| Air Quality in Postunification Erfurt, East Germany: Associating Changes in Pollutant Concentrations with Changes in Emissions Stefanie Ebelt,1 Michael Brauer,1 Josef Cyrys,2 Thomas Tuch,2 Wolfgang G. Kreyling,3 H.-Erich Wichmann,2
and Joachim Heinrich2 1The University of British Columbia, School of Occupational and Environmental Hygiene, Vancouver, British Columbia, Canada
2GSF-National Research Center for Environment and Health, Institute of Epidemiology, Neuherberg, Germany
3GSF-National Research Center for Environment and Health, Institute of Inhalation Biology, Neuherberg, Germany Abstract
The unification of East and West Germany in 1990 resulted in sharp decreases in emissions of major air pollutants. This change in air quality has provided an opportunity for a natural experiment to evaluate the health impacts of air pollution. We evaluated airborne particle size distribution and gaseous co-pollutant data collected in Erfurt, Germany, throughout the 1990s and assessed the extent to which the observed changes are associated with changes in the two major emission sources: coal burning for power production and residential heating, and motor vehicles. Continuous data for sulfur dioxide, total suspended particulates (TSP) , nitric oxide, carbon monoxide, and meteorologic parameters were available for 1990-1999, and size-selective particle number and mass concentration measurements were made during winters of 1991 and 1998. We used hourly profiles of pollutants and linear regression analyses, stratified by year, weekday/weekend, and hour, using NO and SO2 as markers of traffic- and heating-related combustion sources, respectively, to study the patterns of various particle size fractions. Supplementary data on traffic and heating-related sources were gathered to support hypotheses linking these sources with observed changes in ambient air pollution levels. Substantially decreased (19-91%) concentrations were observed for all pollutants, with the exception of particles in the 0.01-0.03 µm size range (representing the smallest ultrafine particles that were measured) . The number concentration for these particles increased by 115% between 1991 and 1998. The ratio of these ultrafine particles to TSP also increased by more than 500%, indicating a dramatic change in the size distribution of airborne particles. Analysis of hourly concentration patterns indicated that in 1991, concentrations of SO2 and larger particle sizes were related to residential heating with coal. These peaks were no longer evident in 1998 due to decreases in coal consumption and consequent decreased emissions of SO2 and larger particles. These decreases in coal combustion and the decreased concentrations of SO2 and particles of larger size classes may have led to decreased particle scavenging and may be partially responsible for the observed increases in ultrafine particles. Traffic-related changes, such as increased numbers of trucks and increased use of diesel vehicles in Erfurt, were also associated with increased number concentrations of ultrafine particles. Morning particle peaks of all sizes were associated with NO and CO (markers for traffic) in both the 1991 and 1998 periods. There were significant differences in the ultrafine particle levels for morning hours between 1991 and 1998, suggesting that traffic was the cause of this increase. Key words: air pollution, coal combustion, environmental exposure, motor vehicles, particles, sulfur dioxide, ultrafine particles. Environ Health Perspect 109:325-333 (2001) . [Online 7 March 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p325-333ebelt/ abstract.html Address correspondence to M. Brauer, The University of British Columbia, School of Occupational and Environmental Hygiene, 2206 East Mall, Vancouver, BC V6T 1Z3 Canada. Telephone: (604) 822-9585. Fax: (604) 822-9588. E-mail: brauer@interchange.ubc.ca Research described in this article was supported in part by the Health Effects Institute (research agreement 95-10) , an organization jointly funded by the U.S. Environmental Protection Agency and automotive manufacturers. Funding was also provided by a Career Investigator Award from the American Lung Association and a Scientist Award from the Medical Research Council of Canada and the British Columbia Lung Association to M. Brauer. Received 29 June 2000 ; accepted 17 October 2000.
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