South Coast AQMD's Governing Board adopts policies and regulations that promote clean air within its four-county area, the smoggiest in the nation. Federal and state law require that South Coast AQMD achieve clean air standards to protect public health. Before it makes decisions that affect local residents and businesses, South Coast AQMD must consider ideas and comments from the public. The opportunity to comment begins in public workshops and ends with a public hearing by the Governing Board where anyone can testify or present written comments. The Board usually meets at South Coast AQMD's Diamond Bar headquarters on the first Friday of each month.