4.—(1) This Part applies in respect of the following pollutants:–
(a)Group A pollutants;
(b)Group B pollutants; and
(c)ozone.
(2) The Scottish Ministers shall ensure that all measures taken under Chapters 2 or 3 of this Part–
(a)take into account an integrated approach to the protection of air, water and soil; and
(b)have no significant negative effect on the environment in–
(i)any other member State; or
(ii)any other part of the United Kingdom.
5.—(1) The Scottish Ministers shall, for the purposes of this Part, divide the territory of Scotland into zones.
(2) A zone shall be classified as an agglomeration for the purposes of this Part where–
(a)it has a population in excess of 250,000 inhabitants; or
(b)in any other case, the Scottish Ministers determine that its population density per km2 is sufficiently high to justify such a classification.
(3) The Scottish Ministers may establish different zones for different pollutants where they consider this appropriate.
6.—(1) Schedule 1 prescribes the following air quality standards–
(a)for Group A pollutants, the limit values set out in Part 1 of that Schedule;
(b)for Group B pollutants, the target values set out in Part 3 of that Schedule; and
(c)for ozone, the target values and long-term objectives set out in Part 4 of that Schedule.
(2) Limit values–
(a)shall be attained by the attainment date specified for the limit value concerned; or
(b)apply when these Regulations come into force if no attainment date is specified.
(3) Target values shall be attained from the attainment date specified, in so far as this is possible through measures required by regulation 7.
(4) In the case of benzene and nitrogen dioxide, the margins of tolerance set out in Part 2 of Schedule 1 apply within the periods specified.