Coal's Air Pollution: A Hazardous Climate Change Legacy

Coal is a carbon-rich black rock formed over thousands of years due to heat and pressure. While it has been a reliable energy source, burning coal releases harmful environmental and health-damaging pollutants. These include mercury, lead, sulfur dioxide, nitrogen oxides, particulates, and various other heavy metals. In 2014, US coal power plants emitted 197,286 tons of small airborne particles, as well as other toxic pollutants. Coal-fired power plants are a major source of fine particulate matter (PM2.5) air pollution, which has been linked to increased mortality, with 50,000 coal-related deaths recorded annually in the US. Climate change, driven by carbon dioxide emissions, is another serious long-term impact of coal, contributing to global warming, rising temperatures, and sea level rise.

Coal's impact on climate change and global warming

Coal is an abundant and inexpensive fuel source that has long been a reliable source of energy in the US. However, it is also a major contributor to air pollution and global warming. The same chemical process that allows coal to produce energy—the breaking down of carbon molecules—also produces harmful environmental impacts and pollutants that harm public health.

When coal is burned, chemical reactions release energy, but they also emit toxic airborne pollutants and heavy metals into the environment. These include particulate matter (soot), carbon monoxide, volatile organic compounds (VOCs), arsenic, lead, cadmium, and mercury. These pollutants have been linked to a range of health issues, including asthma, cardiovascular issues, neurological problems, and cancer.

Coal-fired power plants are also a significant source of fine particulate matter (PM2.5) air pollution, which has been associated with an increased risk of death. Research by the National Institutes of Health (NIH) found that for every 1 μg/m3 increase in coal PM2.5, mortality increased by 1.12%, more than twice the risk associated with general PM2.5 exposure from all air pollution sources. The same study estimated that between 1999 and 2020, 460,000 deaths could have been prevented in the absence of emissions from coal power plants.

Coal is the main offender for global warming, as it is a major contributor to carbon dioxide (CO2) emissions, the primary greenhouse gas produced from burning fossil fuels. In 2022, CO2 emissions from burning coal for energy accounted for about 19% of total US energy-related CO2 emissions and 55% of total CO2 emissions from the electric power sector. The International Energy Agency (IEA) reported that burning coal has been responsible for over 0.3 degrees Celsius of the 1-degree increase in Earth's temperatures since the late 1800s.

Coal mining and extraction processes further contribute to environmental damage. Surface mining, which involves removing soil and rock above coal deposits, was the source of about 63% of the coal mined in the US in 2022. Mountaintop removal and valley fill mining, a type of coal extraction that uses explosives to remove mountain tops, has significantly altered the landscape of the Appalachian Mountains in West Virginia and Kentucky. This technique can result in streams being covered with rock and dirt, and the water draining from these filled valleys may contain pollutants that harm aquatic wildlife downstream.

While efforts have been made to reduce emissions and capture pollutants, such as through the use of scrubbers and carbon capture and storage technologies (CCS), the continued reliance on coal as an energy source poses a significant challenge in mitigating its impact on climate change and global warming.

Coal mining techniques and their effects

Coal mining, particularly surface mining, has been criticised for its environmental impact, including air pollution and climate change. The process involves removing layers of soil and rock to expose underground coal deposits, which can lead to the destruction of natural habitats and the displacement of wildlife.

One of the most prominent surface mining techniques is mountaintop removal, which is used in the Appalachian Mountains in West Virginia and Kentucky. This method involves clearing the land and using explosives to remove the mountaintop, with excess rock and soil dumped into adjacent valleys. This practice has buried over 2,000 miles of headwater streams, causing irreversible damage to wildlife habitats and water sources. The water draining from these filled valleys may contain pollutants harmful to aquatic life downstream, and the degradation of water quality can persist long after mining has ended.

Underground coal mining is considered less detrimental to the environment than opencast mining. However, due to various challenges, there has been a shift towards opencast mining, which has resulted in the release of dust and gaseous pollutants that severely impact air quality. The increased mechanisation of surface mining has also contributed to the deterioration of environmental quality, particularly the concentration of suspended particulate matter (SPM) within and around mining sites.

The handling of coal, from stockpiles to crushing and loading, also contributes to air pollution. Additionally, coal combustion releases pollutants such as sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter, and heavy metals, which have adverse effects on human health and the environment. To mitigate these impacts, the coal industry has developed methods to reduce impurities in coal and improve cleaning processes. Power plants also use flue gas desulfurization equipment ("scrubbers") to remove sulfur and other pollutants from smoke before release into the atmosphere.

Coal's contribution to air toxins and pollutants

Coal is a major contributor to air pollution and has been linked to a range of severe environmental and public health impacts. The burning of coal releases a multitude of toxic airborne pollutants and heavy metals, causing respiratory and cardiovascular diseases, systemic inflammation, neurodegeneration, and even premature death.

One of the most significant toxins released from coal-fired power plants is mercury, a toxic heavy metal. Coal plants are responsible for a substantial proportion of mercury emissions, which can cause damage to the nervous, digestive, and immune systems. In addition to mercury, coal power plants emit substantial amounts of other heavy metals, such as lead, cadmium, and arsenic, which are known to have severe health impacts. For example, arsenic causes cancer in one out of 100 people who consume water with a concentration of 50 parts per billion.

