Airpollution 121021034517-phpapp01

AIR POLLUTION Air pollution defined as the of one or

more contaminants or combinations in such quantities and of such durations as may be or tend to be injurious to human, animal or plant life, or property, or which unreasonably interferes with the comfortable enjoyment of life or property or conduct of business.

Composition of dry atmosphere, by volume

ppmv: parts per million by volume

Gas Volume Nitrogen (N2) 780,840 ppmv (78.084%) Oxygen (O2) 209,460 ppmv (20.946%) Argon (Ar) 9,340 ppmv (0.9340%) Carbon dioxide (CO2)

375 ppmv

Neon (Ne) 18.18 ppmv Helium (He) 5.24 ppmv Methane (CH4) 1.745 ppmv Krypton (Kr) 1.14 ppmv Hydrogen (H2) 0.55 ppmv Not included in above dry atmosphere: Water vapor (highly variable) typically 1%

Mean Atmospheric Water Vapor.

Source for figures above: NASA. Carbon dioxide and methane updated (to 1998) by IPCC TAR table 6.1 [1]. The NASA total was 17 ppmv over 100%, and CO2 was increased here by 15 ppmv. To normalize, N2 should be reduced by about 25 ppmv and O2 by about 7 ppmv.

Minor components of air not listed above include:

Gas Volume nitrous oxide 0.5 ppmv

xenon 0.09 ppmv ozone 0.0 to 0.07 ppmv nitrogen dioxide 0.02 ppmv

iodine 0.01 ppmv carbon monoxide trace

SOURCE AND CLASSIFICATION-1 Natural Man- made or anthropogenic

Natural- pollen grains, volcanic eruptions, forest fires, dust storms, spores, bacteria and other microorganisms.

Man- made- industrial units, thermal power plants, automobile exhausts, fossil fuel burning, mining, nuclear explosions,

Source and classification-2 Stationary Mobile

Point source- large stationary source Area source- small stationary source and mobile source

with indefinite routes Line source- mobile source with definite routes

AIR POLLUTANTS Substance dwelling temporarily or permanently in the air. Alters the environment by interfering with the health, the

comfort, or the food chain, or by interfering with the property values of people.

A pollutant can be solid (large or sub-molecular), liquid or gas . It may originate from a natural or anthropogenic source (or both). It is estimated that anthropogenic sources have changed the

composition of global air by less than 0.01%. Even a small change can have a significant adverse effect on the

climate, ecosystem and species on the planet.

Classification of pollutants: Pollutants can be grouped into two categories:

(1) primary pollutants, which are emitted directly from identifiable sources, and (2) secondary pollutants, which are produced in the atmosphere when certain chemical reactions take place among primary pollutants.

PRIMARY POLLUTANTSThe major primary pollutants include:

particulate matter (PM), sulfur dioxide, nitrogen oxides, volatile organic compounds (VOCs), carbon monoxide, and lead.

Secondary Pollutants Some primary air pollutants react with one another or with other

chemicals to form secondary pollutants. Atmospheric sulfuric acid is one example of a secondary

pollutant. Air pollution in urban and industrial areas is often called smog. Photochemical smog, a noxious mixture of gases and

particles, is produced when strong sunlight triggers photochemical reactions in the atmosphere.

The major component of photochemical smog is ozone.

MAJOR POLLUTANTS SOURCES AND EFFECTS Carbon monoxide (CO)- colorless, odorless, tasteless gas. No effect at normal conc. (0.1ppm) but higher conc. seriously affect.

Volcanoes, natural gas emissions, seed germination contribute to CO.

Transport sector contribute 75% CO.

Residential wood burning 10%, industrial process 15% CO. Effects: Reduce oxygen carrying capacity of blood. Decrease in vision and causes cardio vascular disorders.

Carbon dioxide (C02)- Fossil fuel combustion. Jet plane use O2 and release CO2. BurningEffects: Causes headache and nausea. Effect on climate, increase global temp.

Oxides of nitrogen – NOx group contains NO, NO2, N2O.

Fuel combustion in automobiles and industries. Lightening. Forest fires. Natural ionizing radiations.

Effects: Reduce blood carrying capacity. Causes lung problems.

Oxides of sulphur – generally called SOx, include SO2, SO3.

67% SOx pollution due to volcanic activities and other natural sources.

Remaining due to fossil fuel burning, transportation.

Industrial activities. Effects: Respiratory problems Marbles, clothes, paper, leather also affected. Plants also heavily affected.

Hydrocarbons (HC) – these include methane, ethylene, acetylene, terpenes etc.

