August 2, 2009 : Kataonami Beach
© 安岡喜晴 (JoyShine)
We went to Kataonami Beach in Wakayama prefecture.
The sunlight was so strong, and my friends got sunscreen on the way there.
Actually, we have to be careful when we use sunscreen because there are two kinds of ultraviolet rays, UVA and UVB.
For example, in summer in Japan, UVB is stronger than UVA and we need to block mainly UVB.
But in winter, UVB is reduced to one-fifth, while UVA is reduced to one-half.
For a long time UVA was believed to be harmless to our body but recently it has been found out that it becomes harmful under the existence of UVB.
So in winter we need to protect ourselves from both UVA and UVB.