GEO Brasil - UNEP

the state of the atmosphere
The resulting emissions of fossil fuel burning generate, for
example, immediate local impacts resulting in breathing
problems, destruction of plantations and material
deterioration These same emissions also contribute to the
aggravation of problems felt in a global scope such as the
increase of the greenhouse effect Similarly, the emission
of some gases also contributes to the aggravation of
problems such as the decrease of the ozone layer, a problem
with global effects
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Main Atmospheric Pollutants and their
Impacts on Living Beings
Thermal plants, petrol refineries, steel industries and cement
factories emit great amounts of gases into the atmosphere
Automobiles also throw an infinity of quite harmful gases
into the atmosphere, as for example, carbon monoxide and
dioxide, sulfur dioxide and the gaseous hydrocarbonates
Carbon monoxide is a gas that originates mainly from the
incomplete combustion of fossil fuels The main sources
are automobiles because optimum combustion conditions
are not always obtained This gas is classified as of
systematic suffocation, because it is a substance which
harms the oxygenation of tissues High levels of carbon
monoxide are related to mental confusion, reflex damage,
unconsciousness, brain functions stop and, in extreme
cases, death (CETESB 1999)
Sulfur dioxide originates mainly from processes in which
there is oil fuel burn, coal burn and in Diesel engines In the
living beings, high levels of the gas cause breathing
discomfort, and the aggravation of breathing and
cardiovascular problems, as well as it may lead to the
formation of acid rain, causing several effects on the
environment (CETESB 1999)
the state of the environment in Brazil
In short, atmospheric pollutants are substances that, in
result of their abnormal concentrations, can turn the air
dangerous to living beings’ health, harmful to fauna, to
flora or to materials They may appear straight into the
atmosphere, from the emissions of these substances, or
indirectly, through chemical reactions in the atmosphere
Such reactions loccur due to the concentration increase of
certain gases
The pollutants cause degradation of air quality when present
in amounts superior to the absorption capacity of the
environmental Thus, the amounts of pollutants present in
the air pay direct influence in its quality However, at local
level, the magnitude of their emissions is not the only
decisive factor of air quality The interaction between the
pollutants and the atmosphere, considering the
meteorological variables which will influence in the dilution
capacity of these pollutants in the air, also contributes to
the definition of air quality level in a region
There is a quite high group of gases that, under certain
conditions, may be classified as pollutants, or that may
contribute to its formation Among those which cause the
greatest environmental problems in the atmosphere, at local
extent, the carbon monoxide (CO), sulfur dioxide (SO 2
),
nitrogen dioxide (NO 2
), troposphere ozone (O 3
) and
particulate materials should be pointed out
Nitrogen dioxide mainly comes from combustion
processes in vehicles, in industries and in thermal plants,
which use oil fuel or natural gas In living beings, high gas
concentrations are associated to problems such as asthma,
bronchitis and low resistance to breathing infections High
concentrations of nitrogen dioxide may also lead to the
formation of acid rain (CETESB 1999)
Troposphere ozone is not emitted directly into the
atmosphere; being produced photochemically by solar
radiation on the nitrogen oxides and volatile organic
compounds Therefore, it originates mainly from automobile
exhaust gases and from industrial pollution, and found in
larger concentrations in urban areas The gas is also a
consequence of vegetation burns when, its concentration
rises, reaching high levels, particularly in regions such as
the Amazon
Ozone is a gas that presents several functions, according to
the altitude it is at In the troposphere it behaves as a toxic
gas, which in high concentrations is harmful to living beings
and to man in particular, causing eye irritations and a series
of breathing problems Besides, high concentrations of
ozone can also result in damages to plantations and to the
natural vegetation (KIRCHHOFF 1989)
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