How will a tropical cyclone affect the ambient radiation level in Hong Kong ?

For a tropical cyclone moving over the South China Sea from southeast to northwest towards the south China coast, upon reaching the coast it will normally bring about northerly winds to Hong Kong, carrying with them natural radioactive material from the Mainland. Also, the subsiding air ahead of the tropical cyclone will bring the natural radioactive material aloft downward towards the ground. Furthermore, a tropical cyclone is usually accompanied by rain. All these factors may increase the ambient radiation level drastically (see case 4 given here).