The source of climate-active organic aerosol particles has been discovered by researchers. These particles are extremely low-volatile organic compounds consisting of relatively large molecules which contain an almost equal number of carbon, oxygen, and hydrogen atoms.
The scientists present a plausible explanation supported by numerous experimental findings of how these vapours are formed almost immediately when plant emissions (e.g. monoterpenes) are released into the air.
The vapours can then condense on small aerosol particles (starting from clusters of only a few nanometres in diameter) suspended in the air, causing them to grow to around 100 nanometres - at which size they can reflect incoming sunlight and act as condensation nuclei for cloud formation in the atmosphere.
The researchers' findings have bridged a major gap in knowledge in atmospheric and climate research.
"Thanks to our much improved understanding of the role that naturally occurring substances in the atmosphere play in the formation of organic aerosol particles, we will in future be able to make more reliable assessments of their impact on cloud formation and sunlight scattering, and thus on climate," Dr. Thomas F. Mentel from Julich's Institute of Energy and Climate Research- Troposphere, said.
The study was published in the journal Nature.