Taipei City Government

Sunburn protection is an important topic for preserving healthy skin in the summer. Chen Jian-Yu, physician of the Dermatological Department in Renai Branch of Taipei City Hospital, explains that there are many methods of sunburn protection, and the most effective one is to directly block ultraviolet rays. When it is difficult to stay indoors or hold a parasol, then sunscreen lotion is required.
Sunscreen lotion can be classified into two categories: physical sunscreen lotion and chemical sunscreen lotion. The physical principle of physical sunscreen lotion is to form a reflective film on the skin, so as to reduce the damage of ultraviolet rays to the skin by reflection. The physical screen lotion is usually composed of macromolecules, having obvious colors and being greasy, which won’t easily cause any allergic reaction; they are thus suitable for patients or children with sensitive skin and atopic dermatitis. The principle of the chemical sunscreen lotion is to absorb a great deal of ultraviolet rays and prevent them from entering the skin, which is usually comprised of smaller molecules and is refreshing, but can easily cause allergic reactions and is suitable for patients with oily skin and acnes.
SPF is short for sun protection factor, which refers to the protection of the sunscreen products against UVB rays. SPF represents the prolonged sunburn time. For example, if the skin gets sunburned in 10 minutes without the application of sunscreen lotion, the prolonged sunburn time will be 150 minutes (15 x 10) when SPF15 sunscreen lotion is applied. Sweating will diminish the sunscreen function, so the correct way is to replenish the lotion frequently. PA is short for protection grade UVA, a standard stipulated in Japan, which represents the protection grade of the sunscreen products against UVA rays. PA uses the symbol“+” to show the protection grade; the more “+s”, the higher the protection grade.
Therefore, he reminds consumers to:
1. Ask for a trial product and confirm there are no allergic reactions before the purchase.
2. Check the manufacturing date and shelf life before use.