I ve chronic lung issues, will any quantity of smoke left on him harm me, if my lodger smokes outside but share the house[ not the bedroom] ?

Yes: Yes, the smoke clings to the clothing and can cause worsening of your symptoms. Suggest that he wear a shirt or robe over his clothing while smoking, then take it off when he comes back inside.

Agree w Dr. Sadoun: The effects of off-gassing will continue to expose you to chemicals.

No: Second-hand smoke only causes problems if you breathe it. You are not being "gassed" by particles on someone else's clothing unless you have intimate contact with them, and even then, it probably would not be measurable. Smoking outside must mean outside (not the porch or just outside your windows). In apartment buildings, exposure occurs in other apartments to even distant smoke.