What is Ultraviolet (UV) Radiation?
- Three Types UVA, UVB and UVC
- UV Levels Measured from 0 (low) to 11+ (extreme)
Ultraviolet (UV) radiation is natural energy produced from the sun, which consists of different types of rays. On the electromagnetic spectrum, UV light has shorter wavelengths than visible light, so you can’t see or feel the UV rays, you only see and feel the harmful effects once the damage is done. Ultraviolet is classified in to three primary types: Ultraviolet A (UVA) longest wavelength, Ultraviolet B (UVB) medium wavelength, and Ultraviolet C (UVC) shortest wavelength.
UV radiation can not only come directly from the sun, but also indirectly through scattering and reflection by the atmosphere, clouds, ground, water, and reflective materials such as roofs. Even in the shade it is still possible to be exposed to UV reflection, it is recommended to use more than one form of sun protection.
There are also artificial sources of UV radiation such as lasers, tanning beds, and black lights.
The UV level is affected by a number of factors including time of day, year, cloud cover, altitude, location, and surrounding surfaces. In fact, UV radiation is not related to temperature, as many people tend to believe. UV levels can be damaging even on cool, cloudy days, as well as the warm, sunny days. The UV index is always highest in the middle of the day between 10am and 2pm.
The World Health Organisation’s Global Solar Index measures UV levels on a scale from 0 (low) to 11+ (extreme). The higher the UVI, the greater the potential for damage to the skin and eyes, and the less time it takes for harm to occur. When the UV levels are 3 or higher sun protection is recommended to help prevent the risk of skin damage.
What is UVA (Ultraviolet A)?
- UVA rays lead to premature aging of the skin
- UVA rays deeply penetrate the skin
- UVA exposure can contribute to skin cancer.
UVA rays have lower energy levels but a higher wavelength than other UV rays. As a result, they are far more penetrating to the skin than UVB rays, which means they affect the deeper skin cells. UVA rays are associated with skin aging prematurely, which leads to visible affects such as fine lines and wrinkles. UVA radiation is also proven to contribute to the indirect damage of DNA which can lead to skin cancers.
UVA is EVERYWHERE! UVA rays can penetrate through windows and cloud cover and accounts for up to 95% of the UV radiation that reaches the Earth’s atmosphere. UVA rays maintain the same level of strength during daylight hours throughout the year. This means even in the colder seasons the UV rays are just as dangerous as they are in the warmer seasons!
What is UVB (Ultraviolet B)?
- UVB rays cause redness, sunburn, and blistering
- UVB exposure can contribute to skin cancers and melanomas
- UVB causes damage to the outer layers of the skin
Ultraviolet B rays have shorter wave lengths and higher energy levels than UVA rays. UVB rays are mostly absorbed by the ozone layer but about 5% still gets through. Doesn’t sound like much, nonetheless UVB rays can still cause damage to the outer layers of the skin in as little as 15 minutes of sun exposure! Over-exposure of UVB rays can cause suntan, sunburn, and in severe cases, blistering. Usually, the effects of the UVB burns are delayed, or appear a few hours after sun exposure. The UVB strength fluctuates in different climates and seasons, however, can still damage your skin all year round.
UVB radiation can also occur from man-made sources such as special lamps, or a laser used to treat certain skin conditions such as psoriasis, vitiligo, and skin tumours.
What is UVC (Ultraviolet C)?
- The most dangerous form of UV radiation out of the three
- UVC rays are the shortest in wavelength.
- UVC rays don’t pass through the ozone layer
UVC is the shortest wavelength of the three forms of UV. The shorter the wavelength, the more harmful the UV radiation is. However, UVC is the only UV radiation out of the three that is not able to penetrate the Earth’s atmosphere and is absorbed by the ozone layer. So even though UVC is the most dangerous, the only way we can be exposed to UVC radiation is from artificial sources.
Although naturally occurring UVC rays from the sun don’t penetrate through the Earths atmosphere, there are other sources of UVC radiation that exist. Other sources of UVC radiation can be dangerous if not used properly. Some man-made sources of UVC radiation include welding torches, mercury lamps, and germicidal UVC lighting.
What's the difference Between UVA, UVB and UVC?
All three UVA, UVB and UVC sources of radiation are categorised according to their wavelength. UVC being the shortest wavelength and UVA having the longest wavelength. They all differ in their effect and the extent to which they can penetrate the skin. While the shorter wavelengths are more harmful, it also means that they are less likely to reach the deeper layers of the skin.
