吸烟，氡气与肺癌

研究表明， 吸烟，氡气是导致肺癌的第一第二大原因。其他原因包括石棉，家族病史等。
 

CDC: Research has found several risk factors for lung cancer. A risk factor is anything that increases the chance of getting a disease.

Examples of risk factors for lung cancer include—

• Smoking tobacco and being around others' smoke.
• Exposures at home or work (such as radon gas or a*****estos).
• Personal history (such as having radiation therapy or a family history of lung cancer).

We know a lot about risk factors, but they don't tell us everything. Some people who get cancer don't seem to have any known risk factors. Other people have one or more risk factors and do not get cancer. If a person has several risk factors and develops lung cancer, we don’t know how much each risk factor contributed to the cancer.


因为氡气在裂变过程中会产生电离辐射，因此没有一个绝对安全的数值。

在美国，大气中的氡气含量是 0.4 pCi/L (picocurie/L), 室内的平均值为 1.3 pCi/L。EPA 的标准是如果房子内氡气含量超过4.0 pCi/L （148 Bq/m³ ），就一定要采取措施降低。如果高于 2.0 pCi/L，就建议采取措施。

Health Canada recommends that the higher the radon concentration, the sooner you should take steps to remediate the issue. 

• Over 600 Bq/m³ - Remediate within 1 year
• Between 200 and 600 Bq/m³ - Remediate within 2 years
• 200 Bq/m³ and below - No action required

The World Health Organization

The WHO Handbook on Indoor Radon: A Public Health Perspective indicates that radon exposure is a major and growing public health threat in homes and recommends that countries adopt reference levels of the gas of 100 Bq/m3 which is equivalent to 2.7 pCi/L.

（ 换算： 1 pCi/L = 37 Bq/m³ ； 10 pCi/L = 一天抽一包烟（20枝））

依照美国的标准，即使你的屋内氡气含量达标但接近  4  pCi/L, 也相当于一天抽烟半包。