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What is the UV index: Levels and tanning risks explained What is the UV index: Levels and tanning risks explained
(2 months later)
Ultraviolet (UV) levels in the UK are expected to be high in Friday's sunshine. Temperatures could reach 28C (82F) on Thursday, with the warm weather is expected to bring high levels of ultraviolet (UV) radiation.
UV radiation is emitted by the Sun and penetrates the Earth's atmosphere.UV radiation is emitted by the Sun and penetrates the Earth's atmosphere.
Some UV radiation is essential for our wellbeing, and the sun's rays provide warmth and light. Some exposure is essential for our wellbeing, but too much can cause skin damage.
But balance is key as UV exposure can also cause dangerous skin damage. Temperatures to reach 29C in warmest start to May on record
Is UV dangerous?Is UV dangerous?
We need to control our exposure, says Prof Dorothy Bennett, from St George's, University of London.
UV is beneficial because it enables our skin to produce essential vitamin D.UV is beneficial because it enables our skin to produce essential vitamin D.
This is important for the function of bones, blood cells and our immune system.This is important for the function of bones, blood cells and our immune system.
"But UV is also dangerous because every exposure to UV, especially every sunburn, increases our risk of skin cancer," she said. But we need to be careful about how much time we spend in the sunshine, warns Prof Dorothy Bennett, from St George's, University of London.
"Every exposure to UV, especially every sunburn, increases our risk of skin cancer.
"Melanoma, the most dangerous skin cancer, is now the fifth commonest cancer in the UK, the ongoing rise being attributed to sunbathing.""Melanoma, the most dangerous skin cancer, is now the fifth commonest cancer in the UK, the ongoing rise being attributed to sunbathing."
UV radiation promotes skin cancer by damaging DNA in skin cells.UV radiation promotes skin cancer by damaging DNA in skin cells.
It has also been linked to eye problems, including cataracts. It also plays a substantial role in skin ageing, contributing to wrinkles and loosened folds.
And there is growing evidence that UV light may reduce the body's ability to defend itself against certain diseases. UV exposure has also been linked to eye problems, including cataracts.
What is the UV index?What is the UV index?
Levels of UV radiation vary throughout the day.Levels of UV radiation vary throughout the day.
The highest readings occur in the four-hour period around "solar noon", which is when the sun is at its highest spot in the sky - usually from late morning to early afternoon. The highest readings occur in the four-hour period around "solar noon", when the sun is at its highest - usually from late morning to early afternoon.
The UV Index (or UVI) is a standard, international measure of ultraviolet radiation.The UV Index (or UVI) is a standard, international measure of ultraviolet radiation.
Values start at zero and can rise above 10.Values start at zero and can rise above 10.
The higher the number, the greater the potential for damage to the skin and eyes - and the less time it takes for harm to occur.The higher the number, the greater the potential for damage to the skin and eyes - and the less time it takes for harm to occur.
What are the different UV levels?What are the different UV levels?
Countries close to the equator can experience very high UV levels in the middle of the day, throughout the year.Countries close to the equator can experience very high UV levels in the middle of the day, throughout the year.
Nairobi in Kenya can have UV levels above 10 all year, according to the World Health Organization (WHO).Nairobi in Kenya can have UV levels above 10 all year, according to the World Health Organization (WHO).
Majorca in Spain, will normally hit nine in June and July. Majorca in Spain normally hits nine in June and July.
But the Falkland Islands in the South Atlantic never usually gets above five in December and January (when it is summer in the southern hemisphere). But the Falkland Islands in the South Atlantic never usually get above five, even in summer.
When do you need extra protection? What do the different UV levels mean for people?
According to the WHO, extra sun protection is required when UV levels are: According to the WHO, no sun protection is required when levels are:
11+ (extremely high) 1-2 (low)
8-10 (very high) Some sun protection is required when levels are:
Protection is required when levels are:
6-7 (high)6-7 (high)
3-5 (medium)3-5 (medium)
No protection is required when levels are: Extra sun protection is required when UV levels are:
1-2 (low) 11+ (extremely high)
8-10 (very high)
Children are more sensitive to UV radiation than adults, and therefore require additional protection at lower levels.
WHO: Protecting against skin cancer
How can you avoid UV damage?
