Eye irritation measurements are available from smog chamber solar irradiations of selected hydrocarbon-nitrogen oxide mixtures. These results have been used to compute eye irritation intensity parameters for formaldehyde, acrolein, peroxyacetyl nitrate and peroxypropionyl nitrate. Peroxypropionyl nitrate is the most irritating of these four substances. The relative contribution of various pairs of eye irritants in ambient air mixtures to eye irritation has been calculated from the ambient air concentrations and the eye irritation intensity parameters. The relative contribution of the four eye irritants to a 'typical' ambient air mixture has been computed. Formaldehyde appears to be the single most significant eye irritant. Other potential ambient air eye irritants are discussed. The relationships between hydrocarbon control strategies and eye irritation are considered.