Explanation of sampling methodology

From: David Webb <wd5doc@me.com>
To: Bonita Underbakke <nestree11402@yahoo.com>
Sent: Sunday, September 8, 2013 11:28 AM
Subject: Re: Dr. Crispin Pierce Report on Initial PM2.5 Levels in New Auburn [Wisconsin] September 6, 2013

Last month, Dr. Pierce and coworkers took measurements of airborne particulate matter in New Auburn, Wisconsin, a location that might be expected to show higher levels because of the proximity of frac sand operations.  Attention was appropriately directed to PM2.5 levels, that is, particulate matter of 2.5 microns diameter or less, which are the respirable particulates that pose health risks.

Four different portable measuring devices were used - Dylos, an older model DustTrak, a newer model DustTrak, and an SKC DPS - thereby permitting a comparative look at different methodologies (perhaps the most important take-home from the study).  The Dylos and DustTrak readings were quite comparable; the SKC readings were markedly higher than the other two.  The caveats are that methodology does matter and that one should be skeptical of data that are "cherry-picked" to support a particular bias.  (The most egregious example of this would be presenting data on PM10 levels instead of the PM2.5's.)

In this study, in all cases, regardless of the methodology, the measured PM 2.5's in New Auburn were higher than Wisconsin DNR measured regional background levels.  These data basically confirm the obvious - there are increased PM2.5 levels where there are frac sand operations.

For the most part, Dylos and DustTrak sampling over these three days showed PM2.5 levels less than the EPA annual exposure standard, although a few hour-average Dylos samples did exceed the EPA standard.  (A caveat regarding EPA exposure standards is that levels below the standard do not imply that the exposure is perfectly safe, nor that levels exceeding the standard are uniformly fatal.  An EPA standard is best interpreted as implying that if the standard were exceeded, all thing considered, it would be more economical to do something about it than to ignore it.)

The PM2.5 levels measured with the SKC DPS (Deployable Particulate Sampler) far exceeded not only the DNR regional background levels but also the EPA annual exposure standard.  Dr. Pierce states that the SKC device is the most accurate of the methodologies used.  I am inclined to believe him but am not sufficiently knowledgeable to render an expert opinion.  The SKS website cites the following reference “Effectiveness, Suitability, and Performance Testing of the SKC Deployable Particulate Sampler (DPS) as Compared to the Currently Deployed Airmetrics MiniVol Portable Air Sampler,” Journal of Environmental Health, Vol. 73, No. 3, pp. 16 to 22.

Bottom line:  However, one looks at it, there is increased PM2.5 pollution where there are frac sand operations.  The magnitude of the problem might be under appreciated, depending upon the sampling technology used.

Hope this helps.

Doc

On Sep 8, 2013, at 7:47 AM, Bonita Underbakke <nestree11402@yahoo.com> wrote:

Dear David,

  Have you a suggestion to translate this to layperson talk before I forward it to the e-list of interested locals?

Wishing you well,

Bonita

----- Forwarded Message -----
From: Patricia J. Popple <sunnyday5@charter.net>
To:
Sent: Friday, September 6, 2013 6:16 PM
Subject: FRAC SAND SENTINEL SPECIAL: Dr. Crispin Pierce Report on Initial PM2.5 Levels in New Auburn [Wisconsin] September 6, 2013

Dear Friends and Colleagues,

With this note, I would like to share our initial findings of PM2.5 levels in New Auburn collected August 1-3, 2013. I appreciate the help that Dr. Dale and Carol Crisler provided in setting up sampling sites and collecting data.

Several observations can be taken from these initial data:

1.       Measured PM2.5 levels with the Dylos (p and ¨) and DustTrak (X) were consistent with each other and generally below the EPA annual standard;

2.       Measurements with all instruments found PM2.5 levels higher than DNR regional background levels (Ж); and

3.       The SKC DPS gravimetric sampler (—) measured an average concentration of 51 ug/m3, much higher than levels from the direct-reading instruments and the EPA annual standard.