What you're talking about sounds like something that is possibly already there in the air of your home
, but you aren't smelling it consistently. Airflow in the home
is strange thing, but it's consistent with the fact that it keeps moving.
One thing you can do to help out, with any particle like that of smoke is, you can put in a whole house filter. The best in the business for price and efficiency is the Polarized Media Filters made by Electrobreeze.