4. Part 3 of schedule 1 is amended as follows—
(a)for paragraph 1(a) and (b) substitute—
“(a)the flow around the inlet sampling probe must be unrestricted (in general free in an arc of at least 270°, or 180° for sampling points at the building line) without any obstructions affecting the airflow in the vicinity of the inlet. The inlet sampling probe must normally be some metres away from buildings, balconies, trees and other obstacles and at least 0.5 m from the nearest building in the case of sampling points representing air quality at the building line;
(b)in general, the inlet sampling point must be between 1.5 m (the breathing zone) and 4 m above the ground. Higher siting may also be appropriate if the station is representative of a large area. Any derogations must be fully documented;”;
(b)at the end of paragraph 1(e) add “A ‘major junction’ is a junction which interrupts the traffic flow and as a result causes different emissions from the rest of the road.”; and
(c)after paragraph 1 insert—
“1A. Any deviation from the criteria set out in this Part must be fully documented through the procedures described in Section D of Annex III to Directive 2008/50/EC.”.