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EPA's 2015 Vapor Intrusion Draft RevisionsAfter a very long wait, it’s finally here. Thirteen years in the making and spanning multiple Presidential administrations, it’s finally being released to the public.

I bet you think I’m talking about the new Star Wars movie, right? Wrong, as it’s only been 10 years since the last Star Wars movie was released. Rather, I’m talking about the Oswer Technical Guide For Assessing And Mitigating The Vapor Intrusion Pathway From Subsurface Vapor Sources To Indoor Air  and Technical Guide For Addressing Petroleum Vapor Intrusion At Leaking Underground Storage Tank Sites.

Since our Federal government was so prompt in getting us a final document after releasing the Draft in 2002, many State agencies developed and adopted their own rules.  Over the next several years the State and Federal agencies will (maybe) get on the same page on Vapor Intrusion (VI).

So what is the big deal?  From what I can tell, one of the biggest differences between the 2002 and 2015 documents is the guidance document specific to the UST releases.  UST releases are responsible for the bulk of the VI issues found in the USA as the 2002 Draft document was geared more toward Superfund sites.  The 123 page 2015 Draft document is filled with useful flow charts and diagrams, but is mostly a page of text followed by two pages of references.

Lucky for those of us in the environmental remediation business, technology has not been standing still for the last 13 years.  If you are interested in finding out about the latest monitoring, assessment, and mitigation devices for VI, please contact us at info@enviroequipment.com.

Brian E Chew Sr P.G.
Principal Hydrogeologist


What VOCs Are and How They Affect You

wwhere do VOCs come fromThe next time you’re out shopping, you may notice that some products have the words “low VOCs” on their label. An increasing amount of manufacturers are using this label because of the growing awareness of the harm that VOCs (i.e. volatile organic compounds) pose to human health.

VOCs Defined
Unfortunately, few people have ever heard of VOCs let alone know what they are. So, the first step in understanding what VOCs are and how they affect us is to break down the term itself. If you string each definition of the term together it becomes a “…substance that can easily evaporate and spread through the air, contains carbon in its molecular formula, and consists of two or more separate elements.” It should also be noted here that there are many different ways of classifying and categorizing VOCs, but that discussion is outside the scope of this article.

Now that you have a brief idea of what a VOC is, the next step is to understand how widespread VOCs are.  Many different consumer products contribute to indoor VOCs that people are exposed to, such as personal care products (nail polish, perfumes, hair spray), paints, fuels, cleaning products, and much more.  An example of a specific VOC would be Acetone (Chemical Formula: C3H6O) found in nail polish remover.  If you’ve used or been around nail polish remover before, you know how quickly the smell travels throughout a room.

VOC emissions from motor vehicles, factories, and manufacturing facilities are a large source of VOC emissions outdoors in the environment.  VOCs are also produced from naturally occurring sources, such as vegetation, bacteria, and fossil fuel deposits.

Why We Should Care About VOCs
At this point, you’re probably wondering why we care about VOCs?  The main concern for VOCs indoors are the adverse health effects that some of them have on people and animals.  VOCs from car emissions and other processes contribute to outdoor pollutants such as smog.  Outdoor VOC pollution is an important topic, however, this article focuses mainly on indoor air quality.

VOCs can have health effects such as irritation of the nose, throat, and eyes, headaches, nausea, dizziness, allergic skin reactions, damage to internal organs such as the liver and kidneys, cancer, and more.  One important thing to know is that the health effects vary greatly depending on the VOCs that you are exposed to, the length of exposure time, and the concentration of the VOCs.  Some VOCs are highly toxic and do not take long to have adverse health effects, some VOCs have no known adverse health effects at all.  OSHA and other safety administrations have developed occupational exposure limits for toxic VOCs that workers are not to exceed for safety reasons.  The exposure limits can vary from one organization to another.  Below are some examples of these types of exposure limits:

  • Time Weighted Average (TWA): The concentration in air of a substance that shall not be exceeded in an 8-hour work shift or a 40-hour work week. 
  • Short Term Exposure Limit (STEL): The time-weighted average exposure that should not be exceeded for any 15-minute period. 
  • Ceiling Limit (C): The exposure limit that shall at no time be exceeded.

