中新真探：防晒指数越高防晒霜效果越好吗？
中新网8月23日电 炎炎夏日，防晒霜是人们抵御紫外线伤害的必备品。不少人认为，防晒指数越高，防晒效果就越好。但事实并非如此。
防晒霜的防晒指数通常指的是日光防晒系数（SPF），它衡量的是防晒产品对防护紫外线B（UVB）的能力。SPF值越高，意味着防晒霜能阻挡UVB射线的时间越长。然而，SPF值并非越高越好。
据专家介绍，SPF30的防晒霜能阻挡约97%的UVB射线，而SPF50的能阻挡约98%的UVB射线。二者之间的差别并不大。
此外，防晒系数越高，往往意味着防晒剂浓度越高，容易造成皮肤油腻、厚重，甚至阻塞毛孔，影响肤感和使用体验。
专家建议，选择防晒霜时，应根据自身肤质和户外活动时间来选择合适的SPF值。
对于日常通勤或短时间户外活动，SPF15-30的防晒霜已经足够。而对于长时间户外活动，如登山、游泳等，则可以选择SPF30-50的防晒霜。
除了SPF值，防晒霜的PA值也十分重要。 PA值指的是防晒产品对防护紫外线A（UVA）的能力，它与皮肤的晒黑和老化有关。选择防晒霜时，应选择同时具有高SPF值和高PA值的防晒霜，才能更好地保护皮肤免受紫外线的伤害。
专家提醒，防晒霜应每2-3小时补涂一次，才能有效地防止晒伤和晒黑。 此外，还要注意防晒霜的保质期，过期防晒霜的防晒效果会下降，甚至可能对皮肤造成伤害。
总而言之，选择防晒霜时，应根据自身情况选择合适的SPF值和PA值，并注意定期补涂，才能更好地保护皮肤，享受阳光的同时，避免紫外线带来的伤害。
英语如下：
Is a Higher SPF Sunscreen Always Better? The Truth Might Surprise You!
Keywords: Sun Protection Factor, SPF, Effectiveness
Content:
China News Service, August 23rd – In the scorching summer, sunscreen is a must-have for protecting against the harmful effects of ultraviolet (UV) rays. Many people believe that the higher the SPF, the better the sun protection. However, this is not entirely true.
The Sun Protection Factor (SPF) of a sunscreen measures its ability to protect against UVB rays. A higher SPF means the sunscreen can block UVB rays for a longer period. However, a higher SPF doesn’t necessarily mean better protection.
Experts say that an SPF30 sunscreen blocks about 97% of UVB rays, while an SPF 50 sunscreen blocks about 98%. The difference between the two is not significant.
Moreover, a higher SPF often means a higher concentration ofsunscreen agents, which can lead to oily and heavy skin, potentially clogging pores and affecting the feel and user experience.
Experts recommend choosing an SPF based on your skin type and the duration of outdoor activities.
For daily commutes or short periods of outdoor activity, an SPF 15-30 sunscreen issufficient. For prolonged outdoor activities, such as hiking or swimming, an SPF 30-50 sunscreen is recommended.
Besides SPF, the PA value of a sunscreen is also crucial. The PA value indicates the sunscreen’s ability to protect against UVA rays, which are linked to skin tanning and aging.When choosing a sunscreen, opt for one with both high SPF and high PA values for optimal protection against UV damage.
Experts advise reapplying sunscreen every 2-3 hours for effective protection against sunburn and tanning. Additionally, pay attention to the expiration date of your sunscreen. Expired sunscreen loses its effectiveness and mayeven harm your skin.
In conclusion, choosing the right SPF and PA values based on your individual needs, along with regular reapplication, is key to enjoying the sun while protecting your skin from the harmful effects of UV rays.
【来源】http://www.chinanews.com/life/2024/08-23/10273861.shtml
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