The ozone layer is located in which level of the atmosphere?

The ozone layer is primarily located in the stratosphere, which is the second layer of the Earth's atmosphere, situated above the troposphere and below the mesosphere. The stratosphere is crucial for life on Earth because it contains a high concentration of ozone (O₃) molecules that absorb the majority of the Sun's harmful ultraviolet (UV) radiation. This protective layer prevents the adverse effects of UV radiation on living organisms, including skin cancer in humans and detrimental impacts on ecosystems.

Understanding the importance of this layer also highlights why the other choices are not correct. The troposphere is where weather occurs and contains the majority of the atmosphere's mass, while the mesosphere is above the stratosphere and is characterized by decreasing temperatures and diminishing air pressure. The thermosphere, which is the highest layer of the atmosphere, features very high temperatures but very low air density, and it does not contain a significant concentration of ozone. This context helps clarify why the stratosphere, with its ozone layer, is so vital for shielding the Earth from harmful solar radiation.