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Smell test last step (C) Daniel FriedmanOdor Sensitivity Variations
Individual sensitivy to odors varies widely


This article describes differences in individual sensitivty to smells or odors that in turn can be a problem when finding and fixing the source of smells in and near buildings. Just because person A doesn't smell anything does not mean that person B is imagining the odor!

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Odor Sensitivity

Gas leaks at plumbing vent (C) Daniel FriedmanIn addition to the many causes of variation in intensity of odors themselves at buildings (source, wind, season, humidity, mechanical system operation), there are significant variations in odor sensitivity among people, including at least the following:

This collection of anectodal evidence of reports of smells in and near buildings or their mechanical systems makes clear that odor complaints should be taken seriously even if not everyone observes the smell.

Photo: a subtle and hidden leak in a building plumbing vent stack, pointed to by our green & white pen, illustrates the difficulty in tracking down some smells to their source: to find this odor leak we had to inspect the building vent system using a sewer line camera, then open the wall to expose the broken vent pipe.

[Click to enlarge any image]

Watch out: don't dismiss odor complaints because you don't personally observe the smell. Someone with a more-sensitive sense of smell may be the canary in the mine of your building. And some odors may indicate dangerous conditions such as potentially explosive fuel gas, methane gas, or pathogenic contaminants such as sewage.

At SMELL PATCH TEST to FIND ODOR SOURCE - a procedure for testing specific surfaces or items to see if an odor source of if they have absorbed and are re-emitting an odor - we take advantage of this variation in individual sensitivity to smells by recommending that in the conduct of this test you choose someone known to have an acute sense of smell.

Decades of fielding building owner, occupant, or tenant complaints about solving odor problems in buildings has made clear that individual sensitivity to smells varies enormously. Too often one person complains of an odor while another says they smell nothing.

Watch out: if you are the only person who reports noticing a smell after a significant number of other people have been in the same location at the same time and who report no odor, you might want to check with your doctor to rule out any health or neurological disorder.

Supporting Research Cites Differences in Sensitivity to Odors

Research: odor sensitivity to sewer gas, H2S Methane & Related Hazards and other odors

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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2022-02-05 by Inspectapedia Com Moderator (mod) - check for leaks around toilet base then see this odor diagnostic article

@Jennifer,

Check first for leaks around the toilet base, and confirm that the toilet is securely mounted to the floor. If you don't suspect a problem there, see

INDOOR SEPTIC ODOR, OUTDOOR CAUSES https://inspectapedia.com/odor_diagnosis/Sewer_Odors_Fixture_vs_Drain.php#SewerOdorsa

and

SEWER GAS ODORS - topic home,

where we suggest a series of inspection and diagnostic steps to track down the smell source.

On 2022-02-05 by Jennifer - bathroom smells like a porta-potty

My bathroom smells like one of them porter potties you find at a constuction site. You can smell all through my tailerbut, strongly in bathroom. What can i do to fix this horriable odor

This question was posted originally at SEWER GAS SMELL FAQs

On 2021-04-16 by Anonymous

@mod, Thank you!

On 2021-04-16 by (mod) - sense of smell and sensitivity to odors varies significantly across people

@Anonymous,

It is absolutely well-known and widely documented that the sense of smell and sensitivity to odors varies significantly across people, by a factor of as much as 100! (Koe 1986)

Often women have a more sensitive sense of smell but even among groups of men or groups of women individuals sensitivity to different odors varies.


Therefore it is absolutely incorrect and frankly dangerous for men who are claiming they don't smell something to assert that there's nothing there that needs attention.

Watch out: There are potentially both health hazards and methane gas explosion hazards if there's a sewage gas problem in any building including the workplace.

Research tells us that there are many variables in the ability to detect sewage odor's or other odors besides individual sensitivity such as variations in weather, humidity, temperature, barometric pressure, and of course causes a variation in the source disseminating the gas. If more than one person in this case among the women smells the odor then there is certainly no reasonable basis for claiming the odor is not there.

For completeness I add that occasionally when only one person smells something it's possible that the problem is a medical disorder in that individual. That's one of the things that gets checked out in the course of an odor investigation.

