The purpose of the ambient air monitoring network is to sample air pollution in a variety of settings, assess the health and welfare effects, and assist in determining sources of air pollution. In general, six basic monitoring objectives and five measuring scales are used to determine the network design. Since it is physically and fiscally impossible to monitor the air in every location, representative samples must be obtained. These samples are determined by using the monitoring objectives and the spatial measurement scales. The network must be dynamic enough to maintain a current representative sample of the air quality. Air quality issues such as eight-hour ozone non-attainment boundaries and permits for new sources are diverse and controversial subjects for the citizens of Maricopa County. With its robust air monitoring network and mobile monitoring tools, the department strives to provide the most reliable and relevant air monitoring data to the public.