The effect of ultraviolet radiation on the human body: benefits and harms
The effect of the light of the sun on people is difficult to overestimate his effect in the body run the most important physiological and biochemical processes. The solar spectrum is divided into visible and infrared part, and also on the most biologically active ultraviolet part that has a big impact on all living organisms on our planet. Ultraviolet radiation is imperceptible to the human eye the short-wave part of the solar spectrum, having electromagnetic nature and photochemical activity.
Due to its properties, ultraviolet is successfully used in various fields of human life. The widespread use of UV radiation received in medicine because it can change the chemical structure of cells and tissues, exerting different effects on people.
The range of wavelengths of ultraviolet radiation
The main source of UV radiation is the sun. The proportion of UV light in the total sunlight is impermanent. It depends on:
- the time of day;
- the time of year;
- solar activity;
- the state of the atmosphere.
Despite the fact that the heavenly body is far from us, and its activity is not always the same, to the surface of the Earth reaches a sufficient amount of ultraviolet light. But this is only a small long-wave. Short waves are absorbed by the atmosphere at a distance of about 50 km to the surface of our planet.
Ultraviolet spectrum that reaches the earth's surface, conventionally divided according to the wavelength:
- long (400 – 315 nm) UV – A rays;
- the average (315 – 280 nm) – UVB;
- middle (280 – 100 nm) is a UV – C.
The effect of each of the UV range on the human body is different: the smaller the wavelength, the deeper it penetrates through the skin. This law and determined by the positive or negative impact of ultraviolet radiation on the human body.
The UV radiation of the middle range most adversely affects health and poses a risk of serious diseases.
UV rays must dissipate in the ozone layer, but because of the bad environment reaches the earth's surface. Ultraviolet rays range and less dangerous, with strict dosing, the radiation of long-and medium-range positive effect on the human body.
Artificial sources of UV radiation
The most significant sources of UV waves that affect the human body are:
- germicidal lamp – wave sources UVC is used for disinfection of water, air or other environmental objects;
- industrial arc welding – the source of all wave range of the solar spectrum;
- erythema fluorescent lamps are sources of UV wave range and used for therapeutic purposes and in tanning salons;
- industrial lamps are powerful sources of ultraviolet waves used in the manufacturing processes for fixing dyes, inks or curing of polymers.
The performance of any UV-lamp are the power of its radiation, the spectrum of waves, type of glass, the life. From these parameters depends on how the lamp will be helpful or harmful to humans.
Before irradiation of the ultraviolet waves from artificial sources to treat or prevent illness or disease should consult a specialist for the selection of necessary and sufficient erythemal dose is individual for each person taking into account the type of skin, age, existing diseases.
It should be understood that ultraviolet light is electromagnetic radiation, which has not only a positive effect on the human body.
Germicidal UV lamps used for tanning, will result in substantial harm rather than benefit to the body. The use of artificial sources of UV radiation should only be a professional, well-versed in all the nuances of such devices.
A positive effect of UV radiation on the human body
Ultraviolet radiation is widely used in the field of modern medicine. And this is not surprising because UV rays produce analgesic, soothing, antirahiticheskogo and antispastic effects. Under their influence going on:
- the formation of vitamin D, necessary for calcium absorption, the development and strengthening of bone tissue;
- lowering the excitability of nerve endings;
- increase metabolism, because it causes activation of enzymes;
- expansion of blood vessels and improving blood circulation;
- stimulating the production of endorphins – "happiness hormones";
- increase speed of regenerative processes.
A favorable influence of ultraviolet waves on the human body is also reflected in the change of its immunobiological reactivity of the body's ability to exercise protective functions against pathogens of various diseases. Strictly metered-dose UV irradiation stimulates the production of antibodies, thus increasing resistance of human organism to infections.
Exposure to UV rays causes skin reactions – erythema (redness). Is vasodilation, manifested by redness and swelling. Formed in the skin products of decomposition (histamine andvitamin D), enter the blood, causing a General change in the body when irradiated with UV waves.
The development of erythema depends on:
- the dose of the ultraviolet light;
- range of ultraviolet rays;
- individual sensitivity.
When excess UV-irradiation of the affected skin is very painful and swollen, there is a burn with the advent of the blister and the further convergence of the epithelium.
But burns the skin – this is not the most serious consequences of prolonged exposure to ultraviolet radiation on humans. Unwise use of UV rays causes pathological changes in the body.
The negative impact of UV radiation on human
Despite its important role in medicine, the harm of ultraviolet radiation on health exceeds the benefits. Most people are not capable of precisely controlling the therapeutic dose of ultraviolet and use in a timely manner to the methods of protection, so often it is an overdose, what are the following phenomena:
- the body temperature rises;
- fatigue, lethargy;
- impaired memory;
- heart palpitations;
- loss of appetite and nausea.
