I have a weed like smell coming from my bathroom duct. I smell it there first and then it filters to all parts of my house. I dont smoke weed. The smell lasts about an hour. It is intermittent. Sometimes I smell it 5 times a day, other days I smell it 2 times a day. It happens more when the air is on, but will also happen when the air is not on. I have my own HVAC and do not share ductwork with another else in my townhome complex. I have had my ducts and HVAC cleaned by a reputable company. There is nothing in the ducts. They have checked my coil and there is no build up. The AC guy just installed an air scrubber and it has been a week. I don't know what to do next help?? Any thoughts on who I should have help diagnose this situation. I have lived in my town house for 2 months and apparently it was also a problem when the previous owner lived there.