What is that terrible odor?

Nov 15, 2016

There is an old story that I tell that goes like this.  I am sent to a home where the owners have noticed a strange odor that they want us to identify.  As soon as I enter the door, I am immediately asked “Can’t you smell it?  Can’t you smell it?!!”.  After sniffing around for a few moments, I tell the owners “I smell the oregano from last night’s dinner, I smell the dog, I even smell some wet towels.  But I don’t quite know yet what you are smelling.”

And that is the problem with odor detection.  In truth, every home has its own unique smell, but our minds have the ability to block it out.  We can block out certain odors that we deem to be “normal”, but other odors can stand out and drive us crazy.  What exactly is that odor?

Odors can come from a wide variety of sources.  So in dealing with an unusual odor it’s best to ask some questions.  One question involves asking “what does it smell like?”  At first blush, this seems like a very obvious question.  However, during the last year I have investigated at least eight homes where the owners thought they smelled mold in the property.  In reality, what they smelled were odors associated with a natural gas leak.  In another case, a client noticed that his coats and sweaters had an unusual odor.  He thought it was mold, but in reality it was a heavy stain on his hardwood floor.  

So ask yourself these questions: is the odor that I am smelling “musty” (like in an old basement) or does it have a more “chemical” smell.  Musty odors are usually associated with mold, whereas chemical type smells can be associated with volatile organic compounds (VOCs) that are often affiliated with building materials.  A “rotten egg” smell could be hydrogen sulfide from sewer gas.

Another question that you can ask yourself is “when did you first notice this odor?”  Let’s say that you noticed the odor roughly two months ago.  During that time, what changed in the home?  Did you have a flooding event in your basement?  Did you have some remodeling done in a particular area of the house?  Was there a dead animal somewhere in the property?  Did you switch from heating to cooling?  At first we may think that the odor just suddenly appeared, but in truth we can usually connect it to some event.  

We may also ask, “is the odor particularly worse at a certain times of the day or week?”.   Some clients have noticed that there is a cigarette smell that they suspect comes from a neighbor in an apartment building.  Does the neighbor have a tendency to smoke in the morning?  Late in the evening?  There are some clients who live above a commercial property where they run certain machines or use various chemicals at specific times.  In this regard, it may be best to keep an odor log to see if there are any discernable patterns.      

Once we have determined what the odor is, the next logical question is ‘How do I get rid of it!”  Depending on the source… it depends.  If the odor is musty, then it is highly likely that it is coming from mold or bacteria and the best way to eliminate the smell is to fix the underlying moisture problem and clean the area.   If the odor is coming from a VOC, the solutions can be a little more complex.  If removing the source is too expensive or not feasible, outdoor air ventilation is typically best.  Ventilation is a fancy way of saying open up the windows and allow as much fresh air as possible to flush the area of concern.  I often times recommend having box fans in windows to blow good air in and bad air out.  

So the next time you think to yourself “What on earth is that terrible smell?”, think about some of the questions that I mentioned above.  If all else fails, consider having Indoor Science examine your property for a more thorough investigation.