The idea that a transatlantic flight exposes a person to radiation equivalent to smoking cigarettes per trip is a popular comparison but requires careful examination to understand its accuracy and context.
When flying at high altitudes, such as on a transatlantic flight, passengers are exposed to increased levels of cosmic radiation. This radiation comes from outer space and the sun, and the Earth’s atmosphere provides less shielding at cruising altitudes of commercial aircraft, typically around 30,000 to 40,000 feet. The amount of radiation exposure depends on factors like flight duration, altitude, latitude, and solar activity.
The radiation dose from a typical transatlantic flight is often estimated to be around 0.03 to 0.1 millisieverts (mSv). To put this in perspective, the average person receives about 3 mSv per year from natural background radiation. So, a single long-haul flight adds a small fraction to this annual dose.
Comparing this to cigarettes is tricky because cigarette smoking involves inhaling radioactive substances like polonium-210 and lead-210, which emit alpha particles that damage lung tissue directly. The radiation dose from smoking is cumulative and localized primarily in the lungs, contributing to cancer risk.
Some sources have made rough analogies suggesting that the radiation dose from a transatlantic flight might be “equivalent” to smoking a few cigarettes, but this is a simplification and can be misleading. The types of radiation, exposure pathways, and biological effects differ significantly between cosmic radiation at altitude and radiation from smoking.
Moreover, the radiation dose from flying is external and brief, while smoking delivers radioactive particles internally over time. The health risks from these two sources are not directly comparable just by dose numbers alone.
In summary, while you do receive some additional radiation exposure during a transatlantic flight, equating it directly to the radiation from smoking cigarettes per trip oversimplifies complex differences in radiation type, exposure route, and biological impact. The radiation dose from flying is relatively low and considered safe for occasional travelers, though frequent flyers and aircrew accumulate higher doses over time.
