Atmospheric Chemistry

Abstract

This is a self-study course targeted at Master students who did not follow the bachelor course "atmospheric chemistry" or equivalent, providing a general introduction into atmospheric chemistry. It introduces the relevant fundamental concepts, which are explored in the context of key environmental issues, such as air pollution, stratospheric ozone depletion, and connections to climate change.

Objective

The learning target of this course is a general overview on the most important processes of atmospheric chemistry and the various problems of the anthropogenic impact on the chemical composition of the atmosphere, air quality and climate. The students should understand the chemical processes driving the evolution of the chemical composition in the troposphere and the stratosphere. They will understand how the products of these processes drive regional and global pollution, or affect the ozone layer. The students will also learn how some of these products contribute to particulate matter (aerosol) in the atmosphere, and how this impacts air quality, human health and vulnerable ecosystems.

Content

- Origin and properties of the atmosphere: composition (gases and aerosols), atmospheric structure, UV radiation, transport timescales. - Kinetics of gas phase reactions: rate laws, mechanisms of bimolecular and termolecular reactions. - Stratospheric chemistry: Chapman cycle, catalytic ozone destruction cycles, polar ozone hole, Montreal protocol. - Tropospheric chemistry: oxidizing capacity of the troposphere and the role of OH, oxidation and global budgets of CO and CH4, role of NOx, and the global tropospheric O3 budget. - Surface ozone chemistry: HOx-NOx cycle, role of VOCs, O3 isopleth, ozone production efficiency. - Aerosols: primary and secondary sources, composition, quantities and measures, connections to climate. - Multiphase chemistry: solubility of gases, Raoult’s Law and hygroscopicity, kinetics of gas to particle transfer, N2O5 chemistry, aqueous phase sulfur chemistry, secondary organic aerosol formation. - Air quality: role of planetary boundary layer, deposition processes, summer- versus winter-smog, environmental problems, legislation, long-term trends. - Global aspects: air quality - climate interactions.

Resources