Radioactive background and radionuclides
The radioactive background depends on geology, altitude above sea level, and weather. Gases are released from the soil more intensively at high temperatures and during vertical air currents. Natural radiation, including cosmic rays, is an evolutionary factor to which living organisms have adapted.
Human activity leads to the introduction of artificial radionuclides. The most hazardous long-lived pollutants are:
- Strontium-90: half-life of 29 years. In the body, it mimics calcium, depositing in bone tissue.
- Cesium-137: half-life of 33 years. It replaces potassium, distributing evenly.
They cause internal irradiation, which increases the risk of genetic and somatic mutations. Elimination takes approximately 10 half-lives.
Hygiene of solar radiation
Solar radiation regulates metabolism and circadian rhythms. The optical part of the spectrum reaching the Earth consists of invisible ultraviolet, visible, and invisible infrared rays.
Ultraviolet rays have high biological activity:
- Antirachitic effect: synthesis of vitamin D (from 320 to 290 nm).
- Erythematous-tanning effect (from 400 to 320 nm).
- Bactericidal effect (shorter than 320 nm).
A lack of light (e.g., due to smog or working underground) leads to UV deficiency, for the prevention of which photariums are used. Excess sun exposure poses the risk of skin damage (erythema, cancer) and eye damage (photo- and electroophthalmia).
Impact of electromagnetic and geomagnetic fields
Natural and anthropogenic fields surround humans constantly. Magnetic storms can lead to disruptions in biorhythms, which increases the incidence of myocardial infarctions and strokes and reduces concentration.
Artificial electromagnetic fields (EMFs) are generated by power lines, radio stations, and electrical appliances. EMFs do not possess ionizing capacity, but they cause thermal effects and biophysical changes in cells (alteration of ionic currents and membrane permeability). Damage can be:
- Acute: severe headaches, hemorrhages, unstable blood pressure.
- Chronic: asthenia, emotional lability, early atherosclerosis. A teratogenic hazard for pregnant women is also noted.
Briefly: answers to topical questions
What methods and means exist for the prevention of ultraviolet deficiency in the population?
To prevent ultraviolet deficiency, artificial UV sources and the enrichment of the light flux with the erythematous component are used. The main methods and means include:
- Irradiation in photariums — short-term (2–6 min) massive exposure of the nude body in specially equipped rooms.
- Artificial UV radiation sources — argon-mercury-quartz and fluorescent erythemal lamps.
- Enrichment of the light flux of artificial lighting sources with the erythematous component.
What are the main anthropogenic sources creating artificial electromagnetic fields in populated areas?
Artificial electromagnetic fields in populated areas are created as a result of electrification and the widespread introduction of electrical equipment. The main anthropogenic sources are divided into groups:
- Generating static and magnetic fields — power plants, high-voltage power transmission lines, power cables, electromagnets, and electric transport.
- Generating EMFs in the radio frequency range — radio stations, television centers, radar installations, radiotelephones, navigation and communication systems.
Household and medical sources include television sets, PC monitors, as well as energy-intensive industrial, medical, and household equipment.
Which meteorological factors contribute to the more intensive release of radioactive gases from the soil into the atmosphere?
The release of natural radioactive gases from the soil into the atmospheric air increases during:
- an increase in air temperature;
- an intensification of convective vertical air currents.
Conversely, an increase in atmospheric pressure and air humidity reduces the release of radioactive gases.
Class and exam questions
Which rays possess bactericidal action?
Ultraviolet rays with a wavelength shorter than 320 µm.
What is the danger of constant EMF exposure?
It causes desynchronosis of biorhythms, changes in the central nervous system and cardiovascular system, and may have a teratogenic effect.
What else to study on this topic
- Mechanisms of photochemical reactions in the skin
- Prevention and mitigation of radioactive contamination consequences
- Sanitary standardization of insolation
- Specifics of the effects of permanent magnetic fields in medicine
- Organization of bactericidal sanitation in healthcare facilities
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Other topics in "Chapter 1. Ecological and hygienic problems of atmospheric air"
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