Please note that Richard McKenzie of NIWA, a world authority on UV from Lauder
is giving a talk on 7 April at 12.30pm in the NIWA Conference Room, 41 Market
Place, Viaduct Basin, Auckland Central.

Title:
"How to balance your benefits and risks of solar UV exposure" or
"Balancing Risk and benefits of UV exposure"

Author: R McKenzie, NIWA Lauder

Abstract:
It is well known that overexposure to UV radiation causes sunburn, which
can lead to skin cancer. New Zealand has one of the highest rates of
skin cancer in the world. However, there is also a risk from
underexposure to UV, since it leads to the production of beneficial
vitamin D in our bodies. Many New Zealanders have below-optimum vitamin
D for health, and it is not generally available from diet. I investigate
relationships between erythemally-weighted UV radiation that leads to
sunburn (which can lead to skin cancer) and vitamin D-weighted radiation
that is responsible for synthesis of vitamin D (which protects against
many conditions including bowel cancer). An algorithm is developed using
spectral measurements undertaken at Lauder Central Otago, and is used to
relate vitamin D production to the widely-used UV Index. This is then
used to calculate the behavioural patterns (exposure times and attire)
required to enable the public to optimize their exposure to UV
radiation. In the New Zealand summer at noon, there should be sufficient
UV to photosynthesize optimal vitamin D in ~1 minute for full body
exposure, whereas skin damage occurs after ~15 minutes. Further, while
it should be possible to photosynthesise vitamin D in the winter, the
amount of skin that must be exposed is larger than from the hands and
face alone. This raises the question of whether the action spectrum for
vitamin D production is correct, since previous studies have reported
that production of vitamin D is not possible in the winter at
mid-latitudes. However, evidence suggests that some supplementation of
vitamin D is desirable, at least in the south island winter. I describe
how a new HRC-funded research project involving NIWA addresses these
questions by tracking personal UV exposure and relating this to vitamin D
status.

The presentation is based on a paper that will soon appear in photochem
photobiol.www.photobiology.org .

Personal sketch
Dr Richard McKenzie is Principal Scientist (Radiation) at New Zealand's National
Institute of Water & Atmospheric Research (NIWA). He is based at NIWA's
laboratory at Lauder Central Otago, which is a charter site for the
International NDACC (Network for the Detection of Atmospheric Composition Change
- formerly known as the NDSC). He is closely involved with a wide range of
atmospheric state-of-the-art measurements relevant to ozone depletion and
climate change which are undertaken there. Interests include ozone depletion, UV
radiation and health, aerosols, and interactions between ozone depletion and
climate change. He also participates in UNEP and WMO Panels.
(Contact: r.mckenzie@...).

Richard's academic career:
BScHons(First class) Physics University of Canterbury (1972)
MSc Physics University of the South Pacific (1979)
D Phil Atmospheric Physics University of Oxford (1986)