Study of the dust factor. Industrial dust, as one of the most common occupational hazards, can cause occupational diseases - pneumoconiosis, bronchitis, diseases of the upper respiratory tract, and contribute to an increase in other respiratory diseases (tuberculosis, pneumonia, pneumosclerosis, emphysema, etc.).
In high concentrations, dust is explosive, so combating it is not only hygienic, but also economically important.
Hygienic examination of dust includes its quantitative assessment [based on its weight content in the air (mg/m3)] and qualitative characteristics ( chemical composition, degree of dispersion); They also take into account the shape of dust particles, solubility, electrical charge, crystal structure, etc. At the same time, they study the technological process, raw materials, methods of processing, transportation, packaging, methods of dealing with dust, etc. (in order to obtain approximate information about the composition of the dust). The content of the main harmful components in the dust is determined, primarily free silicon dioxide (the most important and harmful component of the dust, mainly of fibrogenic action).
The dust generated during the grinding of materials is called grinding (disintegration) aerosol: crushing,
grinding, explosions, grinding, stirring, etc. When melting metals or other materials, their vapors arise, which, entering the air, condense, forming a highly dispersed aerosol-aerosol of condensation (fumes).
Sampling is carried out based on the need to assess the dust content of air in the breathing zone of workers during various most typical production operations, as well as during the operation of various anti-dust devices (in different modes).
The main method for determining dust content is the gravimetric method, which is based on the retention of dust from a known volume of air on the filter. The filters are placed in dust tubes (allonges), the latter can be plastic, metal and glass. The air being tested is drawn through the allongi with an aspirator (electric or ejector) equipped with a volume meter for the drawn air (when using a vacuum cleaner or ejector, the volume of drawn air is determined by connecting a rheometer). Analytical aerosol filters of the AFA brand are used (available in several diameters).
Weigh the filters before and after drawing air (without preliminary preparation). The exception is very high air humidity, about 100% (the filter is dried in a thermostat and kept for 1 hour at room temperature). AFA filters are resistant to aggressive substances and dissolve well in organic solvents, which allows them to be clarified and additional studies of the dispersion and shape of dust particles to be carried out.
The filter is weighed on an analytical balance; fold it in four with tweezers and place it in the middle of the scale; after weighing, place it in a bag made of tracing paper, on which the filter number is written down (the mass of the filter is entered in the log); Next, the filter is placed in the cassette, a gasket ring is placed on top and tightened with a nut (the cassette number is entered in the log); The cassette at the sampling site is inserted into the cartridge and secured.
An electric aspirator (blower) creates negative pressure and has 4 rheometers: two with a scale from 0 to 20 l/min (for sampling dust) and two others - from 0 to 1 l/min (for gas analysis). The AERA ejector aspirator is a portable device that draws air through an allonge with a filter (used for sampling in explosive atmospheres, for example in mines). Air draft is created by releasing air from the device cylinders. With low dust levels, up to 0.5 m3 of air is drawn in, with high dust levels - 100-120 m3 (the maximum increase in filter mass should not exceed 25-50 mg). Calculation: from the mass of the filter after taking samples, subtract its mass before taking the sample (an increase is obtained); calculate the volume of drawn air (volume velocity is multiplied by the drawing time); The amount of increase is divided by the volume of drawn air (m3) - the desired air dust content is obtained (mg/m3).
Average short-term (maximum one-time concentrations (MC) are determined, which are compared with the maximum permissible concentration. To assess the magnitude of the dust load (the risk of developing dust occupational diseases), the average shift concentration of dust (CD) is additionally determined. To measure SD, either one continuous sample is taken during the entire shift, or such a number of consecutive samples with breaks that, given the existing spread of measured concentrations, allows us to obtain a reliable average value concentrations indicating the minimum and maximum concentration of dust in the air. To measure SD at dust concentrations below the MPC, air can be continuously drawn through the filter not for one work shift, but for two or more shifts.
