When we think of monitoring radiation levels, Apocalypse images of nuclear fallout immediately spring to mind. However radiation occurs naturally in the environment and we are all exposed to low levels each day.
So who does the monitoring and why is it necessary?
What Is Radiation?
Radiation is the terminology used for the transmission of energy in the environment – either in the form of waves or particles. At its simplest level an example of radiation might be the heat given off by a radiator – hence the expression ‘radiating heat’.
There are two main forms of radiation:
1. Ionising Radiation
2. Non-ionising Radiation
This type of radiation is the one which people mean when they think of ‘harmful’ radioactivity. It is made up energy waves of sufficient strength that they can ionise atoms.
If too much radiation occurs within delicate structures, such as the human body, it can damage a cell and even alter its genetic make-up. This is what happens when radiation causes cancer.
Non Ionising Radiation
Non-ionising radiation is made up of waves which can move energy around but can’t do inherent damage to the DNA of a cell and includes familiar types of energy transmitters such as radio waves, microwaves, electromagnetic fields, and ultraviolet waves.
When monitoring levels of radiation, two different sources of ionising radiation have to be considered; those from:
1. Natural Radiation Sources
2. Artificial Sources of Radiation
The Earth contains some radioactive properties, so that natural materials such as rocks and soil and some foods emit radiation – as does the cosmos outside the Earth’s atmosphere, which emits what are called ‘cosmic rays’. These types of radiation are therefore seen as naturally occurring.
Man can utilise high-energy radiation for his own purposes. A positive example of this would be as in the medical use of radiotherapy to treat cancer, whereas a more controversial use might be in the process of making nuclear energy. Accidents due to man’s harnessing of radiation, such as Chernobyl, have added to the amount of background radiation in the environment.
Alpha, Beta And Gamma Rays
Radiation waves vary in their length, strength, and extent of the harm they can consequently do. Alpha is the least damaging kind of ray, Beta the next and Gamma the most harmful, as penetration is much deeper.
Why Monitor Radiation Levels?
The reason to monitor the levels of ionising radiation we have in the environment is in order to keep note of the amount, type, and strength of radiation we are being exposed to, so that it can be determined whether it poses a health risk and if so how detrimental it may be.
Who Sets Safe Levels?
The government’s Department of the Environment, DEFRA, is responsible for setting the limits for radioactive emissions and for regulating its waste
Who Does The Monitoring?
The monitoring of radiation levels is done by a number of different parties.
The government has overall responsibility and DEFRA authorise specific operators to regularly monitor radiation levels across the country and to make sure that they don’t exceed safe limits.
However since the accident at Chernobyl and the ensuing increase in background radiation levels, councils decided to take independent readings for their own areas. Today more than 300 local authorities carry out their own measurements each month (in addition to those done by the government) and compare them with other areas.
In addition to this, bodies such as hospitals, nuclear establishments, and universities check radiation levels and the National Radiological Protection Board (NRPB) specifically monitors the levels of Radon (found naturally in clay soil and granite rock for example).
Regular readings are taken in order to ensure that levels stay relatively even and any fluctuation in the figures can be monitored.
What Are Safe Levels?
The average level of radon usually found in homes is 20 becquerels (bq) per cubic metre; however levels can vary widely according to where you live.