Radiation plane Tokyo to LAX 3

The background radiation reading at the start of this flight shows 2.5 μSv/hr radiation above Fukushima. 2 hours before reaching LA however, at 39,000 feet, it shows 5.33 μSv/hr (HIGHLY DANGEROUS). Upon landing in LA, the reading drops to approx. 0.19 μSv/hr (Normal background radiation). This indicates there is a radiation cloud high above the Pacific West Coast. People are safe as long as it doesn't rain. If it does, please take shelter, filter your air and especially your drinking water.