The data obtained are supplemented by determining the dust dispersion: the content of particles measuring up to 2 microns, from 2 to 5 microns, from 5 to 10 microns and more is determined. Dispersity is determined by microscopy of coated filters made of FPP fabric used to determine dust content in the air; the filter is placed with the filter surface on a glass slide and held for several minutes over acetone vapor heated in a water bath; The filter fabric melts, turning into a transparent film, in which the dust dispersion can be easily determined under a microscope using an eyepiece micrometer. It is important to set the price for dividing the eyepiece ruler with a lens micrometer; place the dust preparation on the microscope stage instead of the objective micrometer; measure dust particles by their largest diameter, bringing each dust particle in turn under the ruler without choice; the results are entered in the recommended form:
If the dust under study is dissolved in organic solvents, then the dust preparation is prepared by deposition (screening) of a slide or cover glass during natural dust settling: dry glass or glass coated with an adhesive substance (glycerin, petroleum jelly) is placed horizontally (deposition) or vertically (screening) in dusty air and after some time (depending on the intensity of dust emission), covered with a slide or cover glass, examined under a microscope. Preparations on which the dispersion of dust is determined are also used to describe the morphological features of dust: round or irregular needle-shaped or fibrous shape, jagged edges, conglomerates of particles, etc. Currently, electron microscopy is used to study the shape and size of small particles (dust preparations require special training).
Instruments have been developed that make it possible to determine the specific gravity of various dust fractions (up to 5 and more than 5 microns), which is important for assessing the degree of pneumoconiosis hazard of dust. Let us explain that predominantly dust particles with a diameter of 1-2 microns and no more than 5 microns (the most dangerous) penetrate into the lung tissue and are retained; particles less than 0.1 microns penetrate the alveoli, but are capable of being largely excreted in exhaled air without settling in the respiratory organs; particles larger than 5 microns are retained mainly in the upper respiratory tract and bronchi (causing rhinitis and bronchitis). Moreover, the shape of dust particles is significant only for particles of larger sizes (more than 5-10 microns): needle-shaped particles (fiberglass dust, glass wool) injure and irritate the mucous membrane of the respiratory tract and skin; fibrous dust accumulates on the mucous membrane of the bronchi, impedes the cleansing function of the mucous membrane, irritates it, causing a chronic inflammatory process.
The study of dust on filters allows for the simultaneous quantitative determination of metals, polycyclic (carcinogenic) hydrocarbons and other substances of interest to the hygienist in dust.
Determination of free and bound silica in dust - in accordance with the “Guidelines for the determination of free silicon dioxide in certain types of dust” (No. 2391-81).
Preventive actions. The MPC value depends on the composition of the dust, the content of free silica, silicates and other impurities (fibrogenic effect of aerosols).
Preliminary and periodic medical examinations of workers are mandatory (see order of the USSR Ministry of Health No. 555; dated September 29, 1989). Periodic medical examination is aimed at preventing dust diseases and early diagnosis and dynamic monitoring of health status. The examination involves a therapist, a radiologist, and, if indicated, an otolaryngologist and a phthisiatrician; use fluoroscopy, radiography; conduct blood and sputum tests; determine the function of external respiration of the lungs.
Technological measures and technical solutions for dust removal are of decisive hygienic importance, especially at the stage of designing production processes and designing machines: for example, wet grinding and grinding; replacement of sandblasting cleaning of castings with hydroblasting; the use of granular materials instead of powdered ones; use of vacuum transport of dust-producing materials; continuity and tightness of dust-producing processes; mechanization and automatic control of processes associated with dust formation; local exhaust ventilation of residual dust.
The removal of settled dust is carried out using wet methods and using mechanisms. To increase the wetting and settling ability, surfactants (type OP-7, OP-10) are added to water.
Dust control in various industries is carried out by various means (complex measures are the most effective). For example, in the mining industry, significant experience has been accumulated in complex dust removal: preliminary moistening of coal in the massif, irrigation with water on combines, ventilation of workings; normalized wet drilling in mines with dry dust collection and ventilation. Radical are the replacement of conventional methods of coal mining with hydraulic mining and unmanned extraction of minerals, the replacement of dry transport of materials and rocks with hydraulic transport, etc.; see also the organization of technological processes and hygienic requirements for production equipment (Chapter 10).
Measures to combat dust in industries and in a number of production processes are set out in detail in the relevant sanitary rules approved by the USSR Ministry of Health (see “Sanitary rules for enterprises for the extraction and processing of ore, non-metallic, alluvial minerals”, No. 3905-85; “ Sanitary rules for enterprises of the coal industry". No. 4043-85, etc.; "Sanitary rules for enterprises of non-ferrous metallurgy", No. 2528-82). In addition, there are departmental rules and instructions for safe work, which also reflect dust control measures in relevant industries.
In cases where the maximum permissible concentration is exceeded, it is necessary to use respirators, helmets with a supply of clean air (respirators of the “Petal” type; helmets-spacesuits with an air supply - helmets of sandblasters, electric welders, boiler cleaners, etc.).
