AIR POLLUTION: CAUSES & CONTROL BY DR. MUHAMMAD ANWAR BAIG

AIR POLLUTION:
CAUSES & CONTROL
BY
DR. MUHAMMAD ANWAR BAIG
VICE PRINCIPAL
IESE, NUST, RAWALPINDI
CANTT.
The Atmosphere
• Performs several important functions.
Protects us from;
– sun’s UV rays, x-rays, lethal amounts of
cosmic rays
• Without this life will cease to exist.
• The interaction between the earth and
sun is responsible for earth’s climate
and weather.
How climate is caused?
• Heating and cooling of the air
• Horizontal movements of the air due to
earth’s rotation
• Distance from the sun
• The passage that sun’s energy has to
pass to reach the earth’s surface
Green House
Effect
Forest Decline
Acid Rain
Atmospheric Trace
Gases
Global Warming
Ozone Hole
Photochemical
Smog
What is air pollution?
Defined as the presence of chemicals in the atmosphere
in quantities and duration that are harmful to human
health and the environment
Types of air pollutants
• Primary pollutants - products of natural events (like
fires and volcanic eruptions) and human activities
added directly to the air
• Secondary pollutants - formed by interaction of
primary pollutants with each other or with normal
components of the air
The air pollution problem
• Air pollutants are likely to stay near the
earth due to gravity
• air pollutants accumulate as an air mass
moves across the region
• Air pollution is not just an aesthetic
problem but it is also a health problem
• Death occurs in the elderly and the very
young
Classes of air pollutants
Carbon oxides -- carbon monoxide
(CO), carbon dioxide (CO2)
• --CO responsible for half the fatal poisonings
in the US each year
• --The result of incomplete combustion of
fossil fuels or other organic matter. Major
source of CO -- transportation.
• --CO mimics oxygen and can bind to the
hemoglobin in blood and prevent it from
carrying oxygen
Carbon Oxides (CO, CO2)
cont..
• Fuel efficiency reduced ```CO
– Cigarette smoking releases CO
– Exposure to air containing 0.001% of CO for
several hours can cause death
– Can cause headache, drowsiness, and blurred
vision
– Natural processes can convert CO to other
harmless gases like CO2
• Carbon dioxide contribute to Global Warming
Hydrocarbons (HC)
• Internal combustion engine, fuel suppliers,
refineries, and other industries release HC.
• Cause oily film after the rain, some injure
respiratory tract, others cause cancer
• Methane contribute to global warming, others
contribute to Photochemical smog
• Modifications to automobile engines have
reduced HC.
– Recycling some gases, using higher oxygen
conc., better fuel air mixture, use of valves to
prevent escape of gases, catalytic converters
Sulfur oxides -- sulfur dioxide
(SO2), sulfur trioxide (SO3)
• Produced when sulfur in fossil fuels is
released by burning
• When inhaled corrodes the lung
tissue - An irritant to respiratory tissue
• React with water to form acid.
• Can attach to particles and form
sulfur containing acids..
Nitrogen oxides
-- nitric oxide (NO), nitrogen dioxide
(NO2), and nitrous oxide (N2O)
• Transportation and stationary
sources such as power plants
• Cause respiratory distress
• Combine with other air pollutants to
form smog
• A source of acid rain
Suspended particulate matter
• -- solid particles (dust, asbestos, soil) and
liquid particles (sulfuric acid, PCBs, other
pesticides)
• Anything small enough to be carried by
the wind
• In US, particulate air pollution contributes
to deaths of 60,000/yr
• Volatile organic compounds -- large
group of compounds ranging from
coolants in air conditioners, methane,
benzene
Type of air pollutants
• Primary pollutant -- a chemical that has
been added directly to the air by human
activities
• Secondary pollutant -- a compound
produced when primary pollutants
react with each other or with other
components of the air
• Photochemical smog -- a mixture of
primary and secondary pollutants
• produced when nitrogen oxides from
motor vehicles interact with sunlight
• result -- ozone and smaller amounts of
many other gases
Ozone O3
• --- a photochemical oxidant
• good in the stratosphere -- blocks out UV
rays of the sun
• bad close to earth -- has a devastating effect
on crops and humans
• ozone is the pollutant whose health standard
is most frequently exceeded in urban areas
of the US
• affects eyes and respiratory system;
damages cells in lungs and airways,
inducing cellular fluids to seep into lungs;
more susceptible to bacterial infection;
breathing becomes shallow and painful
Photochemical smog
• NO + HC + O2 + Sunlight ---->
Ozone
• Ozone + other air pollutants ---> 100 different secondary
pollutants ( Peroxyacyl nitrates
(PANs for example)
Phenomenon of Thermal
Inversion
• Air near the ground is colder than the
air at higher levels.
