I don't think I breath enough?

Obviously I'm taking in enough air but sometimes i catch myself barely breathing. I used to have asthma, and my nose is almost always closed (like naturally but almost in a congested way, it sucks) I have to make myself take bigger breathes but maybe this is because of my atmosphere? I live in downtown san diego and i go to school at UC Riverside (polluted.) However I grew up Jersey where there is plenty of greenery and fresh air. I notice that whenever im at the beach or park or around some mountains, my breathing really opens up. Other than that, i ignore my lungs. Growing up with asthma i guess i got used to shorter breath because i did so many sports. Nasal spray does not work too well for me and I want to be able to breathe normally without having to think about it. what is up with this?