Now it may appear that, like the defendant's lawyer, I am trying to embarrass Dr. Sattler or ridicule Alisa Rich. That's not the purpose of why I am writing this. My goal is to show how and where their thinking is wrong, misguided, or has become biased. I hold everyone accountable for supporting their beliefs and comments, but I especially hold someone with a MPH, as well as anyone who teaches, with a higher level of accountability. Bad science leads to bad decisions.
What these two professionals have put forth as "based on reasonable scientific probability" is anything but. And it all relates back to their complete lack of understanding of a risk based exposure level (AMCV) and a contaminant level designed to allow for future growth (ESL). All of this - plus a hefty dose of mistrust in the TCEQ - has lead these two down a path of paralogism.
I find it intellectually dishonest to discuss something - especially teach it or use it as the basis of a report to the general public - without attempting to understand it fully. I had no idea what an ESL or AMCV was before I read Alisa Rich's reports to the Town of Dish, Texas. I have the same degree as Alisa Rich so we should have come up with the same understanding. Dr. Sattler is a Ph.D dealing with ESLs. She should understand them fully, or at the very least be able to see how it is illogical to even contemplate a health concern if the value was ".001 micrograms per metered cubed above that."
So lets look at how these two look at the ESL and the AMCV:
Q. What is your understanding of an Effects Screening Level [ESL]?
A. They are used for comparison of dispersion modeling concentrations to assess whether there could be a potential short-term or long-term health impact.
Q. And the [ESL] are used for permitting purposes; are they not?
A. That's correct.
Q, [T]hey are not ambient air concentration levels, or shouldn't be used to compare ambient air concentration levels should they?
A. They have been used that way in the past, until recently when TCEQ came out with the [AMCV], [b]ut they have come out with a new set of values that they say are appropriate to compare ambient measurements with, but the {ESL] are still the appropriate values for comparing dispersion modeling results with.It was at this point that I started to realize that Dr. Satller did not understand the difference between using a dispersion model to predict health impacts to a receptor and using an ambient air sample to conclude possible health impacts. What was happening here is comparing apples to oranges. Even though an ESL looks at health impact to a receptor, when Alisa Rich placed the canister to collect the sample, she was collecting an ambient air sample.
ESLs have never been appropriate for looking at potential health impacts for an ambient air sample since they are designed for permitting purposes. They are purposely made to be 70% more protective than what is actually required. This is why the the TCEQ brought forward the Air Monitoring Comparison Value. Dr. Satller was aware of this, but possibly did not understand what the 70% decrease actually means.
A. The TCEQ Guidance says that the [ESL] are appropriate values to use for dispersion modeling because when your doing dispersion modeling, typically you're looking at the impacts of one source. And so the [ESL] are set lower in some cases than the [AMCV] to allow for, like, future additional sources that might move into the area that arn't accounted for in the dispersion modeling.
So you don't want one source taking up all of the air quality, [a]ll of the room in the atmosphere for emissions of that compound, because there may be future sources that move into the area that may also emit the compound. So in some cases the ESLs are set lower than the [AMCVs].Dr. Sattler sees it, articulates it, but does not understand it. If the ESLs are set lower to accommodate growth, then exceeding them would not indicate a health concern, since they are designed to allow another facility into the area that would emit up to a similar amount.
Simply put; if source A puts 2 ppb into the air, and a new source, B, puts 2 ppb into the air, than the total ppb in the ambient air would be 4 ppb. If the ESL is 2, then it is OK for both A & B to put that amount into the air. So if this is OK, then how should one look at the 4 ppb actually now in the air? That's why they developed the AMCV, because the ESL is appropriate for only one source in an area and is used only for air permitting - to see what additional air pollution devices or setback may be necessary for that one source. The dispersion modeling looks to make sure that a receptor in and around that source will not be exposed to more than the ESL form that source.
If an ambient air sample - like Alisa Rich took in the Town of Dish, Texas - has levels above the ESL, it does not indicate a health concern since the ESL is 70% lower than what is considered to be a safe level.
So, when Alisa Rich and Wilma Subra reported that the ambient levels exceeded the ESL, they were incorrect. When Dr. Sattler produced modeling results that showed receptor concentrations above the ESL, she erred not only in how the source's emission rate was calculated but in her data's ability to now allow Alisa Rich the means whereby she could allude that there was a health issue in the Town of Dish, Texas. Her report under "Results" states:
"The basis of an ESL is health impacts..." and "According to Table 2, short-term and long-term ESLs were exceeded for all pollutants, with the exception of long-term ESLs for styrene and toluene."Now it is my belief that Alsia Rich knew full well how Table 2 would be interpreted by the people in the Town of DISH, Texas, as well as anyone who has a concern about oil & gas production. All her reports are written in such a way as to not make a conclusion of yes or no, but instead are cleverly worded to be truthful without being honest. She must - as an MPH - understand how the ESL is calculated, as should Dr. Sattler. However, Dr. Sattler's lack of a toxicological background may preclude her understanding of Hazard Quotient (HQ) and Cancer Slope factor (see 1.6.1.1 Calculation of ESLs for Nonlinear Effects) which might account for why she has continued down this path and, unfortunately, brought her students along with her.
