However, it is not only harmful to escape, but also beneficial for smoke to spread quickly to other floors if the smoke moves into the vertical escape evacuation routes while it is on fire.

但是火灾发生后，作为人员逃生的竖向疏散通道如果遭受烟气侵害，不仅对人员的逃生不利，而且会加快烟气向其他楼层的蔓延。

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It is estimated that China has more than 300 million regular smokers, and more than 700 million people are routinely exposed to harmful second-hand smoke, according to experts.

椐起专家们估计，在中国经常吸烟的人已超过3亿人，而有超过7亿的人经常暴露在二手烟的危害中。

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