Health Effects of Coal Energy Generation* | 13

ABSTRACT

Access to electricity has a positive effect on the health and well being of people worldwide (Wang, 2002)� The use of coal to generate energy, however, has negative health consequences (Smith et al�, 2013)� Evidence suggests an impact on health at every stage in its use for electricity generation-from mining to postcombustion disposal (Smith et al�, 2013)� The combustion of coal has been well studied, with compelling evidence of widespread health effects on the population� Air pollution produced by coal power plants can affect the respiratory and cardiovascular systems, and coal used for heating and cooking indoors generates pollutants known to cause

9�1 Introduction �� 169 9�2 Background �� 170 9�3 Health Effects of Coal-Fired Power Plants �� 170

9�3�1 Respiratory Effects �� 171 9�3�1�1 Particulate Matter �� 171 9�3�1�2 Sulfur Dioxide �� 172 9�3�1�3 Oxides of Nitrogen �� 172

9�3�2 Cardiovascular Effects �� 172 9�3�3 Reproductive Effects �� 173 9�3�4 Neurologic Effects �� 173

9�3�4�1 Mercury �� 173 9�3�5 Life Expectancy �� 173

9�4 Climate Change �� 174 9�5 Health Effects of Indoor Coal Combustion �� 174 9�6 Hazards of Coal Extraction �� 174 9�7 Cost of Coal Energy Generation �� 175 References �� 175

respiratory ailments and cancer� Coal combustion also contributes to climate change, which can harm human health on a global scale�

We review scientific evidence of health effects from the use of coal for electricity generation, focusing primarily on air emissions from coal combustion� We compile recent evidence of health effects from coal mining, transport, and combustion from the peer-reviewed literature as well as from governmental, international agency, and research institute reports� We searched biomedical research databases (Ovid Medline and PubMed) for articles using the search terms coal or solid fuel and health or burden or economic or cost� We included only English-language articles published in the past 10 years� We also reviewed articles mentioned in the references and included them if appropriate� We gave priority to articles examining coal use in power plants� We generally excluded studies of exposures produced by alternative uses of coal�

When coal is burned in power plants it produces air-borne pollutants: particulate matter (PM), sulfur dioxide (SO2), oxides of nitrogen (NOX), carbon dioxide (CO2), mercury, arsenic, chromium, nickel, other heavy metals, acid gases (HCL, HF), polycyclic aromatic hydrocarbons (PAHs), and varying amounts of radioactive uranium and thorium in fly ash particles�

In 2011, the World Health Organization (WHO) compiled air quality data from 1,100 cities in 91 countries and found that residents living in many urban areas are exposed to persistently elevated levels of fine particle pollution� The report states that in both developed and developing countries, the largest contributors to urban outdoor air pollution include motor transport, small-scale manufacturers and other industries, burning of biomass and coal for cooking and heating, as well as coal-fired power plants (WHO, 2011b)�

Forty percent of the electricity produced in the world is generated from burning coal, and the number of power plants burning coal is likely to rise in the next two decades as energy demand increases worldwide (International Energy Agency, 2007, 2012)� The World Resources Institute estimates that, globally, 1200 new power plants have been proposed, with 76% of them in China and India (Yang and Cui, 2012)� Most of coal’s health burden results from burning it in power plants� The remainder results from other steps of coal’s life cycle-extraction, transport, and disposal (Dones et al�, 2005; Rabl and Spadaro, 2006)�

In their 2007 article in The Lancet, Markandya and Wilkinson summarized the health burden of electricity generation using coal and lignite (the softest and most polluting form of coal)� The authors estimate that for every Terawatt-hour (TWh) of electricity produced from coal in Europe, there are 24�5 deaths; 225 serious illnesses, including congestive heart failure and chronic bronchitis; and 13,288 minor illnesses (Markandya and Wilkinson, 2007)� When lignite is used, each

TWh of electricity produced results in 32�6 deaths, 298 serious illnesses, and 17,676 minor illnesses (Markandya and Wilkinson, 2007)� The International Energy Agency reports that worldwide coal-based energy production was 8572 TWh in 2010 (International Energy Agency, 2012)� On the basis of per TWh estimates by Markandya and Wilkinson, the worldwide health toll from air pollution due to coal combustion is about 210,000 deaths, almost 2 million serious illnesses, and over 151 million minor illnesses per year� These estimates do not include the effects of climate change�

This calculation of health burden used European pollution levels and population density� In countries with weaker air pollution controls, higher use of coal, lower quality coal, or higher population density close to power plants, the health burden is greater� A study in China, reported by Markandya and Wilkinson in 2007 (Markandya and Wilkinson, 2007), estimated 77 deaths per TWh from a coal-fired power plant that met Chinese environmental standards-more than three times the estimate of deaths per TWh for coal combustion in Europe� For all of China, this would result in an estimated 250,000 deaths per year, based on estimates of coal combustion in China (International Energy Agency, 2012)�

Specific pollutants from burning coal harm the respiratory system: PM, SO2, and NOX, and others� Injury to the airways and lungs via oxidative stress leads to inflammation, cytotoxicity (direct harm to cells), and cell death�

9.3.1.1 Particulate Matter Particulates generated by burning coal are characterized by size-particles up to 10 micrometers called PM10, and smaller particles less than 2�5 micrometers (PM2.5), a subset of PM10� PM2�5 travels deeper into airways and is believed to cause more harm� A study of many power plants in China found that of the total mass of PM emitted, PM10 comprised 62%–84% and PM2�5 comprised 8%–44% (Yi et al�, 2006)�

In a report evaluating over 40 studies on the health effects of exposure to small PM (PM2�5), the US Environmental Protection Agency (USEPA) concluded that PM2�5 likely causes respiratory symptoms, the development of asthma, and decrements in lung function in children (USEPA, 2009b)� The EPA concludes that a 10 μg/m3 increase in PM2�5 is associated with a 1%–3�4% decrease in forced expiratory volume in 1 sec (FEV1) (USEPA, 2009b)� EPA also concluded that exposure to PM2�5 increases emergency department visits and hospital admissions for respiratoryrelated symptoms such as infections and chronic obstructive pulmonary disease� Epidemiological evidence from Australia and New Zealand (Barnett et al�, 2005), Mexico (Barraza-Villarreal et al�, 2008), Canada (Chen et al�, 2004), and Europe (de Hartog et al�, 2003) confirms that these effects on the respiratory system are seen wherever communities are exposed to PM2�5� In addition to respiratory illnesses, current evidence suggests that long-term exposure to PM2�5 is causally linked to the development of lung cancer (USEPA, 2009b)�

9.3.1.2 Sulfur Dioxide Exposure to SO2 emitted by coal-burning power plants increases the incidence and severity of respiratory symptoms of those living nearby, particularly children with asthma� For adults and children who are susceptible, inhalation of SO2 causes inflammation and hyperresponsiveness of the airways, aggravates bronchitis, and decreases lung function (USEPA, 2008b)� Community-level SO2 concentration is associated with hospitalizations for asthma and other respiratory conditions, as well as emergency department visits for asthma, particularly among children and adults over 65 years (USEPA, 2008b)� A review of epidemiological studies in cities in Italy, Spain, France, and the Netherlands found that low concentrations of SO2 (less than 10 ppb 24-hour average) are associated with increased risk of death from heart and lung conditions (USEPA, 2008b)� For every 10 ppb increase in SO2 concentration there is a 0�4%–2% increased risk of death (USEPA, 2008b)� Fortunately, ambient concentrations of SO2 in many countries have declined over the last few decades, owing to installation of pollution control technologies at coal-burning power plants� Countries with weaker pollution standards put their populations at risk of SO2 health effects� The ambient concentrations of SO2 in China, for example, increased from 2000 to 2006 at an annual rate of 7�3%, mainly because of emissions from power plants� But in 2005, new policy in China increased the use of flue-gas desulfurization technologies, and SO2 concentrations have begun to decline (Lu et al�, 2010)�

