Twelve European Member States exceeded one or more of the emission limits set by the EU National Emission Ceilings (NEC) Directive, according to recent official data for 2010 reported to the European Environment Agency (EEA). In some instances the limits were exceeded by significant amounts. The pollutant for which most exceedances were registered was NOx.
The European Union sets Limit Values for a range of pollutants that are considered to be harmful to health and the environment. The European Commission can take action against any Member State if the air quality does not meet the Limit Values throughout its territory.
At present there are two health based objectives that have been set for nitrogen dioxide. The first is to make sure hourly concentrations do not go above 200 µg/m3 for more than 18 hours in any year. The second objective is to ensure that the annual average is no greater than 40 µg/m3.
Air quality in many large cities in England and Wales does not meet the European annual average Limit Value for nitrogen dioxide. In central London, air quality adjacent to some busy roads does not meet the hourly average Limit Value for nitrogen dioxide.
All local authorities in England and Wales have a statutory duty to assess air quality. This is detailed in the Environment Act 1995. If levels of pollution don‘t meet the objectives set by the Government, the area must be declared an Air Quality Management Area and an action plan implemented to bring levels of pollution down.
According to the 'City of London Air Quality Strategy 2011-2015' objectives for nitrogen dioxide and PM10 in the City are not being met. Therefore, The City has been designated an Air Quality Management Area for these two pollutants
Notes: EU Limit values are legally binding EU parameters that must not be exceeded. Limit values are set for individual pollutants and are made up of a concentration value, an averaging time over which it is to be measured, the number of exceedences allowed per year, if any, and a date by which it must be achieved. Some pollutants have more than one limit value covering different endpoints or averaging times.
UK Emissions of NOx
Predicted annual average nitrogen dioxide across the city, 2015