6.3c air pollution and acid...
TRANSCRIPT
Acid Precipitation § has a pH of less than that of natural rainwater
(pH 5.6)
§ a decrease of 1.0 on the pH scale means a 10-fold increase in the amount of acid present
Causes of Acid Rain § Natural Sources
§ effects of acidic deposits have been found in
glacial ice in remote parts of the globe
§ emissions from volcanoes and other biological processes contribute acid-producing gases
Acid Rain § principal cause of acid rain is from human sources
§ burning fossil fuels (e.g. coal) § driving cars § producing materials in factories
The Problem with Combustion § burning fossil fuels produces sulfur dioxide (SO2) (very
poisonous gas)
§ cars and power plants produce nitrogen oxides (NOx)
§ when SO2 and NOx are released into the atmosphere, they combine with H2O to form acids
§ SO2 and NOx may also be carried long distance by wind
§ these acids then enter the water cycle and fall to the Earth in the form of rain or snow (acid precipitation)
The Effects of Acid Precipitation
§ Acid precipitation eats away at marble, metal, plastics, and rubber § Parthenon in Athens, Greece § Taj Mahal in Agra, India
Effects of Acid Precipitation on Aquatic Life
§ Increased acidity in water § Stops eggs from hatching (e.g. fish) § Changes population ratios § Affects ecosystems
Example: Lake Trout
Overall, the number of species in the lake at pH 5.1 was 30% lower than normal
1979 – pH 5.6 1982 – pH 5.1
Effects of Acid Precipitation on Vegetation
§ Increased acidity in soil § Slows plant growth § Poisons plants § Creates brown spots in leaves of trees,
(interferes with photosynthesis) § Increases probability of infection through
broken leaves
The Effects of Acid Precipitation on Humans
§ Respiratory problems § Asthma § Dry coughs § Headaches § Throat irritations
Preventive Measures § Reduce SO2 and NOx released into the atmosphere
§ Use less energy (hence less fuel burnt)
§ Use cleaner fuels
§ Use other sources of electricity (i.e. nuclear power, hydro-electricity, wind energy, geothermal energy, and solar energy)
§ Reduce reliance on cars (car-pooling, public transport, bicycle)