Collapsing concrete hotel, La Manzanilla, Mexico Pacific Coast © Daniel FriedmanConcrete Dust & Odor Hazards
Track down the source, evaluate, & cure concrete dust & smell complaints in buildings

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Concrete dust & odor hazard source tracking & remedy: this article describes odor & dust complaints traced to concrete: new pours, sawing or cutting concrete, substances spilled onto and absorbed into concrete, and other concrete or masonry-related odor and dust hazards. We include citations of expert sources on concrete dust exposure hazards, and we discuss how to deal with odors from wet or contaminated or spilled-on concrete floors or walls.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Concrete Odors, Smells, Dust: exposure hazards, sources, remedies

Expansion joints in a new poured concrete floor slab, Tucson AZ (C) Daniel Friedman at ODOR DIAGNOSIS CHECKLIST, PROCEDURE we introduced the concept that while concrete itself is not normally much of an odor source once it has cured, people may observe or complain of "concrete dust" odors in buildings where concrete dust is present, especially when combined with moisture.

[Click to enlarge any image]

Reports of concrete dust odors are particularly likely near concrete cutting operations - a situation that may present an airborne particle hazard.

We have observed a similar odor traced to airborne dust in an area of heavily-trafficed cobblestone-and-concrete streets at the onset of rainfall after a dry spell.

Concrete Absorbs Spills, Animal Urine, Odors, Even MCOCs or VOCs

Other "concrete odors" may be traced not to the concrete itself but to substances that have been absorbed into the concrete, such as animal urine,chemical spills, or cleaning products.

For example, leaving a dog or cat shut in a garage or basement where there is an un-sealed concrete floor eventually means you will want to consult ANIMAL or URINE ODOR SOURCE DETECTION and then ANIMAL or URINE ODOR REMOVAL

At VINYL SIDING or WINDOW PLASTIC ODORS we include a case report of an un-sealed concrete floor absorbing odors from nearby outgassing plastic siding & windows, trim, or soffit materials.

Concrete floor cleaned & sealed with a clear finish leving marks of prior tile installation (C) Daniel FriedmanOur photo (left) illustrates a clean and seal approach to an old concrete floor in a building now used as a restaurant in Poughkeepsie, New York. Vinyl-asbestos floor tile was removed and the floor was cleaned and sanitized.

In a final step the new owners polished then sealed the concrete, leaving old stains in place as a point of interest that shows the building history.

The general approach to curing an odor traced to a spill on raw or un-sealed concrete involves these steps:

  1. Clean the surface using a non-sudsing detergent.
  2. Rinse the surface thoroughly.
  3. Remove all standing water, e.g. using a shop vac.
  4. Dry the surface, using fans and perhaps a dehumidifier if the surface is indoors.
  5. When the surface is dry enough (below 12-18% concrete moisture level) you may need to apply a sealant or a sealant followed by a finish surface of expoxy paint, concrete floor paint, or a finish floor surface such as ceramic tile.

    Also see AIR QUALITY STUDY San Miguel de Allende where we are studying airborne the entrainment of airborned dust and debris during rainfall in a seasonally dry climate.

Do we always need to seal the concrete slab or wall? No.

In contrast with the re-sealed slab-on-grade concrete floor shown above, our wet basement cleanup and repair photograph at below left was a different matter. A crack in the building's foundation wall (center of the distant wall in my photo) leaked roof spillage into the space beneath a basement floor that had been installed on sleepers (2x6 lumber glued to the floor slab).

Wet basement repair (C) Daniel FriedmanNo one noticed that water was beneath the floor until more severe weather conditions combined with snow and ice outdoors put so much water below the floor that it appeared up through the subfloor and onto the carpet-over-plywood that had been installed in this finished basement.

The prolonged presence of water in the sub-floor space led to a flooded basement complaint requiring demolition and cleaning.