What You Need to Know:
Benefits of UV radiation exposure
UV radiation isn’t always bad, it does have some great benefits! In small doses that is…
Soaking up those sun rays have a lot of potential and can do plenty of good for your body, mind, bones, and more. It is recommended to give yourself at least 15 minutes outside each day to give your skin access to a healthy dose of sun rays, usually in the morning or late afternoon to avoid the peak of the UV rays.
Helps Production of Vitamin D
UV radiation from the sun is needed by our bodies to produce Vitamin D. Vitamin D is important as it helps regulate the amount of calcium and phosphate in the body, helping to strengthen our bones, muscles, and immune system. Lack of Vitamin D can lead to bone deformities in children and adults. Vitamin D can also be sourced through certain foods and supplements.
UV radiation is surprisingly also effective on improving your mental health. Research suggests that sunlight increases the brains release of a hormone called “serotonin”. Serotonin is the key hormone that stabilises your mood, feelings of well-being, and happiness. Lack of serotonin may cause signs of depression, anxiety, and trouble sleeping.
The serotonin you soak up from the suns rays not only improves your mood, but it also helps you get a more peaceful sleep at night. Working together with serotonin is melatonin, a chemical in your brain that responds to darkness and helps with the timing of your body clock, and one the sun also helps your brain produce.
Lower Blood Pressure
When the golden sunlight hits your skin, your body releases something called Nitric Oxide into your blood. Nitric Oxide helps your body dilate and constrict your blood vessels, improving your blood pressure and heart health. Maintaining a healthy blood pressure reduces your risk of cardiac disease and stroke. When you are feeling relaxed, so is your body! Feelings of relaxation can also naturally bring down your blood pressure, so boosting your mood by soaking up some rays can also keep your pressure down.
Harmful Effects of UV Radiation Exposure
When UV rays frequently come in contact with your skin, its effects can be long term and detrimental. UV damage is accumulative, so your skin remembers and records all the UV exposure over the years. These effects show up over time when your skin is not protected. Although the UV rays from the sun have some beneficial effects, their long-term harmful effects can be far worse.
Causes Skin cancer
UV radiation is an environmental human carcinogen. The cancer council says that as many as 95% of skin cancers are due to UV exposure. When your skin is unprotected the UV rays can damage your DNA. If your body is unable to repair the damaged cells, they will begin to divide and grow in an uncontrolled way. This will then eventually form a tumour.
Causes redness, sunburn, and blistering
It’s no secret that spending too much time in the sun without protection can result in to that red, tender, dehydrated, painful feeling called sunburn! Sunburn is a burn that occurs when skin cells are damaged. This is caused by the absorption of energy from the UV rays. Extra blood flows to the damaged area in attempt to repair it, which results into the redness of skin when you are sunburnt. While the signs of sunburn fade with time, the damage to your skin can’t be undone and adds to your UV damage tally, this can increase your risk of getting skin cancer.
Damages the eyes
Prolonged UV exposure is not only harmful to your skin, but it can damage the tissues of eyes and can cause burning to the eye surface called Photokeratitis. Photokeratitis is a painful, temporary eye condition caused by exposure to UV rays. The affects usually disappear within a few days but may lead to further complications later on.
UV exposure destroys collagen and connective tissue beneath the top layer of the skin, this results in premature aging to the skin. The visible side effects are wrinkles, fine lines, sunspots, and sagging of the skin to name a few. Up to 80% of fine lines and wrinkles are the result of UV damage. The good news is it is never too late for you to start a sun protection routine and prevent further damage.
How to Protect Yourself from the Effects of UV Exposure
Slip on a shirt
Wearing appropriate clothing is a physical barrier between your skin and the sun, which is one of the easiest and most effective ways to protect your skin from the UV radiation. It is recommended to consider the clothing’s style, fabric, colour, and UPF rating.
When choosing a style, shirt with collars, or high necks, and sleeves are ideal. Trousers or longer shorts and skirts that come below the knees, and clothing that is loose rather than stretched across the skin to still keep you cool on those warmer days.
It is also important to look for fabric that has a close, dense weave. An easy way to find this is by holding the piece of clothing up to the light, the less light that passes through the fabric the better. Natural fabrics such as cotton, hemp, and linen are ideal as they have a tight weave but are still lightweight and cool to wear.
Dark coloured clothing such as navy, black, and dark red absorb the UV rays and prevent them from damaging the skin. Lighter coloured clothing can reflect the sunlight. Clothing may be labelled with a UPF number. UPF is a scale that rates how much UV protection the fabric provides, this does not depend on the style, colour, or design of the fabric. Any piece of clothing rated UPF 15 provides sufficient protection against UV radiation.
