The U.S. Environmental Protection Agency (EPA) has determined the need to develop in-situ continuous or semi-continuous emissions monitoring (CEM) techniques for assessing dioxin, furan, and polycyclic aromatic hydrocarbon (PAH) emissions from municipal solid waste (MSW) incinerators and other sources. The species have a potential public health risk because of their low associated exposure limits. The paper discusses 12 innovative optical sensing techniques, which were evaluated for application to continuous monitoring approaches. The ability of each of the techniques to function as a CEM system is discussed. Two techniques that appear to have the most potential for successful application are Ultraviolet (UV) Direct Measurement and Fluorescence Measurement. Vapor phase UV spectral data for selected dioxins, furans, and polycyclic aromatic hydrocarbons are being generated to determine limits of detection and assess applicability of the techniques.