Our previous investigations have shown that the pK(i) of the interfacial pH and polarity probe 4-heptadecyl-7-hydroxycoumarin (HHC) embedded in neutral monolayers is different at the air-water and the solid-water interfaces. This difference questions the universality of the reference pK(i,o) value defined for each interfacial pH and polarity probe at a chosen neutral interface. The shift pK(i/o)(s/w)-pK(i/o)(a/w) was interpreted as due to oriented dipole layers located in the solid substrate at about 6 nm from the monolayer-water boundary. In the present study we check this hypothesis by investigating the effect of the omega-dipoles of heptadecanol and 16-bromohexadecanol monolayers at the air-water interface on the acid-base equilibrium of embedded HHC. Emission and excitation spectra of the amphiphilic dye were recorded at different pH values, and pK(i) values were evaluated from both emission and excitation titration dependences. The negligible difference between the pK(i) values of HHC in the two matrices implies that remote dipoles have no significant effect. Emission and excitation spectra of the water soluble 4-methyl-7-hydeoxycoumarin (MHC) in the same phosphate solutions applied as liquid substrates for the spread monolayers were recorded and used to obtain the value of the bulk pK(b). From the difference pK(i)-pK(b) the interfacial dielectric constant at the monolayer-water boundary coincide very well with literature data for epsilon(i) for sugar micelles. Because of the important role the saccharide moieties play in biological processes, this coincidence and 55 +/- 5 for 16-bromohexadecanol monolayers coincide very well with literature data for epsilon(i) for sugar micelles. Because of the important role the saccharide moieties play in biological processed, this coincidence underlines the importance of further investigation of spread an deposited monolayers of long chain alcohols as the simplest models of the more complex di- or polysaccharides.