Slop on some sunscreen
It is important to apply sunscreen on a daily basis, even during the colder seasons as the UV rays can penetrate through clouds and reflect off snow, sand, and water. One key point to consider is the sunscreen you are using. To ensure you are getting full protection make sure you are using a sunscreen with broad spectrum protection. This means your sunscreen will have the ability to block out both UVA and UVB rays. It is recommended to use a sunscreen that is minimum SPF 15. SPF 30 is a good choice for everyone. There is very little difference from SPF30 up though, you can read more about why in our Guide to SPF Ratings.
Slap on a hat
Wearing a sun smart hat is not only a fun way of accessorising your outfit but a simple way to protect your face, head, neck, and ears from UV radiation. Your face is exposed to the damaging effects of UV radiation every day! The most common parts of the face to develop skin cancers are the ears, temples, lips, and nose. When choosing a hat, it is important to make sure that it provides adequate shade for the whole face, made of a close weave fabric that does not allow light to get through, and has a dark lining to reduce the UV reflection.
Shade is one of the easiest ways to protect yourself against UV radiation. Good quality shade can reduce UV exposure by up to 75%. Some tips for seeking shade:
- Babies under 12 months have very sensitive skin so should be kept out of direct sunlight
- The shade moves with the sun, so be prepared to move around
- Trees with lots of leaves with a dark, even shade patch are the best types of trees to seek shade from
- Take portable shade with you as a backup. This could be an umbrella or shade tent.
Slide on some Sunglasses
It is recommended by the cancer council to pair a nice set of close-fitting wraparound sunglasses with a sun smart hat. Pairing sunglasses and a sun-safe hat can reduce 98% of UV radiation exposure. UV radiation can cause short term eye problems, such as excessive blinking, swelling, and difficulty looking at strong light. Over time, exposure to UV radiation can cause permanent eye damage, such as skin cancer of the eyelids and around the eyes, cataracts (cloudiness of lens), solar keratopathy (cloudiness of the cornea), and cancer of the conjunctiva (the barrier covering the white part of the eye).
Sunglasses don’t have to be expensive to be effective. However, it is important to consider the below factors when choosing a pair of sunglasses, if you want to make sure you’re blocking out those UV rays.
- The cancer council recommend choosing a pair of sunglasses that meet Australian Standard AS/NZS 1067.1:2016 with a lens category of 2, 3 or 4 on the swing tag. These sunglasses absorb 95% of UV radiation. Anything below does not offer good UV protection.
- Some sunglasses may be marked with an Eye Protection Factor (EPF). An EPF rating of 9 or 10 provides sufficient UV protection, blocking out almost all UV rays.
Get to know your skin
It is important to remember that UV damage is not always visible, most melanomas grow silently without any symptoms. It is recommended to check your skin for any changes or new spots every 3 months, and to have a trained doctor examine them at least once a year. Most melanomas develop in places that are visible for us to see, but only if you look.
Checking your skin and moles and finding a melanoma at the earliest stage means there is a higher possibility of achieving 100% cure rate. If the melanoma grows unnoticed to more than 4mm deep, the survival rate can fall to less than 50%. There are some melanomas that do not have any colours and do not look like a mole, so if you notice any spots that are growing, sores that don’t heal, or spots that bleed or become sore, get an assessment. It is important to remember if you suspect a skin cancer or find something unusual on your skin DO NOT DELAY, go get it checked out!
Facts about UV Radiation
UV exposure helps our bodies produce Vitamin D.
Exposure to UV rays can help improve your mood
UV radiation can help some animals' vision to locate many ripe fruits, flowers, and seeds
UV Aids some species of insects to navigate, which is why you see certain insects attracted to light sometimes.
UV rays are used for disinfecting medical equipment in hospitals.
Elephants coat themselves in mud to protect themselves from the harmful effects of UV exposure.
Scorpions glow under UV light.
Humidity in the weather can increase the effects of UV radiation.
In forensics, ultraviolet can be used in conjunction with special powder to detect fingerprints
Scary Fact about UV Radiation
Australia has the highest rate of skin cancer in the world from UV exposure! Over 440,000 Australians are treated for skin cancer each year. 2 in 3 Australians will be diagnosed with cancer by the age of 70.
Ultraviolet Radiation-Induced Skin Aging: The Role of DNA Damage and Oxidative Stress in Epidermal Stem Cell Damage Mediated Skin Aging: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4842382/
Facts about Sun Exposure: https://stanfordhealthcare.org/medical-conditions/cancer/melanoma/assets/facts-about-sun-exposure.html