Friday, September 02, 2011
Once coal has been mined and processed, the vast majority of it is sent to power plants. This is the second major phase in the dirty life cycle of coal.
Coal burning power stations continue to speed up global warming by filling the atmosphere with vast amounts of carbon dioxide. Coal burning leads to acid rain and smog, and emits more than 60 different hazardous air pollutants such as a variety of toxic metals, organic compounds, acid gases, sulfur, nitrogen, carbon dioxide and particulate matter.
Carbon dioxide (CO2)
On average one 500-megawatt coal-fired power plant produces approximately 3 million tons/year of CO2. Each plant's emissions depend on its size and efficiency. A single power station in Martins Lake, Texas emitted more than 21 million tonnes of CO2 in 2006 - more CO2 than Slovenia, Estonia, Bolivia or Afghanistan emitted in 2004.
Worldwide, the 25 worst CO2 polluting power plants all burn coal. According to CARMA, these plants are responsible for over 570 million metric tonnes of CO2 emissions, the equivalent to the UK’s yearly fossil fuel related CO2 emissions.
Coal-burning power plants are a significant source of Sulphur dioxide (SO2) and nitrogen oxides (NOx), which are major players in acid rain and ground level ozone (smog).
Nitrogen oxides are also greenhouse gasses that react with organic compounds to form smog, which damages plant life, making it vulnerable to disease and extreme weather. It can also impair human health by causing increased risk of asthma, lung damage and premature death.
Acid rain occurs when SO2 and NOX interact with water, oxygen, and other chemicals in the air to form sulphuric acid and nitric acid. This toxin can fall from the sky in rain over a widespread area, killing fish and plants.
Forests are also impacted via direct damage to foliage and where forest soils have been stripped of nutrients by acid rain. The shocking impacts of acid rain on forests around the world have led to progress, in curbing toxic rain in the US and Europe for example, but it is estimated that acid rain still falls on 30 percent of the land in China, and on hundreds of its cities.
The fact remains that coal is still by far the single biggest source of sulphur emissions caused by power generation. In 2004, 95 percent of the 10.3 million tons of SO2, and 90 percent of the 3.9 million tons of NOx, released into the atmosphere by US power plants came from ones fuelled by coal.
Burning coal releases large amounts of the neurotoxin mercury into the air. Globally, coal-fired power plants are the single largest emitter of mercury emissions, accounting for over 50 percent of the mercury pollution caused by humans.
Once released, mercury settles in streams, lakes and rivers and on the earth itself, where it infiltrates the groundwater. From there, it enters the food chain via algae and infects all life forms, from minnows to predator fish to birds and mammals, whose diets include fish. A it goes up the food chain, the concentration of mercury intensifies. Forty-nine US states have issued fish consumption advisories due to high mercury concentrations in freshwater bodies throughout the country.
Mercury is especially damaging to foetuses, infants and young children because it affects the development of the nervous system. Exposure to mercury can cause brain damage, mental retardation, blindness, seizures and the inability to speak. Every year, about 410,000 children are born having been exposed to dangerous levels of methylmercury in the womb. At any one time, eight percent of women of childbearing age have more mercury in their blood than is deemed safe by the US Environmental Protection Agency. Mercuric chloride and methylmercury have been classified as possible human carcinogens by the US Environmental Protection Agency.
Coal-burning power plants release fine particles of sulphate, nitrates, ammonia, sodium chloride, carbon and mineral dust, smaller than the width of a human hair, that penetrate deep into the lung. Breathing these fine particles can decrease lung function, aggravate asthma and contribute to cardiovascular disease. They cause thousands of premature deaths. As the particles are so small, they are more likely to escape the cleaning mechanisms of coal power stations.
Every year, in the US alone, fine particle emissions from power plants are believed to cut short the lives of 30,000 people. Every year, 38,000 heart attacks, 12,000 hospital admissions and an additional 550,000 asthma attacks are a result of power plant pollution.
In India, a study in 2001 found that the inhabitants of 14 of India's 20 largest cities breathe air the government deems “dangerous”. Particle emissions from coal power stations are a major contributor to the poor air quality. (Greenpeace)