Date: Fri, 20 Nov 2009 16:25:28 -0800
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Jean & Ken Smith <smith.j.k**At_Symbol_Here**SBCGLOBAL.NET>
Subject: Re: Latex degradation, low humidity,
Chinese drywall? a bit more information
In-Reply-To: <48A020E1942E024DB0F2A6B68A1312440783A5F1F9**At_Symbol_Here**>

Hi Debbie,

I couldn’t resist a further note on the degradation of latex.  Since Davis is in the Central Valley of California, the prevalence of ozone and NOx compounds in the air make for an oxidizing atmosphere.  Unless the air supply has filters specifically for these oxidizers, a lot will be pumped into the lab and could contribute to the degradation.  You could contact the local Air Pollution District for a sense of what concentrations have occurred around Davis.  Of course it is most concentrated in the summer.

Good Luck on the Quest

Kenneth Smith

Retired CIH, CA Dept. Health, Richmond, CA


-----Original Message-----
From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**] On Behalf Of Debbie M. Decker
Sent: Friday, November 20, 2009 3:36 PM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: Re: [DCHAS-L] Latex degradation, low humidity, Chinese drywall? a bit more information


Thank you all soooo much for your input and ideas.


I think we can safely rule out Chinese drywall.  This is a one pass air building and there is a tremendous amount of air being hogged out of the building.  It’s been up and operating for about 5 years or so.  The walls are carefully sealed and painted with an epoxy-type paint so that the walls are easy to clean.  Minimal organic solvents are used – maybe a bit of alcohol or acetone and all of that work is accomplished in a fume hood.  There is no ozone producing equipment in this part of the building – no printers, copiers, fax machines, “ionizing” air cleaners, etc.  That equipment is in the office area and there aren’t any of these problems there.


But your ideas around chlorine-type cleaning materials and lighting effects have some promise.  We’re going to be looking into what type of lighting is installed.  We think they use mostly quarternary ammonium-type cleaners but we’re not completely sure.  We’ll also ask about pesticides but the air system for the research greenhouses is a separate system and those areas don’t seem to have these problems.


Again, thank you for your input – great discussion!






From: Debbie


I neglected to include in my previous post that I thought of ozone first of all, since I have had that issue before.  0.02 to 0.03 ppm of ozone was detected in the areas in question.


Thanks for your input, so far.


From: Debbie M. Decker

Please excuse the cross-postings:


I’m working with a group that works in a secured, containment facility.  The supply air is one pass, the exhaust is HEPA filtered and air change rates are in the 10-15 ACH.  Rubber bands, latex gloves, the gloves on a glove box, rubber stoppers, etc. degrade very quickly in this building – a matter of months.  This causes consternation among my building occupants – “if latex degrades so quickly, what is this building doing to me?”


I have done the following:  datalogged temperature, %RH, CO and CO2 twice, at different times of year, for a week.  First set showed extremely low humidity – below 20%rh – all other measurements within customary.  Second round showed %rh in a more normal range – 35-40%rh.  Magnetic fields were at or below background.  No radioactivity was detected.  The building doesn’t have any weird smells, evidence of mold or water intrusion.  The mechanical system is working as designed, filters in place and without high pressure drop, coils clean, etc., according to my building engineers.


People complain of headaches and stuffy noses, general malaise after working in the building for some period of time.  Someone has suggested Chinese drywall might be a culprit but I don’t know as it quite fits.


Whaddya think?  All ideas welcome, at this point.






Debbie M. Decker, Campus Chemical Safety Officer
Environmental Health and Safety
University of California, Davis
1 Shields Ave.
Davis, CA  95616
(530)754-7964/(530)752-4527 (FAX)
Co-Conspirator to Make the World A
Better Place -- Visit and join the conspiracy



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