so
as defined in Directive (EU) 2016/2284 of the European Parliament and of the Council of…, Article 3, point (5) (Definitions)
(5)
‘sulphur dioxide’ or ‘SO2’ means all sulphur compounds expressed as sulphur dioxide, including sulphur trioxide (SO3), sulphuric acid (H2SO4), and reduced sulphur compounds such as hydrogen sulphide (H2S), mercaptans and dimethyl sulphides;