To minimize the chances of a costly mold contamination problem (that would have required more extensive demolition) the owners cut up and threw outside the soaking wall-to-wall carpeting and removed other wet items from the basement immediately on discovery of the water problem.

Using a shop vac water was removed, then the subfloor was also removed to give access to the space below.

Questions arose including: should we paint a sealant on the concrete floor surface before restoring the new floor? Is there a problematic mold reservoir on the under-side of the wood sleepers and does that need to be addressed?

We pulled up a few sample sleepers in the floor area that had suffered most protracted leakage (these were the most-stained boards) and saw no mold on the underside (glue had sealed the wood surfaces). When the floor was cleaned, dried there were no odor complaints and there was no visible mold. (We also made use of some air and surface tests. No sealant was applied to the concrete. A new floor was installed.

Concrete dust odor complaints: sources, causes, mitigation

Concrete being placed at a Vassar College construction site, Poughkeepsie NY 2013 (C) Daniel FriedmanCommon Sources of Concrete Dust in Air & Building Dust

Common Sources of "Concrete Odors" found Indoors [Opinion]

Reader question: I visited a school in Boston today. In some parts of the building there was an irritating smell that seemed like cement dust. I was told the smell has been there for at least a year. I had been to the building a few times about three years ago and I noticed no smell then.

Photo at left: fresh concrete being placed at a New York construction project. There may be a "wet concrete smell" associated with new pours but that is not genrally associated with IAQ or odor complaints - Ed.

The smell was exactly like what I remembered coming from a limestone rock I got in central Florida when I washed it. Tonight I smelled the rock when it was dry and put my nose right up to it and no smell. Then I got it wet and it had that same very strong irritating dust smell as the school. So at least with with my limestone rock it is washing and getting it wet that causes it. So it is not like dust you can wash away.

I think a woman at the school said they had done a lot of cleaning. Maybe getting cement/concrete wet? I remember this smell, but never as strong, from when I was a kid. Public schools or maybe my father's university office building built probably in the late 1960s earl 70s with exposed concrete.

The smell at the school really bothered me and one of the staff members was herself bothered by it enough to open a window. I am pretty sure it is not good for you especially if you have asthma. Any ideas you have on this will really be appreciated. - K.H. 9/17/2013

The smell seems so much like dust even though it is couterintuitive that it is caused by wetting my limestone rock. So maybe it actually is dust that is somehow chased out of the rock by wetting. Maybe the folks at the school keep mopping to clean it but that creates it. I remember at the school today the smell made me remember the that dusty smell from right after a school janitor would mop the hall when I was a kid. - K.H. 9/17/2013


Old broken up concrete walk - not likely to be a source of concrete odors but a dust source during demolition (C) Daniel Friedman Take a look at SMELL PATCH TEST to FIND ODOR SOURCE and think about doing a couple of simple tests using that procedure. Kenneth, I've thought about this further and have the same impression as you.

For example, I frequently observe an odor that some people describe as "concrete smell"  in a city in Mexico (San Miguel de Allende) in an area of heavily-trafficked concrete and cobblestone paved streets at the start of a rainstorm after a dry period

. The initial rainfall actually increases the level of airborne dust - a subject that I am studying. AIR QUALITY STUDY San Miguel de Allende (just in its infancy, I need more samples).

My smell patch suggestion earlier was intended to make sure that the reported odor is not traced to something that spilled on the concrete, and that the odor actually is emitted from that source - most likely when wet as you suggest.

Please keep me posted on how things progress, and send along photos of the area you are discussing, or additional details if they occur to you, such as the relationship between the odor detection and time of day, weather, building cleaning operations, operation of HVAC systems etc. Such added details can help us understand what's happening and often permit some useful further comment. What we both learn may help me help someone else.

What are the Harmful Constituents in Concrete Dust

Concrete Dust & Odor References Describe Concrete Expozure Hazards & Silicosis

Some useful references about concrete are below. Some of these address the hazards of concrete dust or its control, others, odor sources.


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