Pop rocks and soda..... baking soda and vinegar ...
Answer:
possible answer from edge
Explanation:
After World War II the only coal available to burn residentially, either for cooking or warmth, was of poor quality and contained large amounts of contaminants that made its fumes toxic. So when millions of homes in London burned this low quality coal and the local atmosphere over and around London stagnated, there was nowhere for the fumes to go. This stagnation allowed the toxic coal fumes to build up until they became physically harmful to humans and animals.
