Environmental Engineering Reference
In-Depth Information
on deaths a year. Among all endemic diseases, including diarrhea, ARI is the most
pervasive cause of chronic illness.
The living conditions that expose people to high levels of indoor air pollution
have been well documented in Africa. The majority of sub-Saharan Africans live
in rural areas. In Kenya, for example, only about 20% of the population lives in
towns and cities. Family homes generally consist of small multipurpose buildings
where the same room or few rooms are used for cooking, sleeping, and working.
In many cases the total indoor volume is less than 40 m
3
. In the extreme case of
Masai homes in Kenya, indoor air volumes in the cooking area can be consistently
less than 20 m
3
. Also, rural cooking houses often have minimal ventilation.
Different fuel and stove combinations have widely different indoor levels of
emissions, not only because stoves are more efficient and therefore take less time
to cook but also because fuels are so different.
These are pollution problems that often originate in cities but then spread over oth-
er geographical areas, frequently crossing national boundaries.
The main regional problems are as follows:
- Acid rain, causing a deposition of sulfuric (H
2
SO
4
) and nitric (HNO
3
) acids and formed
by the reaction of water (rain, snow, etc.) with SO
2
and NO
2
. SO
2
originates in impurit-
ies present in fossil fuels and NO
2
is produced by the combustion of these fuels at high
temperatures, leading to a combination of nitrogen and oxygen, both of which are part
of the atmosphere.
- Pollution of seas and transboundary water bodies through oil leakages and other leak-
ages in interstate or international waters. These leakages result in contamination of un-
derground aquifers via the percolation of toxic substances. The sea is the ultimate sink
for most of the liquid wastes and a considerable fraction of the solid wastes resulting
from human activities on land. More than three-quarters of all marine pollution comes
from land-based sources, through drainage and discharge into rivers, bays, and the open
coast, and from the atmosphere. The remaining sources of marine pollution are ship-
ping, dumping, and offshore mining and oil production, which are energy related.
Concerns about acidification damage were raised in Sweden more than 30 years
ago, when the declining fish population in rivers and lakes appeared to be connec-
ted to changes in acidity of the water, as measured by an indicator named pH.
