Acid rain is basically rain that has a higher than normal acid level (low pH).
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 – precipitation become more acidic.
When we burn fuels, chemicals called 'sulphur' and 'nitrogen' are released into the air. Most of the 'sulphur' comes from power stations Most of the 'nitrogen oxides' come from car and truck exhausts.
Once in the air, they mix with water in the air - rain, snow, etc - and are transformed into different chemicals called 'sulphur dioxide' and 'nitrogen oxides', which can be very dangerous for plants, animals and people.
Sulphur Dioxide ( SO 2) & Nitrogen Oxides ( Nox) are the primary causes of acid rain Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds. Sunlight increases the rate of most of these reactions. The result is a mild solution of sulfuric acid and nitric acid
In the atmosphere, sulphur dioxide is slowly oxidized to sulphur trioxide which dissolves readily in water droplets to form sulphuric acid. SO 2 – OXIDISED TO SO3 SO 3 + H 2 O= H 2 SO 4 Sulphuric acid is also formed when SO 2 dissolves in rainwater: SO 2 + H 2 O => H 2 SO 3
Nitrogen Monoxide when released into the atmosphere combines with atmospheric oxygen to form nitrogen dioxide: 2NO + O 2 --> 2NO 2 In a series of complex reaction, nitrogen dioxide combines with oxygen and water vapour to form nitric acid. 4NO 2 + 2H 2 O + O 2 --> 4HNO 3
Causes of Acid Rain Burning coal. Oil and natural gas in power stations makes electricity, giving off sulphur dioxide gas. Burning petrol and oil in vehicle engines gives off nitrogen oxides as gases. These gases mix with water vapour and rainwater in the atmosphere producing weak solutions of sulphuric and nitric acids – which fall as acid rain.
Acid rain can travel long distances. Often it doesn’t fall where the gas is produced. High chimneys disperse the gases and winds blow them great distances before they dissolve and fall to Earth as rain. The impact of acid rain in Europe has been sever and is most noticed in forests of the northeastern USA
How Acid Rain Affects The Environment Trees Acid rain can have terrible effects on a forest. The acid takes away important minerals from the leaves and the soil. Minerals are like vitamins for trees and plants. Without them, trees and plants cannot grow properly. They lose their leaves and become very weak.
The needles and leaves of the trees turn brown and fall off. Trees can also suffer from stunted growth; have damaged bark and leaves This makes them vulnerable to weather, disease, and insects.
FORESTS - GERMANY 1982 8 % DAMAGED 1983 34% 1985 50% HIGH ALTITUDE FORESTS ESPECIALLY VULNERABLE
ACID DEPOSITION Lakes are also damaged by acid rain. Fish die – this removes the main source of food for birds. Acid rain can even kill fish before they are born when the eggs are laid and come into contact with the acid.
21 ACID DEPOSITION RAINWATER 5.6 Ph < 5 pH kills aquatic life 18000 DEAD LAKES IN SWEDEN
Buildings Acid rain dissolves the stonework and mortar of buildings (especially those made out of sandstone or limestone). It reacts with the minerals in the stone to form a powdery substance that can be washed away by rain
Humans respiratory problems - Asthma, along with dry coughs, headaches, and throat irritations can be caused by the sulphur dioxides and nitrogen oxides from acid rain. Brain damage kidney problems, and Alzheimer's disease has been linked to people eating "toxic" animals/plants.
SMOG Name comes from a mix of “Smoke” and “Fog” First observed in London during the industrial revolution There are 2 types of smog: Industrial Smog (London) and Photochemical Smog (Los Angeles)
Types of Smog Photochemical Smog Industrial Smog
Industrial smog is in the forms of dust, dust, smoke, soot, ashes, smoke, soot, ashes, asbestos, asbestos, oil, oil, lead, lead, heavy metals, heavy metals, and sulfur oxides. and sulfur oxides.
Photochemical fog volatile organic compounds (VOCs) and oxygenated nitrogen (NOx) comes from combustion engines. Photochemical smog is air saturated with ozone, VOCs and aerosol particles
30 VOLATILE ORGANIC COMPOUNDS VOC METHANE- ENTERIC FERMENTATION AND ANEROBIC WETLANDS ETC METHANE CONCENTRATION IN THE STRATOSPHERE INCREASES WATERVAPOUR- GREENHOUSE FROM PLANTS - TERPENE, ISOPRENE
31 NITROUS OXIDE 320.9 PARTS PER BILLION. COMPARED TO A PRE-INDUSTRIAL HIGH OF 275PPB METHANE CONCENTRATIONS AT 1,789 PARTS PER BILLION COMPARED TO 750 PARTS PER BILLION (PPB) IN 1800
Nitrogen oxides (N 2 O, NO and NO 2 ) form a major component of photochemical smog. When they combine with hydrocarbons in the presence of sunlight, the result is ozone (O 3 ), the major component of smog.
33 Photochemical fogs Nitrogenous compounds NO2+UV= NO + O O+O2= O3 NO+ VOC+O2+UV= O3= OTHER OXIDANTS REDDISH BROWN SMOG PHOTOCHEMICAL OXIDANTS PHOTOCHEMICAL SMOG-