Nitrogen-atom behavior in a low-pressure, nonisothermal microwave-generated nitrogen afterglow was studied. N-atom flux was measured by chemical titration. It was found that an increase in power or flow rate, or a decrease in pressure resulted ill larger productions of N atoms. A one-dimensional mass-continuity equation was used to model N atoms’ concentration field in the afterglow. The model, with no adjustable parameters, agreed closely with experimental measurements. The model shows that convection, diffusion, and wall recombination play important roles in the afterglow. In contrast, N-atom generation and homogeneous recombination are of marginal importance. The model was manipulated to assess the impact of the measuring technique, chemical titration, on the N-atom flux. It was found that the N-atom flux profile is only slightly impacted, although the concentration profile is strongly modified.