The graph below shows UK air pollutants, measured in million tonnes,

The line graph illustrates the amount of emissions released into the

air

from three different sources in the UK from 1990 to 2005.

Overall

, the total number of

air

pollutants decreased over the period examined.

This

change can be attributed to the decline in the level of

air

pollution in the industry and domestic sectors.

In addition

, the volume of

air

pollution emitted from transportation vehicles surpassed the industry sector as the most serious problem from 2002 onwards. In 1990, approximately 8

million

tonnes

of hazardous emissions were discharged from all three sectors.

Thereafter

, it decreased considerably to exactly 5

million

tonnes

in 2005. In a similar vein, the figure for the industry sector saw a drastic drop, falling from nearly 6

million

tonnes

in 1990 to precisely 2

million

tonnes

in the final year. Regarding the amounts of

air

pollutants caused by transport and households, both of them started at 1

million

tonnes

in 1990.

Subsequently

,

while

the latter remained at

this

level until 1999, the former had an upward fluctuation, rising to 1.2

million

in 1999. From 1999 onwards, the level of toxic gases emitted from the transport sector increased to exactly 3

million

tonnes

in 2005 ,

whereas

the figure for domestic activities declined to 0

million

tonnes

in the final year.