Brownfield Braintrust Podcast with Matt Winefield: 10 Flaws with the Cal-EPA Attenuation Factor

4/29/2021

In this second installment of the Brownfield Braintrust Podcast, Matt Winefield discusses ten flaws with the Cal-EPA 0.03 attenuation factor (AF) in the Draft Vapor Intrusion Guidance Document. All parties agree that the AF should be based on best available science. Best available science dictates that Cal-EPA must use the AF developed in the 2020 DTSC attenuation factor study, which utilized California data exclusively and has been extensively peer reviewed.

Follow the Brownfield Braintrust Podcast at: https://anchor.fm/brownfield-braintrust
Find Matt Winefield on LinkedIn at: https://www.linkedin.com/in/mattwinefield/

2 Comments

Chris Spengler link

4/29/2021 04:04:30 pm

Hi Matt,

Enjoyed the podcast though I must say it seems that your first 6 or 7 points didn't really point out the flaws in the 0.03AF and repeatedly stated that the DTSC study was the best.

Personally, the biggest issue I see is this one number fits all approach which is ridiculous. The VI for a house on a sublloor v old slab on-grade v new slab are wildly different. How about an apartment building with below grade parking or mixed use with commercial on the first floor or with a parking garage below?

Using published diffusivity coefficients for VOCs and HDPE you can show that HDPE liners practically eliminate flux into the building - AFs that magnitudes higher. This new AF is all about protecting agencies from lawsuits and being wrong in closing cases than it is about protecting human health.

Matthew Winefield link

4/29/2021 04:06:52 pm

Great points, Chris. I agree with everything you've noted.

Brownfield Braintrust Podcast with Matt Winefield: 10 Flaws with the Cal-EPA Attenuation Factor

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