There is growing evidence that air emissions of PFAS are an important environmental contamination route with potential impacts to human health and the environment. Therefore, there is an urgent need for accepted measurement methods for PFAS emissions to characterize what is being emitted and at what amounts. This presentation will cover Other Test Method (OTM)-45 and OTM-50, two PFAS source emissions measurement methods that have been developed in collaboration with EPA’s Office of Air Quality Planning and Standards. OTM-45 was initially released in 2021 and was revised in 2024 to improve method performance and address feedback received from the measurement community, while OTM-50 was released in early 2024. Both methods are intended to provide reliable and comprehensive emissions data to support state regulatory processes and potentially inform federal decision making.