PAH emissions from a municipal waste incinerator stack in central Taiwan were sampled and analyzed by gas phase and particulate phase samples. A modified Gaussian atmospheric dispersion model, industrial sources complex (ISCST3), was used to simulate the PAH concentration in ambient air, which was compared with the measured PAH concentration in the ambient air. Total-PAH emission factor for the municipal waste incinerator ranged between 748 and 992 mg/ton-waste and averaged 871 mg/ton-waste, while the total-PAH emission rate ranged between 21000 and 27900 mg/hr and averaged 24500 mg/hr. The results of dispersion modeling indicated that the contribution of PAHs to the ambient air by the municipal waste incinerator only reached 0.98% of the background concentration. Consequently, other emission sources, especially mobile sources, impact air quality more significantly.