Living with Marijuana user

How does one navigate this issue? I understand not to partake in drug use, however it is around me. I do not purchase it, sell it, posses it knowingly. Maybe get into a car with it, or someone brings it into my car. I am just guessing for someone bringing it into my car. I do not pat people down before driving.

Any tips ? I know my living situation is not ideal but, for now there is nothing I can do and I do not want to ruin my clearance. Thanks.