As many of you know, the sun is our frenemy. While it gives life to us, it also does damage to our skin. The sun also causes a lot of skin problems, to name a few : it accelerates aging,causes pigmentation, overactive sebum secretion, big pores etc.
Do you know with every 1°C increase of your skin temperature, the level of sebum increases by 10% ? This increases probability of your skin being affected by acne, wide pores, etc.
According to the research conducted by Seoul National University – when the skin is exposed under the sun for 15 minutes, the temperature of the skin can rise up to 43 degrees!
So Hope In A Blog has come up with a short and precise guide for your summer sun care products!
The Two Different Type Of Sun Filters
Here is a great chart from skinacea :
How To Read Sunscreen?
In most Asian sunscreen, you’ll notice two readings : SPF and PA
SPF : Stands for Sun Protection Factor – a measurement for UVB Protection
PA : Stands for Protection grade of UVA – a measurement for UVA Rays.
What is the difference between UVA or UVA?
Source : WHO
UV rays are divided into three categories based on their wavelength.
- UVA rays long wavelength (320-400nm)
- UVB rays medium wavelength (280-320nm)
- UVC rays short wavelength (280nm and below)
While shorter wavelength are the most damaging to skin, UVC rays and shorter-wavelength UVB rays are absorbed by the ozone layer and never reach the earth. Therefore, UVA and longer-wavelength UVB rays have the potential to cause the most harm to skin.
UVB is very biologically active but cannot penetrate beyond the superficial skin layers. It is responsible for tanning and burning your skin (sunburn), and makes it look darker ; in addition to these short-term effects it enhances skin ageing and significantly promotes the development of skin cancer. Most solar UVB is filtered by the atmosphere. ( UVB are reflect by glass )
The relatively long-wavelength UVA accounts for approximately 95 per cent of the UV radiation reaching the Earth’s surface. It can penetrate into the deeper layers of the skin and breaks down collagen in our skin. Furthermore, it also contributes to skin ageing and wrinkling. For a long time it was thought that UVA could not cause any lasting damage. Recent studies strongly suggest that it may also enhance the development of skin cancers. ( UVA are not reflected by glass and are let through, so even if you’re indoors, UVA rays can still get to you! )
Measuring The Protection Of SPF and PA
The numeric value indicates how long the sunscreen will allow you to stay in the sun before experiencing ‘sunburn’ or the darkening of your skin.
For example :
It takes 10 minutes under the sun for Sally to experience sun-burn/sun-tan (reddening or darkening of the skin). If Sally uses a sunscreen with an SPF 15, it means that Sally is able to protect her skin from the sun 15 times longer. Therefore, Hyuna is able to stay 10 minutes x 15 (SPF) = 150minutes under the sun protected before she experiences any redness/darkness on her skin.
Soure : Skincareclub
The PA rating system was developed by Shiseido and has then been used in every Asian sunscreens. It is based on the Persistent Pigment Darkening (PPD) reaction reading after 2-4 hours of sun exposure. PA is a protective level of strength to mark the three PA+, PA++ and PA+++. Theoretically, a sunscreen with a PPD rating of 10 should allow a person 10 times as much UVA exposure as would be without protection (same principle with the SPF example).
For example :
PA+ provides some UVA protection with a factor of PPD 2-4. It protects sensitive skin against low to medium UV radiation.
PA++ provides moderate UVA protection with a factor of PPD 4-8. It offers better protection from UVA rays and can be used by people with normal skin exposed to medium UV radiation.
PA+++ provides good UVA protection with a factor of PPD > 8. It is the strongest grade of UVA protection now available. It is designed for normal skin under very strong or direct UV radiation.
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