Steve Jackson/RTP/USEPA/US

01/25/07 04:16 PM

	

To

Dave Mckee/RTP/USEPA/US@EPA

cc

Mike Ray/RTP/USEPA/US@EPA, Rebecca Calderon/RTP/USEPA/US@EPA

Subject

Re: Fw: Accuracy and Bias of Ozone Measurements









Dave, 

My second statement regarding bias should be changed to read as follows.

"Historical records indicate that the ozone concentrations measured
during the ozone exposure studies are accurate within +/- 5% and are
unbiased."

Thanks for opportunity to clarify.  Steve

Stephen T. Jackson

Human Studies Division MD58A

NHEERL/US EPA

RTP, NC 27709

Phone:  919 966 6504

Fax:  919 966 6212

Stephen Jackson/DC/USEPA/US 

01/25/2007 02:52 PM

	

To

Steve Jackson/RTP/USEPA/US@EPA

cc

Subject

Fw: Accuracy and Bias of Ozone Measurements









----- Forwarded by Stephen Jackson/DC/USEPA/US on 01/25/2007 02:51 PM
-----

Dave Mckee/RTP/USEPA/US 

01/25/2007 02:44 PM

	

To

Stephen Jackson/DC/USEPA/US@EPA

cc

Subject

Accuracy and Bias of Ozone Measurements









Stephen,

         I pulled out a couple of key phrases that concisely state the
bottom lines of your earlier emails about accuracy and bias in the ozone
measurements in the ozone chamber studies conducted in Chapel Hill. 
Please let me know if you agree that these representation your
conclusions.  Thanks.

          Dave

"The accuracy we have historically used in conducting our studies,
including the ozone studies,  is +/- 5%.  In the case of the ozone
standard, the .080 ppm measurements can range from .076 ppm to .084 ppm.
 The greatest acceptable variation at the lowest end of the detectable
range is .01 ppm.  These limits are a function of the accuracy of our
instruments."

"Nothing in my experience, either directly or from review of historic
documents, suggests there was or is any bias in our ozone measurements. 
Steve"

 

