Air Pollution
Introduction to Air Pollution
The composition of the atmosphere has been gradually changing
over the past millions of years, it is only during the last two to
three hundred years, since the beginning of the industrial
revolution in Europe and North America, however, that man has
begun to affect this change. The process has accelerated over
the past 50 years as more countries have also embarked on
rapid economic development.
This chapter reviews some of the important trends dealing with
local air quality and regional concerns such as haze and acid
rain, as well as the regional contributions to, and implications
of, global climate change and stratospheric ozone depletion. The
policies and response strategies that are being formulated or
implemented in the Asian and Pacific Region to address these
concerns are also discussed.
Types of Air Pollution-Indoor and Outdoor
Indoor air pollution is caused by smog, tobacco smoke, and
household products. It is found in higher levels compared to
outdoor air pollution, which may come as a surprise. Man-made
and natural sources such as fossil fuel combustion and
agricultural activities can cause outdoor air pollution.
While this chapter deals with the issues of pollution to the
atmosphere and climate locally, regionally and globally, it is
also important to note the significant hazards posed by indoor
air pollution. For example, where a large part of the population
still depends on traditional biomass fuels for cooking and
heating, indoor air pollution may be a larger health hazard than
outdoor pollution. The burning of such fuels in a confined space
usually produces high levels of smoke and other pollutants.
Estimates (for the Asian and Pacific Region) indicate that the
concentrations of particulates may exceed WHO guidelines by
factors of ten or more (WHO 1997) in many households,
particularly in South Asia. The data in Table 6.1 suggest that tens
of millions of people in Asia and the Pacific are being exposed to
indoor levels of air pollution comparable to the notorious
outdoor levels during the “London smog” of 1952, in which about
4 000 deaths occurred due to respiratory diseases.
Indoor air pollution is the air quality contamination in buildings
caused by dust, dirt, and other pollutants. It is broken down into
particle matter and gases. Particle Matter (PM) consists of soot
and dust in the air. While gases include carbon monoxide,
nitrogen oxide, and sulfur oxide are a few examples.
Outdoor air pollution is primarily a result of emissions from
various sources like factories, fossil fuels, cars, and more,
depending on the area.
Sources of Air Pollution
The combustion of fossil fuels (coal, oil, and natural gas) is the
principal source of air pollution in all urban areas, along with
the burning of biomass such as firewood, agricultural wastes
and animal wastes in rural areas and some cities. Most of the
combustion of fossil fuels takes place in industries, homes, for
transportation, and for the generation of electricity. However, in
the vast majority of Asian cities, transportation is the largest
source of air pollution.
The number of vehicles in Asian cities has been growing
exponentially over the last two decades. In Delhi and Manila, for
example, they have been doubling every 7 years (ADB 1999). A
large portion of vehicles in most Asian cities use diesel fuel, and
contribute greatly to the emissions of particulates, especially
those that are less than 10 microns in size and are respirable
(PM10). Several countries, including India, Pakistan, and the
Philippines, still subsidize diesel fuels. In many countries,
transportation fuels contain lead and high amounts of sulphur
and use older engine designs that emit more pollution than
modern ones. Since vehicles in developing countries are
typically kept for longer periods than in the industrialized
countries, they continue to contribute a substantial share of the
air pollution in urban areas as their engines become
increasingly less efficient. The situation is compounded by the
region’s reliance on motor cycles and three-wheel vehicles
which frequently use two stroke engines and consequently
produce up to 10 times more hydrocarbons than normal 4-
stroke engines (ADB 1999).
Indoor Concentrations of Particulate Matter due to
Biomass Combustion :-
Current Levels of Air Pollution
During the process of industrialization in Europe and North
America, air quality declined significantly. The same pattern is
currently being observed in Asia and the Pacific, where in many
urban areas, air pollution greatly exceeds levels considered
safe by the World Health Organization (WHO).Of the 15 cities in
the world with the highest levels of particulate matter, 12 are
located in Asia (ADB 1999). Furthermore, 6 of these cities also
have the highest levels of atmosphere sulphur dioxide. Figure
6.1 depicts levels of total suspended particulates (TSP), sulphur
dioxide (SO2 ), and nitrogen dioxide (NO2 ) against WHO
guidelines, in selected Asian cities. The levels of TSP in several
cities are three to four times those recommended by WHO
although the situation for SO2 and NO2 is better, with only a few
large cities greatly exceeding the recommended safe level.
How to Help Reduce Air Pollution
The less gasoline we burn, the better we’re doing to reduce air
pollution and harmful effects of climate change,” Walke says.
“Make good choices about transportation. When you can, walk,
ride a bike, or take public transportation. For driving, choose a
car that gets better miles per gallon of gas, or choose an
electric car.” You can also investigate your power provider
options—you may be able to request that your electricity be
supplied by wind or solar. Buying your food locally cuts down
on the fossil fuels burned in trucking or flying food in from
across the country. And most important, “Support leaders who
push for clean air and water and responsible steps on climate
change,” Walke says.
How to Protect Your Health
• When you see in the news or hear on the weather report
that pollution levels are high, it may be useful to limit the
time when children go outside or you go for a jog,” Walke
says. Generally, ozone levels tend to be lower in the
morning.
