INDOOR AIR-POLLUTION BY ORGANIC EMISSIONS FROM TEXTILE FLOOR COVERINGS - CLIMATE CHAMBER STUDIES UNDER DYNAMIC CONDITIONS

The time dependence of the emission of organic compounds from a polyam ide floor covering with styrene-butadiene-rubber (SBR) backing was stu died in three climate chambers (0.03, 1.0 and 38 m3) at 23-degrees-C a nd 45% RH. While volatile compounds such as toluene reach a maximum co ncentration in the gas phase within 1 h and decrease in concentration to less than 2% within 60 h, the concentration of less volatile compou nds, such as 4-phenylcyclohexane, decreases slowly over a period of mo nths. If the chamber is well mixed and a defined chamber loading is ma intained the observed concentrations do not depend on the wall size, t he wall material and air velocity. The concentration of the observed e missions is roughly proportional to the chamber loading, Surprisingly it is not inversely proportional to the air exchange rate. Rather, at high air exchange rates mass transfer from the carpet to the gas phase is enhanced. The ''decreasing source models'' of Dunn and Tichenor (A tmospheric Environment 22, 885-894,1988) have been applied to the data . They allow the extrapolation of experimental data beyond the time av ailable for measurement. The model calculations reveal the presence of sink effects. The role of the chamber walls as sinks can be determine d more reliably if constant sources of an organic compound are placed into the chamber and their increase in concentration with time is comp ared with the theoretical predictions neglecting sink effects.