just read your posts and then started doing my own research on the risk of cancer if living on a solid slate bed rock if any??? still not sure if added risk radiation but came across this.
Air travel
Air travel exposes people on aircraft to increased radiation from space as compared to sea level, including cosmic rays and from solar flare events.[38] Software programs such as Epcard, CARI, SIEVERT, PCAIRE are attempts to simulate exposure by aircrews and passengers.[38] An example of a measured dose (not simulated dose), is 6 μSv per hour from London Heathrow to Tokyo Narita on a high-latitude polar route.[38] However, dosages can vary, such as during periods of high solar activity.[38] The United States FAA requires airlines to provide flight crew with information about cosmic radiation, and an ICRP recommendation for the general public is no more than 1 mSv per year.[38] In addition, many airlines do not allow pregnant flightcrew members, to comply with a European Directive.[38] The FAA has a recommended limit of 1 mSv total for a pregnancy, and no more than 0.5 mSv per month.[38] Information originally based on Fundamentals of Aerospace Medicine published in 2008.[38]
http://en.wikipedia.o...ki/Ionizing_radiation