Kris: 

My responses to your questions follow your questions below. I'll put them is italic so you can tell when the question 

ends and the response begins. 

 First, your questions from 6/18 (which I apologize for not responding sooner). 

1. In Section 1.7 of OTM-27 there is a statement regarding the mass of PM that should be 

collected: “...you must extend the sampling time so that you collect the minimum mass necessary for 

weighing on each portion of this sampling train.” This statement is referring to the use of OTM-27 

as a replacement for M5 or M17, however it seems to imply that there is a requirement for a 

minimum mass to be collected for OTM-27. I don’t see any place where the minimum mass is 

specified. Are there any guidelines for what the minimum mass should be? In the ERT report 

that we will need to fill out after testing there is a request to report in parentheses the detection 

limit if the result is under the DL. This is something that is normally associated with methods 

such as M29 or M23, but what about OTM-27? For example, in Oregon the DEQ requires the 

test company report the emissions based on a default of 20 mg if less than 20 mg of sample 

was collected for the entire train, front half plus back half. For OTM-27 we will be using a 5 

place balance and weighing to a constant weight of 0.05mg. In the case of sources that have 

control devices the mass of PM2.5 collected may be very low, even in a 2-4 hour test. If a 

specified mass isn’t required then I would expect that there will be many PM2.5 results that will 

be very low, and potentially meaningless. Another consideration is that the since there is 

normally a bidding process, if Test Company A bids for 2 hour runs and Test Company B bids 

for 8 hour runs, Company A will get the project, but Company B would have provided much 

more representative results. In the absence of a mass requirement, I would be concerned that 

a lot of the data reported may not be representative. 

For the purposes of the ICR, you are only required to perform the testing for the indicated time 

period. If you obtain less than detection limit results with these times, it will become our issue to 

resolve. While Oregon DEQ wold like to have 20 mg of PM collected, this may not be feasible 

in all situations and with good sampling and analytical procedures may not be needed to get 

reliable data. Laboratory data EPA developed many years ago indicates that with good 

techniques, the standard deviation of blank Method 5/17 samples is on the order of 0.4 mg. 

 The precision and accuracy of the balance is probably not the limiting factor in this variation of 

measurements. If one were to assume that this level of precision is achieved with non blank 

samples, the detection limit for PM on filters (say with 201A) is about 1.5 mg and that one could 

be within 10% of actual mass when you collect 4 to 5 mg of sample. 

 

2. In Section 1.6 of OTM-27 there is a statement regarding the maximum stack temperature: 

 “This method may not be suitable for sources with stack gas temperatures exceeding 260°C (500°F).” 

For very clean sources that have good control devices it doesn’t seem that there would be any 

problem just using M5/OTM-28 and assuming that all particulate matter collected is less than 

PM2.5. However, for sources such as small refuse burning incinerators with only secondary 

combustion as a control device, using M5/OTM-28 would bias the PM2.5 results high. This 

might be fine for a “worse-case” compliance determination, but would not be ideal for 

establishing an emission standard. The outlet temperatures may be in the range of 1000-1800 

oF.

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The issues of wet stack conditions and hot stack conditions are issues that we now address 

with the statement to use EPA Method 5 and consider all the material as PM10 or PM2.5. For 

the purpose of the ICR, if you encounter either of these conditions follow the directions and 

guidance in Guideline Documents 51, 51A, 51B and 51C (and any subsequent GD51 

documents). These are located at http://www.epa.gov/ttn/emc/guidlnd.html . 

_________________________________

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 

Ron – I have some additional questions regarding the test methods associated with the Section 

114 letters. I still would appreciate answers to the questions that were in the email below 

(6/18). 

 

1. If only the PM2.5 head is used (without the PM10 head), does this affect the equations 

shown in the method? OTM 27 states that sampling can be performed using only the PM2.5

head, but I don’t see where it mentions if the equations need to be modified. I am talking 

specifically about equations that directly affect the sampling rate and PM2.5 cut diameter. I am 

assuming that the equations don’t need modification, but want to verify that this is correct. We 

are starting our 1st test program on Monday and the test port will not accommodate a 

PM10/PM2.5 head configuration. 

