The NEC Directive was adopted in 2001 in order to limit the
negative environmental impacts of acidification, eutrophication
and ground–level ozone, by establishing for each Member State for
2010 a cap on emissions of sulfur dioxide (SO2), nitrogen oxides
(NOX), non–methane volatile organic compounds (NMVOC) and
ammonia (NH3). Parallel to the development of the EU NEC
Directive, the EU Member States together with Central and Eastern
European countries, the United States and Canada have negotiated
the "multi–pollutant" protocol under the Convention on Long–
Range Transboundary Air Pollution (the so–called Gothenburg
protocol, agreed in November 1999). Between 1990 and 2010,
significant cuts on emissions of several air pollutants were
achieved in the EU: SO2 emissions were reduced by 82%, NOX
emissions by 47%, NMVOC emissions by 56% and NH3 emissions by
28% between 1990 and 2010 (EEA, 2014).