100 Years of Research in Atmospheric Chemistry (Core Science Keynote)

Hundred years ago, very little was known about the chemical composition of the atmosphere and about the photochemical processes operating in the atmosphere. In 1920, the community had just learned that an ozone layer probably existed in the stratosphere, but its altitude was unknown. At the beginning of the century, it was known that considerable amounts of carbonated and hydrogenated gases were emitted by marshes, but the presence of methane in the atmosphere was quantified only in the late 1940’s. Urban air pollution was frequently reported as a consequence of coal burning, but the formation of secondary air pollutants was completely unknown.

The paper will present an historical overview of the progress made in the last 100 years in our understanding of the processes associated with atmospheric chemistry and will highlight the importance of fundamental research to better inform society about the risks related to air pollution and climate forcing.