[Perspective] Atmospheric radical chemistry revisited
Sunlight is the largest energy source for Earth and therefore determines many aspects of our planet's chemistry and climate. For example, light-driven splitting (photolysis) of ozone at high altitude leads to the formation of hydroxyl radicals, which are involved in most oxidative processes in the environment. On page 699 of this issue, Rossignol et al. (1) report on an alternative process. They show that direct photolysis of a fatty acid at an air-water interface leads to the formation of oxidized products in the gas phase and of macromolecular products in water. This example, along with recently reported indirect photolysis of organic molecules (2, 3), shows that radical reactions initiated by absorption of sunlight can follow mechanisms previously unknown in Earth's atmosphere. Author: Veronica Vaida