What is a harmful effect of human exposure to ultraviolet rays?

Ultraviolet (UV) rays from the sun or artificial sources, such as tanning beds, can have several harmful effects on human health, including:

1. Skin Damage: UV rays can cause sunburn, premature aging of the skin (photoaging), and skin cancer. Prolonged and unprotected exposure to UV radiation can lead to the development of various types of skin cancer, including basal cell carcinoma, squamous cell carcinoma, and melanoma, the most serious form of skin cancer.

2. Eye Damage: UV rays can cause damage to the eyes, including photokeratitis (sunburn of the cornea), cataracts (clouding of the eye's lens), and macular degeneration (damage to the central part of the retina), which can lead to vision impairment and even blindness.

3. Immune System Suppression: UV radiation can suppress the immune system, making the body more susceptible to infections and diseases. This effect can increase the risk of certain infections and reduce the effectiveness of vaccines.

4. DNA Damage: UV rays can damage DNA molecules in cells, which can lead to mutations and potentially contribute to the development of various health problems, including cancer.

5. Premature Aging: UV radiation can contribute to premature aging by causing oxidative stress and damaging the collagen and elastin fibers in the skin, which leads to wrinkles, fine lines, and sagging skin.

It's important to take precautions to minimize exposure to UV radiation, such as using sunscreen, wearing protective clothing and sunglasses, seeking shade during peak sunlight hours, and avoiding tanning beds. Regular skin self-examinations and regular eye check-ups are also recommended to detect any early signs of UV-related damage.