1.   Although anthropogenic emissions of sulphur dioxide account for only half of the total global emission, they tend to be very concentrated.

2.   Government officials have acknowledged that existing policies to limit acidic emissions - notably of sulphur dioxide - are inadequate.

3.   The process uses a natural gas flame to break down the effluent into sulphur dioxide.

4.   Particular concern was caused by the fact that Kuwaiti crude included a high sulphur content, which would turn into sulphur dioxide on burning and fall as acid rain.

5.   Some dietary components such as bread, food preserved with sulphur dioxide, and alcoholic beverages such as beer, wine and cider are rich in sulphate.

6.   Nox, together with sulphur dioxide, is one of the leading contributors to acid rain pollution.

7.   The rain is rich in benzene and hydrocarbons, which can be carcinogenic, together with sulphur dioxide and other pollutants.