Environmental Dependence of Formaldehyde Emissions from Pressed-Wood Products: Experimental Studies and Modeling

摘要

An environmental chamber study has been performed to evaluate the dependence of formaldehyde (CH sub 2 O) emissions from weak emitting particleboard underlayment and decorative hardwood plywood paneling materials on temperature, relative humidity (RH), and CH sub 2 O vapor concentration. A broad range of temperature and humidity conditions from those of benign climate controlled dwellings to those of harsh summer periods are used. To evaluate the experimental data, two CH sub 2 O emission models are developed from a simple mass transport theory of the bulk-vapor interphase at the surface of pressed-wood products, Model I examines the change in CH sub 2 O concentration inside a single compartment containing a single CH sub 2 O emitter as a function of temperature, RH and air exchange/loading (N/L) ratio. At a constant N/L = 0.5 m/h, the experimental results indicate a 4 to 6-fold increase in CH sub 2 O concentration between 23 exp 0 C, 50% RH and 38 exp 0 C, 68% RH. An evaluation of the particleboard emissions data of Berge et al. using Model I provides similar results to those obtained in our study. Model II evaluates the change in CH sub 2 O emission rate of the test products as a function of temperature, RH, and the CH sub 2 O vapor concentration resulting from potentially one or more sources. This model is designed to be incorporated in indoor air pollutant concentration models for treatment of multiple emission sources. The results indicate a potential 10 to 30-fold increase in CH sub 2 O emission rate between 23 exp 0 C, 50% RH and 38 exp 0 C, 68% RH at a constant CH sub 2 O vapor concentratin of 0.1 ppM. The results for both Models I and II indicate potential 1.5- and 4-fold inter-product variation in the temperature and RH dependence of the CH sub 2 O emissions, respectively. This report presents the results of the first of two environmental parameters studies for CH sub 2 O emissions from pressed-wood products. 16 refs., 4 figs., 9 tabs. (ERA citation 10:028683)