Radiation monitoring


ANSTO continually monitors environmental gamma radiation from a station located in Engadine NSW. ANSTO uses environmental radiation data to evaluate atmospheric dispersion from its site. This radiation is almost completely natural background radiation. For additional data on non-ionising radiation (ultraviolet radiation) in Australia's main cities, see ARPANSA's real-time UV index.

ANSTO's controlled airborne discharges are occasionally detectable. A range from 30 to 60 nGy/h was measured in the ARPANSA's survey of natural background radiation.

Engadine's local radiation and rainfall levels 


Environmental Radiation graph

Rainfall graph


Engadine's previous radiation levels

Daily average for the last 30 days


Environmental Radiation graph (month)


Monthly average over the last year 


Environmental Radiation graph (year)



Gamma radiation is a penetrating form of short wavelength electromagnetic radiation, similar to X-rays. 

The environmental radiation graph (above) shows measurements in nanoGrays (nGy) which are units of absorbed radiation dose commonly used in environmental monitoring. A nanoGray is one billionth (one thousand millionth) of a Gray. 

A temporary rise in environmental gamma radiation is often detected when it rains. This occurs because rain affects the behaviour of naturally occurring radionuclides, such as the gas radon. These radionuclides can be absorbed by rain drops and temporarily concentrated near the ground. Also, radon naturally builds up in air spaces in the soil and can be released when rain soaks into the ground. 

"Spikes" in the environmental radiation graph (above) may occur during the regular calibration checks (see below) of the instrument that are needed to ensure accurate data. Gaps appearing in either graph are usually associated with delayed radio transmission of data from Engadine. 

See a list of definitions and information on other types of radiation (e.g. alpha and beta particles) in our glossary of nuclear terms.

For further information contact:

email: env-monitoring@ansto.gov.au