For the purposes of this Directive, the following definitions apply:
(1)((1)) ‘emission’ means the release of a substance from a point or diffuse source into the atmosphere;
(2)((2)) ‘anthropogenic emissions’ means atmospheric emissions of pollutants associated with human activities;
(3)((3)) ‘ozone precursors’ means nitrogen oxides, non-methane volatile organic compounds, methane, and carbon monoxide;
(4)((4)) ‘air quality objectives’ means the limit values, target values and exposure concentration obligations for air quality set out in Directive 2008/50/EC and Directive 2004/107/EC of the European Parliament and of the Council (^{12});(^{1});
(5)((5)) ‘sulphur dioxide’ or ‘SO_{2}’ means all sulphur compounds expressed as sulphur dioxide, including sulphur trioxide (SO_{3}), sulphuric acid (H_{2}SO_{4}), and reduced sulphur compounds such as hydrogen sulphide (H_{2}S), mercaptans and dimethyl sulphides;
(6)((6)) ‘nitrogen oxides’ or ‘NO_{x}’ means nitric oxide and nitrogen dioxide, expressed as nitrogen dioxide;
(7)((7)) ‘non-methane volatile organic compounds’ or ‘NMVOC’ means all organic compounds other than methane, that are capable of producing photochemical oxidants by reaction with nitrogen oxides in the presence of sunlight;
(8)((8)) ‘fine particulate matter’ or ‘PM_{2,5}’ means particles with an aerodynamic diameter equal to or less than 2,5 micrometres (μm);
(9)((9)) ‘black carbon’ or ‘BC’ means carbonaceous particulate matter that absorbs light;
(10)((10)) ‘national emission reduction commitment’ means the Member States' obligation in the reduction of emissions of a substance; it specifies the emission reduction that as a minimum has to be delivered in the target calendar year, as a percentage of the total of emissions released during the base year (2005);
(11)((11)) ‘landing and take-off cycle’ means the cycle that includes taxi in and out, take-off, climb out, approach, landing and all other aircraft activities that take place below the altitude of 3 000 feet;
(12)((12)) ‘international maritime traffic’ means journeys at sea and in coastal waters by water-borne vessels of all flags, except fishing vessels, that depart from the territory of one country and arrive in the territory of another country;
(13)((13)) ‘pollution control zone’ means a sea area not exceeding 200 nautical miles from the baselines from which the breadth of the territorial sea is measured, established by a Member State for the prevention, reduction and control of pollution from vessels in accordance with applicable international rules and standards;
(14)((14)) ‘Union source-based air pollution control legislation’ means Union legislation which aims at reducing the emissions of air pollutants covered by this Directive by undertaking mitigation measures at the source.