Expo visitors and workers have been largely compliant in keeping indoor areas smoke-free and limiting outdoor smoking to designated smoking areas.

世博会的游客和工作人员均广泛遵守室内区域禁烟和室外指定有限抽烟区域的规定。

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Interestingly, the biggest benefit from limiting secondhand smoke is from reduction in cardiac disease.

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"An inversion layer is keeping the smoke close to the ground, limiting visibility and reducing helicopter air operations, " Berry said.

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