Research Report 137, The Influence of Improved Air Quality on Mortality Risks in Erfurt, Germany, is the first study to come out of HEI's program on the health impact of regulatory and other actions to improve air quality, known as accountability. The report describes sweeping changes in the economy and energy use that occurred in the former East Germany after the 1990 reunification as a result of stricter environmental controls and modernization of industry, transportation, and household heating. Dr.