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3 LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH This chapter considers the connections between energy choices and human health, with a focus on the health impacts of climate change mitigation and air quality. It is suggested that energy changes could lessen the environmental problems associated with climate change (e.g., increased drought, flooding, heat waves, and storms), while also addressing the high burdens of illness (e.g., cancer, cardiovascular disease, and pneumonia) that impact populations throughout the world. In discussing policy options (primarily looking at the United States), the presenters try to address the difficult trade-offs that may be required to adapt the current energy system to benefit human health. A summary of the presentations is provided. THE ROLE OF PUBLIC HEALTH IN THE ENERGY-CLIMATE CHALLENGE Daniel P. Schrag, Ph.D. Director, Harvard University Center for the Environment Sturgis Hooper Professor of Geology and Professor of Environmental Science and Engineering Harvard University Daniel P. Schrag began his presentation by highlighting that the world energy system has changed substantially from 1800 to the present: transitioning from mostly wood to the onset of coal, then the growth of oil, natural gas, and hydropower, and most recently the arrival of nuclear energy. Roughly 85 percent of the energy in the United States now comes from fossil fuels. Combustion of fossil fuels has resulted in a 41
42 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY steadily increasing concentration of carbon dioxide in the atmosphere; in 1957, the concentration of atmospheric carbon dioxide at Mauna Loa, Hawaii, was 315 parts per million, and today it is nearly 400 parts per million (Keeling and Scripps Institution of Oceanography, 2012; Tans and NOAA/ESRL, 2011). Schrag noted that we know from measure- ments of air bubbles trapped in ice cores that the concentration today is higher than it has ever been for at least the past 800,000 years, and probably for several million years. When carbon dioxide is released into the atmosphere, roughly 50 percent is taken up by the land and ocean within about 1 year (Archer and Brovkin, 2008). What remains is slowly taken up by the ocean over several thousand years, all except for 10 to 20 percent, which will remain in the atmosphere for tens of thousands of years (Archer and Brovkin, 2008). Thus, there is a very long âtailâ of the impact of human activities on the carbon cycle, he said, and our decisions about energy choices over the next several decades will affect the Earth for tens of thousands of years. Carbon dioxide and other greenhouse gases are known to contribute to the radiative forcing1 of climate change (IPCC, 2007). There are many different ways to estimate the sensitivity of Earthâs climate to changes in carbon dioxide concentration, but Schrag cited a useful geological comparison to put the projected changes over the next century in perspective. Twenty-thousand years ago, much of North America was covered by the Laurentide ice sheet, sea level was 130 meters lower than today, and global average temperature was 5 degrees Celsius colder (Bluemle et al., 1999). The transition from that climate, called the âLast Glacial Maximum,â2 to the preindustrial climate took roughly 10,000 years (Clark et al., 2009). Schrag noted that over the next 100 years, models predict that the Earth may warm by approximately 5 degrees Celsius (IPCC, 2007), highlighting that this is the same magnitude of change but 100 times faster. Because the time scale of this temperature change is so much shorter than what the Earth has experienced over geologic history, said Schrag, it is difficult to predict exactly how human society or natural ecosystem will react to these changes. Schrag stated 1 Radiative forcing is used to compare how a range of human and natural factors drive warming or cooling influences on global climate; positive forcing tends to warm the surface while negative forcing tends to cool it (IPCC, 2007). 2 The Last Glacial Maximum is the most recent interval in the Earthâs climate history when global ice sheets were at their maximum extension, which occurred between 26,500 and 19,000â20,000 years ago (Clark et al., 2009).
