MACROAIR

POLLUTANTS

AICD RAINOZONE

DEPLETIONGREEN HOUSE

EFFECT

ACID RAIN

WHAT IS ACID RAIN? Acid gases are

produced when fossil fuels like coal and oil are burned in power stations, factories and in our own homes. Most of these acid gases are blown into the sky, and when they mix with the clouds it can cause rain - or snow, sleet, fog, mist or hail - to become more acidic.

GASES CAUSING ACID RAIN

Sulphur dioxide (SO2)

Nitrogen oxides

Volatile organic compound

REACTION

When CO2 reacts with water, carbonic acid is formed.

CO2 (g)+H2O(l) H2CO3(aq)

When SO2 reacts with water, sulfurous acid is formed.

SO2 (g)+H2O(l) H2SO3(aq)

When NO2 reacts with water, nitric acid is formed.

2NO2(g)+H2O(l) HNO2(aq)+HNO3(aq)

SOLUTIONS

Sulphur dioxide can be removed from power stations chimneys but this process is expensive.

Use renewable energy like wind power, solar panels, tidal power, and geothermal energy.

Fit catalytic converters to vehicle exhausts which remove the nitrogen oxides.

Limit the number of vehicles on the roads and increase public transport.

OZONE DEPLETION

OZONE LAYER

Belt of ozone gas 15 to 50 kilometers above the earth's surface where ozone is present in concentrations of a few parts per million. This layer blocks (absorbs) ultraviolet part of the solar radiation (which causes skin cancer) from reaching the earth's surface.

OZONE DEPLETION

The fragile shield of ozone is been damaged by chemicals released on earth. The main chemicals that are depleting stratospheric ozone are :

CHLOROFLUOROCARBONS

AEROSOLS

HALONS.

GREEN HOUSE EFFECT

The “Greenhouse Effect”

The Earth’s surface thus receives energy from two sources: the sun & the atmosphere – As a result the Earth’s surface is ~33C warmer than it would

be without an atmosphere

Greenhouse gases are transparent to shortwave but absorb longwave radiation – Thus the atmosphere stores energy

Electromagnetic Spectrumincoming outgoing

1. Shorter, highEnergy wavelengths Hit the earthsSurface

2. Incoming energy Is converted to heat

3. Longer, infraredWavelengths hitGreenhouse gasMolecules in theatmosphere

4. Greenhouse gasMolecules in theAtmosphere emitInfrared radiationBack towards earth

78% nitrogen

20.6% oxygen

< 1% argon

0.4% water vapor

0.036% carbon dioxide

traces gases:Ne, He, Kr, H, O3

Methane, Nitrous Oxide

SOLUTIONS

Eliminate/Minimize Fugitive Emissions.

Improve Combustion Efficiency.

Improve Process Efficiency.