煙圈

烟圈^[1]是指烟雾在大气中形成的人類肉眼可见的涡环。吸烟者可能会有意或无意地从嘴里吹出烟圈^[2]。在特殊条件下，一些火山口也会产生巨大的可见的烟圈，例如埃特納火山就會產生煙圈。 ^[3]^[4]

可以產生煙圈的火山和地點编辑

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