To know what the model is designed to do, but completely lack an understanding of what the numbers produced mean, is just....well I don't know what to make of it. I think the idea behind Alisa Rich's dissertation is sound - that the ratio of chemicals detected in the air might be used to determine the possible source - has potential merit. But using the model to back in data without this fingerprinting knowledge - which was done in all three studies provided to Alisa Rich - is unsound, making all this modeling work performed by Dr. Sattler nothing more than guessing. At the very least I will accuse her of being intellectually sloppy in her premise and her understanding of what the true health impact should be identified as.
They don't hand Ph.Ds out to just anyone, so when you have that, along with the title of "engineer" and "professor" at a "major university" by your name, it is assumed that you should have a pretty good understanding of what your are saying. It assumes that you have spent the time necessary to thoroughly research your topic, to know it inside and out. If her topic is air dispersion modeling, then one should reasonably expect that she fully understands what the number the model calculates means. She doesn't, and how many people has she confused because of her failure to look at anything other than the number produced?
Numbers mean something. The air dispersion model numbers mean something. They are used to compare against an ESL. She knows that. So how in the world does she not understand what an ESL is all about?
Q. [Your 6/15/10 email states] "It seems like the TCEQ should have been using AMCVs all along as a basis of comparison for monitoring data." [S]o if someone was taking ambient air tests certainly after June of 2010, the intellectually honest thing to do would be to compare that data to AMCVs, not [ESLs] correct?
A. In my opinion. There are people who suspect the motives of the TCEQ in issuing the AMCVs at this late date; why didn't they issue AMCVs 20 years ago?
Q. [t]he intellectually honest thing to do if you're taking air data from ambient air samples would be to compare it to that, not [ESLs] which are set 70 percent lower than the level at which health effects would be anticipated; correct?
A. I don't think the issue is that simple, because, as I said, if AMCVs were the proper thing to use, why didn't TCEQ come out with them 30 years ago. So there are people that suspect the TCEQ's motives in issuing the AMCVs. And if you're one of those people, you can argue that it's appropriate to go ahead and continue using the ESLs as we have - as they have been used in the past 20 years or whenever it was that they first came out with the ESLsI'm going to interject here. The reason they had to put the AMCVs in place is because of Alisa Rich and Dr. Sattler's misuse of them. Prior to Alisa Rich's "reports," they were used for air permitting, not for ambient air determination of a potential problem or concern. Alisa Rich and Wilma Subra took ambient air samples and compared those values to values that are 70% lower than what is consider to be health based. Then, to top it off, Dr. Sattler "backs in" this ambient air data into her dispersion model and calculates potential concentrations that are, once again, compared to ESLs. This causes the people in these communities and those around oil & gas production sites to believe that they are being harmed. Their (TCEQ) motive was to stop this abuse/misuse.
Oh, but it gets better...so unbelievably better:
Q. Are you one of the people that suspects the TCEQ's motives?So maybe I was wrong to assume that Alisa Rich - who holds an MPH, like me; from a reputable University, like me; with a focus on environmental health, like me - should understand why the ESL was replaced by the AMCV for ambient air monitoring. It's all about the HQ and the Cancer Slope Factor, the BASIC principle behind assigning risk. The TCEQ ESL document explains it all very well.
A. I don't know. I've worked with some people at TCEQ that are technically competent, and I've worked with some people that arn't as technically competent, so I hope that the technically competent people were involved in this decision, but I don't know for sure.
Q. When you said [i]ts reasoning seems OK," have you changed your mind about that since June 15, 2010, as you sit here today?
A: If I read the document and take it at face value, the document seems okay, but there have been some other - decisions that TCEQ has made that I think have not been technically sound since that time.
Q. Do you [h]ave any reason to think that Alisa Rich questions the motives of the TCEQ?
A. Yeah
Q. And what do you base that on?
A. Because she's been reluctant to start using the AMCVs as a basis of comparison.
Q. And why is she reluctant to use the AMCVs as a basis for comparison?
A. Because we've been using [ESLs] to compare monitoring data for the last 20, 30 years, however long the ESLs have been in existence, and so I think she questions why - why they're just now coming up with them; why didn't they come up with them 20, 30 years ago.
Air dispersion modeling is all about looking at risk. To not understand the difference between the ESL and the AMCV, is to not understand the very basis of how we look at potential adverse health effects from one source and all sources combined
Q. If you were doing an ambient air study [w]ould you use the AMCVs as the comparison value as opposed to the ESLs?
A. Yes
Q. And you would do that because you believe that would be the intellectually honest thing to do; correct?
A It would be because I would take the AMCV report at face value and - hope that the people who decided to come up with the AMCV standards were the people at TCEQ that were technically competent.And the TCEQ, environmental professionals like me, and the general public at large, would hope that someone with a Ph.D, a job as a UTA professor, and an engineer in air dispersion modeling, would be technically competent to be able to determine this on her own and not just reluctantly accept it at "face value."
AMCVs are the correct level to use when looking at ambient air concentrations. ESLs are used to look at what level a receptor would be exposed to if the emission rate from the source is known. ESLs are 70% less than AMCVs because they are used for permitting. Exceeding them does not indicate a health concern.
Next Post: Air Quality in the Barnett Shale - Part 18: Dr. Sattler's Deposition - 70% means what?
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