The NHS advises:
spending time in the shade when the sun is strongest - between 11:00 and 15:00 from March to October in the UK
covering up with suitable clothing and wearing sunglasses
using sunscreen which is factor 30 or above and offers at least 4-star UVA protection on your face, neck and other areas of exposed skin
reapplying sunscreen regularly - check the instructions on the bottle
making sure babies and children are protected
Global research shows people often miss parts of their bodies when putting on sunscreen, according to Dr Bav Shergill from the British Association of Dermatologists.
"People often forget the side of their nose - where I have seen a lot of skin cancer," he says.
Other areas which need to be covered include the temples and the upper chest.
As a guide, adults should aim to apply about six to eight teaspoons of sunscreen if covering the entire body.
Can you tan safely?Can you tan safely?
There is no safe or healthy way to get a tan, according to the NHS.There is no safe or healthy way to get a tan, according to the NHS.
If you want one, Dr Bav Shergill, of the British Association of Dermatologists, says the safest way to tan is "out of a bottle" - using self-tan. Dr Shergill recommends using self-tan products instead.
"When you tan, ultraviolet light stimulates your skin cells to produce pigment to try and protect the DNA of skin cells - but that protection is minimal - the equivalent of SP4."When you tan, ultraviolet light stimulates your skin cells to produce pigment to try and protect the DNA of skin cells - but that protection is minimal - the equivalent of SP4.
"That is not much protection at all - so you can still burn very early," he warns."That is not much protection at all - so you can still burn very early," he warns.
Can you tan even when it is cloudy and windy? Can you burn even when it is cloudy and windy?
BBC Weather's Helen Willetts says: "Your skin can burn just as quickly whether it's 30C or 20C. The amount of UV reaching your skin is not driven by the daily temperature, says Dr Michaela Hegglin, from the University of Reading.
"Don't be caught out on cloudy days. UV will still penetrate thin clouds - so even if you don't think it's that sunny, you can still burn."
The amount of UV reaching your skin is not driven by the daily temperature, Dr Michaela Hegglin, from the University of Reading's Department of Meteorology, says.
"UV levels on a bright and breezy late April day in the UK will be about the same as a warm sunny day in August.""UV levels on a bright and breezy late April day in the UK will be about the same as a warm sunny day in August."
What about skin ageing? "Your skin can burn just as quickly whether it's 30C or 20C," warns BBC Weather's BBC Weather's Helen Willetts.
Unprotected exposure to UV rays plays a substantial role in skin ageing - breaking down collagen and elastin fibres in healthy skin. "Don't be caught out on cloudy days. UV will still penetrate thin clouds - so even if you don't think it's that sunny, you can still burn."
This contributes to wrinkles and loosened folds.
The sun's rays also dry out skin, making it coarse and leathery.
How can you avoid UV damage?
Tips from the NHS, include:
Spend time in the shade when the sun is strongest (in the UK that is between 11:00 and 15:00 from March to October)
never burn
cover up with suitable clothing and do not forget sunglasses
use at least factor 30 sunscreen
reapply sun screen every two hours
take extra care with children
Global research shows people often miss parts of their bodies when putting on sunscreen, Dr Shergill warns.
"People often forget include side of nose by eye - where I have seen a lot of skin cancer," he says.
Other areas include the groove by the side of the nose and into the cheek, the temples and the upper chest.
As a guide, adults should aim to apply about six to eight teaspoons of sunscreen if covering the entire body.
I have brown skin. Do I need to worry?I have brown skin. Do I need to worry?
Yes. Yes, according to Dr Shergill.
"I have, for example, seen South Asian people with skin cancer and I have seen people with dual-heritage get skin cancer. "The skin may look darker, but it doesn’t always behave that way from a protection point of view – because there are more genes at play than we think about," he says.
"The skin may look darker, but it doesn’t always behave that way from a protection point of view – because there are more genes at play than we think about, " Dr Shergill says. "I have, for example, seen South Asian people with skin cancer and I have seen people with dual-heritage get skin cancer."
Regardless of skin colour - the risk of eye damage and of potential harmful effects on the immune system remains. The broader risks of eye damage and harmful effects on the immune system from too much UV radiation affect people of all skin colour.