Gymnosperms have no flowers or fruits, and have unenclosed or naked seeds on the surface of scales or leaves, while Angiosperms, also called as flowering plants, have seeds that are enclosed within an ovary (usually a fruit). Gymnosperms are haploid, have spiky, needle-like leaves and are softwood and Angiosperms have a triploid vascular tissue, flat leaves in numerous shapes and hardwood stems, with the latter being generally denser and producing finer and more abundant dusts while it is worked with. The amount and size of particles also differ according to the operations performed on wood, namely; shattering wood cells during sanding operations produces finer particle size than does chipping in sawing and milling industries. Perhaps the most damaging element is the invisible fine dust (sometimes called “coarse inhalable particles” ranging from 2-10 microns).
The tiny particles of sawdust float around the air and the invisible particles get inhaled and cause tiny wounds and scarring to our lungs which causes a very small amount of irreversible damage. The immediate effect is unnoticeable, but over long periods of time, this can result in significantly decreased lung capacity, and a number of other health issues. Since it has the potential health problems, wood dust is covered by the Control of Substances hazardous to Health Regulations (COSHH). These lay out the legal requirement to protect workers from health risks from dust exposure.
Dust Exposure
Pursuit of dust exposure is likely to occur in the machines operations such as sawing, routing and turning, sanding, operations involving processing composite board, housekeeping, compressed airlines to blow dust off the articles, etc.
Health Risks
The most common way that wood dust affects a woodworker is by being an irritant, can irritate the skin, eyes and lungs which may lead to itching, dermatitis, sneezing, coughing, runny nose, rashes, mucosal and non-allergic respiratory effects (changes in the structure and function of the nasal mucosa and respiratory tract such as nasal dryness, irritation, bleeding, obstruction, coughing, wheezing, sneezing, sinusitis and prolonged colds) and asthma-like respiratory problems. Beyond being an irritant, repeated exposures may cause sensitization or allergic reactions, resulting in rashes, boils, severe sinus, respiratory inflammation(Pneumonitis) or pain depending upon the wood species. Some wood is considered to be directly toxic (e.g., Yew) which is capable of causing fatality and some species can be carcinogenic which can cause Nasopharyngeal Carcinoma or Nasopharyngeal Cancer. An Italian study (Innocenti, Valiani, Vessio et al. 1985/ Ex. 1-1037) shows that wood dust develops Anosmia (Loss of smell). In addition, chronic wood dust exposure causes Mucociliary Stasis (i.e., the absence of effective clearance or impaired Mucociliary transport), including pulmonary function decline (Pulmonary Oedema) also.
Control Strategies
COSHH states that, where it is not reasonably practicable to prevent exposure to dust, control of that exposure should only be treated as adequate, through the principles of good practices such as using Respiratory Protective Equipments (RPE- e.g., dust masks, respirators, etc), Local Exhaust Ventilation System (LEV- e.g., air filters, air exhausts, etc), not exceeding the Workplace Exposure Limits (WEL) placed on the amount of dust in the air (both hardwood and softwood dusts of 5mg/m3), averaged over an eight-hours working day and the substance that has the potential to cause cancer or occupational asthma, exposure is reduced to As Low a level As is Reasonably Practicable (ALARP). Besides the good practices, variety of operations can be done with several protective measures such as by the installation of dust collector, cyclone separator, downdraft table and vacuum/ direct dust extraction systems.
Pine is Fine!
Mask Yourself On!
Article written by:
Ananth Tamilmaniarasu
HSE Trainer,
Green World Group,
Dubai