Formaldehyde release parameters

Out of the results of the intersection should follow an equilibrium concentration of 0.35 mg/m, which is not in accordance with the determined equilibrium value. So this experimental set up is a case of a situation which is not well defined and therefore not suitable for measurement of the relevant formaldehyde release parameters of the particleboard. 

The monitoring and toxicological studies of formaldehyde exposure, as well as studies on the emission of this chemical from wood products generate large numbers of samples to be analyzed. Furthermore, it is necessary to monitor the emissions on a routine basis during production to ensure that the material continues to release low level of formaldehyde. In homes, particularly in mobile homes, the amount of formaldehyde release depends on the construction technoloy, ventilation, indoor temperature and relative humidity, and age, structure and porosity of building materials. It is, therefore, necessary to study the emislon of formaldehyde from wood products as a function of these parameters. 

In cooperation with DSM, MCN developed a method of measurement for the determination of the formaldehyde release from particle board, based on a theorie for mass transfer, implying that under steady state conditions the emission of formaldehyde of a given particle board can and should be defined by two parameters of the particular board. These two parameters are (1) Ce defined as the equilibrium formaldehyde concentration (with ventilation rate 0") and (2) kgg defined as the overall mass transfer coefficient of the board. In (ideal mixed) climate rooms the stationary formaldehyde... 

The formaldehyde release of particleboard can, as far as the particleboard is concerned, be described by two characteristic parameters. The equation is ... 

The critical points are the thermal conductivity and heat capacity of the formaldehyde crystal at the low temperature. If these parameters are low enough relative to the rate of reaction and heat release, the reaction may not be occurring at low temperatures. 

The concentration of formaldehyde in the air of a room containing particleboards, will depend on the content of formaldehyde in the boards and on the rate of its release. The formaldehyde content of a particleboard is determined by the binder used to manufacture the board and a number of production parameters. The release rate is affected by the temperature and the relative humidity of the surrounding air, but also by some of the physical properties of the board. The most important one probably is the diffusion resistance of the surface layer, which may be expressed by means of a mass transfer coefficient. 

In the process of wearing and using textile products containing formaldehyde, formaldehyde will be gradually released, which causes harm to humans through the respiratory and skin contact. Exposure parameters and values are different for different exposure pathway, so exposure model suitable for all exposure pathways should be established. On the basis of the EPA s exposure models, exposure models of chemical substances in textiles through skin were established, which was shown as follows. 

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