The Centre for Health Protection notes that ultraviolet (UV) radiation is part of the sun's rays, and exposure to moderate amounts of UV can promote vitamin D synthesis. Located in the subtropics, Hong Kong receives ample sunlight. However, with climate change and increased environmental pollution, we are more likely to be exposed to excessive UV radiation in our daily lives, leading to increased risk of sunburn, accelerated skin aging, and heightened risks of skin cancer and cataracts.
What is Ultraviolet Radiation?
Ultraviolet radiation is an electromagnetic wave in sunlight, categorized into UVA, UVB, and UVC. According to the World Health Organization (WHO), UVC is filtered by the Earth's ozone layer and has minimal impact on humans. UVA and UVB, however, penetrate the atmosphere and directly affect our skin and body.
The Negative Effects of UV Exposure
Short-term Effects
- UVB: With shorter wavelengths, UVB primarily affects the epidermis, causing sunburn, redness, pain, and blisters.
- UVA: Having longer wavelengths, UVA penetrates deeper into the dermis, accelerating skin aging, reducing elasticity, and causing wrinkles and discoloration.
Long-term Effects
Prolonged exposure to UV radiation damages skin cell DNA, potentially leading to abnormal cell growth and increasing the risk of basal cell carcinoma or melanoma, as per research by the American Academy of Dermatology (AAD).
UV radiation also affects the eyes and immune system. The Hong Kong Ophthalmological Society notes that UV, especially UVB, can damage the cornea, lens, and retina, leading to cataracts or eye injuries. WHO also states that excessive UV exposure can suppress the immune system, making individuals more susceptible to viral infections.
The Benefits of UV Radiation
Moderate UVB exposure aids in vitamin D synthesis, promoting calcium absorption and preventing osteoporosis. Also, spending 15-20 minutes in sunlight daily can boost serotonin levels, stabilize mood, and improve overall happiness.
On days with high UV indices, use sunscreen with SPF 30 or higher, avoid prolonged outdoor activities during peak sun hours, wear sunglasses that block 99-100% of UVA and UVB, and wear protective clothing. By adopting these simple preventive measures and developing good sun protection habits, we can reduce health risks associated with UV radiation and enjoy a healthy life under the sun.