LONG-TERM AEROSOL MEASUREMENTS

One of the main topics addressed by the PULE community has, right from the early days of the method, been the measurements of the elemental content in ambient aerosols. The available time series of measurements cover in many cases now more than one decade. Examples of the use of these data are shown by using the results of daily measurements from 1 979 to 1994 in urban and rural areas in Denmark. The cyclic variations as well as the trends of the concentrations are described by using i. a. simple time-series analyses based on auto-correlation. Characterist ic weekly and annual variations are shown for different elements. A st rongly decreasing trend is seen for Pb, while the concentrations of ot her heavy metals and particulate sulphur are only slightly decreasing or almost constant, but it varies with the source areas.