3.—(1) In this regulation “the reference method” means the reference method specified in Annex V to the Directive.
(2) The Secretary of State shall ensure that, at the measuring stations designated or established in accordance with regulation 2 above, concentrations of ozone in the ambient air are measured using either—
(a)the reference method, or
(b)any other method of analysis shown to produce measurement results equivalent to those obtained using the reference method.
(3) The Secetary of State shall designate one or more laboratories to be responsible for evaluating, in relation to the reference method, the methods of analysis used in the United Kingdom.
(4) The Secretary of State shall organise, at national level, intercomparisons between laboratories taking part in the collection and analysis of the data obtained from carrying out the measurements referred to in paragraph (2) above.