Assistant Professor Siddharth Iyer uses computational methods to study aerosol formation

Iyer’s research group employs computational quantum chemistry methods to resolve molecular properties and, along the way, understand how volatile gases transform into “sticky” molecules that lead to aerosol particles. “We can study computationally what is impossible to study experimentally, for example the fate of trace gases with nanosecond lifetimes”, says Iyer. “These transient molecules are nevertheless key to understanding how aerosol particles form.”  

Iyer’s group works closely with research groups studying aerosol formation through laboratory and field measurements, as well as with groups developing air quality and climate models.

Gaseous emissions can form particles quickly

While global temperatures are rising sharply from greenhouse gas emissions, this effect is somewhat mitigated by pollution in the form of aerosol particles. These particles  can reflect sunlight and increase cloud cover, which has a net cooling effect on the planet. While there are many direct sources of aerosol particles, such as pollen, dust, and soot, a majority of them are in fact created “out of thin air” when gases released from biogenic and anthropogenic sources undergo chemical reactions in the atmosphere. These reactions add oxygen atoms to molecules and, in the process, produce a small but nevertheless significant fraction of extremely low volatile molecules that drive particle formation and growth. The formation of such molecules can be extremely rapid. For example, alpha pinene and toluene, two important biogenic and anthropogenic emissions, convert into sticky aerosol precursor molecules in less than a second of being released into the air.

Using computational methods to understand how aerosols form

Using quantum chemistry programs run on supercomputers, Iyer’s research group can study the key steps involved in the transformation of volatile gases into extremely low volatile aerosol precursors. This provides the blueprint necessary for understanding their impact on aerosol formation. The goal of the research group is to combine computational results with direct experimental measurements to improve the reliability of current air quality and climate models.

Siddharth Iyer earned his Master of Science degree in 2015 from Aalto University, Finland, and his doctoral degree in 2019 from University of Helsinki, Finland. He joined the physics unit in the Faculty of Engineering and Natural Sciences (ENS) of Tampere University in 2019 as a postdoctoral researcher, transitioning to an Academy Research Fellow in 2023 and to Assistant Professor in 2026.

Besides work, Siddharth occupies his leisure time with rock climbing and reading.