The sun is shining, the surf is up and public school lets out today — it’s summertime!

Whether your summer days are filled with beach barbecues, pool parties or just long days outside, sun protection should be a part of everyone’s daily routine, especially for children.

Compared with an adult, the cells of a child’s skin are much more susceptible to the harmful effects of UV radiation (sunlight). The sun’s powerful rays not only cause painful sunburns; they also promote wrinkles and skin cancer.

UVA rays have a longer wavelength and penetrate deeper, causing aging and wrinkles. Shorter UVB rays cause sunburns. Both can lead to skin cancer.

Question: Is there any difference in the sunscreen kids and adults should use?

Answer: Infants have more permeable skin and a larger surface-area-to-weight ratio, meaning that they can absorb much more of any product that is applied to their skin. Therefore, be mindful of which products you use and consider the ingredients that they contain. The safety of sunscreens has not been established for infants under the age of 6 months. For babies this young, the real goal should be sun avoidance and use of sun-protective clothing and wide-brimmed hats.

For babies and children older than 6 months, a broad-spectrum sunscreen — particularly one containing zinc oxide and/or titanium dioxide — may be applied to exposed skin. These active ingredients are less likely to cause irritation.

Q: Lotions, sprays, powders, sticks — which is the most effective formula?

A: No matter how great a product is, sunscreen only works when it’s used! So find whatever form will be the most efficient for your lifestyle. Ideally, you should look for a sunscreen that is broad-spectrum (protects against UVA and UVB), SPF 30 or higher, and water-resistant. Sun-protective clothing featuring an ultraviolet protection factor listed on the label is also a great option.

Stick sunscreens are convenient for parents and useful around the eye area as they do not run and will not cause eye irritation.

Many parents prefer spray sunscreens because they are quick and easy. Current FDA regulations on testing and standardization do not pertain to spray sunscreens, but they are better than no protection at all. When using a spray sunscreen, be careful to avoid inhaling the product, which can be harmful — make sure not to spray in a windy area, and never spray directly onto your child’s face (spray onto your hands first, then apply onto the face).

Q: Are there different things to look for when buying a sunscreen for babies, kids and teens?

A: Everyone 6 months and older should use a sunscreen containing zinc oxide or titanium dioxide (or a combination of the two). These are physical blockers, meaning that they physically protect the skin by reflecting UV light, without chemicals.

Chemical sunscreens absorb particular wavelengths of light; ensure that the one your choose protects against UVA and UVB rays, both of which can cause skin damage and cancer.

For teenagers, you should also try to find products labeled oil-free and noncomedogenic, so that they won’t cause or worsen acne.

Q: How important is sunscreen when kids will be mostly indoors or in the shade?

A: UVA can penetrate through window glass, though UVB cannot. Thus, even when sitting in a classroom next to a window, or when sitting in a car, kids should still still wear a broad-spectrum sunscreen.

UV is scattered by clouds and reflects off of water, sand and cement, causing indirect UV exposure even when we think we are sitting in the shade. The amount of sun protection offered by any shade structure (umbrella, canopy, trees) is limited by the amount of indirect UV we are exposed to. Therefore, while better than nothing, shade does not replace sunscreen.

Q: Do kids still need sunscreen if they are just going to a 25-minute swim class?

A: Yes! Sun damage is cumulative and irreversible, so start protection early for healthy skin throughout life.

Q: How early do you need to apply sunscreen to maximize effectiveness outside?

A: Chemical sunscreens should be applied 20 to 30 minutes before going out into the sun, as these agents need to be absorbed into the skin to work. Physical sunscreens (zinc and titanium) can be applied immediately before sun exposure.

Dr. Allyson Spence-Shishido is a fellowship-trained, board-certified specialist in pediatric dermatology at Kaiser Permanente.