It is necessary to use protective clothing made of maleskin fabric (suits, overalls, headdress, mittens), and special footwear. For workers in dusty occupations, ultraviolet irradiation in fotaria and alkaline inhalations are provided.
The fight against industrial dust is one of the most important tasks of occupational hygiene, since a large number of workers can be exposed to dust. Dust is the main industrial hazard in the mining industry (coal mining, metal ores, etc.), in production building materials(refractory products, brick, cement), porcelain-faience, flour-grinding industry, iron-copper-steel and other workshops of the metallurgical and mechanical engineering industry, in preparatory and spinning shops of the textile industry, agriculture and many other sectors of the national economy.
Inhalation of dust can lead to specific diseases (pneumoconiosis), contribute to the occurrence and spread of diseases such as laryngitis, tracheitis, bronchitis, pneumonia, pulmonary tuberculosis, and skin diseases.
The fight against industrial dust is not only a hygienic but also an economic task. Some types of dust (cement, sugar, flour, soda, etc.) are valuable as a product of production, and its loss causes economic damage. Dust contributes to rapid wear of production equipment and can cause defects (precision instrument making, fluoroplastic processing). Dust explosions may occur under certain conditions.
Classification of industrial dust
Dust is a concept that characterizes the physical state of a substance, namely its fragmentation into tiny particles. Solid particles suspended in the air are a dispersed system in which the dispersed phase is solid particles and the dispersion medium is air. A dispersed system of suspended solid particles in the air, i.e. dust, is called an aerosol. If particles that are homogeneous in their physical and chemical properties are suspended in the air, the system is called monogenic, or single-phase; if dust particles suspended in the air differ in their physical and chemical properties, the system is called heterogeneous, or multiphase.
From a hygienic point of view, aerosols, which are characterized by toxic effects due to their chemical properties(for example, aerosols of lead, zinc oxide, arsenic and many others) are classified as industrial poisons.
Based on the nature of the substances from which the dust was formed, the following classification is known:
I) Organic dust:
a) plant dust (wood, cotton, etc.);
b) animal (wool, bone, etc.);
c) artificial organic dust (plastic, etc.).
II) Inorganic dust:
a) mineral (quartz, silicate, etc.);
b) metal (iron, aluminum, etc.).
III) Mixed dust (dust from metal grinding, casting cleaning, etc.).
However, this classification of dust is not sufficient for its hygienic assessment. For this purpose, dust is classified according to its dispersion and method of formation and, accordingly, distinguishes between disintegration aerosols and condensation aerosols.
Disintegration aerosols are formed when any solid substance is added, such as in disintegrators, crushers, mills, drilling and other processes. Moreover, the harder the Body, the smaller the sizes of the resulting particles. Disintegration aerosols largely consist of large dust particles, although they also include ultramicroscopic particles.
Condensation aerosols are formed from vapors of metals, metalloids and their compounds, which turn into solid particles when cooled. For example, zinc and aluminum vapors condense in the air during their melting, and metal vapors during electric welding. In this case, the size of dust particles is significantly smaller than during the formation of disintegration aerosols.
Particles of aerosols of disintegration and condensation also differ in that the former always have an irregular shape, appearing in the form of fragments, and the latter are a type of loose aggregates consisting of individual particles of regular crystalline or spherical shape.
Soviet researcher N.A. Fuks distinguishes two groups of aerosols according to their dispersity:
a) dust - this includes all solid particles formed during disintegration, regardless of their size and including dust particles of submicroscopic size;
b) fumes - these include condensation aerosols with a solid dispersed phase. Smoke can also include aerosols formed during incomplete combustion of fuel, ammonium chloride smoke, etc.
Industrial dust (aerosol)- this is a collection of small solid particles that are formed during the production process, suspended in the air of the working area and capable of having an adverse effect on the body of workers.
Classification of industrial dust. By origin dust is divided into organic (plant, animal, polymer), inorganic (mineral, metal) and mixed.
By place of origin dust is divided into disintegration aerosols, which are formed during processing solids, and condensation aerosols, which are formed as a result of condensation of metal and non-metal vapors (slags).
By dispersion dust is divided into visible (fractions greater than 10 microns), microscopic (from 0.25 to 10 microns) and ultramicroscopic (less than 0.25 microns). Dust grains smaller than 0.25 microns practically do not settle and are constantly in the air in Brownian motion. Dust with particles less than 5 microns is the most dangerous because it can penetrate into the deep parts of the lungs up to the alveoli and linger there (about 10% of dust particles that are inhaled reach the alveoli).
