The line chart illustrates three different sources of emissions that caused air pollution, namely industry, households and transport and the total air pollutants in the UK over a period of 15 years, starting from 1990.
Overall, emissions from industry and households decreased significantly throughout the period, contributing to the dramatic decline in the total of pollutants. Transport emissions, however, witnessed a reverse trend. Industrial sources consistently produced the highest level of emissions, whereas household waste remained the lowest contributor.
Regarding the decreasing figures, the industry sources began the period at approximately 6 million tonnes. Over the next six years, this figure halved to around 3 million tonnes, before continuing to decline gradually and reaching a low of 2 million tonnes by 2005. Despite the significant downturn, they consistently recorded the highest emissions throughout the timeframe. Similarly, household-related air pollution also gradually dropped from 1 to 0.5 million tonnes at the beginning. Nevertheless, it experienced a fluctuation around 0.3 million tonnes by 1996, and then continued to go down by the end. Notably, household waste remained the lowest contributor to air pollution during the entire period. Because of the sharp drop in both sources, the total number of pollutants also experienced a substantial decline of about 4 million tonnes by the end.
In contrast, the quantity of pollutants from transport accounted for 1 million tonnes in 1990, converging with the figures of household sources. Unlike the downward trend seen in other sources, transport pollutants gradually increased, followed by a slight dip. However, they started to go up again after 4 years of reduction and stayed around 1.5 million tonnes by the end of the period, with only a negligible decrease in the final years.