請問防火既煙冒感應器有無輻射 ?

There are different types of smoke detectors (煙冒感應器) used in Hong Kong. Some works on heat sensitive mechanism, but radioactive substance is also commonly used in those smoke sensitive type of detectors.
The radioactive substance used in smoke detectors is Americium-241 ( 鎇-241) which has a half life of 432 years. It decays by emitting alpha particles of energy 5.6 MeV and low-energy gamma radiation of about 60 keV.
Because of the short range in air for alpha, all alpha particles cannot penetrate the ionization chamber inside the smoke detector (the ionization chamber is where smoke particulates from fire absorb the alpha particles hereby triggering an alarm signal). It is only the low-energy gamma radiation that can penetrate into the air. But these gamma radiation is readily absorbed by the air thus causing negligible radiation hazard.
The radiation from ionization type smoke detectors is completely different from that from TV or computer. The former is a type of [ionizing radiation], which has sufficent energy to ionize matter (including body tissues and cells) thus causing harmful effect to human. Radiation generated from TV/computer is a type of [non-ionizing radiation], the energy of which is too weak to cause any ionization in body tissues.

炭粒子,惰性氣體 >>> 都會係放射性物質唔係咩!????
我記得佢係有ga~ 不過佢有個design 擋住~

絕對無！因為煙霧感應器只是<接收煙霧裡面之粒子>若粒子增多<即火警燃著的物件,如炭粒子,惰性氣體>令感應器之<阻值>增加,電路系統立即推動<警鐘或蜂鳴器>令他人產生警覺,檢查或徹離現塲。
感應器之不含放射物質,包括<貧鈾>,所以,比任何家電更安全。