CONCENTRATIONS AND DECAY-RATES OF OZONE IN INDOOR AIR IN DEPENDENCE ON BUILDING AND SURFACE MATERIALS

The decay of ozone in indoor air was measured in a closed chamber afte r contact with different building materials and residential surfaces. The tested materials were: vinyl wall paper, woodchip paper, plywood, latex paint, fitted carpet, and plaster. In the summer of 1996, the en try of ozone from ambient air into indoor air during ventilation and t he ozone decay in indoor air, after windows had been closed again, wer e studied. Measurements were done in a residential house on the outski rts of Berlin. The following results were gained: the chamber measurem ents showed a decay of ozone after contact with most of the materials put inside the chamber. Higher decay rates have been obtained for wall papers, plywood, fitted carpet and plaster. As described in the liter ature, ozone is able to react with olefines inside the materials and i s able to form formaldehyde and other components. This formation of fo rmaldehyde could also be confirmed in our investigations. Thus, in mos t cases, the formaldehyde concentrations were lower than the German gu ideline value of 0.1 ppm. The formation of formaldehyde could be preve nted when a special wall paper that was coated with activated carbon w as used. In the house, a complete ozone diffusion into indoor air took place during ventilation within 30 min. After closing the windows, th e ozone concentrations decreased to the basic level before ventilation within 60-90 min. (C) 1998 Elsevier Science Ireland Ltd. All rights r eserved.