Ozone [was: Other Experiences Denaturing Mycotoxins with Ozone?]

[Guest guest]

Why wait for studies and make you request them. Here's two:

Carl Grimes

Healthy Habitats LLC

-----

Environ. Sci. Technol., 36 (10), 2185 -2192, 2002.

10.1021/es0113089 S0013-936X(01)01308-6

Web Release Date: April 11, 2002

Copyright © 2002 American Chemical Society

Ozone Interactions with Carpet: Secondary Emissions of

Aldehydes

Glenn C. on* and W. Nazaroff

Environmental Engineering Program, Department of Civil and

Environmental Engineering, 633 Hall, University of

California, Berkeley, California 94720-1710

Received for review September 25, 2001

Revised manuscript received March 4, 2002

Accepted March 6, 2002

Abstract:

Ozone-induced formation of aldehydes was studied on the

surface and in the gas phase above carpets and on carpet

components. Samples of four carpets were exposed to 100 ppb

ozone. Emission rates of aldehydes and other organic

compounds were measured from exposed and unexposed

samples. Surface interactions of ozone with carpets produced

C1-C13 n-aldehydes and several unsaturated aldehydes. Total

aldehyde emission rates increased markedly with ozone

exposure, from 1 to 70 g m-2 h-1 for unexposed samples, to 60-

800 g m-2 h-1 during exposure. One exposed sample emitted

large amounts of 2-nonenal (180-230 g m-2 h-1), a compound

with a low odor threshold. Material balance modeling of a

residence with this high emitting carpet suggests (1) that the

concentration of 2-nonenal would be well above its odor threshold

even in areas with only moderate ambient ozone levels and (2)

that odorous levels of 2-nonenal could persist for years.

Reactions of ozone with gas-phase primary emissions from

carpet significantly reduced the levels of 4-phenylcyclohexene

and produced small amounts of branched ketones. Separately

measured patterns of aldehyde emissions from ozone exposure

of linseed and tung oils were similar but not identical to those

observed from ozone-exposed carpets.

Abstract 2:

H. N. Knudsen, P. A. Nielsen, P. A. Clausen, C. K. Wilkins, P.

Wolkoff (2003) Sensory evaluation of emissions from selected

building products exposed to ozone  Indoor Air 13 (3) , 223-231

doi:10.1034/j.1600-0668.2003.00182.x

The interaction of ozone with eight different building products was

studied in test chambers. The products were plasterboard, two

types of paints on plasterboard, two types of carpet, linoleum,

pinewood, and melamine-covered particleboard. Four months of

conditioning prior to the experiment had left the products with a

low emission. The products´ ability to remove ozone from the air

covered a wide range. For three of the products (plasterboard

with paint, carpet, and pinewood), it was shown that the removal

was primarily due to interactions in the products´ surfaces and

only to a minor extent due to gas-phase reactions. Sensory

evaluations were carried out for five of the products, with different

ozone-removal potentials. A sensory panel assessed the

emissions from sets of two specimens of each product; one

specimen was exposed to a high, but realistic, ozone

concentration (10 or 80 ppb) and one specimen was exposed to

no ozone (background level < 3 ppb). The panel assessed odor

intensity and was asked to choose which odor of the two

specimens they preferred. The perceivable changes in emissions

due to exposure of the products to ozone depended on the type

of product. The greatest effect was seen for carpet. Carpet was

the only product that showed significantly higher odor intensity

when exposed to ozone. Besides, the effect of ozone on

preference was strongest for carpet and resulted in a clear

negative sensory evaluation. A similar but less pronounced effect

was seen for pinewood and plasterboard with paint. No clear

preference was seen for melamine and linoleum.