Nitrogen Trioxide: Key Intermediate in the Chemistry of Polluted Air?

It is proposed that peroxyacetyl nitrate and its homologues are formed in polluted air via hydrogen abstraction from the corresponding aldehyde by nitrogen trioxide, followed by (a relatively fast) combination of the resulting acyl radical with oxygen and NO/sub 2/. This mechanism provides a simple explanation for the formation of nitric acid, HNO/sub 3/, as well. Nitrogen trioxide should be able to abstract hydrogen atoms from hydrocarbons, since the H/sup -/ONO/sub 2/ bond strength is about 100 kcal/mole.