How many chemicals are there in a marijuana joint and in a cigarette?

This is a science question. When researching the web I find it amazing that the numbers given vary greatly ranging from 400 to 1000 to 2000 and up to 4000. Answers given in other Fluther questions seem also inconclusive. Why this great variety? With all the sophisticated chemistry labs in the world, it shouldn’t be so difficult to light up a joint and a cigarette and analyze the stuff in it. And of course determine what is harmless and what is potentially dangerous.

This question is not about tetrahydrocannabinol (THC) and how addictive it might be and whether cannabis should be legal or not. But I’m curious, are there other substances in a joint that can also significantly increase the risk of lung cancer or cardiovascular diseases? Why are there so many discussions about the health risks of cigarettes and so few compared to joints? After all when both products are enjoyed a lot of smoke enters the human lungs. Would cigarette smokers be better off switching to cannabis?