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 43 that some of the greatest impacts for human society may include droughts, heat waves, floods, storms, sea level rise, and changes in mountain snowmelt. It is often stated that there is great uncertainty in the predictions of future climate change (IPCC, 2007), and Schrag noted that is correct. He went on to add that no human has ever witnessed carbon dioxide levels as high as they are today (IPCC, 2007), so it is a very challenging scientific problem to predict how the Earth system will respond. However, this uncertainty is sometimes taken to mean that future climate change is likely to be milder than scientists predict. Many lines of evidence suggest that the opposite is true, and Schrag suggested that scientists have been overly conservative in their predictions. He cited the concern about the collapse of Ross Ice Shelf 3 as a good example. The flow of ice from West Antarctica into the Ross Sea is impeded by the Ross Ice Shelf, which is a piece of glacial ice more than 250 meters thick that has flowed out over the ocean (Crary et al., 1962). If the entire Ross Ice Shelf breaks off from Antarctica, it would allow the very rapid flow of ice from West and East Antarctica into the Ross Sea, which could cause sea level to rise rapidly, possibly a meter or more over a century (Oppenheimer, 1998). Schrag stated that this has been described as a low-probability, high-consequence event, but our understanding of whether this will occur is limited by the sparse data available on oceanographic conditions around the perimeter of Antarctica. In fact, he added, the collapse of the Ross Ice Shelf is an event of high consequence and unknown probability; it might be very unlikely or it might be absolutely certain, we just do not know. But because scientists tend to be conservative in their assessments (e.g., relying upon 95 percent con- fidence intervals), the public perception of risk may be lower than reality. Impacts of Climate Change on Human Health Schrag noted that climate change will impact human health in several areas, including ï· changes in the distribution of infectious disease, ï· water scarcity, 3 The Ross Ice Shelf, located in Antarctica, is the largest floating freshwater ice formation in the world (Crary et al., 1962).
44 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY ï· nutritional changes, ï· food availability, and ï· population displacement. Some experts believe that nutrition and food availability will be impacted the most, especially in low-income countries, he said. This will likely result in both direct changes (e.g., malnutrition) and indirect changes (increased diseases). Additionally, Schrag emphasized that the world food system may be further strained by factors other than climate change, such as global economic growth, global population growth, and more countries transitioning to a Western-style diet. These factors are projected to result in a doubling of global food demand by 2050 (Tilman et al., 2011). Schrag stated that models and observational studies show that temperature can have a great impact on agricultural yields. Experimental and crop-based models that investigate temperature changes in the tropics and subtropics show that a 1 degree Celsius increase in growing season temperature can result in a 2.5â16 percent loss in yields of maize, rice, and wheat (Lobell et al., 2008; Peng et al., 2004). These estimates are also supported by observational data from other regions. In 2010, Russian wheat production decreased by more than 30 percent compared to the previous year because of extreme heat waves during the growing season (USDA, 2011). Schrag noted that the country was forced to ban grain exports through the middle of 2011 in order to meet domestic demands throughout this period. With studies predicting a rise in the average temperature for the latter part of the century, the most extreme summer temperatures observed over the last few decades may become the average summer conditions in the future (Battisti and Naylor, 2009). In addition to temperature change, Schrag said the increasing con- centration of carbon dioxide in the atmosphere impacts the concentration of several essential nutrients in todayâs plants. This can cause serious iron, iodine, and zinc deficiencies for those who rely on grains for these micronutrients (mostly people in the developing world); these deficiencies already affect half the worldâs population and lead to serious illness (Loladze, 2002). Overall, Schrag emphasized that climate change can be viewed as an additional destabilization of an already tenuous relationship between humanity and the global resource base. Schrag stated that it is very important to consider the impacts that climate change mitigation can have on health. And, he added, moving away from fossil fuels can be beneficial for health for many reasons.
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 45 Results from the Harvard Six Cities Study show that when adjusting for other health risk factors, particulate air pollution in the United States is associated with mortality (Dockery et al., 1993). Additionally, research- ers have found that when the particulate air pollution decreases (such as during local steel mill closures), hospital admissions for pneumonia, bronchitis, and asthma also decrease (Pope, 1989). Schrag noted that the health community and the climate change community can come together to support cleaner energy sources and move away from obvious failures in the market (such as dirty, conventional coal-fired power plants). Is Technology the Answer? Scientists and policy makers are currently laying out ways to reduce carbon emissions and mitigate climate change. Schrag noted that the proposed solutions appear to fall into three categories: (1) efficiency or conservation of energy sources, (2) nonfossil fuel energy (such as renewable or nuclear energy), and (3) carbon capture and storage of fossil fuel energy. He said it is clear that innovation in technology in each of these areas is an important part of the solution. The public may have some willingness to put a penalty (such as a carbon tax or additional regulation) on fossil fuel technologies that contribute greenhouse gases in the atmosphere, but in the long run, nonfossil technologies will have to be economically competitive. At the same time, he noted, social attitudes may also play an important role, and concerns about health will be of primary importance. Schrag suggested that new policies to reduce the concentration of atmospheric carbon dioxide may require tough choices and trade-offs to effectively rebuild the global energy system. Many of the trade-offs may be based on values, which can impact many of the decisions that lie ahead. Schrag added that the values can change depending on whose health is being considered; addressing global health may involve very different solutions with different mechanisms compared to addressing health in the United States or the developing world. Global efforts may possibly fall short of what is required to prevent massive suffering of human societies and the natural world. He noted that how the world will react is still unknown.
