Particulate matter (PM10) daily limit value
In order to ensure protection against harmful effects on human health a 50 µg/m3 daily limit value for particulate matter (PM10) became effective on 1 January 2005 (Council Directives 1999/30/EC and 2008/50/EC). This value may not be exceeded on more than 35 days per year.
Preliminary character of data
Regular hourly measurements of PM concentrations are taken at many stations to provide up-to-date information for the public. However, the reference method practiced throughout Europe is based on the deposition of the PM10 fraction on a filter and gravimetric determination of mass (mass measurement of filters in the laboratory). This is why the PM10 values determined according to the method are only available about one month later. The “Recent measuring” column takes account of the different measurement methods used. The date indicated provides the last date counted for the number of exceedance days.
Data is initially considered preliminary and is subject to change pending quality assurance measures. Earlier data is gradually replaced by quality-assured data, and preliminary data is reviewed (and corrected if necessary) at a later date by the competent bodies in the German States according to a standardised European procedure. The adjusted data provides the basis for a final evaluation. Besides the preliminary character of the measurement data one should keep in mind that there may be gaps in the data records. This can be due to failures in data transmission from state measurement networks to the German Environment Agency or even in transmission from an individual measuring station to the appropriate monitoring centre. Another cause can be a malfunction of the measuring instruments themselves.
The table is updated daily. A possible exceedance of the daily mean on a given day is reflected in the German Environment Agency table no earlier than the following day.