chemistry - air pollution

AIR POLLUTION

• Air pollution occurs when gases, dust particles, fumes (or smoke) or odour are introduced into the atmosphere in a way that makes it harmful to humans, animals and plant. 

• When we burn fossil fuels and use hydrocarbons from distilla-tion of petroleum, the gases given off pollute the atmosphere and cause harmful effects in the environment.

• These pollutant gases include carbon monoxide, carbon diox-ide, sulfur dioxide and oxides of nitrogen.

• When we burn fuels, tiny particles of solid also get into the air. These particles are called particulates. Examples of particu-late is lead dust and soot.

CARBON MONOXIDE

• Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air.

• Carbon monoxide is made up of a single atom of carbon together with 1 of oxygen.

• Once created, carbon monoxide can wreak havoc on the bloodstream, due to its tendency to bond with hemoglobin and inhibit the blood's absorption of oxygen.

CARBON MONOXIDE

It is produced by the incomplete combustion of solid, liquid, and gaseous fuels.

Boilers Room heaters Furnaces Charcoal grills Cooking ranges Water heaters Vehicles run in closed garages Fireplaces Portable generators Wood burning stoves

LEAD COMPOUNDS

• Lead comes from cars in areas where unleaded gasoline is not used. It can also come from power plants and other industrial sources. Like lead paints and pipes.

• Some lead compounds are not easily broken down in the environment.

• Lead is hazardous if it gets into our food or water supply or if we breathe it in.

• Small quantity of lead in the body can cause damage to the nervous system, especially to the brain in children.

SULFUR DIOXIDE

• It is a corrosive gas that cannot be seen or smelled at low levels but can have a “rotten egg” smell at high levels.

• Sulfur dioxide exposure can affect people who have asthma or emphysema by making it more difficult for them to breathe.

• It can also irritate people's eyes, noses, and throats.

• Sulfur dioxide can harm trees and crops, damage buildings, and make it harder for people to see long distances.

SULFUR DIOXIDE

• When a fossil fuels are burnt the sulfur is oxidised to sulfur diox-ide gas which escape into the atmosphere.

S(s) + O2(g) = SO2(g)

• Volcanoes are also a natural source of sulfur dioxide. The sulfur dioxide reacts with oxygen in the atmosphere to form sulfur tri-oxide.

SO2(g) + O2(g) = SO3(g)

• The sulfur trioxide then reacts with water vapour in the air to form a solution of sulfuric acid.

SO3(g) + H2O(l) = H2SO4(aq)

ACID RAIN

• Acid rain is rain that has been made acidic by certain pollutants in the air.

• Wet deposition is rain, sleet, snow, or fog that has become more acidic than normal.

• Dry deposition is another form of acid deposition, and this is when gases and dust particles become acidic.

• Both wet and dry deposition can be carried by the wind, sometimes for very long distances.

• Acid deposition in wet and dry forms falls on buildings, cars, and trees and can make lakes acidic.

• Acid deposition in dry form can be inhaled by people and can cause health problems in some people.

ACID RAIN CYCLE

EFFECTS OF ACID RAIN

Damages buildings

and objects

Lakes and Rivers

becomes dirty

Harms Forests

Unhealthy

to human

Damages on Buildings and Objects

• Acid rain can also have a damaging effect on many objects, including buildings, statues, monuments, and cars.

• The chemicals found in acid rain can cause paint to peel and stone statues to begin to appear old and worn down.

1908 1968

Effect on Lakes and Rivers

• Acid rain causes acidification of lakes and streams.

• The acid rain makes the waters uninhabitable and many fish in such rivers and lakes die.

• Acid rain causes poisonous substances to be released from the soils on the lake and river beds, which makes it impossible for fish to survive.

Acid Rain Harms Forests

• Acid rain contributes to the damage of trees and many sensitive forest soils.

• Acid rain that seeps into the ground can dissolve nutrients.

•  Trees that are located in mountainous regions, exposed to acidic clouds and fog.

Effects on Humans

• Acid rain can cause many disease.

CATALYTIC CONVERTER

A catalytic converter is a vehicle emissions control device that converts toxic pollutants in exhaust gas to less toxic pollutants by catalyzing a redox reaction.

Catalytic converters are used in internal combus-tion engines fueled by either petrol (gasoline) or diesel.

catalyst helps to convert carbon monoxide into carbon dioxide.

It converts the hydrocarbons into carbon dioxide and water.

It also converts the nitrogen oxides back into ni-trogen and oxygen.

CATALYTIC CONVERTER

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