Hygienic aspects of the use of pressed-wood products in residential buildings. Part II. The effect of environmental conditions (temperature and relative humidity) on formaldehyde emission from particleboards.

The effect of air temperature (25-45 degrees C) and relative humidity (45-85%) upon formaldehyde emission from particleboards produced in three different plants was examined. The plates measuring 40 mm x 100 mm were kept in the climatic chamber in dynamic conditions (1 air exchange per hour) loading factor 1 m2/m3. Air samples from the chamber were collected for 4 subsequent days. A considerable effect of temperature and relative humidity upon the increase of formaldehyde emission was found, especially at simultaneous action of these two factors. The effect of temperature "shock" was determined after a rapid elevation of the chamber temperature from 25 degrees up to 40 degrees C. Several days after the steady state had been established, the temperature was lowered again to 25 degrees C. The temperature "shock" did not change the stable emission rate of CH2O from materials tested.