Disinfection with gaseous formaldehyde. Fourth Part: Influence of aeration on the level of formaldehyde residues.

After a formaldehyde exposition of 100 cm2 aluminium plates covered with a structured lacquer during 60 min at 40 degrees C and relative humidity of about 90% in a model chamber formaldehyde residues of 9.5, 21.9 and 57 micrograms HCHO 100 cm-2 were recorded for plates exposed respectively to 0.75, 1.5 and 3.2 mg HCHO l-1 air. In the model chamber tempered at 40 degrees C the reduction of the HCHO residues after an additional 60 min ventilation with an internal air circulation was 63%. After a passive aeration for 60 min in a room at ambient temperature (24 +/- 3 degrees C) without ventilation the formaldehyde residues decreased by 70-74%. In a heating cabinet tempered at 40 degrees C after an internal active aeration of 60 minutes the residual formaldehyde diminished by 76-82%.