According to the nature of the effect of dust on the body, emit toxic (manganese, lead, arsenic, etc.), irritant (calcareous, alkaline, etc.), infectious (microorganisms, spores, etc.), allergic (wool, synthetic, etc.), carcinogenic (soot and etc.) and pneumoconiotic, which causes specific fibrosis of the lung tissue.
Are important toxicity and solubility of dust: toxic and highly soluble dust penetrates the body faster and causes acute poisoning (dust of manganese, lead, arsenic) than insoluble dust, which leads only to local mechanical damage to lung tissue. On the contrary, the solubility of non-toxic dust is favorable, since in a dissolved state the substance is easily excreted from the body without consequences.
It is believed that charged particles are 2-8 times more actively retained in the respiratory tract and are phagocytosed more intensively. In addition, similarly charged particles remain in the air of the working area longer than oppositely charged ones, which are more likely to agglomerate and settle.
The rate at which dust settles also depends on the shape and porosity of the particles. Round, dense particles settle faster. Dense, large particles with sharp edges (usually disintegration aerosols) are more damaging to the mucous membrane of the respiratory tract than particles with a smooth surface. However, light porous particles well adsorb toxic vapors and gases, as well as microorganisms and their metabolic products. Such dust acquires toxic, allergenic and infectious properties.
Industrial dust causes the development various diseases:
1) diseases of the skin and mucous membranes (pustular skin diseases, dermatitis, conjunctivitis, etc.);
2) nonspecific respiratory diseases (rhinitis, pharyngitis, dust bronchitis, pneumonia)
3) allergic diseases(allergic dermatitis, eczema, asthmatic bronchitis, bronchial asthma);
4) occupational poisoning (from exposure to toxic dust)
5) oncological diseases(from exposure to carcinogenic dust, e.g. soot, asbestos)
6) pneumoconesis (from exposure to fibrogenic dust). Pneumoconiosis ranks first among occupational pathologies throughout the world.
Prevention of dust diseases:
1. Technological activities are aimed at preventing the formation of dust in workplaces by improving technological processes. These include: the introduction of waste-free and closed-cycle technologies; mechanization and automation of production processes; introduction of remote control of the labor process; replacing dry processes with “wet” ones; replacing powder products with briquettes, granules or pastes.
2. Sanitary measures. These measures are aimed at ensuring the sealing of sawmill equipment, installing a powerful ventilation system, and carrying out pneumatic cleaning in the premises.
3. Personal protective equipment: dust respirators, safety glasses, dust suits.
4. Therapeutic and preventive measures.
In hygienic practice, industrial dust is classified according to two criteria: origin and dispersion. Based on their origin, dust is classified into organic (plant, animal), inorganic (metal, mineral) and mixed dust. This classification does not provide sufficient characteristics for hygienic assessment. The classification of dust according to its dispersion and method of formation is important. A distinction is made between disintegration aerosols (formed during the crushing of solids) and condensation aerosols (formed due to the condensation of heated vapors when they are cooled).
Depending on the dispersion, aerosols are divided into: 1) dust - all solid particles formed during disintegration, regardless of their size; 2) fumes - condensation aerosols with a solid dispersed phase. This also includes aerosols formed during incomplete combustion of fuel, ammonium chloride smoke, etc.
From a hygiene point of view, the most unfavorable are particles smaller than 10 microns in size, since they either settle slowly or do not settle at all and remain suspended in the air for a long time. The depth of their penetration into the respiratory tract depends on the size of the particles. Large particles are retained in the upper respiratory tract, while small particles penetrate directly into the alveoli.
To the number important elements The hygienic characteristics of industrial dust include the chemical composition and amount of dust in given specific conditions. Dust may contain toxic impurities (arsenic, lead, chromium, etc.), impurities that have irritating and allergenic properties. The content of free silicon dioxide in dust is especially important, since it plays a specific role in the pathogenesis of the occupational disease pneumoconiosis. The solubility and consistency of the dust also matters.
The dust content in the air of various industries varies widely. The concentration of dust in the air is determined by the gravimetric method in milligrams per cubic meter. The amount of non-toxic dust in production premises should be no more than 10 mg/m3. The exception is dust containing more than 10% quartz and asbestos dust, for which the maximum permissible concentration is set at 2 mg/m3. For dust containing more than 70% free silicon dioxide, the maximum permissible concentration is 1 mg/m3. Industrial dust can affect the body as a whole and its individual tissues. The nasopharynx is a natural filter, where up to 50% of dust particles ranging in size from 1 to 5 microns are retained.
