Assessing chainsaw operators’ exposure to wood dust during timber harvesting

Influence of saw chain type and wood species on the concentration of wood dust in a forestry operation

This study examines the impact of chainsaw chain type and tree species on the concentration of inhalable wood dust generated during motor-manual harvesting in forested areas. The effects of conducting real-world measurements of inhalable dust within the operator's breathing zone during forestry work are investigated. Two different chain types were evaluated: the commonly used 3/8" pitch chain (conventional chain) and the 0.325" pitch chain. Additionally, measurements were taken for three tree species: beech, oak, and pine (including both live and standing dead trees after a fire). Results showed that, overall, using the conventional 3/8" chain type yielded the highest concentration of wood dust for all three tree species. Notably, the highest wood dust concentration was observed in the burned Pinus brutia cluster, also with the 3/8" chain pitch. These findings emphasize the importance of understanding how chain type and tree species contribute to wood dust levels.

Exposure Characterization of Wood Dust Particulate, Endotoxins, and (1-3)-β-d-Glucans, and Their Determinants in Mozambiquan Wood Processing Workers

OBJECTIVES

Dust generated from wood processing comprises a heterogeneous mixture of inorganic and organic particles, including wood fragments, microorganisms, endotoxins, (1-3)-β-d-glucans, and allergens. This study characterized exposure to wood dust and its determinants in the Mozambiquan wood processing industry.

METHODS

A total of 124 personal inhalable samples, collected from a stratified random sample of 30 workers, were analysed for dust particulate, endotoxins, and (1-3)-β-d-glucans. Mixed-effects models were developed to investigate significant exposure determinants.

RESULTS

The geometric mean (GM) inhalable dust particulate concentrations were 3.29 mg m-3, 98 endotoxin units (EU) m-3, and 123 ng m-3 for (1-3)-β-d-glucans. Significant predictors for higher particulate levels included machinery (GMR = 1.93), sawing (GMR = 2.80), carpentry (GMR = 2.77), or painting (GMR = 3.03) tasks. Lebombo-ironwood species was associated with higher dust particulate levels (GMR = 1.97). Determinants of endotoxin concentrations included working with dry wood and damp cleaning methods, which were associated with lower levels. Working in closed buildings (GMR = 3.10) and dry sweeping methods were associated with higher (1-3)-β-d-glucan concentrations (GMR = 1.99).

CONCLUSIONS

Work tasks in certain exposure groups (machinery, sawing, carpentry, painting), processing certain wood species (Lebombo-ironwood) and working in closed buildings were associated with higher exposures, whilst using dry wood and damp cleaning practices reduced exposure levels.

Wood dust and asthma

PURPOSE OF THE REVIEW

Review recent developments on asthma associated with wood dust, given the increasing scale of wood handling and processing activities globally.

RECENT FINDINGS

Work in wood industries is associated with a significantly increased risk of respiratory symptoms, rhinitis and asthma. This can be attributed to traditional processing techniques and newer technologies producing complex bioaerosol exposures, which may include chemicals. Meta-analysis studies indicate strong evidence for wood dusts as occupational sensitizers for asthma, but the underlying mechanisms remain poorly understood. The global prevalence of asthma in wood workers ranges between 6-18% and for rhinitis 16-33%. Exposure estimates show wide variation. Risk factors include atopy and exposure to certain wood species, elevated current and cumulative particulate exposures.

SUMMARY

Future studies should focus on better characterization of wood dust allergens and other bioaerosol components, specific immunoglobulin E responses to different wood species, pathophysiological mechanisms underlying asthma, and modelling dose-response relationships using refined exposure metrics for dust particulate and other bioaerosol components. There is a need for improved health-based international exposure standards and effective workplace control measures to reduce exposures to wood dust particulate (hard and soft woods), endotoxin and β-glucan, to reduce the risks of asthma in wood workers.

The Impact of Body Posture on Heart Rate Strain during Tree Felling

Tree felling is recognized as one of the most difficult and physically demanding work phases in motor-manual wood harvesting, during which maintaining good posture can avert unnecessary loadings to the spine and the consequent musculoskeletal disorders to forestry professionals. This study aimed to (a) quantify the impact of posture selection by means of heart rate measurements and (b) analyze its interactions with the anthropometric and personal information of study subjects. Thirteen forest workers were asked to fell thirty trees in each of the four most common body postures during motor-manual forest operations: (i) stooping, (ii) flexed stooping, (iii) squatting, and (iv) half kneeling. Posture had a significant impact on the amount of heart strain measured as mean heart rate during work (HR_work), heart rate increase over resting heart rate (ΔHR), and relative heart rate index (HRR). The most popular position among the forest workers was flexed stooping, which also caused the most damage, compared with the least physiologically damaging position, half kneeling: HR_work by 12.40 bpm, ΔHR by 10.24 bpm, and HRR by 11.51. On the contrary, overweight and older subjects experienced lower heart rate strain, a finding that has to be further investigated.

Fire Parameters of Spruce (Picea abies Karst. (L.)) Dust Layer from Different Wood Technologies Slovak Case Study

The issue of the formation of wood dust particles in the work environment is still an actual topic in terms of its impact on employee health and the risk of fire or explosion in a woodworking operation. This article deals with the characteristics of spruce dust (Picea abies Karst. (L.)), which was taken from several types of wood technology. Experimental samples of spruce dust were taken from four types of sawing technologies, including grinding, briquetting and from the suction device container. The physical parameters of the samples taken were monitored and the particle size analysis was determined. The granulometric composition of the samples is significantly different. The sample of spruce wood dust from sawing has the most numerous fraction (250 µm), while the sample from grinding has the most numerous fraction 63–250 µm (87%).The aim of the paper was to monitor the minimum ignition temperature of the settled spruce dust layer and to look for a significant dependence of the minimum ignition temperature and ignition time on the type of spruce dust sample. A significant dependence was not confirmed. Significant moisture dependence of the samples was confirmed; the highest humidity was observed in the container, the lowest in sawing.