From: Rima Howell/RTP/USEPA/US

To: Robin Segall/RTP/USEPA/US@EPA, Tom Driscoll/RTP/USEPA/US@EPA

Date: 03/05/2010 07:21 AM Subject: Fw: Quick Question: PS-15

Please see Jeff's message below - detection limits should not be a problem

Rima

----- Forwarded by Rima Howell/RTP/USEPA/US on 03/05/2010 07:20 AM -----



### RE: Quick Question: PS-15

Jeffrey LaCosse to

: Rima Howell

Hi Rima,

One does not need a special cell. We detect HCl at about 50 ppb levels with a 3.2 meter pathlength at 0.5 cm-1 resolution. 20 meters is actually a bit long and can cause problems in measurement of other species at higher

levels.

Regards,

Jeff

Jeffrey P. LaCosse, Ph.D. President and Principal Scientist Spectral Insights LLC

spectralinsights.com

Office: Laboratory: 214 Argonne Drive 3536 Durham Road Durham, NC 27704 Raleigh, NC 27614

Phone: 919-620-6549

Mobile: 919-949-5432

Fax: 919-471-6179

-----Original Message----- From: Howell.Rima@epamail.epa.gov [mailto:Howell.Rima@epamail.epa.gov] Sent: Thursday, March 04, 2010 7:04 AM To: j.lacosse@gte.net Subject: Fw: Quick Question: PS-15

Hey Jeff, I know you have a 20 m cell that can improve detection limits, but can it measure down to under 2 ppm - if so, can it be used as part of a CEMS package? Do you even need a special cell to see HCl at those

levels?Thanks.

Rima

----- Forwarded by Rima Howell/RTP/USEPA/US on 03/04/2010 07:02 AM ----- |------------> | From: | |------------>

>------------------------------------------------------------------------- -------------------------------------------------------------------| |Robin Segall/RTP/USEPA/US |

>------------------------------------------------------------------------- -------------------------------------------------------------------| |------------> | To: | |------------>

>------------------------------------------------------------------------- -------------------------------------------------------------------| |Rima Howell/RTP/USEPA/US@EPA |

>------------------------------------------------------------------------- -------------------------------------------------------------------| |------------> | Cc: | |------------>

>------------------------------------------------------------------------- -------------------------------------------------------------------| |Tom Driscoll/RTP/USEPA/US@EPA |

>------------------------------------------------------------------------- -------------------------------------------------------------------| |------------> | Date: | |------------>

>------------------------------------------------------------------------- -------------------------------------------------------------------| |03/03/2010 04:13 PM |

>------------------------------------------------------------------------- -------------------------------------------------------------------| |------------> | Subject: | |------------>

>------------------------------------------------------------------------- -------------------------------------------------------------------| |Quick Question: PS-15
Hi Rima,

First, some background.......PS-15 has been cited as the HCl monitoring specification in the proposed amendments to Cement MACT (since we know that FTIR technology can measure HCl from cement plants).

Comments on proposed reg cite problems with using FTIR CEMS to measure down in 2 ppm range.

Question, from your perspective is that a reasonable complaint? Over the years, have you gotten any feedback from the real world on application of FTIR CEMS? For HCl, in particular, perhaps? Do they work well? (I have heard from one MWC rep that they love theirs.)

Can you please write back to Tom Driscoll as he has an important meeting

on this tomorrow afternoon. Thanks much!Robin