Overall change in emissions of acidifying substances by country, 1990-2007

The graph shows the change in emissions of acidifying pollutants (sulphur dioxide SO2, nitrogen oxides NOx and ammonia NH3) each weighted by an acid equivalency factor prior to aggregation to represent their respective acidification potentials. The acid equivalency factors are given by: w(SO2) = 2/64 acid eq/g = 31.25 acid eq/kg, w(NOx) = 1/46 acid eq/g = 21.74 acid eq/kg and w(NH3) = 1/17 acid eq/g = 58.82 acid eq/kg.