16.6 Human Activities Have Increased Air Pollution

Ozone in the Atmosphere

An overview of how ozone works to protect us from the Sun's ultraviolet radiation. Plus other fun facts, such as why we only see visible light and why fire engines are painted yellow-green. Duration: 9:22.

Our Atmosphere's Composition

A survey of the composition of Earth's atmosphere introducing the units of ppm and ppb and concluding with a stunning NASA video of worldwide particulates and aerosols. Duraction: 6:48.