Page 160 - IGC BOOK

Similarly, special plastic shields stop beta particles, and air stops alpha particles. Therefore,
inserting the proper shield between you and a radiation source will greatly reduce or eliminate
the dose you receive.

Dose Limits

Dose limits are set to protect workers and members of the public from the effects of ionising
radiation. They are set at a level that balances the risk from exposure with the benefits of using
ionising radiation. The fundamental requirement is for employers to reduce all exposure to
ionising radiations to as low a level as possible and this should be below the dose limits.

International commission on Radiological Protection (ICRP) has set dose limits for ionising
radiation exposure. Which is also available in UK, Ionising Radiation Regulations 2017:

Dose limits are expressed in millisievert

• Occupational Exposure - 20 mSv in a calendar year
• Members of public shall not exceed 1mSv in a calendar year.

The regulation requires a competent person to carry out risk assessment, hence the employer
should appoint a competent Radiation Protection Advisor (RPA) and Radiation Protection
Supervisors (RPSs).

Radon Gas and Health Risks

Radon (chemical symbol Rn) is an odourless, colourless, radioactive gas. It comes from the
natural decay of uranium and radium found in nearly all rocks and soils. Radon can move up
from the ground into buildings through openings in floors or walls that are in contact with the
ground.

Radon can accumulate in buildings and, over time, can pose a serious health hazard. These solid
decay products, which may attach to atmospheric dust and water droplets, can then be breathed
in and become lodged in the lungs and airways. Some of these decay products emit particularly
hazardous radiation called alpha particles, which cause significant damage to the sensitive cells
in the lung

ENSIGN | Unit IG2 – Element 5 – Physical and Psychological 20
Health