Smoking is prohibited near entrances, windows and ventilation systems of all workplaces and public places where smoking is prohibited by the Dee Johnson Clean Indoor Air Act. An individual who owns, manages, operates or otherwise controls the use of a premises subject to the provisions of the Dee Johnson Clean Indoor Air Act shall establish a smokefree area that extends a reasonable distance from any entrances, windows and ventilation systems to any enclosed areas where smoking is prohibited. The reasonable distance shall be a distance sufficient to ensure that persons entering or leaving the building or facility shall not be subjected to breathing secondhand smoke and to ensure that secondhand smoke does not enter the building or facility through entrances, windows, ventilation systems or any other means.