A UV Lamp in the Kindergarten Tanned All the Children in the Class
Some lamps can tan and burn you just like the sun
□ Times reporter, Jiang Dawei, Wang Yanwen
Intern reporter, Xu Bingbing photographer, Lin Yanting illustrator, Communicator Huang Chunyan
When her daughter, Sweetie (a pseudonym), gradually became darker, citizen Ms. Lu initially did not pay much attention to it. However, one day when she went to the kindergarten to pick up her child, she was shocked by what she saw. The more than ten children in Sweetie's class all looked as if they had just returned from Africa, and each one was darker than the other. But the children in other classes were all fair-skinned and rosy. What happened?
The UV sterilization lamp that was never turned off tanned all the children in the class
Ms. Lu took Sweetie to Hangzhou Third People's Hospital, where Dr. Song Weimin of the dermatology department knew at a glance that Sweetie had been tanned by ultraviolet rays. Then, Sweetie's classmates also found Dr. Song Weimin one after another under the guidance of their parents, and the diagnosis results were the same as Sweetie's.
Ms. Lu contacted several other parents and together they found the kindergarten where her daughter attended. However, the kindergarten staff also felt puzzled because from 8 am to 4 pm every day, except for a 20-minute morning exercise session outdoors in the morning, the children spent most of their time in the classroom. How could they be tanned by ultraviolet rays?
All the parents were confused, but a detail unintentionally revealed by the kindergarten teacher led Dr. Song Weimin to find the culprit - a UV sterilization lamp installed in the classroom.
According to regulations, the UV sterilization lamp in the kindergarten classroom should be turned on for about an hour every day. However, due to the kindergarten teacher's unfamiliarity with the operating procedures, the UV sterilization lamp in the classroom was left on all the time. As a result, excessive ultraviolet rays gradually tanned the children's skin.
Nightclub beauties get tanned by spotlights at night
With the arrival of summer, how to effectively prevent sunburn has once again become a topic of great concern to everyone. However, some cases in the dermatology outpatient department of Hangzhou Third People's Hospital indicate that not only sunlight can tan or burn the skin, but also various indoor lights, and some people even get tanned at night.
"The cases of being tanned or burned by light are actually quite common, and those dozen children are not individual cases," said Dr. Song Weimin, a dermatologist who has dealt with many cases of people being tanned or burned by light. There was a young woman who paid special attention to sun protection during the day, but her skin was still tanned. Upon inquiry, it was found out that she loved going to nightclubs and was tanned by the various high-power spotlights in the bar which released ultraviolet rays.
In addition, some female anchors from TV stations often visit Dr. Song Weimin for treatment. Every time they finish recording a program, their skin starts to turn red, and gradually becomes darker and worse. The culprit is also the various lights shining on their faces daily in the studio.
Two types of ultraviolet rays easily damage human skin
Why can light tan or burn the skin? First, you need to understand ultraviolet rays.
Professor Lu Xuanhui, deputy director of the Optics Institute at Zhejiang University, introduced that ultraviolet rays are the general term for electromagnetic wave spectrum radiation with wavelengths ranging from 100nm (nanometers) to 400nm. Among them, wavelengths from 100nm to 200nm are vacuum ultraviolet rays (UV-D), wavelengths from 200nm to 280nm are short-wave ultraviolet rays (UV-C), wavelengths from 280nm to 315nm are medium-wave ultraviolet rays (UV-B), and wavelengths from 315nm to 400nm are long-wave ultraviolet rays (UV-A).
The wavelength of ultraviolet rays is inversely proportional to energy. The longer the wavelength, the stronger the ability to penetrate the skin. The shorter the wavelength, the stronger the energy, and the easier it is to cause skin lesions.
UV-D cannot be effectively transmitted in the air, and the shorter-wavelength UV-C is almost absorbed by the ozone layer. Therefore, the ultraviolet rays in natural sunlight mainly consist of UV-A and UV-B, with UV-A accounting for about 98.1% and UV-B accounting for 1.1%.
"UV-A can penetrate the epidermis to reach the dermis and act on the melanin in the skin's epidermis, thereby causing melanin deposition and making the skin darker," said Professor Lu Xuanhui. "On the other hand, UV-B almost cannot penetrate the epidermis. When higher-energy UV-B acts on the skin for a long time, photodermatitis can occur, resulting in redness, itching, blisters, and swelling on the skin. Excessive exposure to ultraviolet rays can also cause skin cancer."
