To : "Fitzsimmons, Sean [DNR]" <Sean.Fitzsimmons@dnr.iowa.gov>,

Cc: David Mintz/RTP/USEPA/US@EPA, Lewis Weinstock/RTP/USEPA/US@EPA, Rhonda Thompson/RTP/USEPA/US@EPA, Bcc:
Subject: RE: Comment from Sean Fitzsimmons of Iowa DNR on proposed revisions to 40 CFR 50 Appendix P section (2)(b)

Sean,

Thank you for your reply. As we consider all the comments on the rule, this clarification of your concern will be helpful.

Phil Lorang, Group Leader Air Quality Analysis Group, AQAD, OAQPS, EPA 919-541-5463

"Fitzsimmons, Sean [DNR]" 04/06/2010 12:07:59 PM Phil, Thanks for responding to my voic...

From: "Fitzsimmons, Sean [DNR]" <Sean.Fitzsimmons@dnr.iowa.gov> To: Phil Lorang/RTP/USEPA/US@EPA Cc: Rhonda Thompson/RTP/USEPA/US@EPA, Lewis Weinstock/RTP/USEPA/US@EPA, David Mintz/RTP/USEPA/US@EPA Date: 04/06/2010 12:07 PM Subject: RE: Comment from Sean Fitzsimmons of Iowa DNR on proposed revisions to 40 CFR 50 Appendix P section (2)(b)

Phil,

Thanks for responding to my voice message, and clarifying the intent of the proposed rule.

Our concern, also expressed in Iowa's comments to the docket, was that the proposed rule did not appear (to us) to allow substitution of data from a secondary monitor in cases when the primary monitor did not produce valid data. If this were the correct interpretation of the proposed rule, it is our opinion that this provision would undermine the scientific basis of the attainment decision, as it would not make full use of the data gathered at the monitoring site.

In my opinion, the possible modification to the proposed text that appears below clarifies the intention of the proposed rule and addresses our concern.

Thanks,

Sean Fitzsimmons Ph.D. Lead Worker Ambient Air Monitoring Group
Iowa DNR

-----Original Message----- From: Lorang.Phil@epamail.epa.gov [mailto:Lorang.Phil@epamail.epa.gov] Sent: Wednesday, March 31, 2010 4:37 PMTo: Fitzsimmons, Sean [DNR] Cc: Thompson.Rhonda@epamail.epa.gov ; Weinstock.Lewis@epamail.epa.gov; Mintz.David@epamail.epa.gov Subject: Comment from Sean Fitzsimmons of Iowa DNR on proposed revisions to 40 CFR 50 Appendix P section (2)(b)

Sean,

Thank you for your phone message regarding your concern with the proposed revision to 40 CFR 50 Appendix P section (2)(b). Your phone message indicated that you wish to not be prohibited from submitting data from a second, collocated ozone monitor on an hour-by-hour or day-by-day basis if the primary monitor is not operating or has not produced valid data. You interpreted the proposal as prohibiting you from doing that, which was not necessarily the intention behind the proposal.

Can you let me know whether in your opinion the possible modification to the proposed text that appears below would address this concern? Please be aware that your response to this e-mail will be added to the public docket for the rulemaking.

(b) (i)When two or more ozone monitors are operated at a site, the state may in advance designate one of them as the primary monitor. If the state has not made this designation, the Administrator will make the designation, either in advance or retrospectively. (ii) There are two allowed approaches a state may follow for submitting ozone data to EPA from multiple monitors. (A) The state may submit data from each physical monitor using a distinct value for the Pollutant Occurrence Code (POC) data element in the Air Quality System (or the equivalent data element in any successor to the Air Quality System). However, in this approach, if one monitor has physically replaced another instrument permanently at some point in time, data from the two instruments will be submitted under a single POC. If the state has taken this approach, then design values will be developed using only the data from the primary monitor/POC, if this results in a valid design value. If data from the primary monitor do not allow the development of a valid design value, data solely from the other monitor(s)/POC(s) will be used in turn to develop a valid design value, if this results in a valid design value. If there are three or more monitors/POC(s), the order for such comparison of the other monitors will be determined by the Administrator. The Administrator may combine data from different monitors/POCs in different years for the purpose of developing a valid primary or secondary standard design value, if a valid design value cannot be developed solely with the data from a single monitor/POC. However, the Administrator will not combine data from two or more monitors/POCs in the same year at the same site in an attempt to meet data completeness requirements, except when the state has switched the designation of the primary monitor from one monitor/POC to another during the year. (B) Alternatively, the state may submit data from the primary monitor under a certain value for the POC for hours when valid data have been obtained from the primary monitor, and submit data from a secondary monitor under that same value for the POC for hours when and only when valid data have not been obtained from the primary monitor. Under this approach, the state submits anyredundant data from the secondar y ( o r third ) monitor under a second (or third, etc.) POC value for hours when the primary monitor has produced valid data. If the state has taken this approach, then design values will be developed using only the data from the primary POC, if this results in a valid design value. If the data from the primary POC does not result in a valid design value, no valid design value can be determined.

(I think this gives you the gist of this idea. I realize it isn't perfect regulation writing to be putting data submission requirements into part 50 (they belong in part 58). We may shift some of this into part 58, assuming we settle on this approach.)

Phil Lorang, Group Leader Air Quality Analysis Group, AQAD, OAQPS, EPA 919-541-5463