46 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY ENERGY AND HEALTH: WHO IS AT RISK? Paul Wilkinson, F.R.C.P., M.P.H. Professor in Environmental Epidemiology London School of Hygiene and Tropical Medicine Paul Wilkinson stated that the way energy is used has many impacts on human health. He noted that some adverse health impacts arise from a lack of access to adequate energy sources (often seen in low-income settings, though fuel poverty is also a problem in many higher-income settings), while others occur from overdependence on access to energy sources, especially in high-income settings. For instance, too much access may produce overconsumption or sedentary lifestyles at the household level, road injuries or outdoor air pollution at the local level, and climate change or other low-probability, high-impact environmental events at the global level. In contrast, inadequate or inefficient energy sources may result in indoor air pollution or lost human potential at the household level, lack of infrastructure or decreased health protection at the local level, and energy insecurity and price volatility or international tensions at the global level. Wilkinson proposed that the outcomes observed at the global level are difficult to measureâthe consequences of energy price volatility are complex and largely indirect, and those of climate change are somewhat uncertain and largely in the futureâbut they could represent very large impacts on health. Wilkinson stated that it is much easier to quantify events at the local and household levels. For instance, the problem of indoor air pollution can be assessed by investigating the burden of illness related to indoor smoke from burning solid fuels in the home (from which 2 million people die prematurely each year) (WHO, 2011a). Additionally, he noted, overconsumption and lack of physical activity can be depicted in obesity trends (which are increasing throughout the United States and spreading globally), as well as in increased deaths due to cardiovascular disease or other chronic diseases that are partly attributable to these risk factors. When comparing what is known about the health impact of climate change to other burdens of disease that are affecting the world (e.g., lack of access to clean water, malnutrition, and HIV/AIDS), Wilkinson emphasized that the understood direct health consequences of climate change, though appreciable, do not present a uniquely large threat that
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 47 alone justifies an unprecedented social response. Wilkinson stated that the case for transformative action on climate change is based rather on the potentially widespread adverse impacts across many areas, including social, environmental, and economic disruption. Health impacts add to this case, but are only one element of it. Moreover, he noted that many of the threats of greatest concern arise not from the potential for incremental âlinearâ changes but from the smaller and largely unquantifiable chance of catastrophic change that could negate decades of economic and social advance. Wilkinson asserted that behavior change alone, without major change in technology and infrastructure, is unlikely to achieve more than a small reduction in energy consumption, and its effect on greenhouse gas emissions may well be overwhelmed by increasing wealth and economic trends. Nonetheless, he said, behavior change can in principle make a major contribution to population health; the main uncertainty is how to achieve change. It is perhaps more realistic to motivate behavior change with evidence of (near-term) health and societal benefits (which may also help climate change) than motivating it with the need to solve climate change (which may provide some health benefits). He noted that this represents a subtle shift in emphasis for motivating accelerated mitigation action, and emphasizing the potential for social and public health benefits. Wilkinson asserted that achieving a major reduction in the worldâs dependence on carbon-based fuels is importantâin part to tackle the serious threat of climate change but also because of the associated current adverse public health burdens, concerns about energy security, and the potential for improving health and quality of life. He stated that there are many examples of actions aimed at reducing dependence on fossil fuels that also may help address major public health priorities. The health effects, which are often but not universally positive, provide an additional rationale for mitigation action. Wilkinson noted that major change in all sectors of the economy is required to meet greenhouse gas reduction targets, and will be transformative. A modeling exercise looked at a combination of quite major changes for London, including substantial reductions in bus, car, and building emissions and an assumption that 50 percent of shorter journeys will be made in the future by walking, cycling, or public transportation. This model would likely achieve around a 22 percent reduction in carbon dioxide emissions, which is still far short of the needed target of an 80 percent or a 90 percent reduction by mid-century for high-income economies such as the United Kingdom (Woodcock et al., 2009). However, these changes could
