Here's the thing Humanoid, we have evidence of these all over the place, now we can't assume people are blasting off smoke rings via kerosene in a 55 gallon barrel all over the place to explain these, that's just too much to consider, and we have photographic evidence of these rings creating saucer like clouds as shown in the video.
Now a smoke ring from a barrel isn't going to do that. However, what you say makes me think that there might a natural explanation, and so what we really need to do is form some ideas how nature might be able to create this.