We have been studying the basis of the air flow effect which increases the uniformity and stability of negative corona discharge. The possibility that the stability of the negative corona is disturbed by some interruption for the flow of light to the surface of the wire electrode is investigated. Spectra distributions of the corona discharge in air atmosphere and in N₂ atmosphere are measured as a first step. Major peaks are seen in the ultraviolet band. Measured peak heights in negative corona discharge are found to be four times bigger, in air, than those in positive corona discharge. Almost all major peaks in air were confirmed to have the same wavelength as was measured under N₂. The measured difference in the spectrum distribution curves between positive and negative corona discharges indicates differences in the discharge mechanisms and a hint for analyzing the air flow effect in negative corona discharge.