You might want to notify appropriate people in building ownership and management of the possibility of a health and safety concern that in the worst case could include people becoming ill or most-extreme case, a methane gas explosion, and of course you're welcome to print and include our comments and opinion as well as any InspectApedia.com page.

METHANE GAS HAZARDS SEPTIC / SEWER

and

TRACK SEPTIC ODORS to SOURCE

may be of use.

Keep me posted.

On 2021-04-16 by Anonymous - what to do when only some people smell a sewer odor?

What do you do when same time same place I smell gas/or sewage in my workplace.

Women smell the men don't so they don't assess the situation. What do I do? The workplace does no testing just smells and says they don't smell and move on.

Watch out: You might want to notify appropriate people in building ownership and management of the possibility of a health and safety concern that in the worst case could include people becoming ill or most-extreme case, a methane gas explosion, and of course you're welcome to print and include our comments and opinion as well as any InspectApedia.com page.

METHANE GAS HAZARDS SEPTIC / SEWER

and

TRACK SEPTIC ODORS to SOURCE

may be of use to your building managers and safety officers.

Keep me posted.

On 2021-04-16 by Anonymous - men don't smell the sewer gas so refuse to address it

What do you do when same time same place I smell gas/or sewage in my workplace. Women smell the [odor] but the men don't so they don't assess the situation. What do I do? The workplace does no testing just smells and says they don't smell and move on.

On 2020-11-15 - by (mod) - Sewer smell in Bathroom 2nd floor apartment. 1st floor apartment smells nothing.

Carol

Let's start by taking a look at the dianostic suggestions at https://inspectapedia.com/septic/Sewer_Gas_Odors.php SEWER GAS ODORS

Your plumber's on a reasonable track; test the vent system for leak, perhaps using a pressure test;

On 2020-11-14 by Carol - People visiting can smell this but no one of the guys who do work here can.

Sewer smell in Bathroom 2nd floor apartment. 1st floor apartment smells nothing. Stack to roof has been checked, no cracks. New bathroom tub trap has been installed. Smell is not as strong as before but sewer smell is still there but comes and goes not continuous as before.

People visiting can smell this but no one of the guys who do work here can. When first trying to remedy smell,landlord put some type of sanitizer in catch basin directly outside the building. I smelled it very faintly at first but about 3am the sanitizer smell in my apartment was so strong I had to open windows.

Landlord has thrown up their hands they do not know what else to do and out of 200 Co Ops I am the only one with this issue. This is a very old building but my unit has been rehabbed and everything new here. Called a plumber and he said he never heard of 2nd floor with a sewer smell and the only thing he could think of is one of the vent pipes in bathroom is cracked.

Since the bathroom trap has been done it seems to me if there is water running bathroom sink or kitchen sink or tub I am not smelling anything. If water isn’t running some where I smell it. If I use the bathroom during the night it’s the first thing I smell as soon as I walk in. Need to get this fixed. Can’t live like this.

On 2019-09-17 by (mod) - trouble breathing at night

Serge

Have you discussed this breathing concern with your doctor? IF not, do so as there are some specific respiratory complaints associated with exactly the situation you describe: lying down to go to sleep at night.

Be sure you have working smoke and Carbon monoxide detectors.

Do others in the home have respiratory or IAQ complaints?

Has your heating system been inspected for proper operation and safety?

On 2019-09-17b y serge

whenever i go into my bedroom at night, i seem to gasp a bit, for air, and become anxous, and can not sleep well. dru throat in morning, some. feels different whe i am there.

On 2019-07-10 by (mod) - kerosene, gasoline or can bug spray smell

Freon is odorless so that won't explain the smell.

Inspect the property and review its history for use of insect treatments or for fuel smells;

Narrow-down the area where odor is strongest.

On 2019-07-10 by wes recasner - night club has an odor that smells like kerosene, gasoline or can bug spray.

night club has an odor that smells like kerosene, gasoline or can bug spray. Power company came out to check for gas leak but found nothing. Do you think it can it a feron leak.

