Indoor air pollution due to chipboard used as a construction material

Abstract

Chipboard (particle board) is a common building construction material made of wood-shavings held together with a urea-formaldehyde glue. Due to this composition there is a continuous emanation of formaldehyde from chipboard. Measurements in 25 rooms in 23 Danish dwellings where chipboard was used in walls, floors and ceilings showed that the average concentration was 0.62 and the range 0.08–2.24 mg formaldehyde m −3 air exceeding the German threshold limit for occupational exposure (1.2mg m −3). In all rooms the concentration exceeded the German limit for continuous exposure in outdoor air (0.03 mg m −3). In climate chamber experiments the equilibrium concentration of formaldehyde from chipboard was found to be directly proportional with temperature and water vapour concentration in the air (H g H 2O kg −1). A hyperbolic decrease in formaldehyde concentration occurred at increasing ventilation rates. A mathematical model for the room air concentration of formaldehyde has been established. The model is E= (RT+S)(ah+b) 1+( nc α ) mg HCHO m −3 air where a, b, c, S and R are constants depending on type and surface coating of chipboard. T is air temperature °C, n ventilation, air changes h −1 and α area board/room volume, m 2 m −3. The constants a, b, c and S were determined on the basis of the chamber measurements, while R has to be calculated for each room from the results of measurements in the room. The model reproduces the measurements in dwellings and in the climate chamber with correlation coefficients of 0.88 and 0.94 respectively in the intervals 17–32°C, 5–13 g H 2O kg air −1 and 0.4–3 air changes h −1 and may be used for prediction of formaldehyde concentrations in rooms containing chipboard. The adverse health effects of low levels of formaldehyde are irritation of the upper airways and conjunctivitis. The need for air quality standards and control programmes for indoor air in the home is stressed.