2. AIR POLLUTION
Air pollution is the introduction of harmful substances including particulates and biological
molecules into Earth’s atmosphere. It may cause diseases, allergies or death in humans. It may
cause diseases, allergies or death in humans; it may also cause harm to other living organisms
such as animals and food crops, and may damage the natural or built environment. Human activity
and natural processes can both generate air pollution.
3. POLLUTANTS
An air pollutant in a substance in the air that can have adverse effects on humans
and the ecosystem. The substance can be solid particles, liquid droplets, or gases. A
pollutant can be of natural origin or man-made. Pollutants are classified as primary or
secondary
• Primary pollutants
Are usually produced from a process, such as ash from a volcanic eruption. Other
examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur
dioxide released from factories
• Secondary pollutans
Are not emitted directly. Rather, they form in the air when primary pollutants react or
interact.
4. MAJOR PRIMARY POLLUTANTS PRODUCED
BY HUMAN ACTIVITY INCLUDE:
• Carbon dioxide (CO₂) – This is far the most emitted form of
human caused air pollution.
• Sulfur oxides (SOₓ) – particularly sulfur dioxide, a chemical
compound with the formula SO₂ is produced by volcanoes and in
various industrial processes. Coal and petroleum often contain
sulfur compounds, and their combustion generates sulfur dioxide.
• Nitrogen oxides (NOₓ) – Nitrogen oxides, particularly nitrogen
dioxide, are expelled from high temperature combustion, and are also
produced during thunderstorms by electric discharge.
5. MAJOR PRIMARY POLLUTANTS PRODUCED
BY HUMAN ACTIVITY INCLUDE:
• Carbon monoxide (CO) – CO is a colorless, odorless, toxic yet non-
irritating gas. It is a product of incomplete combustion of fuel such as
natural gas, coal or wood. Vehicular exhaust is a major source of
carbon monoxide.
• Volatile organic compounds (VOC) – VOCs are a well-known
outdoor air pollutant. They are categorized as either methane (CH₄) or
non-methane (NWVOCs). Methane is an extremely efficient
greenhouse gas which contributes to enhanced global warming.
• Particulates, alternatively referred to as particulate matter (PM),
atmospheric particulate matter or fine particles, are tiny particles of
solid or liquid suspended in a gas.
6. MAJOR PRIMARY POLLUTANTS PRODUCED
BY HUMAN ACTIVITY INCLUDE:
• Persistent free radicals connected to airborne fine particles are linked
to cardiopulmonary disease.
• Toxic metals, such as lead and mercury, especially their compounds.
• Chlorofluorocarbons (CFCs) – harmful to the ozone layer; emitted
from products are currently banned from use. These are gases which
are released from air conditioners, refrigerators, aerosol sprays, etc.
On release into the air, CFCs rise to the stratosphere.
7. MAJOR PRIMARY POLLUTANTS PRODUCED
BY HUMAN ACTIVITY INCLUDE:
• Ammonia (NH₃) – emitted from agricultural processes. It is normally
encountered as a gas with a characteristic pungent odor.
• Odours – such as from garbage, sewage, and industrial processes.
• Radioactive pollutants – produced by nuclear explosions, nuclear
events, war explosives and natural processes such as the radioactive
decay of radon
8. SECONDARY POLLUTANTS INCLUDE:
• Smog is a kind of air pollution.
• Ground level ozone (O₃) formed from NOₓ and VOCs.
• Peroxyacetyl nitrate (PAN) – similarly formed from NOₓ and
VOCs.
9. WHAT CAUSES AIR POLLUTION
Air pollution can result from both
human and natural actions.
Natural events that pollute the air
include forest fires, volcanic
eruptions, wind erosion, pollen
dispersal, evaporation of organic
compounds and natural
radioactivity. Pollution from
natural occurrences is not very
often.
10. HUMAN ACTIVITIES THAT RESULT IN
AIR POLLUTION INCLUDE:
• Emissions from industries and manufacturing activities
Consider a typical manufacturing plant: You will notice that there are long tubes (called
chimneys) erected high into the air, with lots of smoke and fumes coming out of it. Waste
incinerators, manufacturing industries and power pants emit high levels of carbon monoxide,
organic compounds, and chemicals into the air. This happens almost everywhere that people live.
Petroleum refineries also release lots of hydrocarbons into the air.
11. HUMAN ACTIVITIES THAT RESULT IN
AIR POLLUTION INCLUDE:
• Emissions from industries and manufacturing activities
Consider a typical manufacturing plant: You will notice that there are long tubes (called
chimneys) erected high into the air, with lots of smoke and fumes coming out of it. Waste
incinerators, manufacturing industries and power pants emit high levels of carbon monoxide,
organic compounds, and chemicals into the air. This happens almost everywhere that people live.
Petroleum refineries also release lots of hydrocarbons into the air.
12. HUMAN ACTIVITIES THAT RESULT IN
AIR POLLUTION INCLUDE:
• Burning Fossil Fuels
After the industrial age, transportation has become a key part of our lives, cars and heavy trucks,
trains, shipping vessels and airplanes all burn lots of fossil fuels to work. Emissions from automobile
engines contain both primary and secondary pollutants. This is a major cause of pollution and one
that is very difficult to manage. This is because humans rely heavily on vehicles and engines for
transporting people good and service
13. HUMAN ACTIVITIES THAT RESULT IN
AIR POLLUTION INCLUDE:
• Household and Farming Chemicals
Crop dusting, fumigating homes, household cleaning products or painting supplies, over
the counter insect/pest killers fertilizer dust emit harmful chemicals into the air and
cause pollution. In many cases, when we use these chemicals at home or offices with
no or little ventilation, we may fall ill if we breathe them.
14. SOURCES OF AIR POLLUTION
There are four main types of air pollution sources:
• Mobile sources – such as cars, buses, planes, trucks, and trains
• Stationary sources – such as power plants, oil refineries, industrial facilities,
and factories
• Area sources – such as agricultural areas, cities, and wood burning fireplaces
• Natural sources – such as wind-blown dust, wildfires, and volcanoes
