hello thank you for trusting HCM dear cigarette smoke can cause nasal mucosa irritation and inflammation can cause bleeding,.other possibilities like dryness of mucosa,nasal priking, hypertension,thtombocytopenias,sinusitis,allergic rhinitis etc can cause nose bleed. so stop smoking,use normal saline nasal spray ,video humidifier in room.if severe bleed you can use nasal packing.still symptoms not improved please consult your Ent surgeon he will examine and treat you accordingly. I think I answered to your question if you have any questions please feel free to ask. take care