PEER-REVIEWED ARTICLE bioresources.com Čavlović et al. (2021). “Quantifying hardwood dust,” BioResources 16(1), 643-654. 643 Reliability of the Measurement Method in Determining the Mass Concentration of Hardwood Dust Anka Ozana Čavlović, a Ivan Bešlić, b Željka Zgorelec, c and Josip Ožegović d The reliability of the measurement method in determining the mass concentration of wood dust relates to the sampling time for the detection of wood particles in the ambient air of woodworking places. The aim of this study was to calculate the mass limit of detection (LOD), limit of quantification (LOQ), and the minimal sampling time (tLOD and tLOQ) for determination and quantification of samples, based on the hardwood dust mass concentration at various woodworking places in the sawmills, floor production factories, and carpentries. Determination of the mass concentration of respirable, inhalable, and total hardwood dust from ambient air was performed using personal sampling pumps and three types of filter holders: respirable dust cyclone, Institute of Occupational Medicine IOM inhalable dust sampler, and total dust open-faced filter holder. The average limit of detection amounts to 0.052, 0.083, and 0.167 mg for respirable, inhalable, and total hardwood dust, respectively. The minimal detection sampling time for collecting all observed types of dust fractions ranged between 1.12 h and 1.72 h. The minimal quantification time for all collected hardwood dust samples ranged from 3.75 h to 5.51 h. Pearson's correlation test showed that the reliability of the measurements was affected more by the dustiness of the workspace than the real sampling time. Keywords: Wood dust; Inhalable fraction; Minimal sampling time; Limit of detection; Limit of quantification Contact information: a: Faculty of Forestry University of Zagreb, Wood Technology Department, P.O. Box 422, 10002 Zagreb, Croatia; b: Institute for Medical Research and Occupational Health Zagreb, P.O. Box 291, 10001 Zagreb, Croatia; c: Faculty of Agriculture University of Zagreb, Svetošimunska cesta 25, Croatia; d: SI-CORE Slovenia, Travnik 18, Loški Potok, Slovenia; * Corresponding author: acavlovic@unizg.sumfak.hr INTRODUCTION According to European Union (EU) ‘Strategic Framework on Health and Safety at Work 2014–2020,’ the commission proposes to revise and to introduce exposure limit values for 13 chemical agents because of the fact that cancer is the first cause of work- related deaths in the EU and 53% of occupational deaths are attributed to cancer (European Commission 2014). Wood dust, especially oak- and beech-wood dust from hardwood species are classified as carcinogenic substances. An average 2% of workers from over 179 million in the EU25 Member States are exposed to inhalable wood dust, and that amounts to 3.6 million workers. Increased risk of worker exposure to inhalable wood dust refers to 16% and 25% number of workers exposed to mass concentrations up to 5 mg/m 3 and up to 2 mg/m 3 , respectively (Kauppinen et al. 2006). Oak- and beech-wood dust confer the highest risk of developing intestinal-type sinonasal adenocarcinomas (ITAC). The strong relation of ITAC to exposure to wood dust makes it a professional disease in some countries for carpenters and furniture makers (Llorente et al. 2009). Ramroth et al. (2008) provided