Sources include coal fields, natural fires. Incomplete combustion Forest fires Agricultural burning

Effects: Carcinogenic effect Form ozone and PAN which are harmful. Damage plants, rubber materials, fabric and

paints.

PARTICULATE MATERIALS Particles of different substances suspended in the air

In the form of solid particles and liquid droplets

Particles vary widely in size

Different particulate materials are aerosols, dust, smoke, fumes, mist, fog, fly ash etc.

Fine particles come from a variety of sources:

-diesel trucks and buses-construction equipment-power plants -woodstoves-wildfires

Also, Chemical reactions in the atmosphere can transform gases into fine particles

Effects: Premature death Aggravated asthma Acute respiratory symptoms Chronic bronchitis Decreased lung function (shortness of

breath) People with existing heart and lung disease,

as well as the elderly and children, are particularly at risk

EFFECTS OF AIR POLLUTION ON HUMAN

around 30-40% of cases of asthma and 20-30% of all respiratory disease.

effect our health in many ways with both short term and long term effect.

Short term effect are: irritation to nose, eye, throat, bronchitis, headache etc.

Long term affect are: lung disease, chronic respiratory problem, damage to heart, brain, eyes etc.

Eye irritation due to NOx, O3, PAN, particulates. Nose and throat due to SO2, NOx etc. Gaseous pollutants like H2S, SO2, NO2 and hydrocarbons cause odor

nuisance. Irritation of respiration tract caused by SOx, NOx, CO, O3. Increase in mortality. High conc. of SO2, NO2 and SPM causes bronchitis and asthma. CO and NO react with haemoglobin and reduce O2 carrying capacity

of blood. Heavy metals like lead can cause poisoning. High conc. cause

damage to liver and kidney.

FACTORS AFFECTING HUMAN HEALTH Nature of the pollutants

Concentration of the pollutants

Duration of exposure

State of health of receptor

Age group of the receptor

EFFECTS OF AIR POLLUTION ON PLANT

Decrease yield in agriculture.

Suppressed growth of vegetables.

Leaf injury and damage to young plants.

Decreased growth rate and increased death rate.

EFFECTS OF AIR POLLUTION ON MATERIALS Corrosion of metals due to SO2 in presence of

oxygen and moisture is converted into H2SO4 acid. H2SO4 acid react with limestone, marble and other

building materials to cause deterioration. Soiling and eroding of building materials. SO2, O3, H2S and aerosols damage protective

coating and paints of the surface. O3 and PAN causes cracking of rubber and various

electrical insulations. Deterioration of art work due to SPM.

AIR POLLUTION CONTROL Cannot be fully prevented but can be controlled.1. Preventative measures2. Control measures using equipments.

Preventative measures (source control) Selection of suitable fuel. (Low sulphur coal in

power plant, using of CNG) Modification in industrial process. Selection of suitable site and zoning for

industrial unit.

Control measures

When source control not possible some measures taken to prevent pollution.

Collecting pollutants by using equipments. Destroying the pollutants by thermal or catalytic combustion. Changing the pollutants to less toxic form. By releasing the pollutants through tall chimneys for greater dispersion. Using fuels with low ash content Encouraging people to use public transport, walk or use a cycle as

opposed to private vehicles Ensure that houses, schools, restaurants and playgrounds are not

located on busy streets Plant trees along busy streets as they remove particulates, carbon

dioxide and absorb noise Industries and waste disposal sites should be situated outsdide the city

preferably on the downwind of the city. Catalytic converters should be used to help control emissions of carbon

monoxide and hydrocarbons

PREVENTATION BY LAWS

Various laws has been established for the menace of air pollution.

Air (Prevention & control of pollution ) Act,1981.

Air (Prevention & control of pollution ) Amendment Act,1987.

Motor vehicle Act, 1988. Air (Prevention & control of pollution) Union

Territories Rules, 1983. Environment Protection Act, 1986.

The government is trying to

remove the use of leaded petrol, a major cause of air pollution.

the industrial acts are implemented to

control the harmful emission of gases.

the natural management team work to minimize the effect of various natural disaster like forest fire, volcanic eruption that are causes of air pollution.

AIR POLLUTION CONTROLLING EQUIPMENTS Gravitational settling chamber

Used to remove particles with size greater than 50 μm.

Velocity of flue gas reduced in large chamber. Particles settle under gravitational force.

Advantages Low initial cost. Easy to design. Low pressure drop. Low maintenance cost. Dry and continuous disposal of solid

particulates.

Disadvantages Require large space. Less collection efficiency. Only larger size particles can be collected.