In OTM 27 (and the proposed Method 201A), the equations are the same for all the 

configurations of the particle sizing cyclones. Of course if you do not use the PM10 cyclones 

Equation 32 (Actual Particle Cut Diameter for Cyclone I ) is a moot point since you should not 

care whether you would have achieved the correct PM10 cut diameter if you would have used 

that cyclone. 

 

2. For OTM 28: Is there any reason that ice water can’t be used in the 1st section of the 

sample box where the knockout impinger needs to be kept at less than 85oF? Section 8.4.2 

has the <85oF requirement, but I don’t see why it would hurt to use ice water to cool the 

From: "Kris Hansen" <khansen@hoeflernet.com>

To: Ron Myers/RTP/USEPA/US@EPA, Peter Westlin/RTP/USEPA/US@EPA

Cc: "Angela Hansen" <ahansen@hoeflernet.com>, "Steve Fryberger" <sfryberger@hoeflernet.com>, "Steve Mackey" 

<smackey@hoeflernet.com>

Date: 07/09/2009 04:51 PM

Subject: Section 114 Electronic Reporting

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impinger. 

The purpose of the divided box with somewhat different temperature requirements is to 

minimize the potential to form sulfate artifact in the first two impingers and to maximize the 

collecteion of water vapor for calculating the moisture content of the sampled gas. 

If you do not mind the increased potential to form sulfate artifact in the first two impingers, you 

can put the first two impingers in the same box or part of the box for the impingers that are 

intended to collect water vapor passing through the first two impingers and the back up filter. 

 The temperature at the exit of the back up filter will be much lower than 85F and satisfy the 

requirements of the method. For the purposes of the ICR we would encourage stack testers to 

maintain the exit temperatures as near 85F as they can without exceeding that temperature and 

consistent with minimizing sulfate bias. 

In the stakeholder process to develop the method, there were two considerations for selecting 

the temperature level. The first consideration was the desire to minimize sulfate artifact 

formation. Environment Canada provided information that the solubility of SO2 in water was 

greater at lower temperatures. Decreasing the solubility of SO2 reduces the quantity of SO2 

that can oxidize to SO3 where it can not be removed with the nitrogen purge. The second 

consideration was the desire to establish a collection temperature that is consistent and is 

representative of ambient temperature. In the use of another sampling method that is based 

upon the dilution of the sampled gas with filtered and conditioned ambient air during a hot 

humid day, we were only able to reduce the filtration temperature to 85F. This is a temperature 

that is reasonable as an ambient temperature level and is near the standard temperature and 

within the normal 25F range for maintaining temperature for stack sampling. Also, this 

somewhat elevated temperature addresses concerns that the promulgated Method 202 

condenses organic and inorganic vapors greater than would be consistent with ambient 

temperatures of about 35 to 40F. The dilution in ambient air would further reduce the solid 

concentrations of these compounds. The combination of the lower temperature and the lack of 

dilution would tend to provide a high bias to the particulate matter collected. This information is 

documented in the running commentary on the method development that is in the docket and 

on the FAQ page for Method 202 ( http://www.epa.gov/ttn/emc/methods/method202.html#af ). 

 

3. For ASTM D6784-02 (OHM): Do you have a protocol to handle averaging runs where one 

or two of the runs are under the DL, but at least one run is above the DL? Without guidelines I 

would assume that those runs under the DL would be averaged as zero. Or should we use 1⁄2 

DL or the DL in the average of the runs? 

When you encounter situations where one or more results are below the detection level of the 

analytical (or instrument) you should report the fact that that (those) run(s) were below the 

detection limit and what was that detection limit. I would also be helpful (since some 

laboratories differ widely on their method to determine their limit of detection) to have a brief 

indication on the criteria used to determine the detection limit. 

