PM