Environmental Issues
Pollution is the undesirable change brought about by chemical, particulate
matter, or biological materials to air, water, or soil.
Air Pollution
● Air is a complex, dynamic natural entity, which is essential for
supporting life on earth.
● Air pollutant is a substance that causes harm to the humans and other
living organisms.
● Some of the common pollutants of air:
○ Nitrogen dioxide
○ Sulphur dioxide
○ Carbon monoxide and carbon dioxide
○ Volatile organic compounds
○ Particulate matter
Control of Air Pollution
● Air pollution causes severe respiratory disorders in humans and other
animals and also affects plants. It can be controlled by the following
ways:
○ Fitting smokestacks and smelters, with
filters
to separate
pollutants from the harmless gases
○ Particulate matter can be removed by using an
electrostatic
precipitator
. It contains electrode wires maintained at several
thousand volts, which produce electrons. These electrons cling
on to dust particles and give them a net negative charge and are
attracted by collecting plates, which are grounded. The velocity
of air passing through the plates should be low enough to allow
the dust to fall.
, ○ A
scrubber
can be used to remove gases such as SO
2wherein
the exhaust passes through a spray of water or lime.
○ Vehicular pollution can be reduced by using less polluting fuels
such as
CNG
, which is more efficient and less costly as
compared to petrol or diesel. In 2002, all the buses were
switched to CNG in Delhi and this has indeed led to a fall in
pollution levels in the city.
○ Vehicles can be fitted with
catalytic converters
that have
metals such as platinum, palladium, and rhodium as catalysts.
These catalysts carry out the following conversions:
Unburnt hydrocarbons
→CO
2 and
HO
2
Carbon monoxide
→Carbon dioxide
Nitric oxide
→Nitrogen gas
Unleaded petrol
must be used with catalytic converters as presence of lead
Pollution is the undesirable change brought about by chemical, particulate
matter, or biological materials to air, water, or soil.
Air Pollution
● Air is a complex, dynamic natural entity, which is essential for
supporting life on earth.
● Air pollutant is a substance that causes harm to the humans and other
living organisms.
● Some of the common pollutants of air:
○ Nitrogen dioxide
○ Sulphur dioxide
○ Carbon monoxide and carbon dioxide
○ Volatile organic compounds
○ Particulate matter
Control of Air Pollution
● Air pollution causes severe respiratory disorders in humans and other
animals and also affects plants. It can be controlled by the following
ways:
○ Fitting smokestacks and smelters, with
filters
to separate
pollutants from the harmless gases
○ Particulate matter can be removed by using an
electrostatic
precipitator
. It contains electrode wires maintained at several
thousand volts, which produce electrons. These electrons cling
on to dust particles and give them a net negative charge and are
attracted by collecting plates, which are grounded. The velocity
of air passing through the plates should be low enough to allow
the dust to fall.
, ○ A
scrubber
can be used to remove gases such as SO
2wherein
the exhaust passes through a spray of water or lime.
○ Vehicular pollution can be reduced by using less polluting fuels
such as
CNG
, which is more efficient and less costly as
compared to petrol or diesel. In 2002, all the buses were
switched to CNG in Delhi and this has indeed led to a fall in
pollution levels in the city.
○ Vehicles can be fitted with
catalytic converters
that have
metals such as platinum, palladium, and rhodium as catalysts.
These catalysts carry out the following conversions:
Unburnt hydrocarbons
→CO
2 and
HO
2
Carbon monoxide
→Carbon dioxide
Nitric oxide
→Nitrogen gas
Unleaded petrol
must be used with catalytic converters as presence of lead
