The UK's 15-minute mean objective for SO2 - which allows 15-minute concentrations to exceed 266µg/m3 only 35 times a year - has been exceeded in Grangemouth every year for the past four years, but pollution levels are falling and there have only been four exceedences so far this year.
The council and SEPA had disagreed over the need for an AQMA. Recent and ongoing investment in pollution abatement at the nearby BP/Innovene petrochemicals complex has seen emissions from the plant decline and the council believes this will be adequate to ensure compliance by the end of this year.
SEPA, for its part, is unhappy with uncertainties in the modelling of the pollution and the high number of unattributable exceedences. The AQMA declaration will prompt more detailed assessment work to get to the bottom of the sources.
BP says that none of the four exceedences recorded by the council this year have been attributed to emissions from its complex.