Air PollutionAir Pollution

Dr. R. B. SchultzDr. R. B. Schultz

IntroductionIntroduction

Air pollution TypesAir pollution Types

Sources of pollutantsSources of pollutants

Pollution and weatherPollution and weather

Acid RainAcid Rain

SolutionsSolutions

What is an air pollution?What is an air pollution?

A substance present in sufficient A substance present in sufficient concentration in the air to produce a concentration in the air to produce a harmful effect on humans or animals, harmful effect on humans or animals, vegetation, or materials.vegetation, or materials.

Air pollutionAir pollution

A) NaturalA) Natural B) Man-madeB) Man-made

““Natural” PollutionNatural” Pollution

Air is never perfectly clean. Air is never perfectly clean. Examples of “natural” air pollution include:Examples of “natural” air pollution include:

Ash, Ash, salt particles, salt particles, pollen and spores, pollen and spores, smoke and smoke and windblown dust windblown dust

These are produced naturally, such as, by These are produced naturally, such as, by volcanic activities and bacterial actions.volcanic activities and bacterial actions.

““Man-made” PollutionMan-made” Pollution Examples of “man-made” air pollution include:Examples of “man-made” air pollution include:

CO, CO, COCO22 , , Oxides of nitrogen (NOOxides of nitrogen (NOxx), ), Oxides of sulfur (SOOxides of sulfur (SOxx), ), Particulates, andParticulates, and Volatile Organic Compounds (VOCs)Volatile Organic Compounds (VOCs)

These are produced by human activity due to These are produced by human activity due to increased urbanization, industrialization (such increased urbanization, industrialization (such as electrical power plants), transportation, as electrical power plants), transportation, forest fires, incineration of solid wastes.forest fires, incineration of solid wastes.

Air Pollutant TypesAir Pollutant Types

Although some types of air pollution are recent Although some types of air pollution are recent creations, others, such as London's infamous creations, others, such as London's infamous smoke pollution, have been around for smoke pollution, have been around for centuries. centuries.

One of the most tragic air pollution episodes One of the most tragic air pollution episodes ever occurred in London in December 1952 ever occurred in London in December 1952 when more than four- thousand people died. when more than four- thousand people died.

Pollutants can be grouped into two Pollutants can be grouped into two categories: categories: (1) (1) primary pollutantsprimary pollutants, which are emitted , which are emitted

directly to the air from identifiable sources.directly to the air from identifiable sources.

(2) (2) secondary pollutantssecondary pollutants, which are , which are produced in the atmosphere when certain produced in the atmosphere when certain chemical reactions take place (for example, chemical reactions take place (for example, formation of ozone).formation of ozone).

Air Pollutant TypesAir Pollutant Types

Primary PollutantsPrimary Pollutants

The major primary pollutants include:The major primary pollutants include: carbon monoxide, and COcarbon monoxide, and CO22

nitrogen oxides (NOnitrogen oxides (NOxx), ), sulfur dioxide, sulfur dioxide, particulate matter (PM),particulate matter (PM), volatile organic compounds (VOCs), volatile organic compounds (VOCs), lead. lead.

CO, Carbon monoxideCO, Carbon monoxide

Natural sourceNatural source– atmospheric oxidation of – atmospheric oxidation of methanemethane

2CH2CH4(g) 4(g) + 3O+ 3O2(g)2(g) 2CO(g) + 4H 2CO(g) + 4H22O (l)O (l)

Man-made sourceMan-made source—incomplete combustion of —incomplete combustion of fossil fuels (e.g., petrol used in the internal fossil fuels (e.g., petrol used in the internal combustion engine for transportation), forest combustion engine for transportation), forest fires. fires.

CO, Carbon monoxideCO, Carbon monoxide

Effect on health Effect on health – Metabolic poison. Prevents – Metabolic poison. Prevents haemoglobin from carrying Ohaemoglobin from carrying O22..

Oxides of Nitrogen (NOOxides of Nitrogen (NOxx)) NN22O, NO, NOO, NO, NO22 are important air pollutants. are important air pollutants.

Natural source for NO and NNatural source for NO and N22O O ––

Decomposition of N containing compounds by Decomposition of N containing compounds by bacterial actionbacterial action

NN22 and O and O22 in the air will not normally react in the air will not normally react

(because N(because N22 is very stable and ~ 1500°C is is very stable and ~ 1500°C is

required for them to react). This temperature is required for them to react). This temperature is reached in the reached in the engines of cars, airplanes, engines of cars, airplanes, and trainsand trains, and make N, and make N22 and O and O22 react to react to

produce NOproduce NOxx..

Oxides of Nitrogen (NOOxides of Nitrogen (NOxx))

Other sources: Other sources: SStationary sources (furnaces tationary sources (furnaces fuelled by natural gas), industrial processes fuelled by natural gas), industrial processes (e.g. nitric acid production), agricultural burning, (e.g. nitric acid production), agricultural burning, forest fires.forest fires.

Oxides of Nitrogen (NOOxides of Nitrogen (NOxx))

NONO22 is a is a secondary pollutantsecondary pollutant because NO is because NO is

converted to NOconverted to NO2 2 in the atmosphere. in the atmosphere.

