Environmental Engineering Reference
In-Depth Information
Figure 4.4
Sulphur dioxide emissions in selected countries: 1970-89
Source:
Based on data in World Resources Institute (1992)
every year, or almost double that produced in
North America (Barrie 1986). In Asia, Japanese
industries emit large quantities of SO
2
(Park
1987), while the industrial areas of China are
also major contributors. Annual emissions of SO
2
in China average 15 million tonnes, but have been
as high as 24 million tonnes (Glaeser 1990).
Sulphur dioxide emission levels in the western
industrialized nations peaked in the mid-1970s
or early 1980s, and have declined significantly
since then (see Figure 4.4). In Britain, for
example, the output of SO
2
decreased by 35 per
cent between 1974 and 1990 (Mason 1990).
Similar declines in SO
2
have been recorded for
North America and western Europe, and that
trend is likely to continue as new environmental
regulations are introduced and enforced. In
contrast, emissions of NO
X
continue to rise. This
may be due in part to increased automobile
traffic, but it also reflects the limited attention
given to NO
X
reduction in most acid pollution
control programmes. The trends are less clear
and more difficult to forecast outside western
Europe and North America. As long as the
economic and political disarray continues in
eastern Europe and the former Soviet Union, it
is unlikely that pollution control programmes will
be given top priority, and acid gas emissions are
likely to remain high or even increase. Chinese
economic development will continue to be fuelled
by low-quality, sulphur-rich coal, leading to
increased local and regional levels of atmospheric
acidity (Glaeser 1990). In contrast, Japan—the
leading industrial nation in Asia—was quick to
install pollution control equipment to reduce SO
2
and NO
X
levels in the 1980s (Ridley 1993), and
the decline in emissions there is likely to continue.
The problem of acid rain has received less
attention in Asia than in Europe or North
America, but a new study initiated in 1992 under
