Formaldehyde Release from Resin-Containing Wood Board Dusts: Evaluation of Methods to Determine Formaldehyde

Abstract

Formaldehyde-based resins are commonly used as adhesives for particle board and other wood boards. Workers in the wood board and furniture industries are exposed not only to formaldehyde gas, but also to wood board dusts, which slowly release formaldehyde. The purpose of this work was to study formaldehyde release from resin-containing wood boards, to evaluate and develop analytical methods for determining the formaldehyde content of these products, and to evaluate briefly the significance of the formaldehyde released from some of the most common wood boards. The formaldehyde release rate was found to be dependent on temperature and time. The method recommended for evaluating particle-bound formaldehyde comprises leaching with deionized water (6 hours, 37°C) followed by formaldehyde determination with the acetylacetone method. In this method the analytical conditions are neutral (pH about 6) through the entire procedure and therefore resemble conditions surrounding nasal mucus and skin. The chromotropic acid method and the 2, 4-dinitrophenylhydrizine method greatly overestimate exposure because their strongly acidic conditions release much more formaldehyde than would take place on human mucous membranes. With the acetylacetone method, particle board glued with urea-melamine-formaldehyde resin and medium density fiber board released the highest amount of formaldehyde, exceeding 1000 μg formaldehyde/g dust. The formaldehyde release from dust from particle board and medium density fiber board was estimated to be only about 1/100 of the gaseous formaldehyde encountered in factory air. However, deposited particles remain in the upper respiratory tract for a long time and continue to release formaldehyde after the work shift.