Occupational (industrial) hygiene

A section of preventive medicine studying influence of labor process and the factors of working environment on human organism with the purpose of scientific substantias of regulations and means of prophylaxis of occupational diseases and other unfavorable consequences of effect of working conditions on workers.

Occupational Hygiene researches:

Optimal regimes of work and rest for workers (physiology of labor);

organization of jobs in the system "man - machine" (ergonomics);

measures to reduce the health impact of chemical work environment factors (Industrial toxicology);

measures to ensure optimal hygienic conditions of work (climate, noise, lighting, ventilation, organization, etc. (Industrial sanitation);

OH studies connection of workers’ health with working conditions factors and the labor


Physiology of work.

Section of industrial hygiene studying changes of functional condition of the human organism under influence of industrial activity and developing physiological reasonable means of labor process organization promoting prevention of fatigue and maintenance of a high level capacity for work.

Capacity for work.

It is a human’s state determining by his/her physiological and psychological resources which characterize an ability to do certain work of given quantity and quality within a given period.


is a condition accompanied by the sense of weariness, decrease in work efficiency, caused by an intensive and prolonged activity, and expressed in worsening of quantitative and qualitative indices of work, which are restored after having a rest.


is a pathological state of the organism, which is characterized by functional disorders caused by the progressive accumulation of fatigue during working.

Prevention of fatigue and overfatigue.

· automation and mechanization of work operations .

· rational regimes of work and rest .

· the organization of the work place.

· the perfection of the professional skills .

· change-over to the different kinds of work.

· using different interior elements for the psycho-emotional impact on the human condition.

· physical exercises, massage, functional music,

The estimation of hardness of work and work intensity

All types of muscular work can be allotted on light, middle heaviness, hard work and very hard work .

All types mental work can be allotted on not intense, a little intense, intense and heavily intense.

Occupational environment is classified into 4 classes.

1 class – OPTIMAL occupational environment – conditions where workers maintain the health and the necessary prerequisites are created for high level of ability for work keeping.

2 class - TOLERANCE occupational environment –conditions characterizing occupational hazards level which do not

exceed permissible levels and possible functional disorders are restored to next shift beginning and do not lead to unfavorable influencing on workers health state during

nearest and farther periods.

3 class – UNHEALTHY occupational environment - conditions characterizing occupational hazards level which exceed permissible levels and may lead to worker’s health impairments and his/her posterity.

1 degree - occupational environment characterized the occupational hazards leading to functional changes which exceed physiological fluctuations as a rule (the latter are restored during more longer period the next shift beginning and increase risk to fall in disease).

2 degree - occupational environment characterized the occupational hazards leading to stable functional disorders lead to increasing of occupational mediated pathology (without disability) as a rule, arising after 10 and more years.

3 degree - occupational environment characterized the occupational hazards leading to increasing of occupational mediated pathology also and occupational diseases occurrence by mild and moderate grade as a rule (with disability during occupational activity).

4 degree - occupational environment characterized by occupational hazards leading to grave functional disorders and chronic pathology as well as morbidity with temporal disability rate increasing and grave case of occupational diseases arising (with disability).

4 class – DANGEROUS (EXTREME) occupational environment conditions characterizing the occupational hazards levels which may lead to threat for worker’s existence or acute grave cases of occupational impairments during shift or its part.

Occupational hazards:

Mechanical – lead to traumatism;

Physical (noise, vibration, microclimate, climatic parameters, ionizing and nonionizing radiation, atmospheric pressure, level of light exposure);

Chemical (toxic substances of various aggregative state)

Рhysicochemical (аerosol, dust);

Biological (germs, viruses, insects, snakes, animals, etc.);


Psycho-physiological (physical overloadings, neuro-psychical overloadings)

Organization elements of occupational activity ( poor working posture, overstrain of workers’ organs or systems, shift work, irrational procedure of work and rest, monotony etc.).


Is any undesirable sound or totality of irregularly combined sounds of various frequency and intensity rendering unfavorable effect on the organism, hindering to work and rest.

Acoustic oscillations lying in 16 Hz-20kHz zone are named sound, those with frequency less than 16 Hz - infrasound, higher than 20 kHz - ultrasound.

By temporary characteristics noises are subdivided into:

Constant - the level of sound for working day is changed in time no more than by 5 dBА when

measurements are carried out on temporary characteristic “slowly” of noise-meter (phonometer);


Wavering in the time (sound level change continuously over time)

Alternating (sound level may be reduced to the level of background noise)

Impulse (sound signals for less than 1 second)

Noise measurement

Permissible noise levels are regulated by the state sanitary standards .Permissible equivalent sound level is 50-60 dBA for people of mental work,

80 dBA for the working of mines, factories, railway engine drivers, etc.

Devices (noise-meters or noise and vibration dosimeters ) VShV-1, VShV-003, ShVK-1 are used for the measurement of noise and vibration.

Hearing adaptation

Is a normal physiological response to the noise, which is expressed by the temporary displacement thresholds hearing sensitivity by 10-15 dB. Full recovery should occur within 2-3 min after stopping the noise.

The lack of recovery in this period can be considered as the beginning of cumulative effect of fatigue, which gradually leads to irreversible changes - permanent hearing threshold shift.

Electro-acoustic instrument - audiometer is designed to study the auditory function.

Evaluation of research results presented in the form of audiogram graphs, which showing the state of hearing sensitivity at different frequencies.

Diseases due to noise.

Specific action:

noise disease,

sensory neural hearing loss

Nonspecific action of noise can cause



neurocirculatory dystonias mainly on hypertonic type,

can be also the pathology of system of digestion a gastritis, a stomach ulcer has connected.


