Chemistry
How Atmospheric Aerosols Form and Grow Through Gas-to-Particle Conversion
Quick fact
Atmospheric aerosols can form from gaseous molecules almost out of nothing: a few sulfuric acid and ammonia molecules can clump together to create a new particle smaller than a few nanometers, which then grows into a seed for cloud droplets.
Why this is interesting
Every breath you take carries millions of invisible particles that were once just molecules in the air. How do those particles come to be?