Geography Reference
In-Depth Information
danger to human health. In Britain the burning of coal for heat in
urban areas during periods of calm weather in winter used to be
associated with 'smogs'. Smoke particles mixed with fog give smogs
a yellow colour. Smogs often settled over cities for many days.
During smog periods people suffered respiratory problems and
there were increased fatalities. One of the worst smog episodes in
Britain occurred in London on 4 December 1952. The smog lasted
for five days and resulted in approximately 4,000 more deaths than
usual. In response, legislation was developed to create smokeless
zones where coal burning was banned and this resulted in rapidly
improved urban conditions. However, the increased number of
vehicles within urban areas is now a widespread problem for urban
air quality, especially in regions that receive high amounts of the
Sun's energy such as Athens, Mexico City and Beijing. Here, the
ultraviolet radiation from the Sun reacts with vehicle emissions and
produces a photochemical smog which irritates the eyes, nose and
throat and creates a hazy atmosphere. During the Beijing Olympic
Games in 2008, officials were so worried about this potential effect
that they banned vehicles from large parts of the city, moved whole
factories, halted building construction and replaced coal boilers
with gas ones. This improved air quality substantially and has had
long term beneficial effects upon the city.
SUMMARY
• Theclimatesystemisacloselyintegratedsysteminvolvingthe
atmosphere, oceans, land surface and vegetation.
• TheSunheatsuptheEarth'ssurfacewhichinturnwarmsthe
atmosphere from below.
• Greenhousegasestrapsomeofthisheatsothatatnight-timeit
does not all escape back into space.
• TheenergysurplusfromtheSunattheequatorandthedeicit
at the poles creates an imbalance that leads to heat transfers
through air and water.
• TheEarth'srotationhasalargeimpactonairandwatermove-
ments while the Earth's tilt causes seasonal differences in the
receipt and redistribution of the Sun's energy.
• Thereisazoneofmoist,warmascendingairneartheequator
which yields a plentiful rainfall supply.
