Sun Protection

A regular, moderate level of sun exposure, without protection, is good for you. It is even necessary for optimum health. A little more exposure, enough to gently generate a sun tan, can also be enjoyable and shouldn’t greatly increase your risk of skin cancer. Over-exposure and especially burning, however, is harmful and should be avoided. This is true for both adults and children, although children should perhaps not be encouraged to develop a tan.

Once you have achieved your desired level of sun exposure, and the sun is strong enough (UVI 3 or higher, your shadow is shorter than you), you need to take steps to prevent further exposure. You also need to take into account your skin type when judging the need for protection.

Also, remember that the UV Index is an approximately linear scale, in terms of its burning or tanning effect on the skin. Thus sunlight at UVI 6 is twice as strong as UVI 3, and UVI 9 is three times as strong. Therefore 30 minutes exposure at UVI 3 will be equivalent to 15 minutes at UVI 6, or just 10 minutes at UVI 9. Find out the current (or predicted) local UV Index level and adjust your exposure times accordingly.

The simplest and best method of protecting yourself from over-exposure is to seek shade (or go indoors) or cover yourself with suitable clothing. Any remaining exposed areas of skin should be protected with sunscreen (sun block, sun cream, sun lotion, etc.). Sunscreen should be your last resort method of protection, not your first.

When the sun is particularly strong, for a period of about two hours either side of solar noon and during late spring or early summer in temperate regions (all year round in the tropics), you should take extra precautions. Deliberate sunbathing at these times is also not recommended.

Solar noon, the time at which the sun is highest in the sky, is also unlikely to coincide with noon by the clock. If daylight saving time is in effect, such as British Summer Time, solar noon is likely to occur around 1 o’clock, not 12, and the precise time could vary by up to half an hour or more in either direction, depending on how far east or west you are in the local time zone.

When judging your own exposure level, you should also remember that several factors can cause the local sun intensity to deviate from that expected from the UV Index:

  • UV radiation penetrates clouds by up to 30–40%, so even on a day with 50% cloud cover the UV level is still around 80% of the clear sky level.
  • UV radiation also penetrates water: a swimmer at or near the surface can still receive up to 50% of the above-surface UV level.
  • UV intensity increases by 15% for each 1,000 m of altitude above sea level.
  • Light or reflective surfaces, such as glass, concrete, sand, snow and water can significantly increase – perhaps nearly double – your overall UV exposure by reflecting extra radiation onto you. Such reflected radiation also comes from the side and below, and can therefore bypass shade-producing protection measures such as a hat or umbrella.

If it’s sunny, it’s also likely to be hot, so remember to consume plenty of drinks (not alcohol) to prevent dehydration or sunstroke. Thirst is not a good indicator; drink enough to maintain a healthy urine colour (not dark yellow) and volume (you should need to urinate every few hours).

If you are careful, and take appropriate precautions when necessary, you should be able to enjoy the sun, and all the benefits of outdoor activities, relatively safely.

Safety At Work

Many people, in addition to leisure, sporting and sunbathing activities, are regularly exposed to sunlight while at work. Those at particular risk include:

  • Outdoor workers of all types, such as farm workers, builders gardeners,
  • Drivers of all types of vehicles,
  • Office workers who regularly sit near a sunny window.

These people are at greater risk of over-exposure to the sun due to the longer, and effectively involuntary, duration of exposure, and should therefore take the normal sun protection precautions at times when the sun is sufficiently strong.

Employers in the UK and elsewhere have a duty under health and safety legislation to protect their workforce, and should therefore at least allow, and preferably encourage, the use of appropriate sun protection precautions. For example, a compulsory uniform should provide, or at least allow for, adequate sun protection – adequate skin coverage and use of a hat and sunglasses – and UV filters should be fitted to vehicle and office windows.

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