Month: January 2013

Decorative Oil Lamps: A Surprising Source of Indoor VOCs

January 7, 2013 Jim Okun

Impacts to indoor air quality from volatile organic compounds (VOCs) have been receiving greater attention recently due to a growing awareness of vapor intrusion (VI) from underground oil and chemicals.   VI occurs when chemicals spilled on the ground migrate under structures and then volatilize up into indoor air.  After a recent residential basement oil spill I was called in to provide a second opinion on why high indoor air VOC concentrations persisted in the home after the cleanup had been completed.  Some of the results were very surprising.

Locating VOCs in the Basement

Following the release, a well qualified response contractor had conducted a thorough cleanup.  The remediation included removing portions of the floor slab, wall board, wood framing and most other building materials that had been contacted by the oil.  Despite the cleanup, indoor air concentrations in the basement and first floor of the house exceeded the Massachusetts Department of Environmental Protection criteria.

The contractor suspected the problem was the first course of concrete chimney blocks, which had likely absorbed oil in the aftermath of the spill.  The oil in the blocks was now likely volatilizing into the air.  Removing and replacing the contaminated  blocks presented an obvious structural challenge so initially an epoxy sealant was applied to the entire chimney to prevent further oil volatilization.  However, indoor air testing conducted after the epoxy had cured showed that indoor air concentrations remained stubbornly high.

To assess the cause of the indoor air levels, I visited the subject home with a ppbRAE to see if it would help me locate the source of the organic vapors.  Once in the basement, it did not take long to discover that the epoxy sealant was not preventing VOC migration out of the concrete chimney blocks; the blocks were still off-gassing VOCs to the basement air.  While there were also a few pieces of previously unidentified wood framing off-gassing VOCs, the concrete blocks looked to be the main culprit.

But What’s Going on Upstairs?

With the basement VOC source identified, I went upstairs to check on first floor; what I found there was completely unexpected.  While ambient basement air VOC readings had been just above zero (at some distance from the chimney), ambient levels on the first and second floors were about 200 ppb!  How could this be?  I walked through the house with the home owner trying to identifying potential VOC sources.  After an hour of looking I hadn’t been able to identify a source and almost everywhere in the occupied space I was measuring 200 +/- 40 ppb of VOCs in the breathing zone air; there were no odors.  Big mystery!

Finally, on a high book shelf in the living room I noticed two glass hurricane lamps; each containing several ounces of clear liquid lamp oil.  When I held the tip of the ppbRAE probe over the glass lamp chimneys the instrument’s numerical readout shot up; the mystery of the upstairs VOC source was seemingly solved!  And the source was completely unrelated to the basement oil spill.

What is in lamp oil that causes such a strong response on the ppbRAE?  From my limited on-line research, there does not appear to be a commonly accepted formula for lamp oil.  At one time kerosene was used, but this now seems less common except in outdoor settings.  Whale oil was also once used, a practice now thankfully in the past.  The oil in these lamps had no odor, but beyond that I do not have any information on what it was.  I did not collect a sample for lab testing, so I do not know specifically what the ppbRAE was responding to.

Lessons Learned

This experience was a good reminder of just how sensitive today’s air monitoring equipment has become.  Even very small contributions from sources that do not seem particularly volatile can have a dramatic impact on indoor air testing measurements.  It is important to keep a watchful eye out for unanticipated VOC sources when conducting indoor air testing.

2013 and the Future Looks Bright

January 2, 2013 Jim Okun

After 5 years of challenging economic times I was more than ready for some positive news going into the holiday season.  With the continuing chaos in Washington I knew that was unlikely to be a source of good tidings.  Looking around the globe I was reminded of a favorite Tom Robbins quote, “The world situation is desperate, as usual”.  This piece of wit seems truer today than on the day it was written.  So where can you find good news?  I actually have an answer, let me tell you.

This past spring I received an email from the admissions office at MIT asking if I would be willing to interview high school seniors in my area who had applied to become undergraduates there.  It turns out that the only interview option that MIT (and many other colleges) now provide to prospective undergraduates is with alumni. After thinking it over for a couple of weeks I decided to try it and replied with my own positive email.  I received a thank you email in return and not much else happened until August when bundles of training information began to arrive (also by email).

Unlike in my day, the whole admissions process now takes place almost entirely over the internet.  Prospective students download applications and upload completed application sections; assignments are made for interviews and interview summaries are uploaded back to MIT all over the internet.  So the only real opportunity to connect with prospective students one-on-one is during these interviews; they take place face to face with no electronic inter-mediation.  Interviews are held in “neutral” locations to make the interviewees (and the interviewers) feel more comfortable.

Now for the good news: what I discovered is that these kids were uniformly very impressive.  Well, not just impressive, they were amazing!  They seem much better prepared than was my freshman class all those years ago.  If the group that I met is typical of all the high school students now applying to MIT, then I wish the admissions office staff good luck, because I have no idea how they could choose among all the exceptional candidates that apply to the school.  And from what I have heard, MIT can only accept 8% of applicants.

While this extreme selection is going to lead to some deep personal disappointments in the short run, the fact of the matter is that most or all of these brilliant young people will be going to fine universities somewhere.  So the even better news is that despite everything we hear day in and day out about slipping academic standards, my impression is that there are probably a greater number of brilliant, superbly well prepared young students going on to engineering and science schools than at any time in the past.

What’s my advice to anyone who thinks that our young people are lazier than past generations and that this country is losing its intellectual edge?  Don’t bet on it!  There is no doubt in my mind that the young people I met will go on to make incredible new discoveries, start undreamed of enterprises and advance the overall state of human achievement.  What compensation did I receive for my time and effort?  A renewed sense of optimism from seeing the world through the eyes of talented young people who look to the future and see nothing but opportunity.