• Pollutants are trapped.
• Usually persist only a few hours.
Some times, however, can last for
days.
• Cities located in valleys
(Kathmandu), near the coast, or on
the leeward side of the mountains.
London killer fog - 1952
• London was covered with fog
• failed to mix with air
• Four thousand people died in few
weeks
• More than 50% of the people got
affected.
• These were related to SO2
Controlling Air Pollutants
• Smaller more fuel efficient
automobiles release less emission
• Smoke stacks with electrostatic
precipitators, fabric filters, wet
scrubbers, or other technologies
remove particulate matter.
• Particulates can also be controlled
by sprinkling water
Controlling air pollutants
contd..
• Several methods exist for
removing SO2 but the best option
is to introduce low-sulfur fuel such
as natural gas or non-fossil fuel
energy options such as solar
energy
• Sulfur can also be removed from
coal as in Coal Gasification
Controlling Air Pollutants
Contd..
• Reduction of combustion temperatures
in automobiles reduces the formation
of nitrogen oxides.
• Modification of furnaces and engines to
provide more complete combustion
controls production of both CO & HCs.
( Catalytic afterburners used after the
emission or the catalytic converters to
treat auto-exhaust)
Taxing Polluters
• Sweden taxes on carbon monoxide
and sulfur dioxide emissions
• Since the amount of these
pollutants vary with the type of fuel
this encourages the users to go for
cleaner fuels.
Air Pollution in Developing
Countries
•
•
•
•
Old vehicles with no pollution control devices
Less priority on environment
Dominance of very small number of cities
Mexico city: The fourth largest city in the world
with the worst air quality. ( This is in an elevated
valley )
– 3 million motor vehicles and thousands of
businesses which spew 4.4 million tons of
pollutants
– In 1990, replacing old buses, taxis, delivery
trucks, and cars with cleaner vehicles and by
switching to unleaded gasoline.
– Businesses that violate laws were closed.
Indoor Air Pollution
• Some pollutants may be several times higher
inside the buildings
• Urban residents spent 90% of their time
indoor
• Health effects of indoor pollutants resemble
common cold, influenza, or upset of
stomachs, they are often not recognized. (Sick
Building Syndrome )
Indoor air pollution
• Sick building syndrome -- when occupants of a
building suffer persistant symptoms associated with
certain pollutants
• More dangerous problems: asbestos, carbon monoxide,
formaldehyde, radon, tobacco smoke.
• More common in newer buildings because of lower air
exchange, windows that don't open, and gases given off
by new carpeting and furniture
• Radon Colorless, tasteless radioactive gas. Threat of
dying is greater. Capable of seeping through the ground
and entering the buildings. This gets diluted in outdoors.
Harms only when ingested. Smoking increases risk. Radon
concentrations can be reduced by sealing concrete floors.
