The chemistry of the atmosphere is complicated. Anthropogenic and naturally produced molecules undergo thousands of chemical reactions that affect urban pollution and smog, stratospheric ozone depletion, and global climate, among other things. Each reaction has its own kinetic rate constant, which must be known if the system is to be modeled and its effects understood.
Among the key players in atmospheric chemistry is a class of unstable molecules called Criegee intermediates. Although qualitative evidence for their atmospheric role is strong, until recently no one had ever directly detected a Criegee intermediate in the gas phase, let alone measured its rates of reaction with other molecules.
Now, Craig Taatjes and David Osborn (both at Sandia National Laboratories in Livermore, California) and their colleagues have made several direct kinetic measurements on the reactions between the simplest Criegee intermediate, CH2OO, and four small atmospheric molecules: SO2, NO2,...
