UV

What are UV Rays?

The sun is the source of all energy on earth, and the rays from the sun can be differentiated according to their length into ultraviolet rays, visible light, infrared, and others. Of these rays, the ultraviolet rays are absorbed by the ozone and other gases when entering our atmosphere so as not to cause negative effects on the health of humans. As our ozone is gradually destroyed by man-made pollutants its' absorption rate is decreased, causing UV rays to increase in strength and bring negative effects to the human body on days when there are no clouds in the sky.

	UV-A	UV-B	UV-C
Physical Attributes	Longest length: 400~315nm	Second longest length: 315~280nm	Shortest length: 280~230nm
Radiation when reaching earth's surface	98.9% of UV	1.1% of UV	Near zero
Relationship with ozone	Can pass through the ozone	Mostly absorbed by ozone, but increasing due to damaged ozone	Absorbed by ozone
Note	Can pass through glass to indoor areas and cars. Sun lights and beauty salon UV lights both contain UV-A.	Affect on human health is more apparent

The Relationship Between UV Rays and the Ozone

In 1985 the British scientist Joe Farman discovered a rapid decline in the ozone over the South Pole and since then studies related to holes in the ozone layer have garnered more interest. The decline in the ozone layer and the increase in UV ray strength on earth's surface are both problems that will cause headaches for mankind in the future.

UV Ray Index Monitoring Stations

UV Ray Index Point of Reports

Northern Points: Keelung City, Taipei City, Taipei County, Taoyuan City, Taoyuan County, Hsinchu City, Hsinchu County, Miaoli City, Miaoli County.
Mid Points: Taichung City, Taichung County, Changhua City, Changhua County, Nantou City, Nantou County, Yunlin Doulio, Yunlin County.
Southern Points: Chiayi City, Chiayi County, Tainan City, Tainan County, Kaoshiung City, Kaoshiung County, Pingtun City, Pingtun County.
Eastern Points: Taitung City, Taitung County, Hualian City, Hualian County, Yilan City, Yilan County.
Island Points: Kinmen, Matsu, Penghu, Green Island, Lanyu, Little Okinawa.
Vacation Points: Yang Ming Mountain, Longdong, Shito, Yushan, Hehuanshan、Lishan, Taroko, Alishan、Sun Moon Lake, Taipingshan、Sanhsientai, Kenting.

UV Rays and Health

Description	Symptom and Exposure Information	Commonly Occurring Areas	Symptoms
Melanoma	Watch for especially in children	Upper back of adults, the legs of females	Irregular pigmentation with scaly growth, secretion, bleeding sarcoma, exterior changes come with pain and itching
Non-malignant melanoma	Basal cell carcinoma (B), Squamous cell carcinoma (S) related to chronic UV exposure	Area around the ears, face, lips, and hands.	Could puncture skin and damage bones in light skinned people. Squamous erythema disease can spread to other regions.
Solar Keratosis	Mainly caused by UV exposure	Hands, forearms, V area around neck	Pre-transformation form of melanoma, thicker skin, reddening, toughening of skin.
Cataracts and Others	Pterygium, skin cancer around the eyes, mutation and deterioration of retina	Lens, around the eyes	Lucidity of lens can be damaged and lead to blindness
Damage to Immune System	24 hour exposure will lead to the weakening of white blood cells		Over-exposure, even in dark skinned people can damage the immune system.

UV Index, Levels, and Protection

The Environmental Protection Administration uses the Ultra-Violet Ray Index (UVI) to determine the strength of UV rays to help the public gain a better understanding. Next day UVI has been reported since July of 1998 to remind the public to take suitable precautions.

UVI	Exposure Level	Sunburn Time	Preventative Measures
0～2	Very Low
3～5	Low
6～7	Medium	Within 30 min	hats/umbrellas+sunscreen+sunglasses+stay in shadows
8～10	High	Within 20 min	hat/umbrella+sunscreen+sunglasses+stay in shadows+long sleeve shirts+stay indoors from 10 AM to 2 PM
11 or above	Dangerous	Within 15 min	hat/umbrella+sunscreen+sunglasses+stay in shadows+long sleeve shirts+stay indoors from 10 AM to 2 PM

Measures to Prevent from UV Ray Damage

Watch the UVI report
Damage can occur from snowy plains, beaches, and mountainous regions
Avoid using solar lights and artificial tanning booths
Take suitable physical preventative measures, such as clothes, hats, umbrellas, sunglasses, and others
Continuous application of a suitable amount of sunscreen
Avoidance is the best measure. Avoid activities from 10 AM to 2 PM

UVI: Where to Find

(1) EPA Data Release Schedule

Actual Value: Everyday at 4 PM, the EPA will post the day's actual UVI results for the public.
Estimated Value: Everyday at 5 PM, the EPA will release the next day's UVI data to major media outlets and post the results on the EPA website. The public can retrieve this information from the news, newspapers, or the internet.