Question

Ozone is desirable in the upper atmosphere but undesirable in the lower atmosphere. A dictionary states that ozone has the scent of a spring thunderstorm. How can these seemingly conflicting statements be reconciled in terms of the chemical properties of ozone?

Short answer

Ozone is beneficial in the stratosphere, where it acts as$\text{UV}$ aradiation filter, while it is harmful in the troposphere.

Step-by-step solution

Concept Introduction

Three oxygen atoms make up ozone (${\mathbf{\text{O}}}_{\mathbf{\text{3}}}$), a highly reactive gas. In the Earth's high atmosphere, it is both a natural and a man-made substance. The upper atmosphere (the stratosphere) and the lower atmosphere (the troposphere).

Reaction of Ozone and it’s properties

The ozone layer extends from$\text{10km}$ to$\text{50km}$above the Earth’s surface and

plays a crucial role in protecting us from the harmful effects of theSun’s ultraviolet rays.

${\text{O}}_{\text{3}}\text{+ hv}\to {\text{O}}_{\text{2}}\text{+ O}$

Ozone absorbs radiation at wavelengths below$\text{300nm}$, thereby attenuatingthe spectrum of sunlight at ground level.

Without the presence of stratospheric ozone, much more of this radiationwould reach the surface, resulting in increased mutation and cancer rates.

Ozone is produced naturally by the action of $\text{UV}$radiation on${\text{O}}_{\text{2}}$ in theupper atmosphere. The scent of a spring thunderstorm is the formation of ${\text{O}}_3$during lightningdischarges.

Causes of Ozone

On the other hand, ozone is a powerful oxidant

It has many harmful effects on the human body.

Breathing ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and airwayinflammation.

Therefore, ozone is useful in the stratosphere where it serves as a filter for$UV$ radiation, but is undesirable in the troposphere.