Coal-fired power plants also release particulate matter, often referred to as "soot." These small airborne particles can penetrate deep into the respiratory system, causing chronic bronchitis, aggravated asthma, and cardiovascular issues, including heart attacks. The health impacts of particulate matter are so significant that exposure to it has been associated with increased mortality. Fine particulate matter, known as PM2.5, from coal power plants is particularly deadly due to its high content of sulfur dioxide, black carbon, and metals.

Furthermore, coal combustion releases carbon dioxide (CO2), which is the primary greenhouse gas produced from burning fossil fuels. CO2 emissions contribute to global warming and climate change, leading to rising temperatures, accelerating sea-level rise, droughts, heatwaves, and intensified storms. Other emissions from coal-fired power plants include carbon monoxide, volatile organic compounds (VOCs), nitrogen oxides, and sulfur dioxide. These emissions contribute to smog, haze, acid rain, and respiratory illnesses.

While regulations and coal power plant retirements have led to a decrease in deaths associated with coal-fired power plants, the environmental and health impacts of coal combustion remain profound. Emerging technologies, such as carbon capture and storage (CCS), offer potential solutions to capture CO2 emissions, but they are expensive and have not yet been proven effective at scale.

Coal power plants and their health impacts

Coal power plants have been a major source of air pollution, which has been linked to a range of adverse health impacts. The burning of coal releases harmful pollutants into the atmosphere, including particulate matter, carbon monoxide, volatile organic compounds, heavy metals, and various toxic gases. These emissions have been associated with respiratory illnesses, cardiovascular diseases, neurological problems, and even certain types of cancer.

One of the most concerning pollutants emitted by coal power plants is particulate matter, often referred to as "soot." These tiny particles can penetrate deep into the respiratory system, causing irritation and inflammation. Exposure to particulate matter has been linked to chronic bronchitis, aggravated asthma, cardiovascular issues, and even premature death. People living in proximity to coal-fired power plants have been found to suffer from higher death rates and increased risks of respiratory and cardiovascular diseases, lung cancer, and other health problems.

Coal-fired power plants also release significant amounts of carbon monoxide, which can cause headaches and place additional stress on individuals with pre-existing heart conditions. Additionally, the volatile organic compounds (VOCs) emitted by these plants contribute to the formation of ozone, a harmful component of smog. Heavy metals, such as mercury, arsenic, and lead, are also released into the atmosphere, posing serious risks to human health. Mercury, for example, can damage the nervous, digestive, and immune systems. Arsenic is a known carcinogen, and lead has been linked to a range of developmental issues.

Furthermore, coal combustion is a significant contributor to global warming and climate change. Carbon dioxide (CO2) emissions from coal-fired power plants are a primary driver of the greenhouse effect, leading to rising temperatures, sea-level rise, and increased frequency and intensity of extreme weather events. While carbon capture and storage technologies (CCS) have emerged as a potential solution, their effectiveness at the scale required to address climate change remains unproven, and they do not address the myriad other harmful pollutants produced by coal power plants.

The health impacts of coal power plants have been increasingly recognized, and efforts to reduce emissions and retire coal-fired plants have resulted in decreased mortality rates. However, there is still a clear need for further research to fully understand the severity of health effects from air, water, and soil contaminants. This knowledge will be crucial in designing targeted policies and interventions to mitigate the health impacts of coal power plants and improve public health outcomes.

Coal ash and its disposal

Coal ash is a catch-all term for several kinds of waste left over at power plants that burn coal. It contains harmful substances like arsenic, mercury, cadmium, lead, and chromium. Short-term exposure to coal ash can cause irritation of the nose and throat, dizziness, nausea, vomiting, and shortness of breath. Long-term exposure can lead to liver damage, kidney damage, cardiac arrhythmia, and a variety of cancers. In the US, coal ash is one of the largest types of industrial waste generated, with nearly 130 million tons produced in 2014.

Coal ash is disposed of in different ways depending on the type of byproduct, the processes at the plant, and the regulations the power plant follows. Some power plants dispose of coal ash in surface impoundments or landfills, while others discharge it into nearby waterways under their water discharge permits. In the US, fly ash and bottom ash are generally stored near power plants or placed in landfills. However, improper disposal of coal ash can lead to environmental and health risks. Coal ash impoundment ruptures can cause damage to the environment downstream, and contaminants from coal ash can leach into groundwater and potentially reach drinking water sources, causing significant public health concerns.

To address these risks, the US Environmental Protection Agency (EPA) has established national rules for coal ash disposal and is strengthening controls on water discharges. The EPA's 2015 Coal Ash Surface Impoundment Integrity Assessment Program evaluated the safety of coal ash ponds nationwide, leading to actions that improved structural stability and enhanced environmental and public health protection. The EPA also finalized national regulations in 2015 to provide comprehensive requirements for the safe disposal of coal combustion residuals (CCRs) from coal-fired power plants. These regulations address risks such as leaking of contaminants into groundwater and blowing of contaminants into the air as dust.

In addition to safe disposal, reusing and recycling coal ash can also reduce its environmental impact. Coal ash can be recycled into products like concrete or wallboard, and land previously used for coal mining can be reclaimed for other purposes. Reusing coal ash can reduce greenhouse gas emissions, decrease the need for landfill disposal, and provide economic benefits such as reduced disposal costs and increased revenue from the sale of coal ash. However, despite these efforts, the health and environmental risks associated with coal ash disposal persist, and continued enforcement and innovation are necessary to mitigate these risks effectively.

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