While protecting the deeper parts of the respiratory tract, the upper respiratory tract itself is exposed to dust. With systematic exposure to dust, hypertrophic catarrhs of the upper respiratory tract first develop, then they become atrophic.
The main problem in dust pathology is damage to lung tissue and the general effect of dust on the body. With prolonged inhalation, the occupational disease pneumoconiosis occurs, characterized by the proliferation of connective tissue in the lungs and a decrease in their respiratory surface. It has now been experimentally and clinically proven that pneumoconiosis, i.e. pulmonary fibrosis, can occur when inhaled various types dust.
The most dangerous form of pneumoconiosis, which progresses even after contact with dust is eliminated, is silicosis. It is most often observed among workers in the mining, coal, engineering, glass, porcelain and earthenware industries, etc.
The etiology of silicosis is due to the presence of free silicon dioxide (SiO 2) in dust. The development of silicosis is promoted by diseases of the upper respiratory tract. The individual sensitivity of the body and work experience also matter.
The main measure to combat dust is a radical change technological process, mechanization, automation and sealing it. Sealing allows you to close dust sources and localize dust. To prevent dust from leaking into the room, dust aspiration from shelters is used simultaneously with sealing. Rational ventilation plays an important role in the fight against dust. The type of ventilation should be local exhaust.
The main source of dust formation in mines is drilling. Therefore, changing the drilling method also serves as a measure to combat dust formation. Dry drilling is being replaced by wet drilling, i.e. drilling is carried out while wetting with a stream of water (used in 94-99% of our mines). Wet drilling, along with its advantages, also has some negative aspects: water moistens clothes, shoes, and air. Wet drilling reduces dust by 30-50 times, but does not completely destroy it, since the smallest particles are poorly wetted by water. To increase the wettability of dust, soap naft, sulfanol, etc. are added to water. Water curtains are used to prevent the spread of dust during blasting operations.
Rice. 32. F-45 respirator
The danger of silicosis is great when sandblasting castings. When sand particles hit a part, they are crushed and create a lot of dust. One of the measures to combat dust during such work is to replace sandblasting with hydroblasting or shot blasting.
Measures to combat dust, common to all enterprises, are: 1) covering sources of dust formation with removing dust from the place of its formation; 2) therapeutic and preventive measures - periodic medical examinations of workers with transfer, if necessary, to another job; preliminary medical examinations to ensure that persons with diseases of the upper respiratory tract and lungs are not allowed to work in dusty workshops; 3) personal protective equipment (if other measures do not provide sufficient effect, Fig. 32); 4) systematic monitoring of dust content in the air.
The collection of tiny solid particles formed during the production process and suspended in the air of the working area is calledindustrial dust.
Industrial dust has an adverse effect on the body of workers.
There are several classifications of industrial dust.
Dust is divided
A) by origin , on the:
- organic(plant, animal, polymer);
- inorganic(mineral, metal);
- mixed.
b) by place of education on the:
- disintegration aerosols, formed during grinding and processing of solids;
- condensation aerosols, resulting from the condensation of metal and non-metal vapors (slag).
V) by dispersion on the:
- visible(particles larger than 10 microns);
- microscopic(from 0.25 to 10 microns);
- ultramicroscopic(less than 0.25 microns).
G) by the nature of the effect on the body :
- toxic ( manganese, lead, arsenic)
- annoying(limestone, alkaline, etc.);
- infectious(microorganisms, spores, etc.);
- allergic(wool, synthetic, etc.);
- carcinogenic(soot, etc.);
- pneumoconiotic(causing specific fibrosis of lung tissue).
Toxicity and solubility of dust.
Toxic and good soluble dust penetrates the body faster and causes acute poisoning(manganese, lead, arsenic dust) than insoluble , leading only tolocal mechanical damage to lung tissue.
Vice versa, solubility non-toxic dust is favorable, since in a dissolved state “the substance is easily eliminated from the body without any consequences.
Physico-chemical properties of dust.
§ Dust grains smaller than 0.25 microns practically do not settle and are constantly in the air in Brownian motion.
§ Dust from particles less than 5 microns most dangerous, because it can penetrate into the deep parts of the lungs up to the alveoli and linger there.
It is estimated that about 10% of inhaled dust particles reach the alveoli, and 15% is ingested with saliva.
Dust charge value.
§ Charged particles are 28 times more actively retained in the respiratory tract and are more intensively phagocytosed.
