Page 53 - 6848

Control over toxic substances
The methods used are:
The express method based on colorimetry (change of colour) allows fast and

accurate determination of toxic substances concentration; gas analyzers УГ-2, ГХ-4
are used.
The laboratory method consists of sampling air in the work area and its
physical-chemical laboratory analysis.
A continuous method of registration of toxic substances in the air with gas
analyzers and gas detectors (“ФКТ-3М” for chlorine, “Сирена-2” for ammonium
and “Фотон” for hydrogen sulfide).

7 .5 Occupational Dust and its Effect on Human Body

Airborne contaminants occur in the gaseous form (gases and vapours) or as
aerosols. In scientific terminology, an aerosol is defined as a system of particles
suspended in a gaseous medium, usually gaseous medium in the context of
occupational hygiene is air.
Aerosols may exist in the form of airborne dusts, sprays, mists, smokes and
fumes.
In the occupational setting, all these forms may be important because they
relate to a wide range of occupational diseases.
Airborne dust is of particular concern because they are well known to be
associated with widespread occupational lung diseases such as the pneumoconioses,
as well as with systemic intoxications such as lead poisoning, especially at higher
levels of exposure. But, in the modern era, there is also increasing interest in other
dust-related diseases, such as cancer, asthma, allergic alveolitis, and irritation, as well
as a whole range of non-respiratory illnesses, which may occur at much lower
exposure levels. It is necessary to reduce the risk of these diseases by aiding better
control of dust in the work environment.
The first and fundamental step in the control of hazards is their recognition.
This is essential to establish priorities for action and to select appropriate control
strategies. Furthermore, permanent effective control of specific hazards like dust
needs the right approach to management in the workplace.

Dust as an occupational hazard
According to the International Standardization Organization (ISO 4225 - ISO,
1994),
"Dust: small solid particles, conventionally taken as those particles below 75
μm in diameter, which settle out under their own weight but which may remain
suspended for some time".
According to the "Glossary of Atmospheric Chemistry Terms" (IUPAC, 1990),
"Dust: Small, dry, solid particles projected into the air by natural forces, such
as wind, volcanic eruption, and by mechanical or man-made processes such as

4