A sectional model for aggregate aerosol dynamics accounting for gas-phase chemical reaction, coagulation, and sintering at nonisothermal conditions is presented. The aggregate structure was considered by the implementation of a constant mass fractal dimension on the aggregate collision diameter and an average, but variable, aggregate area within a given volume section. The model showed separately the evolution of the size distribution of the primary and aggregate particles. Model predictions with respect to average primary particle diameters and aggregate particle-size distributions were evaluated by comparing with experimental data for synthesis of titania by TiCl4 oxidation in a furnace aerosol flow reactor. The effects from sintering time and mass fractal dimension are also discussed.