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Urbanization has paved the way for higher levels of comfort and standard of
living.
Rapid urbanization has thus caused an increase in the number of vehicles and
this, on the other hand, is causing another set of problems including lack of
space, reduction in natural resources, environmental pollution, etc.
We need to consider the existence of a future generation and plan the
utilization of our environment and resources wisely.
The following sections discuss how the transportation engineering is helpful in
bringing about welcome changes in the development of a sustainable environment.
For this, we need to have a basic knowledge about fuel consumption, emission
and resulting air pollution, which are discussed briefly below.
Fuel efficiency or Fuel Economy is the energy efficiency of a vehicle,
expressed as the ratio of distance traveled per unit of fuel consumed in
km/liter.
Fuel efficiency depends on many parameters of a vehicle, including its engine
parameters, aerodynamic drag, weight, and rolling resistance.
Higher the value of fuel efficiency, the more economical a vehicle is (i.e.,
the more distance it can travel with a certain volume of fuel).
Fuel efficiency also affects the emissions from the vehicles.
Fuel consumption is the reciprocal of Fuel Efficiency.
Hence, it may be defined as the amount of fuel used per unit distance,
expressed in liters/100km.
Lower is the value of fuel consumption, more economical is the vehicle.
That is less amount of fuel will be used to travel a certain distance.
Air Pollution maybe defined as
The disruption caused to the natural atmospheric environment by the
introduction of certain chemical substances, gases or particulate matter, which
cause discomfort and harm to structures and living organisms including plants,
animals and humans.
Air pollution has become a major concern in most of the countries of the world.
It is responsible for causing respiratory diseases, cancers and serious other
ailments.
Besides the health effects, air pollution also contributes to high economic
losses.
Poor ambient air quality is a major concern, mostly in urban areas.
Air pollution is also responsible for serious phenomena such as acid rain and
global warming.
The substances causing air pollution are collectively known as air pollutants.
They may be solid, liquid or gaseous in nature.
Pollutants are classified as primary and secondary air pollutants.
Primary pollutants are those which are emitted directly to atmosphere, whereas,
secondary pollutants are formed through chemical reactions and various
combinations of the primary pollutants.
Some of the major primary and secondary air pollutants are given in
Table. 1 and Table. 2.
Table 1:
Primary Air Pollutants
Sulphur Oxides  |
Carbon Monoxide  |
Nitrogen Oxides  |
Carbon Dioxide  |
Volatile Organic Compounds  |
Hydrocarbons  |
Ammonia  |
Particulate Matter  |
| Radioactive pollutants |
Chlorofluorocarbons  |
| Toxic Metals like Lead, Cadmium and Copper |
Table 2:
Secondary Air Pollutants
| Photochemical smog |
Peroxyacetyl Nitrate  |
Ozone  |
The sources of air pollution may be natural or anthropogenic.
The anthropogenic sources of air pollution are those which are caused by human
activity.
The major anthropogenic sources include Stationary sources (such as smoke
stacks of power plants, incinerators, and furnaces), Mobile sources (e.g. motor
vehicles, aircraft), Agriculture and industry (e.g. chemicals, dust), Fumes
from paint, hair spray, aerosol sprays, Waste deposits in landfills (which
contain methane) and Military (e.g. Nuclear weapons, toxic gases).
The natural sources of air pollution may be Dust from areas of low vegetation,
Radon gas from radioactive decay of Earth’s crust, Smoke and  from
wildfires, and volcanic activity which produces sulfur, chlorine and
particulates.
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