9.3.1.3 Oxides of Nitrogen NOX are by-products of fossil fuel combustion in automobiles and coal-fired power plants, and other places� NOX react with chemicals in the atmosphere to create pollution products such as ozone in smog, nitrous oxide (N2O), and nitrogen dioxide (NO2)� NO2 and ozone are of particular concern� When asthmatic children are exposed to NO2, they can experience increased wheezing and coughing (USEPA, 2008a)� At low concentrations (0�2-0�5 ppm), NO2 has been found to result in lung function decrements in asthmatics (USEPA, 2008a)� Exposure to NO2 also increases susceptibility to viral and bacterial infections, and at high concentrations (1-2 ppm) can cause airway inflammation (USEPA, 2008a)� Increases in ambient NO2 levels (3-50 ppb) are linked to increases in hospital admissions and emergency department visits for respiratory problems, particularly asthma (USEPA, 2008a)�

Coal-fired power plants contribute to the global burden of cardiovascular disease primarily through the emission of PM� PM2�5 has been causally linked to cardiovascular disease and death (USEPA, 2009b)� The WHO estimates that worldwide, 5% of cardio-pulmonary deaths are due to PM pollution (WHO, 2013)� The mechanism of cardiovascular injury is the same as for the respiratory system: vascular oxidative stress leads to vessel inflammation and cytotoxicity� Long-term exposure to PM2�5 has been shown to accelerate the development of atherosclerosis and increase emergency department visits and hospital admissions for ischemic heart disease and congestive heart failure� The USEPA reports that a majority of the studies it reviewed found a 0�5%–2�4% increase in emergency department visits and hospital

admissions for cardiovascular diseases per each 10 μg/m3 increase in PM2�5 concentrations (USEPA, 2009b)� A 2007 scientific review of the health effects of combustion emissions reported an 8%–18% increase in cardiovascular deaths per 10 μg/m3 increase in PM2�5 concentration in the United States (Lewtas, 2007)� Recent studies conducted in China and Latin America confirm the significant link between outdoor air pollution and cardiovascular events (Liu et al�, 2013; Romieu et al�, 2012)�

Research has documented that exposure to air pollution during pregnancy can cause low birth weight (Sram et al�, 2005)� Studies that investigated the effects of SO2 and PM (China, South Korea), and NO2, CO, and ozone (South Korea), concluded that air pollution containing these constituents was associated with low birth weight (Sram et al�, 2005)� In studies evaluating the association between electricity generation at coal-fired power plants and infant mortality, infant mortality was shown to have increased with increased use of coal in countries that had mid to low infant mortality rates at baseline (1965), such as Chile, China, Mexico, Thailand, Germany, and Australia, although this effect was not seen in those countries with high baseline infant mortality rates (Gohlke et al�, 2011)�

9.3.4.1 Mercury When coal is burned, mercury vapor is released into the atmosphere� The United Nations estimates that 26% of global mercury emissions (339-657 metric tons/year) come from burning coal in power plants (Pacyna et al�, 2010)� The mercury from coal-burning power plants is deposited into waterways, converted to methyl-mercury, and passed up the aquatic food chain (Lippmann et al�, 2003; National Research Council (US), 2010)� Local, regional, and distant mercury emissions contaminate fish� Methyl-mercury-contaminated fish, when eaten by pregnant women, can cause developmental effects in their offspring, such as delayed neurodevelopment, plus subtle changes in vision, memory, and language (WHO, 2007)� Epidemiological studies suggest that many newborns and children around the world have levels of mercury in their bodies that put them at risk of these adverse effects� Data from the United States suggest that more than 300,000 newborns each year are born at risk for these effects (Mahaffey et al�, 2004)� A study in Spain found 42% of the preschool or newborn children tested had mercury levels in their hair above the EPA reference concentration for safety, 1 μg Hg/g� A study in Hong Kong estimates that a majority of children exceed safety levels of mercury because of consumption of mercurycontaminated fish (Diez et al�, 2009; Lam et al�, 2013)�

A study modeling the effect on life expectancy of coal power generation predicted a decrease in life expectancy in countries with moderate life expectancy at the baseline year (1965), including Poland, China, Mexico, and Thailand� In India and

China, years of life lost were estimated to be up to 2�5 years and 3�5 years, respectively (Gohlke et al�, 2011)�

Global climate change is caused by the accumulation of greenhouse gases in the Earth’s atmosphere� Two of the major greenhouse gases contributing to climate change are products of coal combustion: CO2 and N2O� As the concentrations of these gases in the atmosphere increase, the average global temperature slowly increases, setting in motion a host of consequences that further promote climate change such as melting of polar ice and thawing of arctic permafrost�

As the average global temperature increases, researchers predict public health will suffer, particularly in low-income countries that have fewer resources to respond and adapt to the changes brought on by warmer global temperatures (Costello et al�, 2009)� A higher average global temperature and warmer oceans are already increasing the occurrence of extreme weather events such as floods, hurricanes, and droughts that, in turn, increase disease and injury and adversely affect water quality and food security (USEPA, 2009a, 2009c)� Warmer average temperatures alter ecosystems, decreasing some key food-chain supporting species such as corals, and increasing the growing ranges of some weeds, grasses, and trees that may further increase the severity and prevalence of allergies (USEPA, 2009a, 2009c)� Other consequences include the spread of climate-sensitive diseases such as tick-and mosquito-borne diseases and of food-and waterborne pathogens; an increase in ground-level ozone and smog, which aggravate asthmas and increase hospital visits; and an increase in the number of extremely hot days, which can cause heat-related mortality (Costello et al�, 2009; USEPA, 2009a, 2009c; McMichael et al�, 2006; Vardoulakis and Heaviside, 2012)� The mass migration of people to avoid these climate-related consequences may cause conflict and further stress on water, food, shelter, sanitation, and health care resources (International Energy Agency, 2007)�

Using solid fuels such as coal for heating and cooking is estimated to cause 910,000 deaths from acute lower respiratory infections in children under 5 years and 693,000-1 million deaths from chronic obstructive pulmonary disease per year worldwide (WHO, 2011a; Smith et al�, 2004)� Approximately 0�4 billion people worldwide, many of them in China, use coal to cook and heat their homes� In 2000, the WHO conducted a meta-study on the use of solid fuels for heating and cooking and reported that 12�9% adults in East Asia and 2�1% adults in South Asia are exposed to coal smoke from heating and cooking, causing accelerated loss of lung function and over 16,000 deaths from lung cancer per year (Smith et al�, 2004)�

The occupational health impacts of mining coal are well known and must be considered when reviewing the effects of electricity generation with coal� In a 2002 review of 250 studies on coal mining, Stephens and Ahern (2001) calculated that up to 12% coal

miners develop coal workers’ pneumoconiosis and silicosis because of the inhalation of dust during mining operations� Miners are also at higher risk for chronic bronchitis and accelerated loss of lung function� Most research on the health effects of coal mining has been undertaken among miners in large mines in Europe and North America (Stephens and Ahern, 2001)� Small scale mines, many of which are found in developing countries, are often more hazardous, resulting in higher rates of accidents and injuries� They often employ less-experienced workers and children� These populations have increased vulnerability to occupational disease and injury (Stephens and Ahern, 2001)�

The impacts of burning coal can be described in economic terms, and several papers have attempted to estimate the cost of using coal by assigning value to the environmental and public health damage caused during coal’s extraction, transportation, combustion, and disposal� One such study by Epstein et al� (2011) estimated that the external costs of coal-fired electricity production in the United States add an extra USD 0�178 to each kWh of electricity produced; an amount that would triple its cost to consumers� Another US report by Machol et al� (2013) estimated USD 0�19-0�45 per kWh as the cost of the health burden and environmental damages from coal combustion� As part of an analysis for the European Commission in 2005, Rabl et al� estimated the external life-cycle costs of fossil fuels (the most expensive of which was coal) to be 0�016-0�058 €/kWh (Yang and Cui, 2012)�

In 2011, the USEPA estimated the benefits and costs of the Clean Air Act, a law that regulates emissions of SO2, NOX, carbon monoxide, and PM in the United States� The EPA calculated that the ratio of health care cost savings to compliance costs was 25:1 in 2010, meaning that for every dollar spent complying with the Clean Air Act, 25 dollars were saved in welfare, ecological, and health care costs owing to lower disease burden, including a reduction in premature deaths, bronchitis, asthma, and myocardial infarction (USEPA, 2011)�

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