When it comes to the harmful rays of the sun, the first thing that comes to mind is UVB. The SPF factors found in sunscreens provide protection against UVB rays. Have you ever noticed PA+++ rating in the sunscreens along with SPF level? Some people might have just ignored while, some confused. SPF indicates the level of protection from UVB rays while PA indicates the level of protection from UVA rays that can penetrate deeper into skin.
What is UV radiation?
Among the many different types of rays found in sunlight, the rays that cause the most damage to our skin are called ultraviolet (UV) rays. This is because melanin absorbs dangerous UV rays that can do serious skin damage.
There are two main types of ultraviolet rays that reach the Earth’s surface, UVB and UVA. The type of light that causes sunburn is UVB rays. The 5 percent of UV rays are UVB. UVB rays play the biggest role in causing skin cancers, including the deadly form of skin cancer (malignant melanoma).
UVA rays also play a role in the formation of skin cancer. In addition, UVA rays penetrate deeper into the skin and play a greater role in premature skin aging changes, including wrinkle formation (photoaging). Sunlight has about 500 times more UVA rays than UVB rays. About 95 percent of the UV rays that reach the ground are UVA rays. Therefore, in addition to protecting your skin from the effects of UVB rays, it is also very important to protect yourself from the harmful effects of UVA rays. Traditional chemical sunscreen products have been more successful at blocking UVB rays than UVA rays.
The danger posed by UVA radiation can be greatly reduced with simple precautions you can take. With simple, smart preventative measures, you can enjoy outdoor and sea activities while limiting your risk of skin cancer.
When are UV rays strongest?
A number of environmental factors can affect when UV rays are the most powerful. Some of these factors include:
Time of day
UV exposure is highest between 10 a.m. and 4 p.m. During this daily window, the sun’s rays have less distance to cover. This makes them more powerful.
UV exposure is highest in the spring and summer months. During these seasons, the sun is at a higher angle, which increases UV ray intensity. However, the sun can still affect you during fall and winter.
UV exposure is highest in areas on or near the equator, where UV rays have less distance to travel before reaching the ground.
UV rays are more powerful at higher elevations because they have less distance to travel.
The ozone layer provides protection from UV rays. But greenhouse gases and pollutants have caused the ozone layer to thin, increasing UV intensity.
Clouds filter out some UV rays from reaching the ground. However, it depends on the type of cloud. Dark, water-filled clouds may block out more UV rays than high, thin clouds.
UV rays reflect off surfaces such as snow, water, sand, and pavement. This can increase UV exposure.
|Rating||Risk||Minutes to burn||Precautions|
|0 – 2||Minimal||60 minutes||Sunscreen, UV sunglasses|
|2 – 4||Low||45 minutes||Sunscreen, UV sunglasses|
|4 – 6||Moderate||30 minutes||Sunscreen, UV sunglasses and hat|
|6 – 10||High||15 minutes||Sunscreen, UV sunglasses, hat and umbrella|
|10 – 15||Very High||10 minutes||Sunscreen, UV sunglasses, hat, umbrella and avoiding midday sun|
UVA facts and risks
- UVA rays cause tanning, and the shorter wavelengths of UVA also cause sunburn. There is no such thing as a safe or healthy tan. UVA radiation is proven to contribute to the development of skin cancer.
- UVA is connected to the “broad-spectrum protection” you see on the labels of sunscreen products. Early sunscreens only protected your skin from UVB rays, but once it was understood how dangerous UVA rays were, sunscreen manufacturers began adding ingredients to protect you from both UVB and UVA across this broader spectrum.
- UVA rays, while slightly less intense than UVB, penetrate your skin more deeply. Exposure causes genetic damage to cells on the innermost part of your top layer of skin, where most skin cancers occur. The skin tries to prevent further damage by darkening, resulting in a tan. Over time, UVA also leads to premature aging and skin cancer.
- UVA radiation is the main type of light used in most tanning beds. Once thought to be safe, we now know it is just the opposite.
- UVA is everywhere. UVA accounts for up to 95 percent of the UV radiation reaching the earth. These rays maintain the same level of strength during daylight hours throughout the year. This means that during a lifetime, we are all exposed to a high level of UVA rays.
- UVA can penetrate windows and cloud cover.
- If you are going out in the sun, use a sunscreen with SPF 30 or higher. Be sure to choose one that is water resistant and offers broad spectrum protection.
- Use a PA+++ rating sunscreens along with SPF level. PA simply means Protection Grade of UVA rays, which is used to measure the SPF of a sunscreen. This Japanese measurement ranking which is now widely used, is based on the Persistent Pigment Darkening (PPD) reaction reading at 2-4 hours of sun exposure. Protective grade of sunscreen is often leveled as PA+, PA++, PA+++ with the more plus sign the more protection from UVA rays.
- Sunscreens with the active ingredient zinc oxide, a natural sunscreen ingredient that physically—instead of chemically—blocks rays. Only two sunscreen active ingredients approved in the US, avobenzone (butylmethoxydibenzoylmethane) and zinc oxide (ZnO), provide true broad-spectrum protection against UVA wavelengths >360 nm. Zinc oxide protects against both UVA and UVB rays. Many sunscreens with 3% avobenzone that meet the CW of 370 nm only provide an average protection factor of around 3-5 in the UVA1 range for an SPF 30 sunscreen.
- Broad spectrum sunscreens reflect and absorb UV radiation. They provide protection from both UVA and UVB radiation. Apply sunscreen at least 30 minutes before sun exposure and reapply after swimming or sweating.
- And don’t underestimate the amount of protection you can get by covering up.
- A sunscreen shirt can really help fill in the gaps left by sunscreen.
- Wear a wide-brimmed hat and UV-protective sunglasses to shade your head and face.