Air Quality and Health
• In developing countries 0.5 – 1.0 million
people die as a result of exposure to urban
air pollution
• 30 – 40 % of asthma
• 20 – 30 % all respiratory diseases
• Average compound growth rate of vehicles
is 12 % a year (0.8 million - 5 million in two
decades)
• Rickshaws - > two times, Motor cycles – 7
times
Sources of Air Pollution in Pakistan
Vehicles
Trans
boundary
Pollution
Natural Dust
Stone
Crushers
Brick Kilns
Industry
Garbage
Burning
Domestic
Burning
Trend in Population & Vehicle
Growth (Karachi)
•
•
•
•
Population
(million)
1995 - 8.465
2000 10.032
2003 11.819
2005 12.10
Vehicles (million)
• 0.88
• 1.006
• 1.135
• 1.432
• 72 % diesel (60 %
Trucks, 27 % Buses,
11 % Passenger
wagons)
• 28 % Petrol
TSP Load in Major Cities
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Satellite Town – Qta
Attock Refinary- Rwp
Kohat Adda – Pesh
I/9 – Islamabad
Civic Center - Kchi
TSP (ug/m3)
• 996
• 778
• 500
• 530
• 490
• 410
(WHO limit is 150 – 230
in 24 hrs)
PM10 (particles measuring 10
microns or less)
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Satellite Town – Qta
Attock Refinary- Rwp
Kohat Adda – Pesh
I/9 – Islamabad
Civic Center - Kchi
PM10 (ug/m3)
• 368
• 331
• 276
• 350
• 280
• 302
(WHO limit is 150 in 24
hrs)
Oxides of Nitrogen
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Meezan Chowk – Qta
Faizabad - Rwp
Bus Stand – Pesh
Polyclinic –
Islamabad
Garden Road - Kchi
NOx (ppb)
• 60.7
• 60
• 40
• 47
• 39
• 52
(WHO/USEPA limit is
53 ppb in 24 hrs)
Sulfur di-Oxide
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Meezan Chowk – Qta
Faizabad - Rwp
Bus Stand – Pesh
Polyclinic –
Islamabad
Garden Road - Kchi
SO2 (ppb)
• 53
• 46
• 31
• 43
• 35
• 44
(WHO/USEPA limit is
53 ppb in 24 hrs)
Surface Ozone
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Meezan Chowk – Qta
Faizabad - Rwp
Bus Stand – Pesh
Polyclinic –
Islamabad
Garden Road - Kchi
O3 (ppb)
•
•
•
•
•
•
8.5 - 49
11.7 - 44
3.3 - 42
4 – 49.5
6.2 - 38
6 - 48
Carbon Monoxide
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Meezan Chowk – Qta
Faizabad - Rwp
Bus Stand – Pesh
Polyclinic –
Islamabad
Garden Road - Kchi
•
•
•
•
•
•
CO (ppb)
1.3 - 12
3 - 14
1.6 - 8
2 – 10
1.5 - 6
1.6 - 13
Hydrocarbon (methane & non
methane)
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Meezan Chowk – Qta
Faizabad - Rwp
Bus Stand – Pesh
Polyclinic –
Islamabad
Garden Road - Kchi
•
•
•
•
•
•
CH (ppm)
0.45 – 2.8
0.2 – 1.6
0.3 – 2.8
0.2 - 3
0.4 – 2.2
0.25 – 3
Lead Level
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Meezan Chowk – Qta
Faizabad - Rwp
Bus Stand – Pesh
Polyclinic –
Islamabad
Garden Road - Kchi
Lead (ug/m3)
• 3.7 - 5
• 3.5 – 5.7
• 3.5 - 5
• 4 – 5.2
• 2-3
• 4 – 5.5
(USEPA limit 1.5)
QUALITY OF FUEL OIL
Pakistan
• Sulphur in Diesel oil
0.5%
• Sulphur in Furnace oil 3%
Other Countries
of Region
0.05-0.5%
0.5-1%
What is Greenhouse Effect
•
Greenhouse effect is a warming of the lower atmosphere and
surface of a planet by a complex process involving sunlight,
gases, and particles in the atmosphere The amounts of heattrapping atmospheric gases, called greenhouse gases, have
greatly increased since the mid-1800's, due to industrial
revolution
•
The greenhouse effect is so named because the atmosphere
acts much like the glass roof and walls of a greenhouse,
trapping heat from the sun.
•
Since the late 1800's, the temperature of the earth's surface
has also risen
Noise Level
•
•
•
•
•
•
City point
Yateem Khana – Lhr
Meezan Chowk – Qta
Faizabad - Rwp
Bus Stand – Pesh
Polyclinic –
Islamabad
Garden Road – Kchi
• NEQS
dB
•
•
•
•
•
•
95
85
93
92
84.7
99
• 80
dB