I understand the concept of clean and unclean foods, but where in the Torah does it speak about all these rules you are referring to, i.e. "Smell", or are they just rules laid down by men? Not that I’m into smelling pig meat, but I’m finding that you are making all these rules and regulations so difficult to anybody to maintain that it looks virtually impossible to become pleasing to Hashem - ever! Is He that complicated? As much as I like Judaism, I find that all the added rules would repel most young people - and the older ones complain.
I think the termenology prohibited and allowed foods is more accurate and less confusing than clean and unclean. The issue of smell in halacha of forbidden foods exists at two levels. There are things (some of them foods) which are forbidden not only to eat but also to gain any benefit from them. For instance chametz on Pesach and meat cooked with milk. Since aroma is a type of enjoyment, these things should not be smelled if it can be avoided. Pig and non kosher meat are forbidden to eat, but benefit is not forbidden, so it is not forbidden to smell them. If the taste of forbidden food gets into kosher food then the kosher food becomes forbidden because of the taste. The Talmud derives this principle from several Torah sources (SEE PESACHIM 44B AND 45A). There is an arguement in the Talmud and in subsequent commentaries whether taste can be tranferred through aroma (e.g.if two foods, one meat and one dairy are cooked in the same oven without actually touching) The rules of this halacha are complicated and one should consult a Rabbi for specific cases.