资料说吸烟史是第一原因，氡气是第二原因。

How can radon hurt my health?

Radon is the second leading cause of lung cancer in Canada. Radon exposure is estimated to be the cause of 16% of lung cancers.

If you live in a building with high radon levels (or if you spend a lot of time in one), you are at higher risk for lung cancer. Radon is the second most common cause of lung cancer, after smoking.

If you smoke and you live in a home with a high level of radon, you are at an even higher risk for lung cancer.

（http://www.lung.ca/protect-protegez/pollution-pollution/indoor-interieur/radon-radon_e.php）

看吸烟不能只看现在的吸烟率。从吸烟到发病有一个漫长的过程。

所有跟帖： 

• 怎么才能知道周围的氡气有没有超标？ -不急- ♀ (0 bytes) () 11/16/2013 postreply 13:51:35

• 回复：怎么才能知道周围的氡气有没有超标？ -老生偶谈- ♀ (530 bytes) () 11/16/2013 postreply 19:09:42