A parametric study was carried out on a coaxial air-blast injector where a low-speed water jet is atomized by a high-speed annular air flow. The fluorescence induced in the liquid phase by a pulsed laser sheet has been used to derive the near field of liquid volume fraction, Y. Fourteen operating conditions were covered, to study the influences of the Weber number and of the dynamic pressure ratio in the injected fluids on the mean field of Y, on the length of the liquid dart, and on the field of Y fluctuations. Statistical processing was used with a cumulative approach to obtain the local probability density function (PDF) of Y. Between two peaks at Y = 0 and Y = 1 (events with no liquid and full liquid, respectively), the PDF of Y-2-1 has a canonical form. Application of statistical physics provides the local number of degrees of freedom for the liquid elements within the control volume.