• If you exercise outside, stay as far as you can from heavily
trafficked roads. Then shower and wash your clothes to
remove fine particles.
• The air may look clear, but that doesn’t mean it’s pollution
free. Utilize tools like the EPA’s air pollution
monitor, AirNow, to get the latest conditions. If the air
quality is bad, stay inside with windows closed.
• If you live or work in an area prone to wildfires, stay away
from the harmful smoke as much as you’re able. Consider
keeping a small stock of masks to wear when conditions
are poor.
• Wear sunscreen. When ultraviolet radiation comes through
the weakened ozone layer, it can cause skin damage and
skin cancer.
Causes of Air Pollution
Natural and manmade pollution sources may harm human
health. Natural sources include volcanic eruptions, dust carried
by the wind and gases released by living beings. Manmade
activities that cause air pollution include motor vehicle use,
fossil fuel burning and agriculture.
list of the most common air pollution sources:
1. Fossil fuel burning: Fossil fuel burning like that which
happens in factories or other industrial applications emits
sulfur dioxide into the atmosphere.
2. Agriculture: Agricultural activities frequently emit
ammonia, a severely hazardous atmospheric gas.
Insecticides, pesticides and fertilizers cause both chemical
air and water pollution. Farmers also set controlled fires
to fields and old crops to clear them for the next round of
sowing. However, this burning also releases harmful
pollution-causing gases into the air.
3. Landfill waste: Landfills are land areas into which humans
deposit or bury waste, which then generates methane.
Methane is a significant greenhouse gas that is highly
flammable and very hazardous.
4. Industry and factory emissions: Manufacturing industries
deplete air quality by releasing hydrocarbons, carbon
monoxide, organic compounds and other chemicals into
the air.
5. Mining operations: During mining, large equipment extracts
underground minerals. However, this process also
releases dust- and chemical-based air pollutants. Nearby
residents and workers often suffer health consequences
as a result of mining.
6. Indoor sources: Substances like household cleaning
products and painting supplies, for example, contribute to
indoor air pollution.
Effects Air Pollution
1. Public health problems: Air pollution contributes to several
respiratory and heart problems, including asthma, chronic
bronchitis, emphysema, heart attacks, strokes and cancer.
More than 4 million people each year die from air
pollution-related complications.
2. Child health problems: During pregnancy, exposure to high
air pollution can cause miscarriages, premature birth,
autism, asthma and spectrum disorders in young children.
It can also damage early brain development in a child and
cause pneumonia, which kills almost a million
children under five years old. Children are at a greater risk
of short-term respiratory infections and pulmonary
diseases in areas exposed to air pollutants.
3. Global warming: This issue is probably one of the most
well-known effects of air pollutants. Increasing
temperatures across the globe have led to elevated sea
levels from melting icebergs, resulting in habitat loss and
emphasizing the need for preservation actions.
4. Acid rain: Harmful gases like nitrogen oxides and sulfur
oxides are released into the atmosphere when fossil fuels
are burned. Rain mixes with air pollutants to form acid
rain, damaging humans, animals, landscapes and plants.
Sensitive ecosystems such as lakes and forests are
especially susceptible to acid rain damage.
5. Eutrophication: Eutrophication happens when excess algae
form in bodies of water due to the high nitrogen level of
some pollutants. Many lakes and ponds typically have this
green-colored, eutrophication-based algae. Heavy algae
can negatively impact aquatic species like fish and plants.
6. Wildlife harm: Animals may change habitats due to air
pollution. Further, toxic particulates can also impact
aquatic animals when pollutants contaminate the water.
7. Depletion of the ozone layer: The ozone layer protects the
Earth’s inhabitants from the sun’s damaging ultraviolet
(UV) rays. However, atmospheric chlorofluorocarbons and
hydrochlorofluorocarbons are contributing to ozone layer
depletion. A thinning ozone layer causes increased UV rays
to reach the Earth, resulting in potential skin and eye-
related problems. Sensitive ecosystems like parks, forests
and wilderness sanctuaries can experience harm due to
elevated ozone levels.
Control Measures For Air Pollution
The best way to protect air quality is to reduce the emission of
pollutants by changing to cleaner fuels and processes.
Pollutants not eliminated in this way must be collected or
trapped by appropriate air-cleaning devices as they are
generated and before they can escape into the atmosphere.
• Use public transport whenever you can. Also, try to
carpool. It will not only save a lot of fossil fuels but also
reduce the emissions caused by vehicles.
• Opt for a bicycle when you’re taking a short trip so that you
do not contribute to the traffic emissions.
• Use filters in your chimney at home and office. This will
prevent any harmful gases from leaking into the
atmosphere.
• Try using safe paints and varnishes that do not emit any
harmful toxins.
• Whenever you buy any electrical appliances, look for the
star rating and opt for the highest possible star rating so
that more energy is saved.
• Do not burn dry waste like leaves and plastic that can emit
very poisonous gases.
• Do not use wood or timber for burning. It can lead to
emission of gases that cause air pollution.
• Do not use equipment that runs on gasoline. It can
contribute to ozone depletion.
• Avoid excessive use of air conditioners. It can deteriorate
the ozone layer.
