Paul:

If I said that it would be appropriate to eliminate the PM10 cyclone when the duct diameter is less than 18 i nches, then that was not exactly correct. Both OTM Method 27 a nd the proposed Method 201A state that the method can be use for testing for PM10 only, PM2.5 only or for the combination of PM10 and PM2.5. Here is a link to the proposed method ( http://www.epa.gov/ttn/emc/proposed/m

- 201Ar1.pdf ) and OTM27
( http://www.epa.gov/ttn/emc/prelim/otm27.pdf ).

The methods now only have the combined cyclone area to calcu late the blockage and does not address the use on only the PM10 head or only the PM2.5 head. In the method we state that the combined area of both the P M10 and PM2.5 heads is 20.5 square inches. The method indi cates that the maximum 6% blockage is exceeded when the stack duct is about 18 inches We are measuring a few cyclones to get a more definitive information for the blockage of the various components and will revise th e method accordingly. So, if you are required to test f or only PM2.5, then the method allows for the use of onl y the PM2.5 cyclone and by my estimates the minimum duct diameter will drop to about 12 inches. This is based upon my estimate that the PM2.5 cyclone has a total
blockage of about 12 square inches when fully inserted and about 6 square inches on average.

If there is a requirement to test for PM10, and the d uct is less than 18 inches in diameter, then the combine d PM10 and PM2.5 cyclones are more than 6% of the duct ar ea (the combined cyclones block about 20.5 square inches when fully inserted and average about 12 square i nches). The 12 square inches of average blockage will cause excessive disruption of the flow characteristics in the duct. In that case, to decrease the blockage, one would have to reduce the blockage. One way to do that if there is a requirement to test for PM10 and PM2.5 would be to sample for PM10 and PM2.5 separately. Th e PM10 sampling head would be the most problematic since it is the larger of the two. We are re assessing th e duct sizes that comprise the 6% blockage and the lowest
duct size may not be reduced much but may drop to somethin g around 14 or 15 inches for the PM10 head only.

Rather than you informing the state of the details or using the proceedings (which will not have any detail) h ave the State look on the EMC guidelines documents web page ( http://www.epa.gov/ttn/emc/guidlnd.html ) and specifically look in the documents related to Boiler and Process Heater Testing. While the guidelines documents may not address all of your questions, one will address the situation of sampling in small ducts using only the PM2.5 cyclone head. When I have more definitive measure ments and we post an update for the Boiler and
Process Heater Testing the updated size information wil l be one of the questions that will be addressed.

My presentation did not have the above information in i t, but if you would like my presentation, let me know an d I'll
e-mail you a copy.

_________________________________ Ron Myers U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policy and Programs Division Monitoring Policy Group, D243-05

RTP NC 27711

Tel. 919.541.5407

Fax 919.541.1039 E-mail myers.ron@epa.gov

From: "Paul Taylor" <rtaylor@barr.com>

To: Ron Myers/RTP/USEPA/US@EPA

Date: 06/26/2009 12:57 PM

Subject: AWMA ACE 2009 Panel Discussion 

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...Mr Myers:

Would it be possible to obtain the printed material a ssociated with the panel discussion on "PM2.5 NSR
Implementation Issues" that you participated in on 6/18/ 09?

Of particular interest is your comment that, when testi ng stacks smaller than 18 inches in diameter, it would be appropriate to eliminate the larger PM10 cyclone at t he head of the in-stack sampling train.

We are planning to test for PM2.5 on some stacks with di ameters between 12 and 18 inches using the proposed Method 201A (previously OTM 27). The state agency has app roved the use of the method (modified to exclude the PM10 cyclone) but has expressed an interest in seeing any discussion by USEPA of this variation of the

method.

I've been unable to find any reference to the session (E P-1h) on line (http://www.conferencearchives.com/awma/ ) and, although we are ordering the conference proceedi ngs on CD-ROM, we would like to pass on the informatio n to the state agency as soon as possible.

Thanks in advance for any help you can provide.

Paul Taylor, Ph.D. Air Quality Engineer

Barr Engineering Company

4700 West 77th Street Minneapolis, MN 55435-4803 Tel: 952-832-2671 (direct)

Fax: 952-832-2601 e-mail: ptaylor@barr.com

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