Peroxyacetyl nitrate is not the only compound of this sort, as a number of species of the
family of compounds known as the PANs, with the general structure of RCO-OO-NO 2 ,
have been found in the troposphere. However, PAN is the most abundant member of
this group of compounds. The PANs are eye irritants (i.e., lachrymators). They are not
very water soluble, have low photolysis rates, are very slow to react with hydroxyl
radical, and are thermally decomposed into their precursors, peroxyacyl radicals and
nitrogen dioxide. The PANs are therefore important means of transporting nitrogen
dioxide from urban areas on regional and global scales.