That chart you linked states in the middle that 1 flight from NY to LA equals 3 chest x-rays. Don't know how you did your math. If NY to LA is 3 chest x-rays,

That chart you linked states in the middle that 1 flight from NY to LA equals 3 chest x-rays. Don't know how you did your math. If NY to LA is 3 chest x-rays, imagine 3x as long at a higher altitude and higher latitude.