Change in total acidifying substance emissions since 1990 compared with the 2010 targets, EU15

Weighting factors are used to derive acid equivalent so that emissions of sulphur dioxide, nitrogen dioxide and NH 3 can be combined in terms of their acidifying effect: sulphur dioxide * 1 / 32 , nitrogen dioxide * 1 / 46 and ammonia * 1 / 17 . The emission data for Spain exclude emissions from Spanish overseas territories. targets.