How to have a sunburn-free summer

Beach-goers apply sunscreen to each other at Bondi Beach in Sydney, Australia, on January 8, 2013.

Marianna Massey, Getty Images

Last Updated May 20, 2015 5:55 PM EDT

It's time to stock up on sunscreen and brush up on your summer sun safety know-how. Wearing sunscreen can prevent painful sunburn, reduce your risk of skin cancer and prevent or delay wrinkles and other signs of aging. With such great benefits, you'd think everybody would be slathering it on.

But unfortunately, a lot of people still don't do it.

A study published Tuesday in the Journal of the American Academy of Dermatology finds that just 30 percent of women and 14 percent of men regularly apply sunscreen to their face and other exposed skin.

Nearly 40 percent of users were unsure if their sunscreen provided the broad-spectrum protection dermatologists recommend, meaning it blocks both UVA and UVB ultraviolet rays.

To help clear up all the confusion in the sunscreen marketplace, the Environmental Working Group (EWG) is out with its 2015 sunscreen guide. Here is some of its top advice:

Avoid noxious chemicals

Researchers found that 80 percent of the moisturizers, sunscreens and lip balms they reviewed contained worrisome ingredients like oxybenzone and retinyl palmitate. Oxybenzone is a known hormone disruptor and retinyl palmitate is a form of vitamin A linked to skin cancer. These chemicals were also found in some of the children's sunscreen analyzed by the Environmental Working Group.

The group says mineral sunscreens, made with zinc oxide and titanium dioxide, often rate better for safety. A list of recommended products is posted on the EWG website.

Sunscreen manufacturers, however, called some of the findings "misleading and potentially harmful to public health." In a statement from the Personal Care Products Council trade group, they pointed out that sunscreens are regulated by the FDA and called them "safe, effective and...an important part of an overall sun safe regimen."

Spray-on versus lotion

The jury's still out on how effective spray-on sunscreen is. Many researchers say that the sprays may not cover the skin completely and can be harmful if inhaled. EWG writes, "Aerosolized droplets could push sunscreen chemicals deep into the lungs where they could irritate lung tissue or pass into the bloodstream. As well, the FDA says it lacks data to prove that sprays provide the necessary thick, even skin coverage on dry skin, let alone a wet kid."

Until there is more research on the matter, EWG recommends using sunscreen lotion for optimal protection.

SPF Levels

The Food and Drug Administration says that sun protection factor or SPF benefits max out at 50+. Anything beyond that is considered excessive. EWG agrees SPF ratings above 50 provide limited to no extra protection against the sun's rays. While many consumers assume that SPF 100 is twice as effective as SPF 50, dermatologists say the difference between the two is actually negligible.

"The high SPF numbers are just a gimmick," Marianne Berwick, professor of epidemiology at the University of New Mexico, told CBS News when the EWG highlighted that problem in 2013. "Most people really don't need more than an SPF 30 and they should reapply it every couple of hours."

Sunscreens that boast an SPF above 50 may give consumers a false sense of security about how long they can stay in the sun.

For a sunburn-free summer, EWG recommends you should limit time spent in the sun, re-apply sunscreen every couple of hours, and use sunscreens with broad spectrum protection.