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ODORS GASES SMELLS, DIAGNOSIS & CURE
AIR POLLUTANTS, COMMON INDOOR
AIR QUALITY IMPROVEMENT STRATEGIES
BOOK MOLD, Moldy Book Cleaning
CAR MOLD CONTAMINATION
CAT DANDER in buildings
CHEMICAL CONTAMINANTS in WATER
CHLORINE IN DRINKING WATER
COMBUSTION GASES & PARTICLE HAZARDS
DIRT FLOOR MOLD CONTAMINATION
DUCT SYSTEM & DUCT DEFECTS
EMERGENCY RESPONSE, IAQ, GAS, MOLD
Fireplaces & Woodstove Contaminants
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
GASES, EXPOSURE, TESTING
GAS DETECTION INSTRUMENTS
GAS EXPOSURE LIMITS & STANDARDS
GLUES ADHESIVES, EXTERIOR CONSTRUCTION
HEATING OIL EXPOSURE HAZARDS, LIMITS
INDOOR AIR HAZARDS TABLE
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
LIGHT, GUIDE to FORENSIC USE
LP & Natural Gas Safety Hazards
METHANE GAS SOURCES
MILDEW in BUILDINGS ?
MOISTURE CONTROL in BUILDINGS
MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD
MOTHS, MOTHBALL ODORS
MSDS Material Safety Data Sheets
MVOCs & MOLDY MUSTY ODORS
ODORS GASES SMELLS, DIAGNOSIS & CURE
OIL, HEATING, EXPOSURE HAZARDS, LIMITS
OIL HEAT ODORS & NOISES
OIL TANK LEAK & ODOR CAUSES
OIL ODOR SOURCES
OUTHOUSES & LATRINES
OZONE for MOLD OR ODORS
PET ALLERGENS / PET DANDER
PET STAINS & MARKS in BUILDINGS
PET STAINS on WALLS
SEPTIC SYSTEM ODORS
SEPTIC TREATMENTS & CHEMICALS
STAINS on & in BUILDINGS, CAUSES & CURES
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
THERMAL IMAGING MOLD SCANS
UREA FORMALDEHYDE FOAM INSULATION, UFFI
URETHANE FOAM Deterioration, Outgassing
VENTILATION in BUILDINGS
VINYL CHLORIDE HEALTH INFO
VINYL Siding or PLASTIC Window ODORS
WATER TEST CHOICES & WATER TEST FEES
WATER TREATMENT EQUIPMENT CHOICES
These articles explain how to diagnose, test, identify, and cure or remove a wide range of obnoxious or even toxic odors in buildings, in building air, in building materials, or in the building water supply. We discuss odors from a variety of sources including animals including pets, dogs, cats, or unwanted animals or dead animals, formaldehyde odors in buildings from building products or furnishings, plumbing drains, plastic or vinyl odors from building products, flue gases, indoor mold odors, oil tanks or oil spills, pesticides, septic odors, sewer gases, and even abandoned chemicals at properties.
Our page top photo shows our local skunk rummaging on a nearby golf course. This is about as close as you want to be, especially if you see a skunk meandfering in daylight. This skunk was found dead two days after this photo was taken, most likely due to rabies. .
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At left the author demonstrates a smell-patch test that can be used to track down odors to their source in buildings.
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Frequently Asked Questions (FAQs) about tracking down and curing odors in buildings
Question: Odor Traced to HVAC Condensate Pump
[We] had a very bad smell in basement some days worse than others changed seal on toilet at the top basement steps re caulked the lead seals on the two cast iron stacks . The days we washed clothes [the smell] seemed worse so we washed one day and didn't dry until the next day. When we ran the dryer the smell really was bad.
So I got on the floor started smelling every thing I could find. I finally got by furnace and got close condensate pump [on the floor next to] the air handler [heating and air conditioning equipment]. And there it was [the source of the horrible odor].
I had installed [the condensate pump] about five years ago and I had never cleaned it. What a mistake. I [removed and thoroughly cleaned the condensate pump] AND NO MORE SMELLS! - Gene Lovasz
Comment: Odors coming from dirty condensate pump reservoir
Thanks Gene for pointing out that a dirty condensate pump can be a source of unexpected odors and smells.
