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Correspondence


Document
October 26, 1998

Ms. Lloyd Eagan
Director, Bureau of Air Management
Wisconsin Department of Natural Resources
P.O. Box 7921
101 South Webster Street
Madison, Wisconsin 53707-7921


Dear Ms. Eagan:

Thank you for your submittal of the PM 2.5 Monitoring Network Design for Wisconsin. 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 38 PM 2.5 monitoring sites in Wisconsin by the end of Calendar Year 1999. I am pleased that of these, you intend to deploy 28 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 would also like to commend you for your early PM 2.5 monitoring efforts in the Milwaukee area. If at all possible, please submit these data to the Aerometric Information Retrieval System (AIRS). The experience you have gained, as well as the data you have collected will be invaluable to OAQPS in early characterization of the national fine particulate matter concentrations.

I am pleased that more than one third of your proposed PM 2.5 sites will be collocated with ozone monitors, and that several of your proposed PM 2.5 sites will be collocated with meteorologic monitoring. I am confident that ultimately these data will prove to be useful in establishing control strategies for both PM 2.5 and ozone.



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There are several sites in your network at which you plan to sample on a once in six day schedule. You have indicated that all of these sites are Special Purpose Monitoring Sites (SPM). These sites are located in:
Although the minimum sampling frequency for all State and Local Air Monitoring Stations (SLAMS) is once every third day, an SPM may sample according to any operating schedule. As these sites are predominantly population oriented or background sites, I would prefer that these sites be SLAMS.

As there is no available guidance for granting a waiver for a SLAMS to operate with a decreased sampling frequency, however, I will approve these sites to operate as SPM for 1 calendar year. These sites should be operated following all the guidelines for SLAMS except for sample frequency. By the time the first annual network review is conducted, additional guidance on sampling frequency may be available. This will permit the Region to evaluate sampling frequency for current or planned SLAMS and grant waivers for decreased sampling frequency based on recorded PM 2.5 data.

I have some concerns about several sites in your network which you have identified as middle scale source impact sites. These sites are:
You have indicated that these sites have significant population around them, and that the data from these sites will be used for comparison to both the daily and annual PM 2.5 NAAQS. If these sites are representative of middle-scale impacts which are not unique and likely to be representative of many similar situations, such as might occur along traffic corridors, they would then be representative of a neighborhood of small scale sites. Such sites would be appropriate for comparison to both the 24-hour and the annual NAAQS.



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If, however, these sites are representative of unique middle-scale impacts, such as might occur in a hot spot location, 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
1 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 to both the 24-hour and annual PM 2.5 NAAQS.

I have some concerns about one other site in your network. You have identified a new site, in Brown County, near the Scray Hill Quarry in DePere, as a middle scale source impact site, with only a few residences in the immediate area of the source. You have indicated that data from this site will be used for comparison to both the 24-hour and annual PM 2.5 NAAQS. 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. For this reason, the data collected at this site may be more appropriately compared only to the 24-hour NAAQS. I will approve this site to operate as a middle scale site for 1 calendar year. During Fiscal Year 1999, this site 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 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 to both the 24-hour and annual NAAQS.

You have identified all of the sites at which you will be sampling on a once in six day schedule and all of the middle scale sites except the new site in Milwaukee near the Valley Power Plant, the new site in Rock County and the new site in Douglas County as SPM. 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 any SPM site, the site may be upgraded to a State and Local Air Monitoring Station (SLAMS) during the annual network review.


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Regardless of site status in 1999, all population-oriented Federal Reference Monitor sites that sample at least once in six days and produce 3 years of data with 75 percent data capture are eligible for comparison to the 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 National Ambient Air Quality Standard 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 Fiscal Year 1999 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 Wisconsin, and ultimately provide the basis for the development of control strategies. The first complete 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 Wisconsin. 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,

/s/

Stephen Rothblatt, Acting Director
Air and Radiation Division



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