Here is a prank to play on a smoker... Lace one of his/her cigarettes with potassium nitrate. When potassium nitrate burns it products oxygen. The oxygen will cause the cig to burn faster, burning more potassium nitrate, making more oxygen to burn faster... The smoker will suck down the entire pollution load on the same draw used to light the cigarette!
I don't recommend that you actually try this.. It could burn their lips off or generate enough heat to damage their lungs. It might be funny to see but it's probably better to let the cigarettes kill them slowly.