The line graph illustrates the levels of acid rain emissions in the UK, measured in millions of tonnes, produced by four sectors between 1990 and 2007.
Overall, total emissions declined markedly over the period. The electricity, gas and water supply sector was the largest source at the beginning, but it experienced the most dramatic fall. In contrast, transport and communication showed only slight fluctuations, while domestic emissions remained the lowest throughout and decreased steadily.
In 1990, emissions from electricity, gas and water supply stood at about 3.3 million tonnes, making it by far the biggest contributor. This figure dropped sharply during the 1990s, reaching roughly 1.3 million tonnes by 1997 and then falling further to around 0.5 million tonnes by 2007.
A similar downward trend can be observed in other industries, where emissions decreased gradually from just over 2.0 million tonnes in 1990 to approximately 1.2 million tonnes at the end of the period.
By comparison, transport and communication emissions fluctuated between about 0.7 and 1.0 million tonnes, peaking slightly in the mid-2000s before ending at around 0.7 million tonnes. Meanwhile, domestic emissions declined steadily from roughly 0.6 million tonnes in 1990 to about 0.2 million tonnes in 2007.