Which earth’s Atmosphere is the closest to Earth's Surface?

Earth's atmosphere is divided into five main layers: the exosphere, the thermosphere, the mesosphere, the stratosphere, and the troposphere.
The troposphere is the layer closest to Earth's surface. It is 4 to 12 miles (7 to 20 km) thick and contains half of Earth's atmosphere.
Air is warmer near the ground and gets colder higher up.
The stratosphere is the second layer. It starts above the troposphere and ends about 31 miles (50 km) above ground.
Ozone is abundant here and it heats the atmosphere while also absorbing harmful radiation from the sun.
The mesosphere starts at 31 miles (50 km) and extends to 53 miles (85 km) high.
The top of the mesosphere, called the mesopause, is the coldest part of Earth's atmosphere, with temperatures averaging about minus 130 degrees F (minus 90 C).
This layer is hard to study.
The thermosphere extends from about 56 miles (90 km) to between 310 and 620 miles (500 and 1,000 km).
Temperatures can get up to 2,700 degrees F (1,500 C) at this altitude.
The exosphere, the highest layer, is extremely thin and is where the atmosphere merges into outer space.
It is composed of very widely dispersed particles of hydrogen and helium.
Source: www.space.com