Air Quality in the Barnett Shale - Part 26: That's a lot of n's!

In my last post I looked at the quality of the data presented in the ERG report and the TCEQ report for air quality in the Barnett Shale.

Looking at how the data was obtained is important to understanding how valid it is.  Along with this is the number of individual data points - or n's - were collected.

Since we are making an assumption, such as the air "does not pose a health hazard" or the air is "2 times above a threshold where irreversible effects can occur" the quality of the data and the representation of the data to what is actually found becomes critical.

Alisa Rich in her report to the Town of Dish, Texas, modeled the air using only six samples - collected on one day - and analyzed with the wrong method, concluding

Dr. Sattler, using one sample - collected on one day - and analyzed with the wrong method, concluded in the FWLN report:

And with these two assumptions, FWLN had enough information to support their contention that the air quality in the Barnett Shale in the Fort Worth Area is significantly impacted:

I contend that because of the lack of representative sampling (too few n's) and the incorrect laboratory analysis (TO-14 instead of TO-15) the data Rich and Sattler generated is invalid and, therefore, their model's predictions are invalid, which makes these types of statements regarding carbon disulfide in the Barnett Shale area false.

So what do we know about the air in the Barnett Shale and the emissions from oil & gas production sites?

Quite a lot, actually.  Both the Barnett Shale Energy Education Council (BSEEC) TITAN Engineering report and the ERG report - referenced in the FWLN report - provide a considerable amount of data (lots of n's). And that data can be supported as valid because the reports can show precision and accuracy (which Alisa Rich and Dr. Sattler cannot).

Now you can choose to ignore the BSEEC and ERG's data, but the only grounds to do so is because you suspect some kind of conspiricy between O&G and them.  Possible, but not very plausible.  A conspiracy to distort, fake, or hide sample data implies both a lot of conspirators who will presumably attempt to conceal what they have done, and a lot of readers who can be successfully persuaded that the data in these two reports have been purposely distorted.

If you think there is a conspiracy by BSEEC and/or ERG to fake this information then you can stop reading now and go back to your land of implausibility.  Like I said earlier in my posts on the air in the Barnett Shale area, I assume that the data provided by Alisa Rich and Dr. Sattler has not been purposely manipulated.  It may be invalid, but I don't think it has been faked, tainted, or manipulated.  The same is true for BSEEC and ERG's data.  I assume it to be truthful and honest.

The BSEEC tested the air over four time periods in June, at nine (9) different locations.  EPA Method TO-15 found the following results for 93 samples (n's) of carbon disulfide:

The BSEEC report identified the following concentrations for carbon disulfide and carbonyl sulfide tested using ASTM Method D 5504-08 for sulfur compounds .  Please note that the number "4" by the quantity indicates:

Which means that it may have come from the bag itself and not from the air sampled:

A significant factor in the selection of filter media used for air sampling is the formation of artifacts due to the sorption of sulfur and nitrogen oxides on the filter. These artifacts can erroneously increase measured particulate concentrations. (1)

Here is what the BSEEC reported:

Thats over 21 samples (n's) for carbon disulfide, and of these samples, nine (9) were non-detectable.  Assuming that the concentration reported for this method were not artifacts, the highest concentration of  carbon disulfide was 11 ppbv.  

It should also be noted that only Tables 10, 14, 20, 23, and 26 showed a higher concentration of either contaminant downwind as compared to upwind ("D" = downwind in sample number)  The highest carbon disulfide concentration, 11 ppbv, was found in the upwind sample!

So the BSEEC report brings us a total of 114 n's for carbon disulfide.

Now lets look at the ERG Report, also referenced in the FWLN report.  ERG sampled nine (9) unique O&G sites plus one site designated as background:

At these sites a total of 92 detections for carbon disulfide were found with an average concentration of 0.243 ppbv and the highest concentration detected as 1.64 ppbv for a 24-hour sampling period:

So what do we know about the concentration of carbon disulfide in the air around oil & gas production facilities in the Barnett Shale?

Out of 206 samples (n's) the maximum concentration of carbon disulfide found in the air in the Barnett Shale area was no higher than 11 ppbv.

If Dr. Sattler's contention is true that from her one sample used in the FWLN was found to produce an emission rate that could produce up to 78 ppm (that's 78,000 ppb).  At the backed in calculated emission rate that she believes is emitting carbon disulfide, don't you think we would have seen concentrations above 11 ppbv in at least one of the 206 samples?

And the reason we are not seeing anything higher than 11 ppbv (or 10.8 if we assume the TIC she reported is accurate) is for one simple reason;  you cannot back in an ambient concentration into a Gaussian air dispersion model without placing directly downwind from the site and subtracting the upwind concentration from the result: (2)

The presence of carbon disulfide in the Barnett Shale area, regardless of source, is consistently way below the permitting ESL and the health based AMCV.

206 n's tell us this...and that's a lot of n's!

Next post: Air Quality in the Barnett Shale - Part 27:  Plot 2; Artifact or the Real Deal

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