Under the right conditions, nanoparticles can form spontaneously in the air. Atmospheric nanoparticles are an important missing factor in understanding global climate change, because they could influence cloud formation and change how the Earth reflects or retains heat, said Anthony Wexler, professor of mechanical and aeronautical engineering at UC Davis.
They may also have health effects. Wexler's laboratory uses and develops equipment to detect these extremely small particles.
On the coast at Bodega Bay, California, they found particles as small as three nanometers forming when winds are onshore. The composition of these particles has not yet been determined but they may be composed of sulfuric acid, Wexler said. The source material could be dimethyl sulfide emitted naturally by biological processes in the ocean, or sulfur dioxide emitted from passing ships.
Wexler has also developed models to study how similar particles form close to freeways in Los Angeles.