UVInfo
What is the difference between UVA and UVB?
The Sun emits ultraviolet radiation in the UVA, UVB, and UVC bands, but because of absorption in the atmosphere's ozone layer, 98.7% of the ultraviolet radiation that reaches the Earth's surface is UVA. UVA and UVB refer to different wavelengths in the light spectrum. UVB is more damaging to the skin especially for skin cancer. Both UVA and UVB are responsible for photoaging (premature aging of the skin and wrinkles) and sunburn. Tanning beds produce both UVA and UVB rays.
Harmful Effects
An overexposure to UVB radiation can cause sunburn and some forms of skin cancer. In humans, prolonged exposure to solar UV radiation may result in acute and chronic health effects on the skin, eye, and immune system.[9] However the most deadly form - malignant melanoma - is mostly caused by the indirect DNA damage (free radicals and oxidative stress). This can be seen from the absence of a UV-signature mutation in 92% of all melanoma.
What is sunburn?
Sunburn is literally a burn on your skin. It is a burn from ultraviolet (UV) radiation. The consequence of this burn is inflammation of the skin. Injury can start within 30 minutes of exposure.
Sunburn symptoms
Mild and uncomplicated cases of sunburn usually result in minor skin redness and irritation. Untreated and with enough exposure, you can experience shock (poor circulation to vital organs) and even death (sun poisoning). Sufficient exposure can become remarkably painful.
Initially, your skin turns red about 2-6 hours after exposure and feels irritated. The peak effects are noted at 12-24 hours.
More severe cases (sun poisoning), such as those experienced by rafters (Cuban and other island peoples fleeing their countries on homemade rafts) are complicated by severe skin burning and blistering, massive fluid loss (dehydration), electrolyte imbalance, and infection. Blistering - May range from a very fine blister that is only found when you begin to "peel" to very large water-filled blisters with red, tender, raw skin underneath
How to treat sunburn
What is SPF?
SPF is an acronym for Sun Protection Factor. The SPF of a sunscreen is a laboratory measure of the effectiveness of sunscreen — the higher the SPF, the more protection a sunscreen offers against UV-B (the ultraviolet radiation that causes sunburn). The SPF indicates the amount of UVB radiation that can reach your skin before the skin burns. The SPF does not indicate the amount of time a person can stay in sun exposure. In practice, the protection from a particular sunscreen depends on factors such as:
How to protect yourself from UVA and UVB
The best prevention is to avoid the sun whenever possible, especially during the peak time of day (from 10:30 am – 3:00 pm). Sometimes this is obviously unavoidable, so the following measures should be taken whenever possible:
Who is at the highest risk?
People that travel to or live in the southern United States, regions close to the equator, and places at high altitudes all offer the unwary visitor an opportunity to be injured by sunburn. Certain light-skinned and fair-haired people are at greater risk of sunburn injury.
How do I check myself?
Basal cell cancer. Most often found in areas that get exposed to a lot of sun, such as the head, neck, and arms; flat, firm, pale areas; small, raised, pink or red, translucent, shiny, waxy, "pearly" areas; may bleed after minor injury; may have one or more abnormal blood vessels, a lower area in their center, and/or blue, brown, or black areas; larger areas could be oozing or crusting; small blood vessels may be seen;
Squamous cell cancer. Most often found in areas that get exposed to a lot of sun, such as the head, neck, and arms; lumps with rough, scaly, or crusted surface; flat reddish patches that grow slowly; sometimes accompanied by ulceration or bleeding
Melanomas. Look for changes in size, shape, or color of a mole or the appearance of a new spot during adulthood. Use the "ABCD rule".
Examine your entire body. - It can be helpful to have a list in front of you. Don't skip any of these steps as you perform your self-exam:
the skin underneath.
backside to the large mirror and use your hand held mirror to see your reflection.
but you will need to use a hand held mirror to see the bottoms of your feet, your calves, and the backs of your
thighs.