This is why products containing potentially toxic VOCs recommend that you use them in a well ventilated area.  In an enclosed room, the more fresh air you add the less concentrated the VOCs become.

Measuring VOCs
So how do you measure VOCs?  Unfortunately, that is a complicated question.  This quote from the EPA website on VOCs provides useful information:

“All available measurement methods are selective in what they can measure and quantify accurately, and none are capable of measuring all VOCs that are present… The range of measurement methods and analytical instruments is large and will determine the sensitivity of the measurements as well as their selectivity or biases.”

For identifying the presence of VOCs, organic vapor analyzers such as photoionization detectors (PIDs), including the MiniRAE 3000 or ppbRAE 3000, can be used to measure Total Volatile Organic Compounds.  An important note about these meters is that they do not tell you the exact VOCs that you are measuring, just that VOCs are present.  Some VOCs require stronger lamps to be installed for detection, and others cannot be detected by PIDs (see our article on PID Lamp Selection).  If you know that only one VOC is present or if you know the exact mixture percentages of compounds where you are monitoring, then you can multiply the reading you get by a correction factor to get a more accurate reading for the compound(s). See RAE Systems Tech Note 106 for more details.

Other methods include colorimetric gas tubes that offer quick on-the-spot measurements of many different gases and vapors.  These tubes react with the compound in question and change color based on the concentration present.  The color can be compared to a color scale to get a value.

The most accurate method of testing VOCs involves collecting a sample using a SUMMA canister or air sampling pump with a tedlar bag and having it analyzed in a laboratory.  This method is best left to consultants who are trained professionals and know the correct sampling methodology.

Questions or Comments?
I hope this article answers some common questions that it may have about VOCs.  If you have any questions or comments, we would love to hear from you!  If you like to know more about VOCs, I recommend reading the following sources:


QT service station pumpThese days the service stations being built have quite the curb appeal.  I have noticed in the southeast QT® (i.e. Quick Trip) has built a number of facilities with quite a nice layout and beautiful landscaping.  These stores are very clean and have just about everything you need to get in a single stop.  I realize many of those reading this blog are environmental consultants who don’t own service stations, but you do have Clients who own them.

When a gasoline leak occurs at one of these new stations, the work that is required to fix the leak systematically destroys the appearance of these stations. There is no getting around doing the assessment to determine the impact of the release, but when it comes to remediation the choices are broad.

Some of the most successful cleanups I was involved in used Sparge\Vent technology.  This meant installing numerous Sparge wells and Vent wells, and cutting up that beautiful smooth pavement to install the underground lines between the wells and the equipment building.  These systems were quite effective, but noisy, smelly and not so pretty.  This is not what you want to see, hear and smell when you are pulling off the road to stretch, gets some gas, and a quick bite to eat.  The typical systems will be operated for a period of 2 to 5 years before being decommissioned.  But what if you didn’t have to install those wells and cut trenches through all that smooth pavement?

I know in the last two decades there have been a lot of snake oil salesmen offering to pour different concoctions into your monitoring wells to make your problems go away.  Most of the time all that happened good money was wasted, and in some cases, these concoctions made matters worse.  In some States, like South Carolina, pouring chemicals or bacteria into monitoring wells is not allowed.

However, what if you could remediate your site without using your monitoring wells for anything but monitoring?  You can – and it is not snake oil.  What I am talking about is cleaning up your site using a special blend of activated carbon in a carbon based injectate (CBI) and the indigenous bacteria.  This CBI is injected by direct push technology into the impacted formation to sequester the contaminants and allow the naturally occurring bacteria to do its job.  This is the way Mother Nature handles contaminants and does not require trenches, remediation wells and equipment compounds.  It is also relatively fast compared to other technologies and typically a lot cheaper.  It is not a solution for all sites, but no remediation technology is. If you are interested in getting more information about this technology contact ericchew@geologicrestoration.com

Brian E Chew Sr. P.G.
Principal Hydrogeologist