My husband told me that these were weeds and not to be complaining about my allergies if I was going to be messing with them, but I could see those lovely little tiny lavender flowers, weeds or not!
These look like wild asters, and they are probably not the cause of your allergies--usually it's ragweed that is the problem. These are a beautiful autumn wildflower and I love the airy delicacy of your capture of them, fav for me.