48 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY make an appreciable contribution to addressing high burdens of public health illness while also helping to lessen environmental problems. For instance, vehicle transport is responsible for environmental pollution and climate change, but it also causes road injuries, contributes to physical inactivity (with consequences on chronic disease and mental well-being), and leads to overweight and obesity. Wilkinson stated that promotion of active transport (increased walking and cycling with reductions in car use) could therefore address multiple public health burdens. Modeling based in London shows that large increases in walking or cycling in place of motor transport can result in a 10â19 percent reduction in total ischemic heart disease burden, a 10â18 percent reduction in cerebro- vascular disease burden, and a 12â13 percent reduction in total breast cancer burden, although with some increase in risk of road injury (Woodcock et al., 2009). Increased active transport is also associated with much greater reductions in disability-adjusted life-years (DALYs) when compared to interventions that only lowered motor vehicle carbon dioxide emissions and air pollutants (7,332 DALYs compared to 160 DALYs saved per million population per year, respectively) (Woodcock et al., 2009). Wilkinson noted that public health benefits are also measurable with respect to changes in home heating. A study that compared the effects of outdoor temperature on cardiovascular death showed a stronger association between outdoor temperature and mortality in colder (less energy efficient) homes than in warmer (more energy efficient) homes, (Wilkinson et al., 2009). In other words, he said, warmer homes were associated with a protective effect against cold-related cardiovascular death. Models show that improved energy efficiency or retrofitted insulation (roof insulation, window upgrades, etc.) can also protect against increased indoor temperatures during periods of overheating, and potentially against the ingress of harmful pollutants from the outdoor air (although there is a risk of increasing the concentration of pollutants from indoor sources, including radon, secondhand tobacco smoke, and combustion-related particles) (Mavrogianni et al., 2011). Finally, Wilkinson said, the source of primary energy used for electricity generation is relevant not only for mitigation but also to air pollution and occupational risks to health (Markandya and Wilkinson, 2007). He added that lignite, coal, and oilâwhich have the highest emissions in terms of carbon dioxideâare the most dangerous in terms of serious illness and death from air pollution (Markandya and Wilkinson, 2007). Wilkinson emphasized that among the options with both low greenhouse gas
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 49 emissions and low health impact is nuclear energy, which overall appears to have one of the lowest levels of adverse health impact under normal plant operations. He noted that the estimate changes when nuclear accidents or disaster health effects are incorporated, but they are still low compared with the high burdens associated with fossil fuel burning (Markandya and Wilkinson, 2007). Who Is at Risk? Wilkinson stressed the importance of looking at the impacts of climate change interventions and assessing the potential co-benefits to health. He pointed out that to some degree everyone is at risk of energy- related exposures (and consequent climate change), but the burden falls disproportionately on the poor. The risks are of different forms: some are deferred (e.g., those associated with climate change); some are not readily visible but pervasive (e.g., air pollution); and some are very visible but uncommon (e.g., nuclear risk). Wilkinson emphasized that future sustainable energy plans may involve many often difficult choices, which will need to take account of the different forms of risks and benefits and the overarching imperatives for climate change. He noted that nuclear energy is a particularly difficult issueâdespite its feasibility and ability to reduce emissions, and its historically low overall health impactâbecause of public perceptions and fears. Wilkinson asserted that all choices entail advantages and disadvantages. But as a general principle, he said that the move to a low-carbon economy can have the potential for appreciable ancillary impacts on public health, which are important to consider in any decision process. ENERGY AND NONCOMMUNICABLE DISEASES: HOUSEHOLD AIR POLLUTION Kirk R. Smith, M.P.H., Ph.D. Professor of Global Environmental Health University of California, Berkeley Kirk R. Smith began by stating that among all species, humans alone can control fire, which suggests that controlling fire is the oldest occupation in human history. He noted that perhaps a million years ago,
