Can someone tell me if second hand smoke harmful to my child if i do it only for one day?

Smoke somewhere else: Smoking where a child can breathe in second-hand smoke is not healthy for that child, even once. Certainly, long-term exposure is very unhealthy, with increased colds, sinus infections, asthma and allergy, but even short exposures can cause coughing and allergic reactions. If you are not dependent on tobacco, why are you doing this, even for a day? If you must, do it outside.

It lingers: Studies have shown the breakdown products of smoke in a babies urine 2 weeks after its only exposure. The particulate matter breathed into the nostrils will attach to the nasal membrane and remain until shed/washed out. Exposure doubles risk of upper respiratory illness.