Employees at carpentry workshops, wood products factories, the wooden house industry, etc. are all exposed to wood dust at work. Such workplaces are exempt from the prohibition on recirculation of air, a prohibition placed to prevent the accumulation of harmful substances in the working atmosphere The exemption is granted even though exposure to wood dust is associated with an increased risk of lung, nose and sinus cancer as well as other respiratory diseases, such as asthma, chronic bronchitis and rhino-conjunctivitis. However, a removal of this exemption will have major economic implications for companies that recirculate heated air in winter.

Particle size and composition

Since it is unknown what impact recirculating the air has on workplace exposure, a systematic mapping of wood dust exposure among employees in the construction industry has been  conducted.  The aim was to obtain the representative and comparable measurements necessary to assess the exposure differences in companies with and without air recirculation.

In this project, STAMI will obtain more detailed knowledge about exposure during wood processing, including characterization and size distribution of dust particles. This cannot be read out of the wood dust exposure level based on the dust mass. Since small particles weigh less but deposit deeper in the lungs than large particles, the size distribution of the dust particles will provide important information about health risks regardless of weight.

Components in wood dust, such as resin acids, endotoxin, fungi and bacteria, as well as volatile compounds such as monoterpenes, aldehydes and total VOCs, are all known to cause health problems. These include irritations of the eyes and skin, respiratory ailments such as asthma, bronchitis, cough, breathing problems, reduced lung function and inflammation of the nose. However, the content of these components in wood dust is not constant, nor is it always related to the weight.

A better basis for risk assessment

Increased knowledge about the presence of and exposure to these components in work environments could improve the basis for assessing whether ventilation and air filtration are effective measures in relation to all health-relevant components and particle sizes, and thus for assessing health risks associated with wood processing.   It is also important to consider whether the existing limit values for wood dust are acceptable in relation to the health risks represented by components in the dust that are not directly related to dust weight.

The dust and its contents’ potential to create oxidative stress and inflammation will be tested in cell models in the laboratory. This will provide information about effect mechanisms that may be important in risk assessments.

Project leaders: Ine Pedersen and Anne Straumfors
Project staff: Torunn Kringlen Ervik, Erika Zardin, Anani J. K. Afanou, Oda A. H. Foss, Nils Petter Skaugset
Partners: Housing Producers’ Association, Norwegian Wood Products, Norwegian Labour Inspection Authority
Financial contributor: Norwegian Association of Construction Industries (BNL)