NZers at high risk of burning over summer

MEDIA FOR SUNSMART WEEK 2002/03

Main release for SunSmart Week

Embargoed till midnight Nov 10, 2002

New Zealanders at high risk of burning over summer warns Cancer Society

A unique set of factors means that New Zealanders have an extremely high risk of sunburn in summer. That’s the warning from the Cancer Society at the beginning of SunSmart Week. Sun exposure and sunburn increase people’s risk of developing skin cancer – and New Zealand already has one of the highest rates of skin cancer in the world.

“Our clear skies, closeness to the sun, and relatively low ozone amounts mean that the ultraviolet radiation that reaches New Zealand is particularly strong”, says Health Promotion Programme Manager Liz Price. “Add our predominantly fair skinned population into the mix, and you have a highly risky situation.

“Ironically, greater pollution in the atmosphere over Europe means that some ultraviolet rays are reflected or absorbed, offering some protection to those countries. In New Zealand the ultraviolet rays get straight through. To compound things, the Earth is closer to the sun during the Southern Hemisphere summer than during the Northern Hemisphere summer.”

But the news is not all bad. Ms Price says you can have fun this summer and still be safe from the sun.

“Remember to slip, slop, slap and wrap – slip into some loose clothing, slop on heaps of sunscreen, slap on a hat, and wrap on some sunnies. The sun is particularly strong between the hours of 11am and 4pm – so seek shade whenever you can during these times.”

The strength of the sun’s ultraviolet rays is not linked to heat, she says, and this can catch people out.

“Because it is not always particularly hot in parts of New Zealand in summer, people think it is safe to be outside without covering up against the sun. In fact, even on a cooler day, ultraviolet rays can be extremely strong and can burn.”

Dr Richard McKenzie from the National Institute of Water and Atmospheric Research (NIWA) says that the ozone hole over Antarctica was remarkably small this year due to unusual weather patterns which resulted in the hole being split into two in September, well before its usual breakup period. Ozone levels in Antarctica have nearly recovered now, about a month earlier than last year.

“However ultraviolet radiation is likely to be as intense as it was last year. In New Zealand, it is estimated that ozone losses since 1980 have caused sunburning radiation to increase by 10-12%.”

Dr McKenzie said that although we do not expect the ozone hole to be as benign next year, there was some good news on the ozone front - the repair of the ozone layer is now expected to happen more quickly than originally predicted. The success of the Montreal Protocol has been identified as the main reason for this accelerated repair of the ozone layer.

“However, a full recovery is by no means certain – there are still many unknowns. At best the full recovery is still decades away. We are currently living in the period of greatest risk, and it is important that people remember to continue protecting themselves against the sun in summer”, he says.

ENDS

BACKGROUND INFORMATION

Skin cancer

- Skin cancer is the commonest cancer in this country.
- New Zealand has one of the highest rates of skin cancer in the world.
- There are nearly 50,000 new skin cancers a year, including 1800 new cases of melanoma.
- You are most likely to be burnt on your face, neck, shoulder, and lower arm.
- The face and neck are the most common places for skin cancers particularly squamous cell carcinoma - a raised, crusty, non-healing sore, or basal cell carcinoma – a pale, red or pearly raised lump.
- New Zealanders are particularly at risk of skin cancer because of our clear skies, our outdoor lifestyle and our countries closeness to the sun.
- While we can consider ourselves blessed to live in such a beautiful country as New Zealand we can’t afford to be blasé about possible downsides.
- Our high rate of skin cancer, and melanoma in particular, is disturbing, especially given that most melanoma is preventable.

Further information can be found on the Cancer Society website: www.cancernz.org.nz.

The ozone layer

Ozone in the atmosphere occurs mainly in the stratosphere, at altitudes 10-30 kilometers above the Earth's surface. It forms a natural screen that absorbs most of the damaging UV radiation present in sunlight. The amount of ozone in the layer at any one time and location is subject to natural variation caused by the variations in the solar radiation received and atmospheric circulation patterns. Variation in the solar cycle (sunspots), and volcanic activity also have minor effects. Over the past 15 years the total amount of ozone screening the Earth from UV radiation has decreased significantly, with the largest changes occurring at high latitudes. These changes cannot be explained wholly by natural factors.

