Case 1: The effect of rain on the ambient radiation level in Hong Kong

After heavy rain in the early morning of 19 July 2005, both radiation monitoring stations at Sha Tau Kok and Sai Wan Ho recorded an increase in the radiation level. On the other hand, the radiation level at Tsim Bei Tsui, which is outside the rain area, remained steady.

The above radar pictures indicate a rainband moving south from the New Territories, passing through the eastern districts of Hong Kong.

The rainfall (bar) and radiation levels (curve) recorded by the three radiation monitoring stations during 18th-19th July 2005.