4.—(1) The National Assembly must take the measures necessary to ensure that throughout Wales in each zone concentrations of relevant pollutants in ambient air, as assessed in accordance with regulations 5 to 8, do not exceed the limit values set out in Schedule 1—
(a)where a date is specified in that Schedule in relation to the limit value for that pollutant, from that date;
(b)in any other case, from the date on which these Regulations come into force.
(2) The measures taken must—
(a)take into account an integrated approach to the protection of air, water and soil;
(b)not contravene Community legislation on the protection of the safety and health of workers at work; and
(c)have no significant negative effects on the environment in the other Member States.