Core Points - The article emphasizes the importance of sun protection during summer due to increasing ultraviolet (UV) radiation levels [1] - It discusses the necessity of sun protection even on cloudy days, as UV rays can still penetrate through clouds [1] Summary by Categories UV Radiation - Ultraviolet radiation is a major cause of skin damage, aging, and melanin deposition [3] - The sunlight reaching the ground mainly consists of long-wave UVA and medium-wave UVB [3] Sunscreen Indicators - Sunscreen products typically display two key indicators: PA and SPF, which are essential for selecting effective sun protection [5] - PA measures the protection against UVA, categorized into three levels based on the number of "+" signs, indicating the strength of protection [7] - PA+: Effective for 2-4 hours - PA++: Effective for 4-8 hours - PA+++: Effective for over 8 hours - SPF measures the protection against UVB, with values indicating the multiple of time before skin reddening occurs [7] - SPF15: Blocks approximately 93% of UVB - SPF30: Blocks approximately 97% of UVB - SPF50: Blocks approximately 98% of UVB Recommendations - It is advised to use products with SPF greater than 30 and PA greater than two plus signs for regular daily activities [7] - For activities in particularly strong sunlight, it is recommended to use products with SPF greater than 50 and PA greater than three plus signs [7]
阴天没阳光也需要防晒 如何选择合适的防晒霜？
Yang Shi Xin Wen·2025-06-03 06:24