I suppose that on an HVAC system whose condensate pump runs only seasonally, water left in the pump body may support both algae and bacterial growth that could smell horrible. Cleaning the pump with household cleaner or even a dilute bleach solution was a smart step. I'd take a look at the condensate pump tubing as well; sometimes crud can collect in a low spot in the plastic drain tubing that ultimately blocks drainage.
Question: Sweet / Fume type smell in a two story house
For the past three weeks my father has had a sweet/fume type smell in his two story house. The odor is concentrated in his bedroom. Professionals have come out to clean the air vent/ducts, the carpet cleaned, home inspector etc. and have not been able to determine the source of the odor. He has open all the windows, run the heat any and everything suggested nothing has worked. He has had to throw furniture, bedding etc. away because of the odor. The odor has gotten so bad he is unable to live in the house.
The service people who have been to the house have no clue and also aren't able to direct us how to determine what the problem is and how to fix it. Environmental companies said they need to know specifically what they are testing for such as mold etc. There is no construction going on in the area. He is at his wits end. He lives in Houston, TX. Any assistance anyone can provide would be greatly appreciated. - T. Wilson 8/7/11
Reply: distinguish between sweet fumes and mold odors
Please see Six Steps in an Organized Approach to Finding & Curing an Indoor Chemical Odor below in this FAQ section.
Question: Burning or Electrical Heater Odors: tracking down a burning smell when the air conditioning is on
For the past 3-4 months, some of our employees are complaining about a burning smell ( like the smell when you turn on the heater after a very long time) in the building when the air conditioning is on. I had a couple of HVAC companies come and check out our system but they couldn't find anything wrong. Any ideas? - Fieldpiece 9/12/11
Question: Animal or pet feces or urine odors: tracking down a rancid sweet wet paint odor in one room - suspected pet odors from urine or feces
What could be the source of an odor that smells like rancid, sweet, wet paint? The smell is contained to one room of our house, it builds up when doors and windows are closed, is all the time and we can't pinpoint exactly where in the room. We moved in 4 months ago, and it smelled.
We thought it was wet paint (previous owners painted) even after weeks and weeks and no other room (that was painted) smelled. We wound up gutting the walls down to the studs, replaced insulation, drywalled, and painted. It smelled like fresh wet paint, and when that dried we were back to the same offensive odor. We've tested for mold with an IH, tests were negative. Please help!!!
We are desperate, it's my youngest daughters room and she has been sleeping in her sister's room until we can figure this out! Thank you. Wendy K. 11/6/11
Unbelievable Wendy but we seem to have the same thing going on in one small area of our house, a slightly sweet paint, disinfectant or perfume smell. We aren't sure which. (We moved in 12 months ago and have looked behind the walls in the soffits and in the adjacent crawlspace and found nothing.) We have been ventilating the entire time but the smell is still there when we close the room up today. I am going to do the patch test next week. - Chris 11/18/11
Hey Chris, did the patch test help you identify anything yet? Did the previous owner have pets? Ours had a big dog and after all our attempts, we are down to the floor. We are thinking (hoping) it just might be an abundance of dog urine that soaked through the wood floor. My husband found a product at PETCO that addresses this, something specific for dog urine removal. It is kind of perfume itself but we doused the floor twice and are crossing our fingers. Good luck! - Wendy 11/28/11
We had a dog defecating and peeing and leaving it on cement in garage and tile in basement entry, so it's not discovering the cause but curing it. One door frame and the door (as its' a set) was affected and will need to be replaced- but can the floors be cured of the odor? A company that was supposed to take away that smell came and failed to do so. I heard that putting pet product liquids for pet waste is another way to work on it. What would you recommend? - Elaine 3/8/12
Reply: pet odors in buildings and success with removing them: clean & seal surfaces or remove materials
Chris & Wendy:
Our experience is that dog urine can soak deeply into wood flooring, especially if the floor was covered by carpeting and the urine thus remained for a long time. Odors from dog feces are usually easier to cure if the feces were on a hard finished surface, but feces dropped on concrete (a garage floor) or tile (grout joints) can leave oils and fluids that soak into those surfaces.
While commercial deodorizers can reduce the complaint, and some enzymes can actually break down organic molecules that are part of an odor problem, it's often the case that sanding, re-finishing, sealing, or even flooring or drywall and trim replacement are needed.
