Ambient air quality standards are set to protect public health. There are currently both Federal and State ambient air quality standards by USEPA and state air quality agencies, CALEPA for California. California air quality standards are generally more stringent that federal standards. Continuous air monitoring by these agencies and BAAQMD ensure that air quality standards are being met and improved. An emission inventory identifies and quantifies sources of air pollution to assist air quality planning and rules development efforts to achieve and maintain ambient air quality standards.