Cyclone separator Centrifugal force is utilized to separate the particulate matter. It can remove 10 to 50 μmparticle size. Used mostly in industries.

Advantages Low initial cost. Require less floor area. Simple construction and maintenance. Can handle large volume of gas at high

temp.

Disadvantages Requires large head room. Less efficiency for smaller particles (<10μm). Sensitive to variable dust load and flow rate.

Electrostatic precipitators

Works on the principle of electrical charging of particulate Matter (-ve) and collecting it in a +ve charged surface.

99% efficiency.

Can remove particle size range of 0.1 μm to 1 μm.

Advantages High collection efficiency. Particles may be collected dry or wet. Can be operated at high temp. (300-450˚c). Maintenance is normal. Few moving parts.

Disadvantages High initial cost. Require high voltage. Collection efficiency reduce with time. Space requirement is more. Possible of explosion during collection of

combustible gases or particulates.

Fabric filters(BAG HOUSE) Flue gas is allowed topass through a woven Fabric, which filters outParticulate matter. Small particles are retained on the fabric. Remove particles up to 1 μm. Its efficiency up to 99%.

Advantages Higher collection efficiency for smaller than 10 μm particle size. Performance decrease becomes visible,

giving prewarning. Normal power consumption.

Disadvantages High temp. gases need to be cooled. High maintenance and fabric replacement

cost. Large size equipment. Fabric is liable to chemical attack.

Scrubbers

Particulate matters are incorporated into liquid droplets and removed from the gas stream.

Different types of scrubbers are-- Spray tower- Venturi scrubber- Cyclone scrubber

Flue gas made to push up against a down falling water current.

Particulate matter mix up with water thus falls down and gets removed.

Spray tower

Cyclone scrubber

Advantages Simultaneously remove particulates and gaseous

pollutants. Hot gases can be cooled down. Corrosive gases can be recovered and neutralize.

Disadvantages Lot of waste waters produced. Poses freezing problem in cold countries. Maintenance cost is high when corrosive

materials are collected.

NATIONAL AMBIENT AIR QUALITY STANDARDS

The national ambient air quality standard (NAAQS) are standards established by the united states environment protection agency under authority of the Clean Air Act(42 U.S.C.7401 et seq) that apply for outdoor air throughout the country.

They are of two types: 1.Primary standards 2.Secondary standards

PRIMARY STANDARDS Primary standards are designed to protect human

health, with an adequate margin of safety, including sensitive population such as children, the elderly and individuals suffering from respiratory diseases.

SECONDARY STANDARDS:•Secondary standards are designed to

protect public welfare from any known or anticipated adverse effects of a pollutants.

POLLUTENTS TYPES STANDARDS AVERAGING TIME

SO2 PRIMARY 0.14 ppm 24 hoursSO2 PRIMARY 0.030 ppm AnnualSO2 SECONDARY 0.5 ppm 3 hoursPM10 Primary &

secondary150 mic. gm/cubic meter

24 hours

PM2.5 Primary & secondary

35 mic. gm/cubic meter

24 hours

PM2.5 Primary & secondary

15 mic.gm/cubic meter

annual

CO PRIMARY 35 ppm 1 hourCO PRIMARY 9 ppm 8 hourO3 Primary &

secondary0.12 ppm 1 hour

O3 Primary & secondary

0.075 ppm 8 hour

NO2 Primary & secondary

0.053 ppm Annual

Pb Primary & secondary

0.15 mic.gm/cubic meter

Rolling 3 months

AQI: Air Quality Index

•Indicates whether pollutant levels in air may cause health concerns.•Ranges from 0 (least concern) to 500 (greatest concern)

Air Quality Air Quality Index Protect Your Health

Good 0-50 No health impacts are expected when air quality is in this range.

Moderate 51-100 Unusually sensitive people should consider limiting prolonged outdoor exertion.

Unhealthy for Sensitive Groups

101-150 Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.

Unhealthy 151-200Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion, everyone else, especially children should limit prolonged outdoor excertion.

Very Unhealthy (Alert) 201-300 Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion everyone else, especially children, should limit outdoor exertion.

WHAT’S INDOOR AIR POLLUTION? Indoor Air Pollution is the term used to describe

the amount of contaminants in the air inside a building from sources such as cigarette smoking, fuel combustion for heating or cooking, certain wallboards, carpets, or insulation as well as the geology of the area (radon in soil or rocks beneath the structure).

WHAT’S RADON?

Radon is a naturally-occurring radioactive, but inert gas part of the decay chain that starts with uranium and ends with plumbum.

