Re: Off-gassing from joint compound?

[Guest guest]

Can anyone explain the chemistry of this reaction, Terry and I have talked about

this before. I ran into this when a paint manufacturer tried to use this as the

excuse of why their paint smelled on occasion particularly when they had a Miss

mix in their paint of an undisclosed chemical. I found the odor more consistent

with a rise or drop in water vapor pressure in the surrounding air that caused

vapor movement in and out of the drywall/paint. Of course either would happen

when people opened the windows on a cool humid day or an arid day. We believe

the chemical to have been associated with Carbon Disulfide that stinks at very

low PPB, and the odor was consistent with an unpleasant sulfurous odor

(Mercaptan like or sewer gas like) what you would expect from that chemical if

it had impurities such as the commercial grade does.

I've heard this ozone theory a couple of times, and haven't bought into it, but

I confess I've never understood the mechanism, seems if the material reacts with

ozone at 20 PPB it has to be a highly reactive chemical to begin with, which I

guess Carbon disulfide is highly reactive (so I've been told). It also seems as

if there has to be a chemical there that shouldn't be there.

It is used in insecticides and antimicrobials used in anti-fouling paints and

treatments.

Other common uses are solvents and cleaners.

Can anyone shed light on this Ozone theory, I know I'd appreciate it?

Ron

RE: Re: Off-gassing from joint compound?

Jeff,

The odor is intermittent?

Does it get better or worse when the windows are open?

If it does might be the old 20-30 ppb ambient ozone reacting with something in

the taping compound?

Keep me posted. It's a good mystery. Might tie into a couple of cases I've had

over the last two years.

Happy holidays,

Terry Brennan

[Guest guest]

Ron and Terry,

I am famiiar with the odor of carbon disulfide and the odor of the Sherwin

paint off-gassing problem is quite different. Carbon disulfide

(CS2) is an extremenly volatile solvent and I cannot imagine any chemical

reaction with ozone that would produce it.

One lab that analyzed the paint odor from my case claimed that the odor was

due to carbonyl sulfide (OCS, which differs from carbon disulfide by having

an oxygen in place of a sulfur)from the carpet. I am not familiar with the

odor of this compound but I understand that it is not pleasant either.

I do not believe that ozone is involved either, since this would probably

oxidize the sulfur.

The odor from the joint compound was quite different, similar to that of

Impregon which contains a chlorinated phenol.

I just encountered another house in which there was a strange, fishy odor

only on holidays. The origin was ceiling fixtures in the guest rooms, where

the lights were only on when guests visited. That odor is due to

hexamethylene diamine (similar to cadaverine and putriscine, other diamines)

present in decomposing nylon from the insulating base for the Edison bulb

base.

Happy holidays to you all too.

Jeff

Ron writes:

> Can anyone explain the chemistry of this reaction, Terry and I have talked

about this before. I ran into this when a paint manufacturer tried to use this

as the excuse of why their paint smelled on occasion particularly when they had

a Miss mix in their paint of an undisclosed chemical. I found the odor more

consistent with a rise or drop in water vapor pressure in the surrounding air

that caused vapor movement in and out of the drywall/paint. Of course either

would happen when people opened the windows on a cool humid day or an arid day.

We believe the chemical to have been associated with Carbon Disulfide that

stinks at very low PPB, and the odor was consistent with an unpleasant sulfurous

odor (Mercaptan like or sewer gas like) what you would expect from that chemical

if it had impurities such as the commercial grade does.

>

> I've heard this ozone theory a couple of times, and haven't bought into it,

but I confess I've never understood the mechanism, seems if the material reacts

with ozone at 20 PPB it has to be a highly reactive chemical to begin with,

which I guess Carbon disulfide is highly reactive (so I've been told). It also

seems as if there has to be a chemical there that shouldn't be there.

>

> It is used in insecticides and antimicrobials used in anti-fouling paints and

treatments.

>

> Other common uses are solvents and cleaners.

>

> Can anyone shed light on this Ozone theory, I know I'd appreciate it?

>

>

> Ron

>

> RE: Re: Off-gassing from joint compound?

>

> Jeff,

>

> The odor is intermittent?

>

> Does it get better or worse when the windows are open?

>

> If it does might be the old 20-30 ppb ambient ozone reacting with something in

the taping compound?

>

> Keep me posted. It's a good mystery. Might tie into a couple of cases I've

had over the last two years.

>

> Happy holidays,

>

> Terry Brennan

>

>

>

>

>

C. May

May Indoor Air Investigations LLC

1522 Cambridge Street

Cambridge, MA 02139

www.mayindoorair.com

www.myhouseiskillingme.com

[Guest guest]

Steve,

The odor is definitely not due to microbial activity in the dried paint film

since none of the homes where I have observed this were the least bit damp.

On the other hand, there must be some chemistry involved as the occupants

did not notice any odor for about a year, also reducing the likelihood of

microbial activity in the can before application; I also checked left over

cans of paint and there was no comparable odor. The odor seemed worse with

the windows open and in warmer weather, though the former could be due to

mixing caused by movement of the room air due to breezes.

The fishy odor from the center ceiling light fixtures was not very apparent

when the heat was off since the odor was more or less stratified at the room

ceiling. As soon as the heat came on, there was very strong movement of air

at the ceiling due to convection and rapidly rising air at the baseboard

convector at the exterior wall. The odor moved quickly to the room entry as

it was pushed across the ceiling and down at the opposite interior wall.

Jeff

May Indoor Air Investigations LLC

1522 Cambridge Street

Cambridge, MA 02139

www.mayindoorair.com

www.myhouseiskillingme.com

AirwaysEnv@... writes:

> Hi Ron,

>

> I don't know about the ozone theory but I have encountered some bad paint

> odors before. My theory was that there was either a " bad batch " from the

> manufacturer or more likely that there was inadequate biocidal control or the

shelf

> life of the antimicrobial additive was exceeded and microbial growth occurred

> in the paint can before use. The sulfur odor would be consistent with

> anaerobic bacterial growth (sulfur reducers) and the water-soluble odor

molecules

> would migrate to the surface and offgas as a function of moisture content in

the

> paint. Consistent with your theory, I think an intermittent odor from paint

> could very well be due to varying humidity levels.

>

> Steve Temes

>