Geography Reference
In-Depth Information
The measures discussed above have been
confined to the Northern Hemisphere, where the
impact of acid precipitation has been most intense
and most extensive. By
c
. 1750, industrialisation
and the large-scale burning of fossil fuel were
occurring, so there have been nearly 250 years of
uncontrolled emissions of sulphurous and nitrous
acids. The impact has been particularly severe in
areas of acid bedrock (such as granite) that are in
receipt of air masses from industrialised regions.
While measures to curb acid precipitation have
facilitated a degree of ecosystem recovery in parts
of the temperate zone of the Northern
Hemisphere, the problem is now spreading into
the tropics as developing countries industrialise,
especially in Southeast Asia and China. Acid
precipitation is thus rapidly becoming an
environmental issue of global proportions.
THE NATURE OF THE PROBLEM
The chemistry of acid precipitation
Acid precipitation is produced when oxides of
sulphur and nitrogen combine with water in the
Figure 3.1
The formation
(simplified) of the major
components of acid rain in
the troposphere.
Source:
Mannion 1997.