On 2018-11-01 by (mod) - only one person reporting that there is a smell

Smell test setup (C) Daniel FriedmanJohn

I appreciate that this is a difficult subject to handle tactfully and effectively. However if you have looked carefully at the situation and are unable to find any corroboration for the teachers complaints it seems to me that it would be appropriate to encourage the teacher to get advice from her doctor.

If her doctor or his doctor says that the teachers complaints could be caused or aggravated by something in that teachers environment then we might look further. But the doctor may also say that there is not such a basis which simplifies the problem from your end.

Unfortunately the total Spectrum screen for chemicals or particles or other contaminants that will capture all possible issues.

Therefore part of a review of the applications of pesticides or other events that could have left a lingering issue. I also look at building materials for possible known sources of common off-gassing in recognition that people's sense of smell and environmental sensitivity varies.

But back to my initial point of view if none of those then the next step is for the teacher to see a doctor. I appreciate that. Keep us posted and be sure to ask for their follow-up questions if we can be of any possible help.

...

I meant to say but mistyped that there is unfortunately no single broad spectrum screen or test that can possibly capture all of the possible gas chemical or particulate environmental contaminants. That's why an investigation needs to be based on interviews and physical data and observations.

On 2018-11-01 by John - No one that has been sent to do the smell test has reported smelling anything out of the ordinary.

We have a teacher that says she smells an odor that is causing respritory problems and is causing her eyes to burn.

She also states that 1/3 of her students are having asthma problems because of it. When questioned, the students say they do not smell anything and they are not having problems.

The teacher states that it only happens on certain days then changes her story that it is happening everyday. No one that has been sent to do the smell test has reported smelling anything out of the ordinary.

So, where do we go from here. No other classrooms report an odor. The A/C has been checked out and all is normal as far as we can tell. The return air is a common open air return above the ceiling.

 

On 2017-01-15 by mod) - dead animal may be an odor source

Look for a dead animal in the duct system or in the air handler

On 2017-01-15 by Trina - My dog jumped up and started smelling the 2 vents

My dog jumped up and started smelling the 2 vents in my living room, then proceeded to go to the basement door, so I opened the basement door and she walked down as I followed her. She went straight to the furnace, water heater, and the dryer and started smelling around them intensely.

All mentioned is electric. Just curious if anyone would know of any cause or odor, I might not smell, but my dog does? Thank you

On 2016-11-26 by (mod) - service tech says can't smell a thing - We were sick, from the fumes!

Steven

I agree that you need an *independent* expert to confirm that there is an oil smell and to help find its source.

Watch out: not only might fumes be unhealthy to breathe, if there are fumes from leaking oil burner exhaust or fumes from improper oil burner operation, the heating system would be unsafe.

The fact that a cleaner (Simple Green) was sprayed suggests more that there was a leak or spill during service, and perhaps the leak was not fully cleaned-up or the fumes from the spill have invaded nearby soft materials such as insulation.

On 2016-11-25 by Steven Paden - techs can't find the smell, sprayed with Simple Green

We got are 1 year tune-up on our oil furnace., after the tech left oil fumes radiated the home.

We spent the night in the camper, aired out the house.

The second tech came up, said "I can't smell a thing. We were sick, from the fumes.The Tech left when leaving he said "everything is alright you need a new blaster, which they don't make any more". A third tech came up "I can't smell a thing, he went thru the system, put some simple green and left.

The home still has oil fumes in it.Is there a device that registers diesel oil fumes in the house,so we have documentation of the smell level? The people they keep sending out are lying,my family is still getting ill.

This Q&A were posted originally at HVAC SYSTEM ODOR FAQs

On 2015-09-08 by (mod) - smells vary by time of day

Perhaps still night air, cooler temperatures or depending on the actual odor source, an industrial process or vent that operates only at night can explain why you perceive an odor only in the early morning.

Changing the indoor relative humidity might affect smell transport or perception but it certainly won't address the odor source nor the possible hazards involved.

Few buildings can tolerate having regular water running through the building without structural damage, rot, insect attack, or mold contamination. Find and fix the spring leak through the walls.

On 2015-09-08 by Anonymous - why would this smell only occur during these early hours?

