Burning questions: How to pick the right sunscreen - and which ones to avoid

Summertime means outdoor fun in the sun. But that can lead to painful sunburn - or worse. Melanoma rates have tripled over the past three decades, according to the National Cancer Institute.

Using a good sunscreen can help protect skin from exposure to harmful ultraviolet rays. But with about 750 sunscreens on the market, the choices are daunting.

The Environmental Working Group's (EWG) annual sunscreen guide is at ewg.org/sunscreen.

Here's an FAQ:

How much should I use?

More than you think. The SPF values listed on the product labels are measured using a very thick coating of the product, explained Sonya Lunder, a senior analyst with EWG. And it's best to reapply every two hours.

What about bug sprays combined with sunscreen?

Not recommended. Sunscreen should be applied more often, and directly to the skin. Bug spray is better applied to clothing.

Which ingredients are effective - and safe?

The ones with minerals are better for kids because they produce lower rates of skin allergies and reactions. Typically, they contain zinc oxide or titanium dioxide.

Watch out for two common - and potentially toxic - ingredients: oxybenzone and retinyl palmitate. Oxybenzone is a hormone disrupter that mimics estrogen. A federal study found that animals exposed to Retinyl palmitate and UV light had more skin tumors and lesions than animals whose skin was not treated with it.

What level of SPF protection do I need?

Nothing higher than 50.

At what age can I start putting sunscreen on my child?

Six months.