PART 2Group A and Group B pollutants and ozone
CHAPTER 4Assessment
Assessment methods13
1
Subject to paragraph (2), the Secretary of State shall assess concentrations of a Group A pollutant by fixed measurement where—
a
the assessment takes place within an agglomeration; or
b
in any other zone, representative concentrations of that pollutant exceed the relevant upper assessment threshold.
2
Where the zone concerned is the same as that established under the Air Quality Limit Values Regulations 2003 M1 (“the 2003 Regulations”), the Secretary of State may continue to use the method by which concentrations of a Group A pollutant were assessed within that zone under the 2003 Regulations (“the 2003 method”).
3
Except where fixed measurement is required by paragraph (1) or he continues to use the 2003 method in accordance with paragraph (2), and, in the case of nitrogen dioxide, subject to the requirements imposed by regulation 15(7), the Secretary of State may assess concentrations of a Group A pollutant by any one of the following methods—
a
fixed measurement;
b
combined measurement; or
c
the sole use of modelling or objective estimation techniques, provided that representative concentrations of the pollutant in the zone concerned are below the relevant lower assessment threshold.
4
The Secretary of State shall assess concentrations of a Group B pollutant by fixed measurement in any zone in which representative concentrations of that pollutant exceed the relevant upper assessment threshold.
5
Except where fixed measurement is required by paragraph (4), the Secretary of State may assess concentrations of a Group B pollutant by one of the following methods—
a
fixed measurement;
b
combined measurement; or
c
the sole use of modelling or objective estimation techniques, provided that representative concentrations of the pollutant in the zone concerned are below the relevant lower assessment threshold.
6
For the purposes of paragraphs (1) and (3) to (5), the Secretary of State shall determine the representative concentrations in accordance with Part 3 of Schedule 4.
7
The Secretary of State shall review the method by which concentrations of a Group A or Group B pollutant are assessed at least once every five years or earlier if there are significant changes in activities affecting concentrations of the relevant pollutant within the zone concerned.
8
Where the Secretary of State continues to use the 2003 method, the date from which the period of review commences is the later of—
a
the date the zone was classified under regulation 7(1) of the 2003 Regulations; or
b
the date on which that classification was last reviewed under regulation 8 of those Regulations.
9
The Secretary of State shall assess concentrations of ozone by fixed measurement if, within the zone concerned, concentrations have exceeded a long-term objective during any of the previous five years of measurement.
10
Where fewer than five years' information on concentrations is available, the Secretary of State may assess concentrations of ozone by—
a
measurement campaigns of short duration at times and locations which he considers are likely to be typical of the highest pollution levels; and
b
results from emission inventories and modelling.