Even if only on occasion cigarette and pot smoking is a risk factor for the virus. Inhaling smoke is not good for the respiratory system period. Said pot smoking is worse because it burns at lower temperatures and produces more particulate matter that is inhaled.
https://nypost.com/2020/04/10/both-cigarette-and-marijuana-smoking-raise-coronavirus-risk/
https://nypost.com/2020/04/10/both-cigarette-and-marijuana-smoking-raise-coronavirus-risk/