The Environmental Quality Protection Foundation yesterday launched a scale that it developed to measure ultraviolet A (UVA) rays to help boost public awareness of the long-term effect UVA has on skin.
The scale was created by first switching the radiation volume measured by the Environmental Protection Administration (EPA) to a UVA index.
Researchers then developed five intensity levels based on the index, from "low: (UV-A 0~2), to "moderate" (UV-A 3~4)" "high" (UV-A 5~6), "very high" (UV-A 7~9) and "extreme" (UV-A >10).
Foundation chairman Liou Ming-lone (
He said clinical research, especially in the EU, has indicated that prolonged exposure to UVA could age skin and eventually damage the body's immune system.
Liu Chung-ming (
According Liu, UVC has the longest wavelength and can cause the most damage to skin, but it is mostly filtered out by the ozone layer before it enters the Earth's atmosphere.
UVB is rated second in terms of its intensity and wavelength. It can cause immediate damage to the skin and eyes, notably sunburn.
However, a majority of UVB rays do not enter the atmosphere, except when they are able to enter through holes in the ozone layer.
UVA has the longest wavelength of the three and consists of a major portion of ultraviolet rays, Liu said. It can penetrate the ozone layer, but will not cause immediate damage to the skin. However, constant exposure to UVA could prove detrimental, as it can cause aging of the skin and potentially induce skin cancer, he said.
Liu's analysis of the EPA's statistics showed that the radiation volume from UVA is a hundred times more than that of UVB. While both UVA and UVB rays are strongest between 10am and 3pm, UVA poses a stronger influence when it is before and after that time frame, he said.
In particular, UVA's influence remains strong in the winter, he said, adding that it can reach levels from "very high" to "extreme."
Chao Chao-ming (趙昭明), a dermatologist at the Tri-Service General Hospital, said the scale will help educate the public about the impact of ultraviolet rays on health, specifically the cumulative effects of ultraviolet rays on the skin.
Chao said he has seen a growing number of elderly people with skin cancer in recent years.
Chao suggested that sunscreen with Sun Protection Factor (SPF) of 15 is adequate to protect the skin from harm, provided that it contains compounds that can block both UVA and UVB rays from penetrating the skin. Such suncreens must also be reapplied several times a day, he said, depending on the weather and skin types.
The latest UVA Index report from the EPA can be accessed on the Internet at cats.gcc.ntu.edu.tw/UVA/welcome.html.