Teacher's Column
Hello, This is Izumi!
Sunshine, UV rays and my favorite summer
It is summer now. I like summer, though I do not like the heat and the humidity in this season. I like the sunshine in summer. The sunshine in summer is dazzling and it makes things more colorful and clearer.
But what exactly is sunshine? Is it just a light that comes from the sun?
Yes, it is a light emitted from the sun but it is not a simple light. Sunshine is an aggregate of various kinds of light, otherwise known as wavelengths or particles of electromagnetic radiation. There are five main types of light in sunshine: gamma rays, x-rays, ultraviolet (UV) rays, visible radiation and infrared rays. The former two types of radiation do not reach the ground because the ozone layer absorbs them. So, the latter three types of light make up the sunshine we see around us. The aggregate of these three types of radiation provide us with heat and light, which is vital for almost all the creatures on the earth. We should be happy to have such an important, limitless substance without charge.
However, since a couple of decades ago, we have been scared of exposing ourselves to sunshine. Why? It is because the ozone layer, which is supposed to prevent dangerous radiation from getting to the ground, has been shrinking due to the effect of the diffusion of massive amounts of CFCs (chlorofluorocarbons) into the atmosphere. CFCs had been used to support our modern life. They had previously been utilized in refrigerators and air-conditioners as a coolant and they had also been used in spray cans as a propellant.
It is ironic that we emitted a lot of CFCs to build a more comfortable and convenient society and that action has made the ozone layer thinner, thereby making life more uncomfortable and inconvenient. We are now confronting the danger of being exposed to harmful light.
The harmful light in sunshine that we now most concern ourselves with is UV radiation. The risks of getting a suntan are well known: spots, wrinkles, deterioration of eye function and skin cancer. In order to prevent the risks we now not only put on sunscreen and wear a hat and sunglasses but also wear clothes that have been impregnated with UV protection, when we go outside in daylight.
Despite the fact that we get great benefits from sunshine, we cannot enjoy sunshine. It is really a shame. I hope that some technology will be created that will bring back our NORMAL summer in the near future, if possible within my lifetime.