Is a mechanical resilient oscillations with frequency by more 1 Hz which are transmitted to human body

Local (transmitted to the human hand from hand-held pneumatic and electrical machines, the grinding, etc.)

General (vibration workplaces, which is transmitted through the bearing surfaces of the body of a sitting or standing person, isolated transport, transport-technological and technological)

Diseases due to local and general vibration

Vibration disease (local vibration )

I stage. Initial. Pain and paresthesia in the hands, reducing the threshold of vibration sensitivity.

II nd. Moderate. To join the growing symptoms of vasomotor disturbances, male, pain spreading all over his hand, hypothermia, cyanosis and sweating hands.

III rd. Expression. Vascular disorders characterized by severe bouts with vasospasm and whitening finger syndrome (dead fingers). Noticeable changes are observed in the functional status of the central nervous system, cardiovascular system, endocrine system, metabolism.

IV th. Generalized disorders. Characterized by generalized vascular disorders, including coronary and cerebral vessels.

General vibration disease is characterized syndromes

1. Angiodystonic and peripheral syndrome (paresthesia in the legs, hypothermia, cyanosis, sweating feet).

2. Sensory neuropathy (pain in the lower extremities, decreased pain sensitivity).

3. Angiodystonic cerebrovascular syndrome (headache, dizziness, asthenoneurotic reaction).

4. Vegetatively-vestibular syndrome (violation of vestibular responses).

5. Dysfunction of the digestive glands.

6. Myocardial.

7. Visceroptosia (drooping of the abdominal cavity).

8. Degenerative - dystrophic changes in the musculoskeletal system.

9. Violation of ovarian-menstrual cycle in women and potency in men.

10. Infertility, miscarriage, birth defects in children.


it is an aerosol for air considered as dispersion medium and hard partials as an dispersion phase.

By particles size ( fineness of pulverization):

visible – diameter more the 10 mkm.

microscopic – from 0,25 till 10 mkm.

ultramicroscopic - under 0,25 mkm.

By formation method:The aerosol of a disintegration - is formed at mechanical decomposition, crashing and destruction of hard substances or mechanical processing of industrial goods.

The aerosol of condensation is formed at refrigerating and condensation of molten materials fumes.

Industrial toxicology

Toxicology studies the mechanisms of the harmful effects of substances on humans and animals, the regularities of emerging pathological processes, developing methods of diagnosis, treatment and prevention of poisoning, etc.

Classification of industrial poisons

By the character of effect on the human organism (general toxic, irritant, sensitizing, cancerogenic, mutagenous, influencing the reproductive function);

By the way of penetration into the organism (producing their effect through the respiratory tract, digestive system, skin);

By chemical classes of compounds (organic, inorganic, hetero-organic etc.);

By the degree of toxicity (extremely toxic, high - toxic, moderately toxic, slightly toxic);

By the degree of effect on the organism (extremely dangerous substances, highly dangerous substances, moderately dangerous, slightly dangerous ones).

Occupational disease

Is a disease caused by exposure to harmful factors in production and confirmed in due course.

Principles of prevention of occupational diseases.

1. Legislation.

1.1. Hygienic standardization of occupational exposures (eg, the establishment of maximum permissible concentrations of substances in the air of the shop, the permissible levels of ionizing radiation, noise and vibration, etc.).

1.2. Environmental and statistical monitoring. Thermal environment, toxic substances, ventilation, lighting etc. would have to be monitored. Such monitoring should be done by joint collaboration of doctors and engineers.

1.3. Research. There are two kinds of research - pure research and research for the improvement of, or in connection with a manufactured product.

2. Engineering measures

2.Design of building. Measures for the prevention of occupational diseases should commence in stage of the preventive public health inspections .

2.Changing production technology. By substitution is meant the replacement of a harmful material by a harmless one, or one of lesser toxicity.

2.Mechanization and automation of production processes. The plant should be mechanized to the fullest possible extent to reduce the hazard of contact with harmful substances.

2.Hermetic sealing equipment in which there is a processing toxic or dusty materials. Wet methods should be tried to combat dust before more elaborate and expensive methods are adopted.

2.Isolation harmful and dangerous industrial processes. Sometimes it may be necessary to isolate the offensive process in a separate building so that workers not directly connected with the operation are saved from exposure. Isolation may not be only in space, but also in time. Certain operations can be done at night in the absence of the usual staff.

6. General ventilation. In rooms where dust is generated there should be an efficient exhaust ventilation system. Good general ventilation decreased the air-born hazards to the workers, especially hazards from dusts and gases.

7. Local exhaust ventilation. In this way, the breathing zone of workers may be kept free of dangerous dust and poisonous fumes.

8. Protective devices. Personal protective equipment should not be used as substitute of other prevention methods. There are respirators, ear plugs, ear muffs, helmets, safety shoes, aprons, gloves, gum boots, barrier creams, screens and goggles. The worker should be instructed in the correct use of protective devices.

3. Medical measures

1. Pre-placement medical examination. The men suffering from certain disease are contraindicated for certain types of work.

2. Periodical medical examination. Slow development of occupational diseases , very often, leads to their non-recognition in the early stages and this is harmful to the worker. Ordinarily workers are examined once a year.

3. Medical care. Within the factory, first aid services should be made available.

4. Biological methods of prevention:

General - the rational organization of work and rest, mass physical culture and sports, nutrition, etc.

Special - breathing exercises, inhalation, massage, bath and exercise therapy, medical preventive nutrition for the prevention of certain diseases.

5. Health education and counseling.