Paragraph 4 I1
England and Wales
An hourly mean is a mean calculated every hour. F1The hourly mean for a particular substance at a particular location for a particular hour is the mean of the levels recorded for that substance at that location:
(a)
in the case of benzene, at a frequency of not less than once during the hour; and
(b)
in the case of carbon monoxide, nitrogen dioxide and sulphur dioxide, at a frequency of not less than once every 10 seconds during the hour.
Annotations
Textual amendments
- F1
Words in Sch. Pt. 2 para. 4 substituted (31.12.2002) by The Air Quality (Amendment) (Wales) Regulations 2002 (S.I. 2002/3182), regs. 1(1), 2(3)(c)
Commencement
- I1
Sch. Pt. 2 para. 4 in force at 1.8.2000, see reg. 1(1)