Excessive tanning affects the skin, eyes and immune (protective) system. Feel and visible consequences of excess UV exposure (skin burns and mucous membrane, dermatitis and allergic reactions) take place in a few days. Ultraviolet radiation is accumulated for a long time and is a very serious disease.
The effect of ultraviolet radiation on the skin
A nice tan is the dream of every person, especially the fairer sex. But it should be understood that the cells of the skin darken when exposed to eye-catching them in coloring pigment melanin to protect from further irradiation with ultraviolet light. Therefore a tan is a protective reaction of our skin to damage its cells by ultraviolet rays. But it does not protect your skin from more serious effects of UV radiation:
- Photosensitivity – an increased sensitivity to UV light. Even a small dose causes severe burning, itching and sunburn skin. Often this is due to the use of drugs or use of cosmetics or certain foods.
- Photoaging. UV rays And penetrate into the deeper layers of the skin, damage the structure of connective tissue, which leads to the destruction of collagen, loss of elasticity, to early wrinkles.
- Melanoma – skin cancer. The disease develops after frequent and prolonged stays in the sun. Under the influence of excessive doses of ultraviolet radiation is the appearance of malignant tumors on the skin or degeneration of the old mole cancer.
- Basal cell and squamous carcinoma – non-melanoma cancers of the skin, not fatal, but requires removing the affected areas surgically. It is noticed that the disease is much more common in people, long working in the open sun.
Any dermatitis or sensitization phenomena of the skin under ultraviolet light are provoking factors for developing cancer of the skin.
The influence of UV waves on the eyes
Ultraviolet rays, depending on the depth of penetration can negatively affect the human eye:
- Fotoatelje and electronically. Is expressed in redness and swelling of the mucous membrane of the eye, lacrimation, photophobia. Occurs failure to comply with safety regulations when working with welding equipment or people in bright sunlight on the snow-covered area (snow blindness).
- The growth of the conjunctiva of the eye (pterygium).
- Cataracts (clouding of the lens of the eye) is a disease that occurs in varying degrees, the overwhelming majority of the people to old age. Its development is associated with exposure to ultraviolet radiation on the eye, accumulating in the course of life.
Excess UV rays can lead to various forms of cancer diseases of the eye and eyelids.
The effect of ultraviolet radiation on the immune system
If metered use of UV radiation enhances the protective forces of the body, excess exposure to UV light depresses the immune system. This was proven in a research of U.S. scientists on the herpes virus. UV radiation alters the activity of cells responsible for the immunity in the body, they can't hold the viruses or bacteria, cancer cells.
A basic measure of security and protection from UV radiation
To avoid the negative effects of UV rays on the skin, eyes and health, every person needs protection from UV rays. Forced prolonged exposure to the sun or at a workplace exposed to high doses of ultraviolet rays, be sure to find out normal whether the index is UV radiation. Enterprises do this using a device called a radiometer.
When calculating the index at the meteorological stations taken into account:
- wavelengths in the ultraviolet range;
- the concentration of ozonelayer;
- solar activity and other indicators.
UV index is an indicator of the potential risk to the human body as the result of the impact of the dose of ultraviolet radiation. The index is scored on a scale from 1 to 11+. The norm of the UV index is the measure of no more than 2 units.
At high index values (6 – 11+) increases the risk of adverse effects on eye and skin of a person, so it is necessary to apply protective measures.
- Use sunglasses (special masks for welders).
- Under the open sun, be sure to wear a hat (with a very high index – a broad-brimmed hat).
- Wear clothing that covers arms and legs.
- Clothes in uncovered areas of the body to apply sunscreen with a protection factor of at least 30.
- Avoid being in the open, not protected from sunlight, the space between noon and 16 hours.
Follow simple safety rules will help to reduce harmful UV exposure to humans and to avoid the occurrence of diseases associated with the adverse effects of ultraviolet radiation on his body.
Who ultraviolet radiation is contraindicated
You should be cautious with exposure to ultraviolet radiation the following categories of people:
- with very fair and sensitive skin and albinism;
- children and adolescents;
- those who have many moles or nevi;
- suffering from systemic or gynecological diseases;
- for those who have a close relatives had skin cancer;
- some receiving long-term medications (consult a doctor).
UV light such people, even in small doses, the degree of protection from sunlight should be maximized.
The effect of ultraviolet radiation on the human body and its health can not be called positive or negative. Too many factors to consider when it impacts on the environment and in radiation from different sources. Remember the rule: any impact of ultraviolet radiation on humans should be minimal to consultation with a specialist and dosed strictly according to recommendations of the doctor after examination and investigation.