The compliance challenge from measuring PM10 concentrations
The First Air Quality Daughter Directive (1999/30/EC) establishes limit values for ambient concentrations of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter (PM10) and lead. This includes a 24-hour PM10 compliance limit that entered into force in January 2005. This provision limits to 35 the number of exceedance days above a daily average concentration of 50 μg/m3. It was not long into that year before a number of Member States were expressing great concerns over their ability to meet this requirement at many of their measuring sites. At some locations the whole of January 2005 were exceedance days. The reaction to this was felt in a number of arenas, not least in the ongoing debate in the Council and Parliament over the finalisation of the Ambient Air Quality Directive which will ultimately replace the First Daughter Directive1. There has been much discussion over the implications of these compliance problems for the new Directive. In this article we explore the key issue of the measurement protocol that has undoubtedly contributed to these problems in a number of Member States.