This document consists of the attainment demonstration, maintenance plan, and redesignation to attainment request for the Douglas Sulfur Dioxide (SO2) Nonattainment Area. The purpose of this document is to demonstrate how the State of Arizona has met the National Ambient Air Quality Standards for SO2 and intends to maintain compliance with the NAAQS in the Douglas area. Air quality standards are divided into two types: primary standards based on health effects and secondary standards based on environmental effects such as damage to property, plants, visibility, etc. Both standards are established by EPA for criteria air pollutants such as sulfur dioxide.