50 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY cooking hearths became a regular feature in human habitation. Today, a smaller percentage of the world population uses solid fuels (consisting of coal and various forms of biomass, such as wood, crops, and dung)4 to cook than any time in human history (approximately 40 percent) (WHO, 2011b). However, the absolute number of people using solid fuels throughout the world is still rising because of persistent population growth and poverty (WHO, 2011a). Smith emphasized that there were more people using solid fuels for cooking in 2010 (nearly 3 billion) than the total world population in 1950 (Smith, 2011; UNDP and WHO, 2009). Overall, Smith stressed that the absolute scale of this practice is showing no sign of abating. Smith stated that the three main solid fuels used globally are coal, crop residues, and wood. He noted that the smoke from biomass fuels in simple stoves contains many toxic pollutants, such as respirable small particles (PM2.5), carbon monoxide, nitrogen dioxide, hydrocarbons (e.g., benzene and 1,3-butadiene), oxygenated organics (e.g., formaldehyde and methanol), and chlorinated organics (e.g., methylene chloride and dioxin) (Naeher et al., 2007). Coal combustion has these pollutants plus a range of other contaminants. Additionally, researchers have found that the exposures from a typical wood-fired cookstove in India exceed the health-based standards for small particles (often the best single indicator of overall air pollution), carbon monoxide, 1,3-butadiene, and two IARC Group 1 carcinogensâbenzene and formaldehyde (Smith, 2011). In a study based on thousands of measures combined with modeling across India, the average personal concentration of PM2.5 exposure for households using solid fuels was far beyond the U.S. Environmental Protection Agency standard and the World Health Organization (WHO) guideline (285 Âµg/m3 compared to 15 Âµg/m3 and 10â35 Âµg/m3, respectively) (Balakrishnan et al., 2011). Smith went on to state that the 2000 Comparative Risk Assessment Project, managed and first published by WHO in the World Health Report 2002 as part of the Global Burden of Disease Project, was able to 4 âBiomass fuelsâ include wood, crops, and dung that are burned to support the basic energy needs of daily life, including cooking, lighting, and climatic control (Sinha and Nag, 2011). The term âsolid fuelsâ includes biomass fuels, along with coal, which can produce different air pollutants compared to biomass when burned (Sinha and Nag, 2011). Smith provides evidence on the environmental and health effects of burning biomass fuels, coal, and solid fuels (the two together) throughout his presentation.
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 51 show consistent associations between indoor use of solid fuels and three diseases: (1) acute lower respiratory infections in children, (2) chronic obstructive pulmonary disease (COPD), and (3) lung cancer (WHO, 2002). When ranked with all major risk factors, the top risk factor in 2000 was malnutrition, followed by unsafe sex, and other factors that affect many populations (high blood pressure, tobacco consumption, and alcohol consumption) (WHO, 2002). The first environmental risk factor on the list, unsafe water and sanitation, appears at number six, and indoor smoke from solid fuels was listed at number eight (WHO, 2002). Revised estimates for the attributable burdens of disease from about 60 risk factors worldwide were provided in the Global Burden of Disease Study 2010 and published in The Lancet in late 2012. In addition to better estimates of household air pollution exposure5 and risks for the diseases in the previous version, sufficient evidence has become available to include the risk of additional disease categories, including cardiovascular disease and cataracts. For the year 2010, household air pollution ranked as the fourth most important risk factor globallyâafter high blood pressure, smoking, and alcohol useâand second overall for females (Lim et al., 2012). RESPIRE: Quantifying Health Effects of Household Air Pollution RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects) was initiated to address a request by the international health community for randomized controlled trials (RCTs)âthe gold standard for assessing causalityâthat assess linkages between household air pollution and potential health effects (including acute lower respiratory infections [ALRI]). Smith noted that public health budgets are minimal in many poor countries, and it is difficult for public health officials to divert money from supplying antibiotics or vaccines when the benefit of improved cookstoves has not been quantified. (A natural experiment that introduced improved cookstoves to China in 1980 did demonstrate a reduction in COPD rates [Chapman et al., 2005], but this study was not randomized.) In the 1980s, a randomized control study measuring ALRI in children was designed, but it remained unfunded until the U.S. National Institute of Environmental 5 Household air pollution includes the air pollutants (including organic, inorganic, and particulate matters) that are produced from the combustion of solid fuels in the home (Sinha and Nag, 2011).
