The line graph illustrates the changes in UK air pollutant emissions from three distinct sources—industry, transport, and households—between 1990 and 2005, measured in million tonnes.
Overall, the total volume of pollutants fell consistently throughout the fifteen-year period. A notable divergence occurred in the trends for different sectors, as industrial and household emissions decreased, whereas transport-related pollution rose significantly.
In 1990, industry was the primary source of pollution at 5.8 million tonnes, significantly higher than transport and households, which both stood at 1.0 million tonnes. Industrial emissions followed a downward trajectory, dropping to 2.0 million tonnes by 2005. Similarly, household emissions remained stable at 1.0 million tonnes until 1999, before declining to zero by the end of the period.
Conversely, transport emissions showed a different pattern. After fluctuating between 1.0 and 1.5 million tonnes in the 1990s, they climbed steadily to reach 2.9 million tonnes in 2005, overtaking industry as the largest source of pollution. Consequently, the total pollutant output dropped from 7.8 million tonnes in 1990 to 4.9 million tonnes in 2005, reflecting the substantial impact of reduced industrial activity on overall air quality.