AISS 2024 Atmosphere and Environment Notes

may contains Air pollutants (refer to table) Air pollution is the condition in which air contains a high concentration of chemicals that may harm living things or damage non-living things. Clean, dry air The Atmosphere Carbon cycle (Box A) Carbon cycle is the mechanism that maintains the level of carbon dioxide in the atmosphere. The Atmosphere and Environment Pollutants Sources (how they are produced) Harmful effects How to reduce the effect? Carbon monoxide (CO) Incomplete combustion of fossil fuels in power plants, factories or combustion engines of vehicles due to lack of oxygen • Reacts irreversibly with haemoglobin in blood to form carboxyhaemoglobin which reduces the ability of haemoglobin to transport oxygen to rest of the body • Results in breathing difficulties, fatigue and even death. • Catalytic converters (Box E) Sulfur dioxide (SO2) • Combustion of fossil fuels which contain sulfur impurities in motor vehicles, power stations and factories • S (s) + O2 (g) → SO2 (g) • Volcanic eruptions • Irritate the eyes and lungs and cause breathing difficulties • Reacts with water in atmosphere to form acid rain (Box B) which corrodes metal and limestone structures and harms aquatic life and plants. • Liming (adding calcium carbonate to neutralise and hence restore lakes and rivers polluted by acid rain) – expensive and effects are temporary. • Flue gas desulfurisation (Box F) Oxides of nitrogen (NO and NO2) • Internal combustion of engines • Lightning activity *temperature must be high for oxides of nitrogen to be formed. N2 (g) + O2(g) → 2NO (g) 2NO(g) + O2 (g) → 2NO2 (g) • Irritate the eyes and lungs and cause breathing difficulties • Reacts with water in atmosphere to form acid rain (Box B) which corrodes metal and limestone structures and harms aquatic life and plants. • Leaches nutrients from the soil and causes plants to wither and die. • Liming (adding calcium carbonate to neutralise and hence restore lakes and rivers polluted by acid rain) – expensive and effects are temporary. • Catalytic converters (Box E) Unburnt hydrocarbons Released in vehicle exhaust fumes and chemical plants • Health: cause cancer • Environment: react with nitrogen oxides to form ozone which can damage crops • Catalytic converters (Box E) Methane Colourless and odourless gas Decay of plant and animal matter • It is a greenhouse gas which causes global warming (Box C) and thus cause melting of large quantities of ice in north and south poles, resulting in floods that destroys crops and buildings. Ozone (O3) Pale blue pungent gas • Health: forms photochemical smog which irritates the eyes and lungs and causes breathing difficulties • Environment: damages crops, reduce visibility for traffic Chlorofluorocarbons (CFCs) – compound that contains carbon, fluorine and chlorine. Propellants in aerosols, as well as coolants in refrigerators and air conditioners, release CFCs into