A round-trip flight from New York to London exposes you to about the same amount of radiation as a chest X-ray.

Cosmic radiation consists of high-energy particles, such as protons and atomic nuclei, that originate from the sun and outside our solar system. The Earth's atmosphere and magnetic field act as a shield, absorbing most of this radiation before it reaches the ground. However, as altitude increases, the atmosphere becomes significantly thinner and less effective at blocking these particles.Commercial aircraft typically fly at altitudes between 30,000 and 40,000 feet. At these heights, the radiation dose rate is much higher than at sea level. According to the Health Physics Society and the CDC, a typical chest X-ray delivers a radiation dose of approximately 0.1 millisieverts. A one-way flight from New York to London results in a dose of about 0.04 millisieverts, meaning a round-trip journey nearly equals the exposure of a single X-ray.The level of exposure can vary based on several factors, including the flight path and solar activity. Flights near the Earth's poles, such as those traveling over the Arctic, experience higher radiation levels because the magnetic field is weaker there. During solar flares or periods of high solar activity, the intensity of cosmic rays can increase significantly, though these events are monitored by aviation authorities.While this sounds alarming, the risk to occasional travelers is considered negligible by organizations like the Federal Aviation Administration (FAA). For perspective, the average person receives about 3,000 microsieverts of background radiation annually from natural sources like radon and soil. Frequent flyers and cabin crew are the only groups typically monitored for cumulative exposure over their careers.