Why do my grains smell like my room?
Anything absorbent will absorb smells. That's why fabric picks up smells easily, wood will over time, and glass won't. As I'm sure you know from cooking grains, they are quite absorbent, and that applies to smells as well.
All techniques I can think of to remove smells from other items aren't ideal for using on food, so your best bet is probably to cover it up with some strong spices. To prevent your grains from picking up smells in the future, store them in something airtight so air and smells won't permeate the container and reach your food. Open containers are the worst, tightly closed cardboard boxes and thin plastic bags are a bit better, sturdy airtight plastic containers are better still, and glass containers with metal lids are the best.