How risky is secondhand smoke?

二手烟到底有多危险？

How can secondhand smoke be avoided?

该如何避免吸入二手烟？

Avoid secondhand smoke.

避免吸二手烟。

000 nonsmokers die every year from secondhand smoke.

每年有5万3千名非吸烟者死于二手烟。

Studies of secondhand smoke have indeed moved outdoors.

二手烟的研究确实已经移至户外。