WOOD DUST CONCENTRATIONS FOR 3 HARDWOOD SPECIES AND MOISTURE CONTENTS

Wood dust monitoring surveys conducted by the Appalachian Hardwood Cen ter and discussions with employees and employers indicate that differe nt species of wood appear to generate more wood dust than others. The inherent differences between hardwood and softwood species represent o ne component of difference. In addition, according to wood product emp loyees, some species of hardwoods appear to produce wood dust levels c onsiderably higher than other species of hardwoods. In personal interv iews, employees claim the denser woods (such as white oak) create much higher dust levels compared to the less dense hardwoods. It was not k nown whether these statements were factual or if employees were aware of some wood dust levels more than others due to irritating effects to the respiratory system. An airborne wood dust monitoring experiment w as conducted under controlled conditions. The experiment was performed with a straight-line ripsaw using three different species of hardwood lumber (red oak, yellow-poplar, and black cherry). The purpose of the study was to determine if the species of wood and its moisture conten t affect airborne wood dust levels generated by the straight-line rips aw. Each species of hardwood was conditioned prior to processing to th e following moisture levels: 6 to 10 percent (kiln-dried), 14 to 17 pe rcent (air-dried), and wet/green (at or above the fiber saturation poi nt). The study results support early findings in that the more dense a nd dry lumber generated more airborne wood dust during processing.