The present study comprises a large body of physical and chemical mass-related aerosol data which were collected over the industrialized basin of Leipzig, Germany, during the time period 1983 to 1997. For the period 1996/1997 consistent mass size distributions over the range 0.01 to 10 μm (PM10) were determined with a differential mobility analyzer and an aerodynamic particle sizer. The modal size distribution parameters were compared to similar lognormal data from the United States of the 1970s, yielding lower concentrations and coarse particle geometric diameters. In both accumulation and coarse mode, narrower distributions than over the United States were found which may be real or due to instrumental limitations in the 1970s. Within the range of measurement uncertainties and with reasonable assumptions about particle densities, chemical mass closure could be achieved with results of daily PM10 samples. However, the results of a harmonic analysis of the physical and chemical time series indicated that there may be significant aerosol components which were not covered by our analyses, possibly organic compounds. Since 1990 a significant downward trend in gravimetric mass concentration and since 1993 clear changes in aerosol composition were found which are consistent with similar findings in precipitation samples over eastern Germany. ¿ 1998 American Geophysical Union