52 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY Health Sciences offered financial support in 2001. The design of RESPIRE allowed a chimney cookstove to be randomly given to households in place of open cook fires in a community in the highlands of Guatemala (Smith et al., 2011). Smith stated that passive diffusion tubes that are often used by industrial hygienists were worn by inhabitants to measure exposures. Before the intervention, there were similar levels of carbon monoxide in the kitchens; after the intervention, however, there was a 90 percent reduction of carbon monoxide levels in the kitchens of those who received a stove (Smith et al., 2011). Never- theless, the personal exposure for the children was reduced only by 50 percent (Smith et al., 2011). In fact, the level of carbon monoxide exposure among some children with the chimney stoves overlapped the level of exposure for some children with the open fire, and some of the children with the chimney stoves even had higher levels of carbon monoxide exposure than the children with the open fire did (Smith et al., 2011). Thus, in spite of being highly popular, well used, and reducing household air pollution substantially, the chimney stove was not very good at reducing actual carbon monoxide exposure, the important parameter for health (Smith et al., 2011). Additionally, much of the childrenâs carbon monoxide exposure was occurring not in the kitchen, but around the home, and the chimney contributed to this exposure by venting smoke to the outdoor area (Smith et al., 2011). Smith stated that the overall lesson here is that it would be better to eliminate the pollution in the first place rather than moving it somewhere. In this study, the primary health outcome was physician-diagnosed pneumonia, where a strong exposure-response relationship was observed (Smith et al., 2011). From these data, it is possible to estimate that a 90 percent reduction in smoke exposure will eliminate 85 percent of severe pneumonia confirmed by X-ray (Smith et al., 2011). Smith emphasized that this is a significant effect, and arguably larger than the impact of any vaccine or nutritional supplement. Thus, he stated, exposure to household air pollution is an important cause of ill health, at least in certain populations throughout the world. Beyond the Kitchen: Impacts on Outdoor Air Quality and Climate Combined data from several international air pollution data sets show that household air pollution from solid fuels are a significant source of ambient air pollution in many regions (Lim et al., 2012). Globally, household air pollution represents 16 percent of the burden of disease
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 53 from ambient particulate matter pollution (Lim et al., 2012), but in some heavily polluted regions such as India, it accounts for more than 25 percent (Chafe, 2010). Smith noted that the densely populated river valleys of India and China, rather than the cities, are where many households are burning solid fuels poorly. Smith argued that the significant outdoor air pollution found in China and India, as well as many other middle-income countries, cannot be solved without addressing household air pollution sources as well as others. In addition to the health implications, Smith pointed out that there is also a global climate impact from the combustion of biomass fuel. For example, Unger and colleagues (2010) provide an instantaneous look at the radiative forcing at 2020 due to continuous year 2000 emissions. It is interesting to note that biomass fuel use exerts the second largest net positive radiative forcing among the economic sectors examined (Unger et al., 2010). Smith stated that use of biomass fuel impacts the climate partly because of the deforestation it causes and carbon dioxide emissions it produces, and partly because of the nonâcarbon dioxide pollutants it emits. Cardiovascular Disease and Household Air Pollution Smith described the results of a study that might shift how the public health community approaches air pollution. A recent seminal analysis from Pope and colleagues (2009) compared the adjusted relative risks of cardiovascular and cardiopulmonary mortality from ambient (outdoor) air pollution, environmental tobacco smoke, and active smoking. Active smokers inhaled the greatest amount of PM2.5 per day, higher than 10 mg (and some exposures were greater than 100 mg) (Pope et al., 2009). People exposed to ambient air pollution and environmental tobacco smoke inhaled lower doses of PM2.5, less than 1 mg per day (Pope et al., 2009). Smith noted that the authors found a clear relationship between the inhaled doses of PM2.5 and cardiovascular disease mortality. However, the relationship is highly nonlinear in that the estimated relative risk for ambient air pollution is 1.2, compared to 2.0 for active smoking when the inhaled dose of PM2.5 is increased by three orders of magnitude (Smith and Peel, 2010). Smith added that there is a gap in the data in the range of 1â20 mg of PM2.5 per day; but, this range correlates to the exposures observed worldwide for the women in households using solid fuels (Smith and Peel, 2010). Based on this model, he said, a 1.5â 1.6 relative risk of heart disease would be expected for these women.