Where a surface is to be left in place, such as a garage floor, try using a commercial concrete or tile cleaner followed by thorough rinsing (vacuum up the rinse water if it's in a basement or garage that can't be hosed to outdoors. Then when the surface has thoroughly dried, if odors remain you may need to try coating the floor with a sealant. Some of the fungicidal sealants used in mold remediation or odor-controlling sealants used in response to fire damage in buildings can cure the remaining problem.
Details about tracking down & removing animal odors (or human odors) in or on buildings are at ANIMAL ODORS IN BUILDINGS.
Details about sealants for these applications are at FUNGICIDAL SPRAY & SEALANT USE GUIDE.
Question: dead fish (dead animal? odors in the kitchen
There is an odor in my kitchen that is likely a dead small something. I have looked behind refrigerator and stove, and removed anything that can be looked under. But there are floors under cabinets that would require carpentry to remove the shelf....want to know that that is the spot before I begin. How can I identify the location of the odor? Is there any gadget for that? - Jane
Reply: try a borescope before destroying cabinets or walls
I'm not sure it'll work in this case, Jane, but try our
I'd see if the odor can be traced to a drain line.
Also, look for a dead mouse or other dead animal under an appliance (fridge, dishwasher), or under a cabinet, or even in the walls;
Finally, you may find a local home inspector who has a flexible borescope that can peer into tight areas such as under cabinets either by snaking the scope through an existing gap or opening or by drilling a small unobtrusive hole such as i the top of kick plates below your cabinets or in walls where odors seem strongest. An example of using a borescope is provided at HIDDEN MOLD, HOW TO FIND.
Question: musty odor through interior partition wall, worse in damp or rainy weather; high VOCs at kitchen drain; possible sewer gas odors
I have a musty odour coming from the wall that separates my kitchen and living room which worsens when it is damp, rainy, there is no heat on or the AC unit is running. An environmental inspector did an AQ test for mold from the electrical outlet on the living room side, where the odour was quite strong but the results showed very low concentrations of mold spores compared to outside. T
he inspector also used a PPB Rae to measure volatile organic compounds at the kitchen drain which showed extremely elevated levels of VOC's between 35000 to 83000 ppb when initially operating the water. The numbers dropped significantly after the water had been running. The conclusion of the inspector was that plumbing is likely to need repair in the wall cavity and potentially the main trap at the entrance to the building.
Would a camera inspection be able to show if there is a problem in the wall cavity or should the wall be opened up? I have concerns about the latter because of the possibility of contamination from whatever is causing the musty odour. I have smelled sewer gas on at least two occasions, first under the kitchen sink and the second time in the electrical outlet on the living room side. Thanks! - Denise 1/13/12
Recently my neighbor has done some extreme excavating, removing two home and making a parking lot. I have at times noticed an extremely awful smell in my basement(rotten sauerkraut), I think it is sewer gases, but how do i check. City sewer line I am the next to last home on the line. I have had severs head aces nausea, not all the time,I don't have much money for a lot of testing, who do I call? - Beth firstname.lastname@example.org 4/10/12
Watch out: Beth, since you are describing possible damage to and potentially dangerous (explosive) leaks from a public sewer, you should call your city building department promptly to describe the odor, and construction, and worry about what might be a dangerous sewer gas leak.
Denise, running HVAC equipment, fans, or even changes in how windows or doors are open or shut, or changes in indoor or outdoor temperature and similar conditions or changes all affect how air moves in buildings. In cases of enough negative pressure indoors (rising air currents, running exhaust or whole house fans, for example), these can cause backdrafting out of building drains - a condition that is made worse if drains are not properly vented or if the vents are blocked.
I'm not sure what sense it makes to measure VOCs at a building sink drain. I have never measured a sink or tub drain in a building that had seen use that did not cause the instrument to respond - the contents of traps are often a bit smelly on close inspection. On the other hand, dry traps, or traps that are siphoned dry during plumbing system use, or defective or blocked building vent piping can be a serious, even dangerous source of sewer gases. Some odors traced to building walls were in fact traced to openings in a vent piping system in the wall.