§ Likely charged particles remain in the air of the working area longer than oppositely charged ones, which agglomerate and settle faster.
Industrial dust causes the development of various diseases, primarily:
§ diseases of the skin and mucous membranes (pustular skin diseases, dermatitis, conjunctivitis, etc.),
§ nonspecific respiratory diseases (rhinitis, pharyngitis, dust bronchitis, pneumonia),
§ diseases of the skin and respiratory system of an allergic nature (allergic dermatitis, eczema, asthmatic bronchitis, bronchial asthma),
§ occupational poisoning (from exposure to toxic dust),
§ oncological diseases (from exposure to carcinogenic dust, such as soot, asbestos),
§ pneumoconiosis (from exposure to fibrogenic dust).
Specific occupational dust diseases.
The most important among them are pneumoconiosis, chronic lung diseases resulting from prolonged exposure to industrial dust of a certain composition.
Pneumoconiosis develops in workers engaged in
Concentrating factories,
In the metalworking industry (chopping, molding, electric welders);
Workers at asbestos mining enterprises, etc.
Pneumoconiosis is a common disease and occurs through 1-10 years work in highly dusty conditions.
There are five groups of pneumoconiosis:
I. Caused by mineral dust :
Silicosis;
Silicates (asbestosis, talcosis, kaolinosis, olivinosis, mulitosis, cementosis, etc.).
II. Caused by metal dust :
Siderosis;
Aluminosis;
Beryllium;
Baritosis;
Manganoconiosis, etc.
III. Caused by carbonaceous dust :
Anthracosis;
Graphitosis, etc.
IV. Caused by organic dust :
Byssinosis (from cotton and flax dust);
Bagassosis (from sugar cane dust);
Farmer's lung (from agricultural dust containing fungi).
V. Caused by mixed dust :
Silico-asbestosis;
Silico-anthracosis, etc.
The greatest danger, due to its widespread and irreversible course, is silicosis (dust fibrosis , caused by inhalation of free dustsilicon dioxide).
Silicosis refers to one of the most important sections of occupational pathology, since it affects workers in a wide variety of industries.
The fight against silicosis is one of the main tasks in the problem of occupational health.
Silicosisusually develops after 5-10 years working in dusty conditions, however in in some cases The disease can also occur over a short period of time.
According to its course, silicosis is divided into three stages.
I. The first stage is characterized by complaints of chest pain, shortness of breath with great physical stress, slight dry cough. X-ray examination shows increased shadowing at the roots of the lungs and shadows of the lymph nodes, increased pulmonary pattern, the appearance of cords and a looped network, the presence of single nodules with a diameter of no more than 2 mm, mainly near the roots of the lungs. Basal emphysema cannot be excluded.
II. The second stage is characterized by greater severity of the above symptoms, an increase in the number and size of nodules, which are already found in the peripheral areas of the lungs. If silicosis develops slowly, without the formation of nodules, in the form of diffuse interstitial sclerosis of the lungs, then along with an intensification of the pulmonary pattern and expansion of the roots of the lungs, symmetrically scattered shadows in the form of cells, cords and spots of various shapes are noted. .Patients often complain of shortness of breath with moderate physical exertion or even at rest, and constant chest pain. Cough is dry or with phlegm. Emphysema is significantly pronounced.
III. In the third stage, radiographs reveal merging and fused large nodules, their clusters and massive fibrous areas. Dense cords going into different directions, predominantly downward, limit the mobility of the diaphragm. In stage III, functional impairments are clearly expressed:
Increased breathing at rest;
Pathological reaction to exercise testing;
Decreased vital capacity of the lungs.
Silicosisis a progressive disease.
The lowest stage, as a rule, passes into the next, the result is pulmonary failure, development of cor pulmonale, its decompensation and death of the patient.
It must be remembered that the development of silicosis continues, even if the patient has stopped working in an industry associated with dust, the disease may develop after stopping work.
Such cases, however, are characterized by slower progression (up to 10 years).
One of the properties of silicosis is a predisposition to the development pulmonary tuberculosis.
The more severe the silicosis, the more often it becomes complicated (the first stage - in 15-20% of cases, the second - in 30, the third - in 80% of cases).
It's important to note that silicosis is relatively rarely complicated by lung and bronchial cancer.
Most often, malignant neoplasms of the lungs occur in asbestosis And berylliose.
Prevention of dust diseases.
Prevention of occupational dust diseases includes:
1. hygienic standardization;
2. technological measures;
3. sanitary and hygienic Events;
4. personal protective equipment;
