A study of carbonyl formation within an innovative indoor air pollution abatement system

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Virginia Tech


Testing was conducted on the pre-prototype unit of an innovative indoor air pollution abatement system which used catalytic ozonation as a mechanism for oxidation and removal of organic contaminants. The system was evaluated for carbonyl production when the system was challenged with chemicals used to simulate polluted indoor air. Carbonyl compounds, which are potentially toxic partial oxidation products, were monitored using EPA Method I P-SA. The objectives of the study were to qualitatively and quantitatively determine if carbonyls were formed in the airstream when the system was operated, and if so, to determine what factors affected the concentrations of these compounds.

Trials were conducted using benzene and 2-butanol as challenge chemicals. A variety of test conditions were used to determine factors affecting carbonyl concentrations, including temperature, presence of challenge chemicals, sample location, relative humidity, presence of ozone in the airstream, and two interaction variables. No carbonyls were detected in the airstream within the air cleaning system when benzene was used as the challenge chemical. When 2-butanol was used, four carbonyls were detected at various stages of the system, under varying conditions. The carbonyls detected during these trials were formaldehyde, acetaldehyde, acetone, and butanone. Statistical analyses of the data indicated that the pre-prototype unit of the air cleaning system caused increased levels of acetaldehyde and butanone, and possibly formaldehyde, in the airstream when challenged with 2-butanol. Acetone concentrations in the system were affected only by humidity conditions.