Question

Why may the levels of radiation exposure be greater inside of some buildings than in open spaces?

Answer 1

Radiation exposure:

Ionizing radiation is radiation, traveling as a particle or electromagnetic wave, that carries sufficient energy to detach electrons from atoms or molecules, thereby ionizing an atom or a molecule. Ionizing radiation is made up of energetic subatomic particles, ions or atoms moving at high speeds (usually greater than 1% of the speed of light), and electromagnetic waves on the high-energy end of the electromagnetic spectrum.

Gamma rays, X-rays, and the higher ultraviolet part of the electromagnetic spectrum are ionizing, whereas the lower ultraviolet part of the electromagnetic spectrum and all the spectrum below UV, including visible light, nearly all types of laser light, infrared, microwaves, and radio waves are considered non-ionizing radiation.Typical ionizing subatomic particles found in radioactive decay include alpha particles, beta particles and neutrons. Other subatomic ionizing particles which occur naturally are muons, mesons, positrons, and other particles that constitute the secondary cosmic particles that are produced after primary cosmic rays interact with Earth's atmosphere.

Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources. Background radiation is defined by the International Atomic Energy Agency as "Dose or dose rate attributable to all sources other than the one specified. Background radiation originates from a variety of sources, both natural and artificial. These include both cosmic radiation and environmental radioactivity from naturally occurring radioactive materials, as well as man-made medical X-rays, fallout from nuclear weapons testing and nuclear accidents.

Sources of radiation--

Ionizing radiation is generated through nuclear reactions, nuclear decay, by very high temperature, or via acceleration of charged particles in electromagnetic fields. Natural sources include the sun, lightning and supernova explosions. Artificial sources include nuclear reactors, particle accelerators, and x-ray tubes.

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) itemized types of human exposures.

Type of radiation exposures:

Natural sources-Cosmic radiation, Terrestrial radiation, Metal mining and smelting, Phosphate industry, Coal mining and power production from coal, Oil and gas drilling, Rare earth and titanium dioxide industries, Zirconium and ceramics industries, Application of radium and thorium, Other exposure situations, Cosmic ray exposures of aircrew and space crew, Exposures in extractive and processing industries, Gas and oil extraction industries, Radon exposure in workplaces other than mines.

Man-made Sources-Nuclear power production, Transport of nuclear and radioactive material, Application other than nuclear power, Nuclear tests, Residues in the environment. Nuclear fallout, Nuclear power industries, Medical uses of radiation, Industrial uses of radiation, Miscellaneous uses.

There are three standard ways to limit exposure:

Time: For people exposed to radiation in addition to natural background radiation, limiting or minimizing the exposure time will reduce the dose from the radiation source.

Distance: Radiation intensity decreases sharply with distance, according to an inverse-square law.

Shielding: Air or skin can be sufficient to substantially attenuate alpha and beta radiation. Barriers of lead, concrete, or water are often used to give effective protection from more penetrating particles such as gamma rays and neutrons. Some radioactive materials are stored or handled underwater or by remote control in rooms constructed of thick concrete or lined with lead. There are special plastic shields that stop beta particles, and air will stop most alpha particles.