2NO (g) + O2NO (g) + O22(g) (g) 2NO 2NO22(g)(g)

Oxides of Nitrogen (NOOxides of Nitrogen (NOxx))

Effect on health Effect on health -- breathing problems, -- breathing problems, irritation of the respiratory tract, pulmonary irritation of the respiratory tract, pulmonary edema.edema.

Oxides of Sulfur (SOOxides of Sulfur (SOxx)) SOSO22, and SO, and SO33..

SecondarySecondary : SO : SO33

2SO2SO22 (g) + O (g) + O22(g) (g) 2SO 2SO33(g)(g)

Natural source for SONatural source for SO22 – volcanic and – volcanic and

bacterial activitesbacterial activites

Oxides of Sulfur (SOOxides of Sulfur (SOxx)) SOSO22, and SO, and SO33..

SecondarySecondary : SO : SO33

2SO2SO22 (g) + O (g) + O22(g) (g) 2SO 2SO33(g)(g)

Sources: Sources: Combustion of sulfur containing Combustion of sulfur containing fossil fuels (e.g., coal), some fuels used by fossil fuels (e.g., coal), some fuels used by ships and power stations, Sulfuric acid ships and power stations, Sulfuric acid factories, smelting plants. factories, smelting plants.

Oxides of Sulfur (SOOxides of Sulfur (SOxx))

Effect on HealthEffect on Health : Acid rain formed, irritation of : Acid rain formed, irritation of the respiratory tract, affecting the asthma the respiratory tract, affecting the asthma sufferers.sufferers.

Particulate MatterParticulate Matter

Solid particles suspended or carried in the Solid particles suspended or carried in the air.air.

Natural sources Natural sources -- sandstorms, volcanoes, -- sandstorms, volcanoes, forest fires started with lightning.forest fires started with lightning.

Particulate MatterParticulate Matter

Man-made sourcesMan-made sources-- smoke produced by -- smoke produced by combustion of coal petroleum, wood, etc., combustion of coal petroleum, wood, etc., dust from mechanical break-up of solid dust from mechanical break-up of solid matter, asbestos from industrial plants, matter, asbestos from industrial plants, metallic particles (e.g., Hg, As, Pb, metallic particles (e.g., Hg, As, Pb, compounds of Pb) from industrial plants, fly compounds of Pb) from industrial plants, fly ash (unburnt carbon and oxides of many ash (unburnt carbon and oxides of many metals) from coal burning power plants.metals) from coal burning power plants.

Particulate MatterParticulate Matter

Effect on health Effect on health -- irritation of the lungs, -- irritation of the lungs, asbestosis (scarring of the lungs), some asbestosis (scarring of the lungs), some metal poisonings (e.g., Be poisoning).metal poisonings (e.g., Be poisoning).

Volatile Organic Compounds Volatile Organic Compounds (VOCs)(VOCs)

Hydrocarbon gases (e.g., CHHydrocarbon gases (e.g., CH44), petroleum ), petroleum

(mixture of organic compounds), solvents (mixture of organic compounds), solvents used in paints.used in paints.Natural Sources Natural Sources ––

- CH- CH44 : biological anaerobic bacterial : biological anaerobic bacterial

decomposition of organic matter swamps, decomposition of organic matter swamps, rice fields, rivers, and lakes (this also rice fields, rivers, and lakes (this also produces terpenes); as a digestive gas by the produces terpenes); as a digestive gas by the cows.cows.

Volatile Organic Compounds Volatile Organic Compounds (VOCs)(VOCs)

Man-made Sources Man-made Sources – Petroleum extracting, – Petroleum extracting, refining, transporting, and use; paint refining, transporting, and use; paint production; incomplete combustion of production; incomplete combustion of gasoline, coal, wood.gasoline, coal, wood.

Volatile Organic Compounds Volatile Organic Compounds (VOCs)(VOCs)

Effect on Health Effect on Health – some are carcinogenic, irritation of – some are carcinogenic, irritation of mucous membrane.mucous membrane.

Secondary PollutantsSecondary Pollutants Atmospheric sulfuric acid is one example of a secondary Atmospheric sulfuric acid is one example of a secondary

pollutant. pollutant. Air pollution in urban and industrial areas is often called Air pollution in urban and industrial areas is often called

smogsmog. . Photochemical smogPhotochemical smog, a noxious mixture of gases and , a noxious mixture of gases and

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

The major component of photochemical smog is The major component of photochemical smog is ozoneozone. . Although considerable progress has been made in Although considerable progress has been made in

controlling air pollution, the quality of the air we breathe controlling air pollution, the quality of the air we breathe remains a serious public health problem. remains a serious public health problem.

Strategies to deal with air Strategies to deal with air pollutionpollution

LawsLaws Catalytic converters, Catalytic converters, Burn “ban” days Burn “ban” days Cleaner burning fuels and gas “scrubbing”Cleaner burning fuels and gas “scrubbing”

More public transportMore public transport Cut emissionsCut emissions

ConclusionConclusion

Air pollution TypesAir pollution Types

Sources of pollutantsSources of pollutants

Pollution and weatherPollution and weather

SolutionsSolutions