There has been considerable public debate regarding airborne disease transmission in the passenger cabin of commercial aircraft. An initial study to develop a numerical tool, using computational fluid dynamics (CFD) methods, for investigating the potential of disease transmission in commercial aircraft, is completed and reported in this paper. To gain insight of the general airflow pattern, a detailed CFD model of a section in the passenger cabin of a B767-300 passenger cabin was built and a Reynolds-averaged Navier-Stokes (RANS) simulation was performed. By comparison with the available test data, the RANS simulation substantially under predicted the turbulence intensity, especially in and around the breathing zone (Lin et al. 2004). A separate large eddy simulation (LES) was conducted to obtain a more realistic turbulent energy transport in a generic cabin model. The LES-predicted turbulence level is in fairly good agreement with the test data, as reported separately in Lin et al. (2004). Based on the LES results, the k and e equations used in the RANS simulation were modified by using a special user subroutine. A RANS simulation with adjusted turbulence was then employed to simulate the dispersion of airborne pathogen in the detailed passenger cabin model. These adjustments allow for the simulation of disease transmission using less than 1/100 the computing hardware resources required for an equivalent LES of airflow and particle transport. This paper is an elaboration on the numerical study of the transport of airborne pathogens in an aircraft cabin.