Joseph Sobanko's patients often ask him which sunscreen is best.

That's especially true this time of year, when people are going outside and the sun's rays are at their brightest - and most damaging.

Whether the patient is blond or dark, freckled or fair, the Penn Medicine skin-cancer specialist has the same answer: Whichever sunscreen you'll actually use.

Far too few of us do, he says.

About one in five Americans will develop skin cancer - the most common kind of cancer - in their lifetimes. Sobanko is especially distressed to see the high numbers of patients in their 20s and 30s with skin cancer already.

Perhaps not surprising, given the state's great beaches, New Jersey has high rates of melanoma, which is the culprit in about 75 percent of skin-cancer deaths.

Cape May County ranks among the highest 2 percent of counties nationwide for diagnoses.

So, slather on a broad-spectrum product with an SPF of 30 or more.

What you're guarding against are the sun's ultraviolet rays. UVB rays are the primary cause of sunburn. UVA rays wrinkle and age your skin. Both contribute to skin cancer.

More of those rays are reaching the Earth now than in past decades because we've thinned the world's natural sunscreen - the ozone layer.

NASA scientists say that solar radiation has been increasing since the mid-1970s, although they expect that to level off now that we've reduced our use of harmful refrigerants and other ozone-depleting substances.

Meanwhile, the sunscreen aisle is getting crowded. In a recent report on sunscreens, the nonprofit Environmental Working Group analyzed 1,400.

The labels look different this year, due to new guidelines from the U.S. Food and Drug Administration.

If a sunscreen is labeled "broad spectrum," it must block specified amounts of both UVA and UVB.

No longer can labels use the word "sunblock" or "waterproof." None of the products is that good.

What the new regulations don't do is keep mounting sun protection factor - SPF - claims in check.

Dermatologists recommend a minimum SPF of 30. And 50 is good, too. In the SPF numbers game, 30 will block out close to 95 percent of the harmful rays.

Beyond that, you're fooling yourself if you think an SPF of 75 means you can stay out in the sun 75 times longer than without sunscreen.

The Environmental Working Group, which is focused on potentially harmful chemicals, released its annual guide to sunscreens last week. (Find it at www.ewg.org.)

It found that most products were meeting the new federal requirements, although it noted that one in seven products had that potentially deceptive above-50 SPF.

And, the group finds that only a quarter of products offer strong UV protection without posing safety concerns.

EWG favors mineral sunscreens that provide a literal block by scattering the rays. These contain titanium dioxide and zinc oxide - yes, the stuff of lifeguards' white noses, but now it's in the form of nanoparticles and doesn't show.

The group cautions against sprays, which might be inhaled. Your lungs don't need UV protection.

The group also is concerned about two widely used ingredients - oxybenzone, which they say could act like estrogen in the body, and retinyl palmitate, a version of Vitamin A that they say could speed the development of tumors in sun-exposed skin.

Mainstream dermatologists don't share their worries. The head of an industry group, the Personal Care Products Council, dismissed the EWG report as unscientific.

For Sobanko, it comes down to this: "The most harmful thing in all of this is ultraviolet light, not any of the ingredients in the sunscreen."

But Sonya Lunder, the EWG's senior research analyst, said that, since you can select sunscreens without these ingredients - her report lists 184 - why not?

Sunscreen Tips

From the American Academy of Dermatology and other experts:

  • If the product is expired, replace it.
  • For full body coverage, use an ounce of sunscreen - the size of a golf ball, or enough to fill a shot glass.
  • Apply 15 minutes before going out.
  • Don't forget your lips and, if you have thinning hair, your scalp.
  • Reapply after swimming or sweating heavily. Otherwise, reapply every hour or two.
  • For maximum protection, practice sun avoidance. Stay in the shade from 10 a.m. to 4 p.m. Or wear a broad-brimmed hat and a long-sleeved shirt.

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"GreenSpace," about environmental health, appears every other week, alternating with Art Carey's "Well Being" column.

Contact Sandy Bauers at 215-854-5147 or sbauers@phillynews.com, or follow on Twitter @sbauers. Visit her blog at www.philly.com/greenspace.