Just to say that at the nursery my children currently attend, I have never seen anyone standing outside smoking at all. I dont think you can be a smoker and do a job like that as the smell stays on your clothes and you can compromise the health of your children that way especially if any have tendencies to breathing difficulties.

I was once sent a trainee from Lewisham College on a home placement for a few months. We both filled in copious forms and had a long chat with her and and her supervisor before she started. There was so much emphasis on health and safety on both sides. She was a smoker and I only found out on her first day when she asked to go outside into the front garden- so much for health and safety then.
I was really desperate for help but dispensed with her albeit free services on the spot as a result. One of my children had just been hospitalised with bronchiolitis and had just come home- there was no way that I would entertain a smoker in close proximity to her and I dont think any respectable nurseries would do either. Unfortunately smokers do carry the smell of cigarettes around with them and it never goes away. I work with a few smokers in my office and really detest it when they all come back in from a fag break as the place reeks for ages afterwards. I doubt whether someone whose nursery is based in their home would take on a smoker either for that reason either.