Uranium-238 Decay Chain

WHERE DOES RADON COME FROM?Natural source:

Earth and rock beneath home;Well water; Outdoor air;

Artificial source:Daily life materials: leather; low density plastic

(like plastic bags, etc.); paintsBuilding materials: gypsum board (sheetrock),

concrete block, mortar, sheathing paper (tarpaper), wood paneling, and most insulation.

Some uranium is present in all earth materials. On continental surfaces the rocks, sediments and soils typically

contain between 1 and 3 parts per million (abbreviated ppm) of uranium. Some earth materials may have more.

Cracks in solid floors

Construction joints

Cracks in walls

Gaps in suspended floors

Gaps around service pipes

Cavities inside walls

The water supply

How does radon get inside buildings?

Radon from soil gas is the main cause of radon problems.

How much of radon reaches the surface depends on the uranium content of the underlying earth materials together with their depth and permeability (that is, the presence of fractures and interconnected pore spaces that act as conduits for radon).

Enter the lowest level of a building using whatever pathways are available.

SOIL

For structures with basements or slab-on-grade foundations, the entry points include Cracks and pores in floor slabs, walls, and floor-wall joints; Openings around sump pumps, floor drains, and pipes penetrating

floors and walls.

•Structures with a crawl space between the ground and lowest floor level may be less vulnerable to radon, which tends to escape to the outside air when appropriate vents are installed, but can still admit some of the gas through cracks in the flooring.

WATER

Radon can also enter into homes through the water system.

This is mainly true for houses in which ground water is used as the main water supply.

Small public water works and private domestic wells often have closed systems and short transit times that do not allow radon to decay to harmless by-products before entering a home.

Once inside, radon escapes from the water to the indoor air as people take showers, wash clothes or dishes, or otherwise use water. The areas most likely to have problems with radon in ground water are those with have high levels of uranium in the underlying rocks.

Water in rivers and reservoirs usually contains very little radon, because it escapes into the air.

Thus homes that rely on surface water usually do not have a radon problem from their water.

In big cities, water processing in large municipal systems aerates the water, which allows radon to escape, and also delays the use of water until most of the remaining radon has decayed.

THE AVERAGE LEVEL OF RADON FOUND IN A HOME

Based on a national residential radon survey completed in 1991, the average indoor radon level is about 1.3 picocuries per liter (pCi/L) in the United States. The average outdoor level is about 0.4 pCi/L.

THE SAFE LEVEL OF RADON

There is no safe level of radon--any exposure

poses some risk of cancer.

THE RISK OF LIVING WITH RADON Radon gas decays

into radioactive particles that can get trapped in your lungs when you breathe.

As they break down further, these particles release small bursts of energy. This can damage lung tissue and lead to lung cancer over the course of your lifetime.

Smoking combined with radon is an especially serious health risk.

Children have been reported to have greater risk than adults of certain types of cancer from radiation, but there are currently no conclusive data on whether children are at greater risk than adults from radon.

RADON RISK IF YOU SMOKE/NEVER SMOKERadon Level

If 1,000 people who smoked were exposed to this level over

a lifetime*...

If 1,000 people who never smoked were exposed to this

level over a lifetime*...WHAT TO DO:

Stop smoking and...

20 pCi/L About 260 people could get lung cancer

About 36 people could get lung cancer Fix your home








About 4 person could get lung cancer

Consider fixing between 2 and 4 pCi/L

1.3 pCi/L About 20 people could get lung cancer

About 2 people could get lung cancer

(Reducing radon evels below 2 pCi/L is difficult.)

0.4 pCi/L About 3 people could get lung cancer

Note: If you are a former smoker, your risk may be lower.* Lifetime risk of lung cancer deaths from EPA Assessment of Risks from Radon in Homes (EPA 402-R-03-003).** Comparison data calculated using the Centers for Disease Control and Prevention's 1999-2001 National Center for Injury Prevention and Control Reports.

EPA estimates that radon causes thousands of cancer deaths in the U.S. each year.

REDUCING RADON RISKS There are two ways to protect yourfamily from Radon.

First, the hard way Holding Your Breath

Lower the Radon Level in Your HomeYour Family Will Breathe A Lot Easier.

HOW TO LOWER THE RADON LEVEL The most effective way to

lower the radon level is set a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside.

There are also other ways: Test your home for radon. Be careful when you choose building materials. Fill the gaps and cracks in the ground, floor, and walls. Pay more

attention to the basement and the first floor where there is a high level of radon.

Don’t smoke in the room, especially the one for children and elders.

Bibhabasu MohantyAssistant Professor

Department of Civil EngineeringSAL Institute of Technology &

Engineering Research