Hello, I just wrote the e-mail about waking up at 4:30 am. My question is why would this only occur during these early hours?

The smell goes away later in the morning and I do not smell it during the day or evening.
Thanks! juliem4@comcast.net

 

On 2015-07-03 by (mod) - get some help finding the odor source by using people coming in from fresh air

Dolly

You'll want to get some help finding the odor source by using people coming in from fresh air to give an opinion of where odor is strongest; also see our smell patch test procedure as that may help you out.

On 2015-07-03 by Dolly

We have had this strange chemical like odor in our house for about a month. I thought it was the sewer. I called a plumber. Not one but 3 different ones on 6 different occasions. Nothing. I called the gas co.

Nothing. I called the Health Dept. Nothing. It is so strong sometimes I can't stand to be in the house and is worse at night time. Any suggestions? I even slept in my car a couple of nights. I really don't know what to do next. Help

Originally posted at CHEMICAL ODOR SOURCE CHECKLIST FAQs-2

 

On 2015-06-17 by (mod) - electricity & gas companies said no problem found

at INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING ODOR DIAGNOSIS & CURE that index lists quite a few things to try.

On 2015-06-17 by alberta - burning wire smell

i have an odor in my house, that i cannot determine what it is. i had the furnace checked, the electricy and also the gas compamy.

they said they don't find a problem. at first it smelled like an electrical wire burning smell. but now it a smell that gives me a headache and maybe a cough.

don't know what to do, or who to call. i recently had a new roof installed on my house, could they have blocked a vent? please help.

On 2015-03-05 by (mod) - bacterial growth in water

Karen, bacterial growth in water can produce a variety of smells as can fungal growth.

I'd want to know if the heater or it's relief valve has been leaking - which is a safety worry. Next I'd look for leaks into a building wall, floor or ceiling cavity - that can produce hidden but smelly mold.

On 2015-03-04 by Karen - I have asked other residents if they have had this odor but no one else has noticed it.

I get a garlic smell in the hot water heater closet under the stairwell in my townhouse. It is on an interior wall between 2 units. There is a small pcv vent pipe in the space between the two walls that comes into my closet.

I have asked other residents if they have had this odor but no one else has noticed it.

It is very strong and comes & goes for weeks or months at a time. I've lived here over 20 years & it just started suddenly last summer. I haven't been able to find any pattern of weather that I can relate it too. Is there anything specific like a mold, etc. that would cause that garlicky smell.

 

Question: odors in a high rise building hallway - others smell it but I react to it

(June 25, 2014) Arlene said:

I live in a high rise building (more than 30 floors). Since February, there has been an odor in the hallway outside my neighbor's apartment and now also outside my apartment and sometimes coming into my apartment.

Others smell this, too. But I seem to be the only one having a reaction (I can feel it on my tongue and in my stomach).

The building did a test for organic compounds (unfortunately when I was away). I have the "negative" results, and the building intends to do nothing else.

The smell is intermittent. Sometimes it is as if it was never there. Sometimes it is weak. Sometimes very strong. People think it is a chemical odor; some think it seems like strong cleaning materials. The building management denies any responsibility for the odor.

There were 2 times that wallboard was breached in repairs since I moved in over 2 years ago: (1) to deal with some leak that was not in my apartment but apparently originated within a chase in my apartment that caused a leak of a fresh water pipe in the storage room; (2) repairs in the ceiling outside my apartment; I am unsure what was fixed. I cannot tie the origin to either repair but cannot rule them out. My understanding is that it is possible that the repairs breached fire stops that were not repaired.

I do not know what to do next. The smell makes me feel ill. I cannot figure out what we are smelling or what the path to my area of the building might be.

Reply:

Arlene,

Unfortunately, doing a "test for organic compounds" may have been a bit of an unreliable shot in the dark, as the chemistry of gases and odors can be complex so that choosing a rather specific test may not give an assurance that "nothing is present".

Keeping an odor log that relates smells to various changing factors such as weather, occupancy, operation of equipment, and using a smell patch test approach can usually narrow down the source.

