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UNIT 1: WHERE DO WE STAND? THE STATE OF THE GLOBAL ENVIRONMENT
025
The major emitters of acidic gases today are India, China, the USA and the east
European economies in transition.
SO2 emissions from fossil fuel burning
1980 1990 1995 2000 2010
(millions of tonnes of sulphur dioxide)
Europe 59 42 31 26 18
United States 24 20 16 15 14
Asia 15 34 40 53 79
Note: per capita emissions in Asia are still many times lower than
those in Europe or the United States
Source: Worldwatch Institute 1998
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Impacts of Acid Deposition
• Acid deposition affects human health. Sulphur dioxide interacts in the
atmosphere to form sulphate aerosols, which can be transported long
distances through the air. Most sulphate aerosols can be inhaled: high
concentrations are associated with respiratory and lung disorders such
as bronchitis and asthma.
• Acid rain increases the acidity and lowers the pH of surface water
bodies such as lakes and streams that have a limited ‘buffering
capacity’, or ability to neutralise acid compounds. An increase in the
acidity of lakes in Scandinavia and Canada has led to the complete
eradication of some species of fish. Acidity also affects acid-tolerant
aquatic invertebrates by changing them from high-calcium-bearing
prey to low-calcium-bearing. Furthermore, high acidity increases the
amounts of toxic heavy metals in invertebrates that are prey to
numerous species of water-breeding birds. The combination of these
two effects can lead to serious disruptions further along the food chain
and affects the reproduction and survival of many species of aquatic
fauna.
• Acid rain is also linked to impaired tree growth and therefore causes
forest degradation. For example, acidic cloud water at high elevations
is reported to increase the susceptibility of red spruce trees to winter
injury. This is significantly impairing the health of high-elevation
spruce forests in Northern America and Northern Europe.
• There are also concerns about the impacts of acid rain on forest soil. As
it passes through soil, it can strip away vital plant nutrients: this poses
further threats to forest growth and productivity.
• Acid rain and dry deposition contribute to increased corrosion of
materials and the deterioration of stone and paintwork on buildings,
structures and vehicles. US car manufacturers use acid-resistant paints
at a cost of five dollars per vehicle (a total of $61m a year) to
reduce acid deposition damage to paintwork. Dry deposition also
increases the dirt on buildings and structures, resulting in increased
maintenance costs.
Forest damage
and the loss
of species due
to acidification
mean the
degradation
of some of
the tourism
industry’s
primary
resources.