The Indiana Department of Environmental Management (IDEM) has released the Criteria Pollutants Air Quality Trend Analysis Report (1980 - 2010). This report provides a detailed analysis of air quality trends in Indiana over the last thirty years. Each region of the state has a section in this report that provides detailed information including monitoring data, trend charts, health and environmental impacts, and health-based standards for the six criteria pollutants regulated under the Clean Air Act. The six criteria pollutants are particulate matter, sulfur dioxide, nitrogen dioxide, ozone, carbon monoxide, and lead. Each region does not necessarily monitor for each of the six criteria pollutants but all available data for each region is included in the presentation. These regions were developed to provide information that is more detailed so that readers can focus on the area of the state where they live and work. A detailed overview of the report can be found under the Air Quality Introduction link below. These regions have no policy or legal implications. Our goal is to present historical air quality data in an easy to read format.