How can I reduce the pungent odor of split pea soup?
Bake bread to go with the soup as you make it. 

The smell of bread baking (sourdough in particular!) is usually enough to cut the smell of lentil / split pea / chic pea / fish soups and stews while adding the right elements of savory aroma to make the combined smell almost, if not actually desirable and palatable. 

Any good yeasty bread recipe should do the trick. Another thing you can do is bloom some saffron, which mixes delightfully with the smell of split pea soup. 

In short, taste your soup as you smell other things. When you hit on winning combinations, they're aromatically complimentary and create a sensory affinity. Many bistros (and bakeries themselves) rely on this technique to lure passers-by.