Question: dirt floor smells over possible outhouse location
We live on a farm it has a double garage open front dirt floor. on the back is a small area which i think was a old drop hole toilet witch is filled in and open to shed . when you walk past or go in shed there is a very strong smell of sewage . what can be put on the dirt to get rid of smell thanks - Bernie 2/25/12
Reply: use an impermeable membrane below the soil to reduce odors in a shed over an old outhouse pit
Bernie, indeed the soil where an outhouse previously stood can continue to hold concentrations of waste for years because of the concentration of sewage with comparatively low water content, deep in the soil where there is a lack of aerobic bacteria, and probably because often lime was added to control odors, also preserving the waste from bacterial action. Usually, where the soil is open to the air outdoors it's not a source of complaints if it was buried with several feet or more of clean fill.
But in a shed or enclosure odors from gases passing out of the soil may indeed be a problem. I would not try treating the dirt itself with any chemical or deodorant - not only will it probably not work, it may simply be a new contaminant. You might find success by removing a top layer of soil, installing an impermeable membrane (rubber EPDM roofing would work, or a plastic intended for soil burial such as sold by geotextile and foundation waterproofing manufacturers), and burying that layer again with soil.
Question: How can we track down the source of a chemical smell in our condo?
I currently own and live in a condo and for several months now my wife and I have noticed a very strong smell in one of our bedrooms. The smell has been strong enough to make it impossible for us to be in that room without the window open and as the smell continued we finally reached out to have the air tested in the bedroom. We found (having tested 3 times) high level of various VOCs, most prevalently 1,4 dichlorobenzene.
Unfortunately, while we've established something is wrong, none of the air testing companies we used could figure out where it was coming from (not really their specialty). We'd hoped the building would get involved and spent months dealing with them but things have become more urgent as my wife is pregnant and due in 2 months.
We can't bring a newborn into this environment and so are looking for someone to help us find the source of the contamination (rather than just confirm that it exists). Is this something you can do? If so (or if not, if you don't mind) please get back to me ASAP. Between waiting too long and the frustration of dealing with various service providers and our own building we are really in a rush to have this resolved. - Anon. 5/31/12
You may have already read that dichlorobenzene is often used in pesticides, mothballs (see Are mothballs an indoor air quality or health concern?) , disinfectants, and deodorants. If you are confident that your tests identifying this chemical were accurate AND that it is most likely the chief or only contaminant present, those uses may help suggest how to track down the actual odor source.
The fact that the odor is traced particularly to one bedroom will be helpful, but depending on what we think has happened in your home, I'd suggest being cautious in concluding that the risks are only in that area. For example, if the odor is due to use of a pesticide, it would more commonly have been applied in multiple areas.
Question: desperate for help tracking down chemical drug smells in apartment
I am desperate for your help. On your web page there is mention of neighbors cooking drugs in a section titled "question:chemical odors,air fresheners, ozone,secondary air pollutant hazards; i can't pin down the source of a chemical odor in my house." this is a big problem in the apartments where i live too.
However my sister who is disabled with m.S. Has severe reactions to these smells. She moved from here to a house in a "nice" place. To make it short - her neighbors are probably cooking a drug called spice and the odors are making her extremely ill. (racing heart, nausea, burning eyes etc). The big problem is few people are there in the middle of the night when it happens.
Her aide called me and said she can smell it.
The fire dept and police want her to prove it before they will do anything.
Her landlord thinks she is nuts.
I know her to be on target with all of the terrible drug smells from this place and we tried to get her out of it. If you have any advice or devices please contact me. I am afraid she will end up in the hospital and no one will help her at all. My e-mail is [redacted] i am home in the am and work in the aft. & evening. Thank you for putting this info online. I look forward to talking to someone soon.
Oh i also bought her detectors recommended by the fire dept(riddick- i think) and they go off at 22 which is high and still nothing can be done until we prove something. - M.B.
I'm doubtful that the "detectors" you purchase are suitable for detecting chemical odors or odor sources. Typically the detectors recommended by a fire department will be smoke detectors or carbon monoxide detectors. Both of those are devices that you and family members should have properly installed and working wherever you live, for fire and carbon monoxide hazard safety, but these devoces are not intended for nor useful for tracking down chemical contaminants.
Your other options include
- ask your local health department for help
- hire an expert - if so make sure (by asking) it's someone who actually has expertise and experience in odor diagnosis and cure, not a general-practitioner hygienist or home inspector who may lack that expertise. Something I'd avoid is paying someone to just stop by to perform a specific chemical, gas, or air test - it's too much like shooting in the dark and is at too much risk of giving a false negative result.
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