## 1 Introduction  
In analysing particulate matter in the environment and workplace, it is of great importance to determine the concentration of particles, as well as the duration of exposure to these concentrations, in order to obtain a more realistic assessment of the health risks to the exposed individuals. Additionally, it is important to consider particle concentrations within different size fractions [1, 2, 3]. Among the basic parameters that directly affect the level of influence on humans and technical systems are the shape, size, and dimensions of particles, alongside the chemical composition of particulate matter. The behaviour, deposition, and fate of each particle after entering the human respiratory system depend on their natures and the specified parameters [4, 5, 6]. Based on this, we can conclude that the importance of measuring particle size and shape distribution lies in the fact that the properties of dispersed materials depend on the uniformity of their distribution. Similarly, significant differences in particle size and shape play a crucial role in assessing exposure and the intensity of the organism's biological response [7, 8]. Epidemiological studies, development of standards in the field, as well as measurement and protection devices, are also based on the examination of particle size and morphological characteristics. One of the primary interests of researchers is examining and understanding the adverse health outcomes that can result from intermittent or continuous exposure to particulate matter. These include pneumoconiosis, occupational asthma, chronic bronchitis, cancer, and systemic poisoning, such as lead poisoning, especially with prolonged exposures [9; 10; 11]. Additionally, there is growing interest in other diseases associated with dust inhalation, such as hypersensitivity pneumonitis and irritations, as well as a range of non-respiratory diseases that can occur even with short-term exposures [12]. Subfractions of inhalable dust include the nasopharyngeal, tracheobronchial (or thoracic), and alveolar (or respirable) fractions. The nasopharyngeal fraction includes a spectrum of particles that are deposited in the airways between the point of air entry, i.e., the mouth or nose, and the larynx. Particles smaller than 2.5 \(\upmu\)m are deposited below the larynx before reaching the deepest parts of the lungs. These particles can later be eliminated through mucociliary clearance. They are generally finer than the nasopharyngeal fractions, and their primary deposition mechanisms are impaction and, to some extent, gravity. Smaller particles can penetrate the alveolar region, where inhaled air can reach the blood vessels. Regarding aerodynamic diameter, only about 1% of 10 \(\upmu\)m particles reach the alveolar region, so an aerodynamic diameter of 10 \(\upmu\)m is usually considered the upper size limit for penetration into this region. In this area, particles with an aerodynamic diameter of 2 \(\upmu\)m are the most frequently deposited. For smaller particles, most deposition mechanisms become less effective, so deposition of particles with an aerodynamic diameter smaller than 2 \(\upmu\)m is less efficient. For particles with an aerodynamic diameter of 0.5 \(\upmu\)m, deposition efficiency is only 10-15% [13; 14]. Most of these particles are exhaled without being deposited. However, in the case of even smaller particles, diffusion becomes a more efficient mechanism, and the likelihood of deposition in the body increases, although electrostatic forces can also play a significant role in the deposition of these fractions [11; 15]. Although, in medical literature, exposure to dust is commonly associated with miners, industrial and construction workers, the materials used in dental technology have rendered dental technicians a population segment at greater risk [16; 17; 18]. Dentists and dental technicians are exposed to aerosols generated from different materials for the entire duration of their working hours, generated from different materials [19; 20; 21; 22].