The Atmosphere — Chemical Reactions in the Atmosphere

About this lesson

This unit focuses on chemical reactions in the atmosphere, specifically the formation and depletion of ozone. It explains how ultraviolet (UV) rays from the Sun cause photodissociation of oxygen molecules (O2) into individual oxygen atoms, which then combine with other O2 molecules to form ozone (O3). The text describes the role of stratospheric ozone in absorbing harmful UV radiation and details the consequences of ozone layer depletion, including effects on human health such as skin cancer, weakened immunity, and cataracts. It also discusses causes of depletion, such as chlorofluorocarbons (CFCs), and suggests actions to reduce it, like choosing eco-friendly products and avoiding ozone-depleting substances. Additionally, the unit covers the formation of tropospheric ozone from nitrogen oxides and hydrocarbons in sunlight, and its negative effects like smog, plant damage, and material corrosion. By the end, students should be able to describe the steps of ozone formation, explain ozone depletion and its health impacts, and identify ways to reduce depletion and the effects of tropospheric ozone.