What Are the Dangers of UV Exposure?

Ultraviolet radiation, also known as ultraviolet radiation, has a wavelength range of 100 to 400 nm. It is the shortest wavelength (100 nm) and the largest energy (12 eV) in the non-ionizing radiation spectrum. The exposure route is divided into daily outdoor activities or outdoor work, exposure to sunlight ultraviolet rays; occupational production activities in the environment with ultraviolet radiation, such as ultraviolet lighting, arc welding, metal smelting electric furnace and so on.

UV exposure to human exposure

(1) Daily outdoor activities or outdoor work, exposed to sunlight ultraviolet rays, such as farmers, construction workers, road maintenance workers, people staying in the mountains and snow.

(2) Operations with ultraviolet radiation in the environment of professional production activities, such as ultraviolet lighting, arc welding, metal smelting electric furnaces, etc. The route of exposure is direct absorption by the skin and eye tissues. The UV exposure of an individual artificial light source is usually lower than that of sunlight. However, for some individuals, UV light from an artificial light source may account for most of their total lifetime exposure.

UV exposure to human health risks

In solar radiation, an appropriate amount of ultraviolet rays has a positive effect on human health, such as producing vitamin D3, which is necessary for the human body, but excessively strong ultraviolet rays are harmful to the body. The World Health Organization has identified nine adverse health effects caused by exposure to UV radiation. They are skin malignant melanoma, skin squamous cell carcinoma, skin basal cell carcinoma, corneal or conjunctival squamous cell carcinoma, photoaging, burns, cortex Cataracts, pterygium, and cold sores are reactivated.

Harm to skin from exposure to UV radiation in the UV environment

(1) Skin tumors. The International Agency for Research on Cancer has concluded from animal experiments that sunlight, broad-spectrum UV, and UVA, UVB, and UVC can all cause cancer. Population epidemiological studies show that there are four main types of evidence supporting UV radiation to cause skin tumors: residents living in areas with strong solar radiation have a higher incidence of skin tumors; skin cancers in people sensitive to sunlight and certain genetic diseases High incidence; individuals with high exposure to solar radiation are susceptible to skin cancer; skin cancer is more common in parts of the body exposed to the sun. In the United States and Australia, the closer to the equator, the higher the incidence of non-melanoma skin cancer, with a growth slope similar to that of men, women, and all ages.

UV is a determinant factor that causes squamous cell carcinoma of white skin, and it is a possible factor that causes basal cell carcinoma. Race is one of the important risk factors for non-melanoma skin cancer. For people of color, the possibility of UV causing skin cancer is very small. There is a significant difference in the incidence of non-melanoma skin cancer between whites and people of color, especially Caucasians have a higher susceptibility, and the incidence of non-melanoma skin cancer is very high among blacks, Asians, and Hispanics. low.

The amount of ultraviolet radiation received during childhood is equivalent to one third of the cumulative lifetime dose. 80% of sunlight damage occurs before the age of 18, but the results of ultraviolet radiation appear in the form of skin photoaging and skin cancer after many years. The amount of UV exposure in adolescence is related to the incidence of skin tumors in adulthood.

(2) Acute erythema effect. Generally, the skin appears identifiable erythema after UV irradiation for 1 to 6 hours, and gradually disappears after a few days. A study of non-tanned, light-skinned individuals found that the threshold for erythema was between 1.5 and 3 standard erythema doses (SED). Ultraviolet rays of 280 to 320 nm are the main bands that cause skin erythema, and the amount of UVA required to achieve the same erythema response is three times that of UVB. Different parts of the skin are sensitive to sun erythema, with the trunk being the most sensitive and the hands the worst. ^[1]

(3) Skin photoaging. People with different skin tones have different levels of skin photoaging, and people with light skin tones are more severely affected, mainly in the face, neck, and outstretched parts of the upper limbs that are often exposed to sunlight. Chronic sunburn can lead to solar keratosis, a precancerous condition. The disease burden caused by solar keratosis can be 100% attributable to ultraviolet radiation exposure.

(4) Pigmentation. Pigmentation can be divided into immediate pigmentation and delayed pigmentation. Skin pigmentation at the exposed site increases with age, while non-exposed sites are independent of age.

(5) Photosensitivity. Using certain drugs or topical skin application of certain substances, such as some perfumes, topical preparations, etc., after receiving UV radiation, the skin immediately or within a few hours after the photosensitivity manifestations of burning pain, erythema, blister, rash.

Harm to eyes due to exposure to ultraviolet radiation in the ultraviolet environment

(1) Cataract. Long-term eye exposure to solar radiation can increase the risk of developing cortical cataracts. 5% of all cataract-related burdens can be directly attributed to UV radiation exposure.

(2) Photokeratitis and photoconjunctivitis. Corneal epithelial cells and conjunctiva absorb superficial ultraviolet rays and cause superficial tissue burns. Acute inflammation occurs. They are called photokeratitis and photoconjunctivitis. They are mostly caused by long-term walking in natural snow, deserts, salt fields, wide water surfaces or Due to operation. Occupational photokeratitis and photoconjunctivitis caused by electric welding or metal melting in artificial environment are also called electrooptic ophthalmitis. Onset is usually 0.5 to 24 hours after exposure to ultraviolet light, which manifests as eye irritation, inflammation and edema. Most patients are cured within 1 to 3 days after the onset of the disease, but if the disease is repeated, it can cause chronic blepharitis and conjunctivitis.

(3) Wing-shaped carcass. 40% to 70% of the diseases caused by pterygium can be attributed to ultraviolet radiation exposure. The incidence of pterygium in residents near the equator is high, and exposure to more UV is one of its risk factors. ^[1]

The role of UV radiation in the UV environment on the immune system

Ultraviolet radiation can affect the body's immune function, which is related to factors such as the dose, time, wavelength, and state of the body. Irradiation with a small area of threshold erythema and a large area of sub-erythema can stimulate the agglutination of blood lectin, increase the titer of lectin and enhance the body's immunity. Excessive doses of ultraviolet light can suppress the body's immune function. In addition to its role in the onset of skin cancer, sun exposure can also reduce the body's ability to inhibit the development of skin tumors.

Many studies have confirmed that environmental UV exposure levels can alter some cells' body-dependent immune responses, so high UV levels may reduce the effectiveness of the vaccine given. Sun exposure can increase the risk of viral, cellular, parasitic or fungal infections, which has also been demonstrated in many animal studies.

Other biological effects of UV exposure to UV environment

As an important environmental factor, the UVB band also has anti-rickets effect. Ultraviolet artificial light source has sterilization effect. In addition, ultraviolet rays have certain effects on the functions of organs or systems such as the nerves, muscles, respiratory tract, digestive tract, endocrine, gonads, blood and blood circulation, and metabolism of the human body.