A study has revealed that those who use sunlamps to maintain their tan during winter months could be exposing themselves to more radiation than even sunbathing at the beach during summer.
Atmospheric physicist Dr Richard McKenzie said that tests on several tanning machines found that overall they were emitting ultraviolet radiation at about the same level as the machines' users would be exposed to in the middle of a bright New Zealand summer's day.
However, McKenzie, of the National Institute of Water and Atmospheric Research, said that for some wavelengths in the UV-A band, the levels were higher.
"It's a precautionary message. You should be aware when you use a sunbed that you are exposing your skin to some wavelengths of radiation that are several times higher - maybe five times higher than natural sunlight," the New Zealand Herald quoted him as saying.
He said the health risks of these wavelengths were not known.
Last year, the International Agency for Research on Cancer reclassified ultraviolet radiation as a definite cause of cancer.
The Cancer Society has long been pushing, without success, for the Government to introduce regulations to control solariums.
The society's health promotion manager, Jan Pearson, said that because solarium standards were voluntary, "you get huge variations in the amount of UV you get from different solariums.
"Most operators wouldn't know how much UV or what wavelength their machines were giving. Most solariums are in places like gyms or beauty therapists. The operators aren't really trained or knowledgeable around what the machines are capable of doing," he added.
The Niwa study, involving 500 people and being done with Auckland, Canterbury and Otago universities, is also considering vitamin D, which is produced in the skin from UV exposure.
McKenzie said that because of the wavelengths from sunbeds, using them would make less vitamin D than natural sunlight.