Final answer:
Exposure to ionising radiation includes natural sources like cosmic rays, soil, and radon gas, as well as man-made sources such as medical procedures. Protective measures include shielding, distancing, and minimizing exposure time. Despite these, complete avoidance of radiation is not possible, and understanding sources and exposure management is crucial.
Step-by-step explanation:
Routes of Exposure to Ionising Radiation - External Radiation
Understanding the routes of exposure to ionising radiation is critical for health and safety. External radiation can come from natural sources such as cosmic rays, which originate from outer space and are partially filtered by the Earth's atmosphere. Another natural source is terrestrial radiation from soil and building materials, which contain radioactive elements like uranium and thorium. Moreover, radon gas, a decay product of uranium found in the soil, can accumulate in buildings and is another significant source of external radiation.
Ionising radiation can also be man-made, arising from medical procedures like X-rays and CT scans, or industrial applications. To minimize exposure to radiation, strategies like shielding with materials that absorb radiation, increasing distance from the source, and reducing exposure time are employed. Despite these efforts, complete avoidance of ionising radiation is not possible due to its ubiquitous nature, with a large percentage of exposure originating from natural sources.
Long-term radiation exposure can have various effects on the human body, which depend on the radiation type, energy, location, and duration of exposure. An understanding of these sources and protective measures is essential for managing and mitigating risks associated with radiation exposure.