1 is like directive. When you want her/him(no smoking at that time) to smoke in the lobby. 2 is like attention. For example, he/she is smoking in other than ''smoking room''. You use ''2'' phrase to him/her. To be more precise, not ''o''(お in Japanese). In this case, we use ''wo''(を). Pronounce is a little bit different I think🤔 But almost same. And pronounce of ''wa''(わ) is same. But we write ''ha''(は).