Background radiation
Background radiation refers to exposure to ionizing radiation in day-to-day life, excluding occupational exposures. It is measured in millisieverts (mSv). Ionizing radiation occurs naturally in the environment:
- radioactive gas (e.g. radon, thoron): 0.2-2.2 mSv/year
- external terrestrial (e.g. building materials): 0.3-1 mSv/year
- ingestion (i.e. diet): 0.2-1 mSv/year
- cosmic radiation: 0.3-1 mSv/year
Geographic variables in background radiation include altitude (higher altitude results in higher cosmic radiation exposure) and percentage of radioactive gas in the atmosphere. In Australia, the average background radiation is 1.5-2 mSv/year , while in the USA it is 3.2 mSv/year .
Sometimes but not always medical exposure is considered part of background radiation with average doses of 1.7 mSv (Australia) to 3.0 mSv (USA) per person per year , although this figure will vary dramatically depending on availability and technology.
See also
