An air bearing assembly supporting a turbine driven rotatable motor shaft is provided. The assembly includes a composite cylindrical air bearing having alternating, bonded segmented porous carbon sections and nonporous carbon sections. The composite bearing has a sleeve installed circumferentially therearound. The sleeve has openings therein, therethrough and therearound such that the openings are adjacent the porous carbon sections and are oriented so as to be in longitudinal and circumferential registry with the porous carbon sections. Air passageways deliver supplied air into and through the sleeve openings, thence into and through the porous sections, thereby providing frictionless support for the rotating shaft. The assembly includes “O”-rings installed circumferentially therearound, one at each end of the assembly. A specific embodiment, namely a rotary bell cup atomizer driven by a turbine mounted on a rotatable motor shaft supported by the air bearing assembly, is disclosed and claimed.