Automatic Dependent Surveillance Broadcast (ADS-B) uses GNSS and other sensors to provide aircraft positions to air traffic controller (ATC) and other airspace users. This project seeks to use ADS-B messages to rapidly detect and localize interference events allowing for better protection and situational awareness for operations that rely on GNSS being available. This project first characterizes the effects of known GNSS interference events on ADS-B outputs. We then utilize these observed behaviors to identify suspected interference events at other locations. This paper performs this analysis using publicly available records of ADS-B transmissions. The events that we sought to identify were based on pilot reports of interrupted GNSS service to aircraft on approach to a San Francisco bay area airport. Approach procedures may be more likely to encounter interference due to the closer proximity to the ground and therefore to potential radiofrequency interference (RFI) sources. Further, these procedures have the most stringent safety requirements.