The line graph illustrates the information about the amount of toxic substances in the air in four different categories in UK over a period of 15 years.
Overall, while the quantity of total air pollutants and industrial emissions decreased considerably throughout the period, the figure for transport pollutants remained stable, and fluctuations were seen in the number of contaminants in the bracket of households.
In 1990, more than 7 million tons of hazardous materials were reported in total, whereas the biggest share was demonstrated by industry, constituting 5.5 million tons. Meanwhile, both figures went down marginally in the next three years, and it was followed by a significant decline in 1996. Afterwards, the amount of total contaminants in the air and industrial polluting compounds dropped progressively, translating to 3 million and 2 million tons respectively in 2005.
As far as the level of deleterious substances that were released from transport is concerned, only 1 million tons of air pollutants were discharged by transport sector, and this figure plateaued during 15 years. Finally, households had been the least polluting group among others, beginning with almost 1 million tons of detrimental materials in the air. After variations in the quantity of toxic substances, the final figure was nearly equal to 0 in 2005.