In these Regulations—

• “ambient air” means outdoor air in the troposphere, excluding workplaces as defined by Council Directive 89/654/EECM1 where provisions concerning health and safety at work apply and to which members of the public do not have regular access;

• “AOT 40” (expressed in (μg/m³).hours) means the sum of the difference between hourly concentrations greater than 80 μg/m³ (= 40 parts per billion) and 80 μg/m³ over a given period using only the one-hour values measured between 0800 hours and 2000 hours Central European Time each day;

• “arsenic”, “cadmium”, “nickel” and “benzo(a)pyrene” mean the total content of those elements and compounds within the PM₁₀ fraction present in ambient air;

• F1“Directive 2004/107/EC” means Directive 2004/107/EC of the European Parliament and of the Council relating to arsenic, cadmium, mercury, nickel and polycyclic aromatic hydrocarbons in ambient air;

• F2“Directive 2008/50/EC” means Directive 2008/50/EC of the European Parliament and of the Council on ambient air quality and cleaner air for Europe;

• “fixed measurements” means measurements taken at fixed locations, either continuously or by sampling from time to time, to determine levels of pollutants in accordance with the relevant data quality objectives;

• “indicative measurements” means measurements which meet data quality objectives that are less strict than those required for fixed measurements;

• “margin of tolerance” means the percentage of the limit value by which that value may be exceeded in a given year;

• “oxides of nitrogen” means the sum of the volume mixing ratio (ppbv) of nitrogen monoxide (nitric oxide) and nitrogen dioxide expressed in units of mass concentration of nitrogen dioxide (μg/m³);

• “ozone precursor substances” means substances which contribute to the formation of ground level ozone;

• “PM₁₀” means particulate matter which passes through a size-selective inlet as defined in the reference method for the sampling and measurement of PM₁₀, EN 12341: 1998 M2, with a 50 per cent efficiency cut-off at 10 μm aerodynamic diameter;

• “PM_2.5” means particulate matter which passes through a size-selective inlet as defined in the reference method for the sampling and measurement of PM_2.5, EN 14907: 2005c, with a 50 per cent efficiency cut-off at 2.5μm aerodynamic diameter;

• “particulate matter” means PM_2.5 and PM₁₀;

• “pollutant” means any of the following:—

  1. a

     sulphur dioxide;

  2. b

     nitrogen dioxide;

  3. c

     oxides of nitrogen;

  4. d

     particulate matter;

  5. e

     lead;

  6. f

     benzene;

  7. g

     carbon monoxide;

  8. h

     arsenic;

  9. i

     cadmium;

  10. j

      mercury;

  11. k

      nickel;

  12. l

      benzo(a)pyrene or other polycyclic aromatic hydrocarbons;

  13. m

      ozone;

• “polycyclic aromatic hydrocarbons” means those organic compounds composed of at least two fused aromatic rings made entirely from carbon and hydrogen; and

• “total gaseous mercury” means elemental mercury vapour (Hg⁰) and reactive gaseous mercury, being water-soluble mercury species with sufficiently high vapour pressure to exist in the gas phase.

The Scottish Ministers are designated as the competent authority for the purposes of Directive 2008/50/EC (other than for the purpose specified in Article 3(f) of that Directive) and for the purposes of Directive 2004/107/EC.