QUIZ: In the winter of 1952 "smog" blanketed London

QUIZ: In the winter of 1952 from Friday 5 December until Tuesday 9 December smog slowly crept over London, England, and by a set of unusual climatic events remained trapped in the atmosphere.

Questions:

1) How many people ultimately died?

2) By what name did the event eventually come to be called?

3) What major ingredient did Wales contribute to the disaster?