Some lamps emit ultraviolet rays
Halogen lamps not recommended for home use
Let's take a look at the UV sterilization lamp in that kindergarten again. To achieve the best sterilization effect, the wavelength of the UV sterilization lamp is usually set at 253.7nm, which belongs to the strongest-energy UV-C. It's no surprise that the children got tanned.
"Some lights can also release ultraviolet rays, and the radiation intensity varies depending on the type, power, color, and manufacturing process of the lamps," said Dr. Song Weimin, deputy director of the dermatology department at Hangzhou Third People's Hospital. "Especially those high-power metal halide lamps, the medium-long wave ultraviolet rays they release are the same as the ultraviolet rays released by sunlight and can harm the skin."
Professor Lu Xuanhui from Zhejiang University also pointed out that many public places such as bars, restaurants, malls, and stadiums often use lamps with strong ultraviolet radiation. These radiations have wavelengths ranging from 300nm to 400nm, belonging to medium-long wave ultraviolet radiation, which have a significant impact on human skin.
"Nowadays, many people like to use metal halide lamps to decorate their homes during renovation, and some even install them in their bedrooms. Although these lamps are bright and beautiful, prolonged exposure can have considerable effects on people," said Professor Lu Xuanhui.
No safety quantification standards for lamp UV radiation intensity
Although the ultraviolet rays emitted by lamps can tan and burn the skin, Professor Lu Xuanhui indicated that there are currently no safety quantification standards for lamp UV radiation intensity in China. However, the degree of harm caused by lamp UV to the human body depends on various factors, such as the performance of the lamp, the distance from the human body, and the duration of exposure.
Among the lamps we commonly come into contact with, metal halide lamps, UV sterilization lamps, and UV insect traps have relatively strong UV radiation intensity. On the other hand, ordinary incandescent lamps do not produce UV.
As for fluorescent lamps and energy-saving lamps, although their luminescence principle involves emitting thermal electrons through electrodes to excite mercury atoms to release UV, after the UV passes through the fluorescent powder coated on the inner side of the lamp tube and is converted into visible light, only a trace amount of UV within the UV-A range is emitted, which will not significantly affect the human body.
For people who work under lamps with more UV radiation or are too close to the lamps for a long time, the chances of skin damage are higher, such as store clerks, restaurant waiters, and TV anchors. However, ordinary people do not need to worry too much as long as they do not stay under these lamps for too long or directly stand under or closely contact them.
How to combat UV rays
Should we apply sunscreen every 15 minutes like Big S?
Experts from Hangzhou Third Hospital: This concept is worth learning
There are UV rays in sunlight, and some lamps also have UV rays. In the face of omnipresent UV rays in life, how should we protect our skin? Should we follow what famous artist Big S wrote in "Beauty King" and reapply sunscreen every 15 minutes to ensure that the skin is not harmed?
Dr. Song Weimin, deputy director of the dermatology department at Hangzhou Third Hospital, said that although applying sunscreen every 15 minutes might be exaggerated and impractical, this concept is worth promoting because the awareness of protecting against UV rays among Chinese people is still relatively poor.
Excessive UV exposure can easily trigger skin diseases
According to statistics, Hangzhou Third Hospital diagnoses nearly a thousand skin cancer patients each year, and this number is increasing year by year.
"Compared to Caucasians, Asians have a relatively lower incidence of skin cancer and skin diseases, but our measures to protect against UV rays are still relatively insufficient," said Director Song. Many skin diseases are related to excessive UV exposure.
"Moderate exposure to sunlight every day can supplement calcium and is beneficial to the body, generally 15 minutes a day is enough. If exposed to too much UV radiation, it will damage the skin," said Director Song. In addition to tanning and burning the skin, UV rays can also accelerate skin aging.
Physical sun protection is more reliable
Reapply every two to three hours
In addition to using umbrellas and clothing to block UV rays, Director Song believed that correctly using sun protection products is also necessary, and these sun protection measures are not exclusive to women; men should also follow suit.
"There are mainly two types of sunscreens available on the market: physical and chemical. The former has better sun protection effects and can effectively resist most UV rays from harming the skin, but its downside is that it tends to clog pores," said Director Song.
The other type is chemical sunscreen. Using this type of sunscreen makes the skin feel relatively fresh, but compared to physical sunscreen, its effect is much weaker. Moreover, after using chemical sunscreen, it generally takes half an hour to take effect; otherwise, it will not provide any sun protection or UV resistance.
Regarding Big S's practice of applying sunscreen every 15 minutes, Director Song believed that although it is somewhat exaggerated, the habit of many people who only apply sunscreen once in the morning and then don't reapply all day is even less advisable. The correct frequency of using sunscreen is to reapply according to the environment every two to three hours, which can provide effective protection.
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