Want to try that viral snow cream recipe or a wintry wooder ice? Not so fast, say Pa. experts.

Deciding to eat snow is very dependent on your situation. Are you clinging to the edge of life searching for water? Are you outside making snow angels and feeling a bit curious? Is the snow “yellow?”

In most circumstances, it’s usually recommended not to eat snow, especially the kind found on the ground in Philadelphia, says the city’s top doc.

“The short answer is no, for people living in the city, I would not eat snow, or at least not snow that has landed. There are a pretty wide variety of substances that could be in it (dog poo anyone?) that shouldn’t be consumed,” said Philadelphia health commissioner Cheryl Bettigole, who grew up with winters in Buffalo. “Anyone who wants to catch it in their mouth as it falls should feel free as long as they are standing somewhere safe when they do it.”

Fresh snow is blanketing the Philly region and that means between snowball fights, snow angels, and sledding, curious minds may venture a taste of the frozen water vapor and air. In fact, almost the entirety of snow is made up of air and very little water. In the Philly region for every foot of snow, there is only one inch of water.

You’re sort of eating and drinking air when consuming snow.

Despite the lack of refreshment, the reason health experts and scientists won’t advise you to eat snow is because of the plethora of possible pollutants found in it.

According to Penn State University professor of chemistry, Miriam Freedman, snow is formed when water vapor condenses around a particle in the air. These particles can be dirt, bacteria, or salt (like found on your kitchen table), among countless other particles.

“Even in the most pristine conditions, the snow is going to have a tiny bit of salt and it’s going to be a little bit acidic from carbon dioxide,” Freedman said, who studies air particles. “To eat a little bit of snow doesn’t matter so much, but I wouldn’t eat a ton. If you’re talking about in a more polluted area, pollutants in the air can end up in the snow and I’d be more hesitant.”

The more polluted the air, the more polluted the snow is going to be. But what if we’re talking about a life or death situation — does it matter if the snow might contain pollutants? Dan Wowak, a woodsman and nature survivalist who appeared on History Channel’s survival show, Alone, says no.

Water is the most important element to survival and the lack of water is one of the first things that can lead to health issues or worse, death, said Wowak, who operates Coalcracker Bushcraft — an outdoor survival school and gear shop — two hours outside of Philadelphia.

Remember, said Wowak, the human body can only go three days without water.

If you do want or need to eat snow, there are a few tips that can make the process more efficient.

First off, snow isn’t your best source of water in cold weather, it’s ice. While snow is mostly made up of air, ice is mostly water and will be easier to hydrate with. But, if you only have snow available that’ll work, too — you’ll just need a lot more of it, said Wowak.

“The number one thing is if you’re dehydrated and you need water, by all means you can eat snow and you can get some hydration from that,” said Wowak. “We always advise people in an emergency-type scenario, if you can get ice — which is only about 10% air — use ice by eating that or melting it.”

“Ice is going to be way more bang for your buck when it comes to finding something in a cold weather environment to actually hydrate yourself.”

The best way to clean snow or ice to drink is to boil it first — all you need is a fire and a pot. However, according to Wowak, that’s not going to disinfect the water from chemicals and pollutants.

“You’re not going to be able to remove chemical contaminants no matter what we do, unless we use filtering processes, and generally we don’t carry things to remove chemicals in the outdoors,” he said.

For those looking to get serious about eating snow, or outdoor survival gear, Wowak recommends picking up the Grayl water purifier. These water filters can clean your water in an easy-to-carry portable bottle for around $100.