Chlorine (Cl) contained in synthetic chemicals called chlorofluorocarbons (CFCs) is partly responsible for this ozone depletion. Since the 1940s CFCs have been used as, for example, refrigeration agents and propellants in aerosol sprays. They have a very long lifetime in the atmosphere. When they diffuse into the stratosphere, sunlight causes the molecules to break up, releasing Cl atoms. Cl reacts catalytically with ozone in a process which regenerates Cl, so that each atom can destroy thousands of ozone molecules. Bromine (Br) is an even more effective ozone-depleter on a per molecule basis, but its atmospheric concentration is much less than that of chlorine.

Since the late 1970s an ozone "hole" has formed over Antarctica during early spring, caused by the special meteorological conditions of the cold atmosphere which make CFCs much more destructive. At this time, more than half of the ozone over Antarctica can be destroyed. This hole cannot shift over New Zealand, but it is thought to contribute to global ozone changes because the ozone recovery in Antarctica during the late spring/early summer dilutes the available total ozone. Evidence of ozone destruction has also been observed recently over the Arctic.

Based on the Montreal Protocol, regulations to minimise future ozone depletion are now in effect. As a result, it is predicted that the amount of chlorine in the stratosphere will peak just before the end of this century. Because CFCs last so long it will be several decades before Cl reverts to pre-ozone depletion levels.

Further information can be found on the NIWA website: www.niwa.cri.nz/services/uvozone/
Being SunSmart

SLIP into a shirt - and slip into some shade, especially between 11am and 4pm when the ultraviolet rays are most fierce

SLOP on some sunscreen before going outdoors.
- Put sunscreen on any skin not covered by clothes.
- Choose a sunscreen that meets the Australian and New Zealand Standard AS/NZS2604.
- Use an SPF30+ broad-spectrum sunscreen. Wipe it on thickly at least 15 minutes before going outdoors.
- Reapply; do this 15 minutes after the first application to ensure complete coverage, and also after physical activity, swimming or towel drying.

SLAP on a hat with a brim or a cap with flaps. More people get burned on the face and neck than any other part of the body, so a good hat is important.

WRAP on a pair of sunglasses. Choose close fitting, wrap-around glasses that meet the Australian Standard AS1067.

Ultraviolet Index

The Metservice provides daily forecasts of ultraviolet (UV) radiation expected around New Zealand, which are calculated for clear sky conditions by the National Institute of Water and Atmospheric Research (NIWA). The ozone information needed for these calculations is based on satellite data.

The UV Index (UVI) is an international standard that applies to all skin types, and is a guide to the possible risks of sunburn.

The index assesses the danger on a scale from 0 to a maximum of about 14 in New Zealand, with the higher the number the higher the danger. (Note. The scale is open ended. At high altitudes, the UVI can exceed 15, but for most locations on the Earth’s surface, the maximum UVI is less than 20. In New Zealand the UVI rarely exceeds 14. Outside the Earth’s protective atmosphere, the UVI can exceed 300).

UVI Range Risk
1 – 5 low to moderate
6 – 7 High
8 – 10 very high
10 – 15 extreme

The index is expected to reach a maximum value of 13 to 14 during summer (with higher values in the North), and is highest between 1pm and 2 pm local time.

To avoid skin damage protection is required once the UVI is over 6 – this is usually daily during the New Zealand daylight saving period

In addition, NIWA provides to the public at no charge:

- Maps of predicted noon time UV (and ozone) for the NZ region
- Plots of measured UV compared with the UV calculated for clear skies at five sites:

- Leigh (near Auckland)
- Paraparaumu (near Wellington)
- Christchurch.
- Lauder (Central Otago)
- Invercargill.

Check out the NIWA website - http://www.niwa.co.nz/services/uvozone – for this UVI information.

NIWA can also provide "UV Atlas" CDs from which UV can be calculated throughout NZ for the period 1979 to the present. The Atlas is currently being updated. There is as small charge for this product (see NIWA website http://www.niwa.co.nz/services/uvozone/atlas).

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