Keep in mind that elevator shafts, stairwells, HVAC systems, vent systems and other mechanical means can transport odors in tall buildings.

Question: Multiple chemical sensitivity from mold, VOC sensitivity

(Mar 17, 2014) joseph williams said:

my35 year old daughter and husband bought a modular home 2 years ago. she has now gone from slight case of multiple chemical sensitivity from mold in their first house. and moved into a modular home,

now 12 years old has caused her sensitivity to any voc producing products that she is not able to spend more than a few minutes in the house before starts reacting with nausea and headaches. for the past year, she and her husband (he is not affected) live in an outdoor shed. a series of air quality tests last year showed very high levels of multiple chemicals

including very high amounts of formaldehyde. they got rid of all furniture, had all carpet and padding removed, only furniture left in house is their bed they can't use.

They have no heating system in place because the propane made her sick. she wears a triple filtered face mask over her nose and down to her chin when entering the house. selling the house is not an option.

plus she can not get near husband coming home from work until he showers and bags all his clothes and changes. there seems to be no solution on the horizon. Is there any way they could legally get out of the mortgage from her severe health concerns?

Reply:

Joseph, I'm sorry to read of the health concerns you describe, but this is a legal question not one for a building diagnostician. Your daughter and husband will want to discuss their concerns with their bank and if necessary with their attorney.

I caution that for someone suffering from MCS bailing out of a home, ruining one's credit, undergoing legal and financial stress around that topic, may be only jumping from the frying pan into the fire so to speak: that is, how do we know in advance that the new home will be less problematic than the current one?

 

Question: how to clean pipes in an old building - sensitive to smells because of restricted airway disease

(May 10, 2014) Jessica said:

I clean in very old buildings with very old pipes. I am told to put water down the drains to take care of this problem. I have seven buildings but two in particular that horrible fumes come out on windy and hot days. Rust also comes out of the sink and toilets when the sprinkler pipes are flushed making the toilet & urinal water brown.

I am sensitive to smells because of restrited airway disease. I know I am in the wrong business and I did get sick at my work in a different area in the past.

This building was checked out on the third day of the horrible fumes and of course by then, they has abated. I did not put water in the trap on purpose because this not what all the fumes were from. I wanted them to see that was not the problem.

This building and it's pipes are from the late 50's early 60's. I was told the pipes are broken up under the building and obviously very old by some of the older Craft employees.

The fumes are in two of the four bathrooms on one side and the custodial closet. In the custodial closet there is an underground that is coverd and that room reeks too. Because the third day the fumes were not there, I looked like I didn't know what I was talking about.

I did get sick on top of my restrictive airway disease and that scared me even more. I came down with horrible head cold and headaches.

Making my breathing even more difficult. What would make the fumes come and go? Is it dangerous? Can it be fixed? Would it cause the added effects that I mentioned? I know alot of questions but I have to have my ducks in a row when I return to work from being sick. Thank you so much for yur time.

Reply:

Jessica

There is more building specific information that one would need to give a reliable diagnostic answer to what's going on.

Rusty water is not necessarily dangerous; but sewer gas, if that's entering the building, could be quite dangerous both as a health hazard and an explosion hazard - IF that is what is present. The causes are not what one could diagnose from just a text message, though our articles on sewer gas odors list many common causes such as blocked drains and defective plumbing vents.

If you see open drain cleanouts, sewage spills, leaky pipes, or smell what you think is sewer gas (sewage smell or sulphur or methane gas smell) you should report those to appropriate building management as safety and health hazards for everyone.

Question: sewer smell in storage room under staircase

We have been having sewer smell in the storage room underneath our staircase for 2 years. We tried a lot of things including buying a combustible gas detector.

The 0.01ppm detector detected nothing. But our nose can still smell it. Occasionally we had smelled the same in the adjcent bathroom (they share a wall).

But it wasn't consistent and not always. It's so misterious and we are desperate to get it resolved. Any help/advice will be highly appreciated!!! - Still Searching 3/11/12

Reply:

Try the diagnostic suggestions at ODOR DIAGNOSIS CHECKLIST, PROCEDURE

 



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