What Is the Environmental Impact of Mining and Burning Coal?

By Alecia M. Spooner

Mining and burning coal for fuel is harmful to the environment; but, because coal is so abundant and cheap, many people are reluctant to give it up as a fuel source.

Coal starts as peat, or sections of partially decomposed organic matter that accumulate on the earth’s surface. Over millions of years, the peat is buried and heat and pressure transform it into increasingly pure forms of coal called lignite, sub-bituminous, bituminous, and anthracite coal.

These fossil fuels are limited or nonrenewable resources; after they serve their fuel purpose, they can’t be recycled back into a useful energy source. Their supplies are finite; when they’re gone, they’re gone. True, more coal, oil, and gas supplies may be created over time, but that won’t occur in our lifetime; fossil fuel production takes many millions of years.

Coal is found in layers of rock that have been compacted and folded into mountains. Coal resources are fairly abundant throughout the world, though like any geologic resource, they aren’t evenly distributed. The largest coal sources in the world appear in the U.S., Russia, China, India, and Australia.

The purest coal forms (bituminous and anthracite) provide the most energy, but in general, coal requires little to no refining before it can be burned as fuel. Coal’s abundance and ease of use make it an inexpensive fuel resource, particularly for developing nations that don’t yet have fancy industrial refineries.

• Burning coal releases toxins. Coal contains sulfur and other elements, including dangerous metals such as mercury, lead, and arsenic, that escape into the air when coal is burned. Burning coal also produces particulates that increase air pollution and health dangers.
• Burning coal emits large amounts of carbon dioxide into the atmosphere. Coal is composed almost entirely of carbon, so burning coal unleashes large amounts of carbon dioxide (CO2) into the atmosphere. These emissions have been shown to increase the greenhouse effect in the atmosphere and lead to global warming.
• Subsurface coal mining is dangerous. Coal is often mined in subsurface mines, which may collapse and trap miners. And the air in subsurface coal mines leads to black lung disease, where coal particles and pollutants fill the lungs and cause inflammation and respiratory illness.
• Surface coal mining damages the environment. Mountaintop removal mining is used to access layers of coal buried deep within mountains. This mining technique alters the landscape and damages ecosystems.

Because coal is so abundant and relatively inexpensive, many people are reluctant to give it up as a fuel source.

The U.S. contains one-quarter of the world's coal reserves, which could provide more energy potential than all the known recoverable reserves of oil. More than half of the nation's energy comes from coal, according to the U.S. Department of Energy. This domestic energy source reduces the U.S.'s reliance on foreign fuel sources and provides jobs to Americans.

For too long the coal industry has used our atmosphere like an open sewer for its airborne pollution. These emissions fuel climate change, but they also pose a serious threat to our health and environment. These threats include smog, acid rain, toxic mercury, and fine particles that embed deep in our lungs.

About airborne pollutants from coal plants

Burning coal is the biggest single source of carbon dioxide emissions from human activity. But coal power plants emit many harmful pollutants into the air, including:

• sulphur dioxide (SO2)
• nitrogen oxides (NOx)
• particulate matter (PM)
• various trace metals including mercury (Hg)

Once these pollutants enter the air from coal plant stacks they can disperse and cause harm over large areas.

Burning coal leads to acid rain and smog

Coal power plants release large amounts of sulphur dioxide and nitrogen oxides.

Nitrogen oxides are greenhouse gases, but these pollutants also react with organic compounds to form smog (ground level ozone). Harmful to our health, smog increases risk of asthma, lung damage and premature death. It also damages plants, making them vulnerable to disease and extreme weather.

Nitrogen oxides and sulphur dioxide also contribute to acid rain.

When these pollutants mix with water, oxygen, and other chemicals in the air, they form nitric and sulphuric acid. The resulting acid rain can spread over a wide area, killing fish and plants. In forests, acid rain damages tree leaves and strips nutrients from soils.

Coal burning releases toxic mercury

Globally, coal-fired power plants are the largest single source of mercury emissions. They release over half of the mercury pollution from human activity.

Mercury is a neurotoxin; it has harmful effects on the brain and nervous system.

Mercury released from power plants settles into the environment, spreading into groundwater and entering the food chain via algae. From there it infects all life, from minnows to fish that prey on them, and on to fish-eating birds and mammals. Passing from lower to higher levels of the food chain, mercury concentrations increase.

• In the USA, forty-nine states have issued fish consumption advisories due to high mercury concentrations in freshwater bodies.

Particle pollution hurts our lungs

Also called particulate matter, or PM, particle pollution is possibly the most harmful emission from coal power plants. These very small unburned pollution particles released directly from coal plant smokestacks cause an estimated 800,000 premature deaths each year.

When inhaled, particle pollution can have wide-ranging and harmful health effects, including asthma attacks, lung tissue damage, stroke, heart attack and premature death.

• Particles 2.5 microns (PM2.5) or smaller can penetrate deep into the lungs, and caused five percent of global deaths, making this the sixth leading global risk factor in 2013, according to the Global Burden of Disease (GBD) study.
• The first analysis on death and disease due to coal power plants in India estimates 80,000 to 115,000 people died prematurely in a single year due to particle pollution 10 microns in size (PM10).
• Research co-authored by Greenpeace in China shows that PM2.5 pollution from the 196 coal-fired power plants in the Beijing-Tianjin-Hebei capital region caused 9,900 premature deaths and nearly 70,000 outpatient visits or hospitalizations during 2011. Seventy-five percent these premature deaths were caused by Hebei province's 152 coal-fired power plants.

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.

Other gases

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.

Mercury poisoning

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.

Particle emissions

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.