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Depending on the effect on the human body, the following types of dust are
distinguished:
1) Toxic dust dissolves in the biological environment of the body and causes
its poisoning. For example, lead and arsenic dust, when getting into the

human body through breathing , affect the nervous system, blood supply
organ and gastrointestinal tract, which leads to acute or chronic body
poisoning.
2) Non-toxic dust affects the human body less dramatically: it irritates skin,
mucous membranes, conjunctiva; dust getting into lungs causes
occupational diseases such as the black-lung disease (organic changes in
lung and reduction in their function, which causes anoxaemia). Dust that
contains SiO2 causes silicosis; cement kiln dust causes cemenosis and slack-
anthracosis.
Non-toxic dust can absorb toxic and radioactive substances and gain a certain
electric charge, which makes it more harmful.

Dust Protection Methods:
1) Ventilation (local and general);
2) Capsulation of dust sources with aspiration (local aspiration);
3) Moisturizing of dust-like materials;
4) Briquetting and granulation of flours;
5) Individual protection – respirators, gas-masks, overalls, goggles.

Methods of Defining Dust Level at Workplace
Dust levels are defined with the help of the following methods:
- Weight method is based on the principle of making up the weight of
analytical filter by blowing a certain volume of the examined air through it. Dust
mass in air volume units is defined in mg/m .
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- Conimeteric , or calculative method (“coni” (Gr.) – dust) is based on
prior separating dust from air by precipitating it on wet glass in a unit of time and the
following calculation of the number of particles using the microscope. Dust
concentration is expressed by the number of particles falling at a unit of air volume.
- Photoelectric method. The general number of dust particles in a certain
air volume is defined according to the difference of light fluxes before and after
dusted air blowing. The light flux changes when dusted air is blown.
- Electrometric method lies in the electrification of aerosol dust particles in
a negative corona discharge field and further measurement of electric charge that
accumulates on the walls of measuring chamber and is proportional to dust level in
the air.

7.6 Meteorological Conditions

Thermal Comfort
Maintenance of thermal comfort is important to ensure a safe, healthy and
productive workplace. The feeling of hot or cold is not only dependent on the air

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