Amazon has plenty of odor detectors for ~$50: https://www.amazon.com/odor-detector/s?k=odor+detector https://www.amazon.com/odor-detector/s?k=odor+detector I a

Amazon has plenty of odor detectors for ~$50: https://www.amazon.com/odor-detector/s?k=odor+detector https://www.amazon.com/odor-detector/s?k=odor+detector I assume there are sensors available suitable for Waymo taxis.