Primer on Automobile Fuel Efficiency and Emissions - Pollution Probe

Environmental Problems Associated with the Automobile
If emissions were of no health or environmental consequence, then we would not be concerned about them.
However, as detailed previously in Table 1-1, automobile emissions need to be taken very seriously. Of great concern
are the greenhouse gas emissions that trap heat in our atmosphere and contribute to climate change. Other emissions
combine to form smog that threatens the quality of our air and the health of our environment. Even the
health of our lakes and oceans is threatened
by automobile emissions: NOx and
GRAPH 1-1
Atmospheric Build-up of CO
SOx emissions contribute to the formation
of acid rain, while excess CO2 in the
2
(1750-2000)
(Source: ARIC, Atmosphere, Climate & Environment Information Programme)
atmosphere is absorbed into the oceans
forming carbonic acid that can negatively
360
impact coral reefs and marine ecology.
Climate Change -
The Greenhouse Effect
Atmospheric concentration of CO2 –
parts per million (ppm)
340
320
300
Energy from the sun drives the Earth’s climate.
As the sun’s energy reaches the Earth’s
280
surface, some of it is reflected back and
260
some of it is absorbed. The absorbed energy
warms the Earth and is then radiated back
Year
out towards space as infrared energy. Certain
chemical compounds in the Earth’s atmosphere act as “greenhouse gases,” absorbing the radiated infrared energy
and thereby trapping some of the heat in the atmosphere, which then warms the Earth’s surface to an average of
14°C. This phenomenon, called the “natural greenhouse effect,” keeps the Earth in a temperature range that
allows life on this planet to thrive. Without it, the sun’s heat would escape and the average temperature of the
Earth would drop to -19°C. However, any changes in the atmospheric greenhouse gas concentrations will affect
the amount of energy stored in the atmosphere and disrupt the balance of the global climate system. For example,
when the amount of carbon dioxide – a major greenhouse gas – is increased, more heat is trapped in the atmosphere.
1750 1800 1850 1900 1950 2000
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Chapter 1 | Emissions from Automobiles