选购合适的防晒产品，看这篇指南就够了

Group 1 - The core concept of sunscreen is to protect against ultraviolet (UV) rays, specifically UVA and UVB, with UVB being the primary cause of skin damage [2][3] - Sunscreen is necessary year-round, not just in summer, as UV rays can still be harmful during cloudy days or in indoor environments where UVA can penetrate glass [3][4] - There are two main types of sunscreen: physical (using barriers like hats and clothing) and chemical (using creams and sprays to absorb UV rays) [4][5] Group 2 - It is recommended to combine both physical and chemical sunscreen methods for optimal protection, as each has its advantages and disadvantages [5] - All demographics, including children, need to be mindful of sun protection, with specific recommendations for infants and young children to primarily use physical methods [5][10] - The SPF (Sun Protection Factor) and PA (Protection Grade of UVA) ratings are crucial indicators of a sunscreen's effectiveness, with higher values indicating better protection [6][8] Group 3 - Different environments require different levels of sunscreen protection, with specific SPF and PA recommendations based on activity and exposure [9] - When selecting sunscreen for children, it is advised to choose products with SPF 30 or higher and PA++ or higher, considering their unique skin characteristics [9][10] - The use of sunscreen sprays for children is discouraged due to the risk of inhalation and potential health hazards [12][13] Group 4 - Consumers should be cautious when purchasing sunscreen products, ensuring they check for proper labeling, SPF and PA values, and ingredient suitability for their skin type [14][15] - Proper application techniques are essential for effective sun protection, including applying sufficient amounts and reapplying every two hours during outdoor activities [15] - Sunscreen should be removed at night to prevent skin irritation, with specific cleaning methods recommended for different types of sunscreen [17]