The first layer of Earth's atmosphere that touches the surface is the troposphere.

Here's why:

* The troposphere is the lowest layer of the atmosphere, extending from the Earth's surface up to about 7-15 kilometers (4-9 miles) in altitude. This layer is where we live, where weather happens, and where the air we breathe resides.

* The stratosphere, the next layer up, begins above the troposphere. While the stratosphere contains the ozone layer, it is not in direct contact with the surface.

So, when you're standing on the beach, feeling the wind and the sun, you're experiencing the troposphere.