What is UV rays and how is it harmful to human health?
Ultraviolet (UV) rays, or ultraviolet radiation, have many harmful effects on the human body. Most of the UV rays are absorbed and reversed by the ozone layer in the atmosphere, which is Earth’s most powerful protective layer from UV rays. However, today the environment is increasingly polluted, along with the greenhouse effect causing the Earth to heat up every day, the ozone layer is severely reduced.
Therefore, you need to have a certain understanding of UV rays and its harmful effects in order to take the necessary measures to protect your health and the community.
What is UV rays?
Ultraviolet rays, also known as ultraviolet radiation, are invisible rays, part of the energy coming from the sun, that can burn skin and cause skin cancer. UV radiation is made up of 3 types of rays – ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC).
Most of the UV rays humans are exposed to originate from the sun. However, about 10% of the sunlight is UV light, and only 1/3 of this is capable of penetrating the Earth’s atmosphere. UVC is the most dangerous type of ultraviolet rays, but it cannot penetrate the ozone layer of the atmosphere. Therefore, it poses no threat to the life of humans, animals or plants on Earth. Broad spectrum ultraviolet radiation – including UVA and UVB rays – are the most harmful substances to organisms on Earth.
Of the UV rays that can reach Earth, 95% are UVA rays and 5% are UVB rays. UVA is weaker than UVB but it goes deeper into the skin. Many studies also accept that both UVA and UVB cause skin cancer, including melanoma. For this reason, it is often recommended to use sunscreens and UV-resistant masks to block both types of radiation.
What are the harmful effects of UVA and UVB radiation?
UVB rays often affect the outer layer of the skin, damaging the skin. It can lead to several types of skin cancers such as melanoma, basal cell carcinoma, and squamous cell carcinoma. UVA rays are much less intense than UVB rays but reach the deeper layers of the skin about 50 times and cause more damage than UVB rays.
The acute effects of UVA and UVB are short-lived and reversible, such as sunburns and dullness. The long-term effects of UV rays are much more serious and dangerous, which can be life-threatening, including aging of the skin, suppression of the immune system, eye damage and skin cancer.
What factors does the UV index depend on?
Sun elevation: The more the sun stands, the greater the degree of UV radiation. UV radiation varies with time of day and year, with maximum levels around noon during the summer months. During the day, UV rays are usually highest near noon and early afternoon (from 10am to 16pm), especially in late spring, summer and early fall. So UV levels change throughout the day, lower in the morning, maximum mid-day, and gradually decrease as the sun goes down.
Cloud cover: UV radiation is highest when it is clear. However, even when it is cloudy, UV radiation remains high due to UV scattering by water molecules and fine particles in the atmosphere. The shade of the clouds barely reduces the effects of UV rays. Therefore, UV rays can still harm the skin and eyes, even in winter and cloudy or rainy days.
Altitude above sea level: The higher it is above sea level, the less UV radiation is filtered out by the atmosphere. For every 1,000 m rise above sea level, UV levels increase by about 10-12%.
Depends on latitude: The closer to the equator, the higher the UV radiation. The further away from this location, the less the risk.
Surface Reflectance: UV radiation can “turn on” backwards when exposed to reflective surfaces including water, sand and snow. Snow can reflect up to 80% of UV radiation, dry beach sand reflects about 15% and seawater about 25%. As a result, swimmers, skiers, anglers or swimmers can be affected by increased UV radiation from both above and below.
Dependent on the ozone layer: Ozone absorbs some of the UV radiation in the sunlight that falls on Earth. The greater the amount of ozone, the more protective filters are provided by the atmosphere. Ozone depletion has the potential to exacerbate health effects from exposure to UV radiation. As the ozone layer becomes thinner, people will be exposed to higher levels of UV radiation, especially UVB rays.
According to WHO , scientists predict a 10% reduction in current ozone could cause 300,000 additional non-melanoma skin cancers , 4,500 melanomas, and 1.6-1.75 million cataracts. crystal all over the world every year.
The scale indicates the danger level of UV rays
The UV index predicts the intensity of UV radiation at noon and is calculated on a scale of 1 to 11+.
UV Index 0-2.9: This index shows that the amount of solar radiation during the day is very low. You will be less affected by the harmful effects of UV rays. Most people can stay in the sun for about an hour during peak periods (from 10am to 16pm) without getting sunburned.
UV Index 3-5.9: At this time, the amount of UV radiation is at average level. UV problems for the skin will be a bit more serious but still within the threshold. People with sensitive skin are susceptible to sunburn within 20 minutes. Wear a hat with wide brim and sunglasses to protect your eyes. Always use a sunscreen with an SPF of at least 30 and wear a long-sleeved shirt when outdoors. At the same time, it is advisable to add endogenous sunscreen pills to help with sun protection and stronger skin protection.
UV Index 6-7.9: This index shows the amount of solar radiation is quite high. You should be more careful every time you go out. Wear a wide-brimmed hat and sunglasses to protect your eyes, nose, and ears. You should also wear a sunscreen with an SPF of at least 30, wearing long clothing.
UV Index 8-10.9: Summer days usually have very high UV amounts, from 8-10. If you’re not careful, your chances of getting a sunburn are very high. People with sensitive skin can burn in less than 10 minutes. Minimize sun exposure from 10am to 4pm. Wear a sunscreen with an SPF of at least 30. You should wear sunglasses and long, thick clothing when outdoors.
UV Index more than 11: UV level during the day is alarming. You can get burned in as little as 5 minutes without protection. It’s best to stay indoors and close the door instead of going out into the street at this time.
Does temperature affect the UV index?
The spectrum of radiation received on Earth from the sun includes infrared radiation, visible radiation and ultraviolet radiation. The light spectrum ranges from purple to red. Purple is the UV rays, overexposure can be harmful to humans. On the other end of the light spectrum, red is infrared (heat radiation), which is the radiation that produces warmth.
Many people still mistakenly believe that heat radiation and ultraviolet rays are the same. In fact, they represent different regions of the spectrum and are distributed from the sun in different ratios.
Common ways to avoid UV rays?
Normally, when people hear about avoiding the sun and UV rays, people easily think of sunscreens that have been present for a long time on the market. However, because sunscreen is a cosmetic applied to the skin, sometimes women have to spend more time choosing the right cream for their skin. Sometimes when people have a job, they only go out of the house for a short period of time, then applying the cream before going out is quite time consuming and annoying.
So is there a simpler and faster way? The answer is masks! Most of the masks available on the Vietnamese market are low-price masks, which are definitely not resistant to UV radiation because of the cost of manufacturing a fabric material that is resistant to UV rays is not cheap.
Active fiber mask Kissy are the leading masks brand in Vietnam that has been on the market since 2004, achieving a lot of achievements and certifications of units, organizations and state agencies for quality. and service. In addition to conventional features such as anti-smoke, fine dust, and air pollution, the active fiber mask Kissy also has UV protection.