14.—(1) Where the Scottish Ministers assess concentrations of a Group A or Group B pollutant by fixed measurement, whether alone or as part of combined measurement, they shall ensure that–
(a)measurements of the relevant pollutant are taken at sampling points either continuously or by random sampling, subject, in the case of nitrogen dioxide, to the requirements imposed by regulation 15(7); and
(b)the number of measurements is sufficiently large to enable concentrations of that pollutant to be properly determined.
(2) Where the Scottish Ministers assess concentrations of a Group A or Group B pollutant by fixed measurement, they may supplement information from sampling points for fixed measurement with information from modelling techniques in so far as they consider this will provide an adequate level of information on ambient air quality.
(3) Where the Scottish Ministers assess concentrations of ozone by fixed measurement–
(a)they shall ensure that–
(i)the measurements are taken at fixed sites continuously; and
(ii)the number of measurements is sufficiently large to enable concentrations to be properly determined;
and
(b)they may supplement information from sampling points with information from modelling techniques or indicative measurements.