Ozone transport assessments within the state of California

The California Clean Air Act (the "Act") requires each air pollution control and air quality management district in which a state ambient air quality standard for ozone is exceeded to develop a plan and an emission control program to attain the standard. The Act recognizes that ozone and ozone precursors can be carried by winds over long distances and thereby contribute to air quality problems outside the district or air basin where they originated. To address this, the Act directs the Air Resources Board (ARB) to assess the impacts of such transport and to establish mitigation requirements for upwind districts. The objective of this paper is to present ARB’s techniques for assessing the impacts of ozone transport within California.