The line graph illustrates the amount of air pollutants emitted in the UK from four different sources, namely industry, transport, households, and the total level of pollution, between 1990 and 2005.
Overall, the total volume of air pollutants decreased significantly over the period. Industry was the largest contributor throughout the years, although its emissions fell considerably. By contrast, transport emissions remained relatively stable, while pollution from households declined steadily and became the smallest source by 2005.
In 1990, the total amount of air pollutants stood at approximately 7 million tonnes. This figure fell continuously over the following years, reaching around 4 million tonnes in 1999 before declining more gradually to about 3.3 million tonnes in 2005.
A similar trend can be seen in industrial emissions. Starting at roughly 5.5 million tonnes in 1990, pollution from industry dropped slightly to 5 million tonnes in 1993 and then decreased sharply to 3 million tonnes in 1996. It continued to fall, ending at only 2 million tonnes in 2005.
In comparison, transport emissions showed little variation during the period. They increased marginally from about 0.8 million tonnes in 1990 to around 1 million tonnes in 2005. Household emissions, however, declined steadily from approximately 0.8 million tonnes to just 0.2 million tonnes, making it the least significant source of pollution at the end of the period.