 

4. The electronic Emission Test Template states: “Facilities on the Boilers and Process 

Heaters test plan that were selected to test for HCl that do not use Method 26A to test for HCl 

or HF”. This is a little confusing, because what if you are using M26A – wouldn’t you want to 

use the same form? 

Perhaps that statement is a little confusing in that it does not address the use of Method 26. 

 Both method 26 and 26A are supported in the ERT. That statement is in the ICR because we 

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had already received a comment/request to use EPA Method 320 or the ASTM method for HCl. 

 Since Method 320 is not supported, HCl and HF would not have to be reported with the ERT. 

 

I have cc’d Peter Westlin on this email. Is there anyone else that might be able to help me with 

these questions? We are starting the Section 114 testing this Monday (7/13) and will be 

performing this test program for a variety of clients almost weekly for the balance of the 

summer. I really appreciate your assistance. 

 

Thanks, 

Kris 

Kris Hansen, QEP 

Sr. Consultant 

AmTest Air Quality, 

a Division of Hoefler Consulting Group 

PO Box 525 

Preston, WA 98050 

425-222-7746 

425-222-7849 (fax) 

khansen@hoeflernet.com 

www.amtestairquality.com 

 

From: Kris Hansen 

Sent: Thursday, June 18, 2009 3:14 PM

To: 'Myers.Ron@epamail.epa.gov'

Cc: 'Steve Fryberger'; Steve Mackey; Angela Hansen

Subject: Section 114 Electronic Reporting & OTM 27 

 

Ron – I have a couple of questions regarding OTM-27 and the Section 114 letters: 

 

1. In Section 1.7 of OTM-27 there is a statement regarding the mass of PM that should be 

collected: “...you must extend the sampling time so that you collect the minimum mass necessary for 

weighing on each portion of this sampling train.” This statement is referring to the use of OTM-27 

as a replacement for M5 or M17, however it seems to imply that there is a requirement for a 

minimum mass to be collected for OTM-27. I don’t see any place where the minimum mass is 

specified. Are there any guidelines for what the minimum mass should be? In the ERT report 

that we will need to fill out after testing there is a request to report in parentheses the detection 

limit if the result is under the DL. This is something that is normally associated with methods 

such as M29 or M23, but what about OTM-27? For example, in Oregon the DEQ requires the 

test company report the emissions based on a default of 20 mg if less than 20 mg of sample 

was collected for the entire train, front half plus back half. For OTM-27 we will be using a 5 

place balance and weighing to a constant weight of 0.05mg. In the case of sources that have 

control devices the mass of PM2.5 collected may be very low, even in a 2-4 hour test. If a 

specified mass isn’t required then I would expect that there will be many PM2.5 results that will 

be very low, and potentially meaningless. Another consideration is that the since there is 

normally a bidding process, if Test Company A bids for 2 hour runs and Test Company B bids 

for 8 hour runs, Company A will get the project, but Company B would have provided much 

more representative results. In the absence of a mass requirement, I would be concerned that 

a lot of the data reported may not be representative. 

 

2. In Section 1.6 of OTM-27 there is a statement regarding the maximum stack temperature: 

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“This method may not be suitable for sources with stack gas temperatures exceeding 260°C (500°F).” 

For very clean sources that have good control devices it doesn’t seem that there would be any 

problem just using M5/OTM-28 and assuming that all particulate matter collected is less than 

PM2.5. However, for sources such as small refuse burning incinerators with only secondary 

combustion as a control device, using M5/OTM-28 would bias the PM2.5 results high. This 

might be fine for a “worse-case” compliance determination, but would not be ideal for 

establishing an emission standard. The outlet temperatures may be in the range of 1000-1800 

oF. 

 

Sorry to keep bothering you, but we want to make sure that we do the best job as possible for 

our clients. 

 

Thanks, 

Kris 

Kris Hansen, QEP 

Sr. Consultant 

AmTest Air Quality, 

a Division of Hoefler Consulting Group 

PO Box 525 

Preston, WA 98050 

425-222-7746 

425-222-7849 (fax) 

khansen@hoeflernet.com 

www.amtestairquality.com 

 

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