54 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY Recalling that 40 percent of the worldâs population is exposed to similar concentrations of household air pollution, Smith proposed that the global burden of cardiovascular disease due to household air pollution exposure is likely high. Smith stated that because the results support a nonlinear model, appropriate policy decisions can be difficult to determine. He noted that transitioning a moderately dirty city to a clean city appears to result in greater reductions in cardiovascular disease mortality than providing a good chimney or even a plain stove to households with much higher PM exposures. An improved stove has little effect on the health of those exposed to household air pollution, he said, since the PM exposures need to decrease to levels much lower than those observed with stove use to make any difference in the cardiovascular disease mortality risk. Similarly, Smith added, the household air pollution exposures to children need to decrease greatly to observe a health benefit and reduce pneumonia rates. When comparing rates of pneumonia in children exposed to an open household fire with those exposed to a chimney stove, only a small difference is detected. Smith noted that more than 40 percent of the children exposed to the open fire contracted pneumonia every year. Even the very well operating chimney stove in RESPIRE provides a relatively small benefit by reducing the rate of pneumonia only to 35 percent or so, he said, but the goal should be to decrease the pneumonia rate substantially. Again, Smith emphasized the lesson from all of this is that it is not enough just to move the household air pollutionâthe pollution should be eliminated or significantly decreased. From this work and other studies on smoking and ambient air pollution, Smith stated, it is recognized that combustion particles cause more health effects than do other environmental contaminants. He noted that active smokingâplacing a burning object directly into the mouthâ results in the most premature deaths, nearly 6 million per year (WHO, 2011d). Smith added that environmental tobacco smokeâbeing surrounded by others as they place burning objects in their mouthsâ causes approximately 600,000 deaths annually (WHO, 2011d). Additionally, ambient air pollution, which is largely but not entirely the result of fuel burning, causes 3 million deaths each year (Lim et al., 2012). But, he added, the oldest burning practice, solid fuel for cooking, still causes more ill health than any other particle source except smoking, leading to 3.5 million deaths per year (Lim et al., 2012). Smith asserted that the message is clear: even with some overlap among smokers, those
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 55 exposed to environmental tobacco smoke, those exposed to urban pollution, and those exposed to household air pollution, there is substantial global ill health from combustion particles. Noncommunicable Diseases and the âBottom Billionâ Smith stated that the classic epidemiological transition is usually defined as the trend of declining infectious diseases and rising noncommunicable diseases (NCDs) as economic development proceeds (Omran, 1971). He outlined that the âbig fourâ of the NCDs are cancer, cardiovascular disease (CVD), COPD, and diabetes. Smith said that this is commonly misinterpreted, however, and instead should be regarded as a mortality transition, not one relating to the risk actually experienced by individuals going through their lives. He noted that when the numbers of young people dying of infectious diseases are reduced in developing countries, these youths become older adults. As older adults, he said, they still must die from something, and they likely die from NCDs. As societies progress up the socioeconomic ladder, the sharp decrease in communicable diseases actually acts to reveal an already existing high rate of NCDs (Smith and Ezzati, 2005). For example, COPD is common in both developing and developed countries. In fact, the death rates from these respiratory diseases are higher in poor countries (WHO, 2011c), and 90 percent of deaths attributable to COPD occur in low- and middle- income countries (WHO, 2011c). Smith stated that a previous hypothesis specified smoking as the primary risk factor for COPD. But, he noted, the incidence of COPD is high in developing countries despite the fact that women in Africa, India, and China do not smoke. Smith described that the risk factors commonly associated with NCDs in rich countriesâlack of physical activity, high-fat diets, obesity, and smokingâdo not generally apply to the 2 billion poorest of the worldâs population. Smith proposed that there are some infectious agents of poverty that contribute to NCDs (for example, rheumatic heart disease), but the use of solid fuels is the one environmental risk factor that is shared by essentially 100 percent of the bottom 2 billion people living in poverty. Currently, he said, three of the four major categories of NCDs are strongly associated with household air pollution, the exception being diabetes (although dioxin, a byproduct released during the incomplete combustion of solid fuels, may be linked to diabetes). Smith pointed out that solid fuel use is thus an important factor in this NCD burden among the poor.
56 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY Smith outlined how the environmental health risk transition that underlies the epidemiological transition demonstrates that as economic development proceeds, the household-level risks fall, the community- level risks rise and then decline, and the global-level risks increase (see Figure 3-1). Smith stated that data on solid fuel use have altered the environmental health risk paradigm: risk factors that were once considered solely household burdens are now recognized as affecting outdoor air pollution in communities and also global climate change. Smith noted that the environmental health risk transition is a helpful framework that lays out some of the connections, so that data can be used to further describe the relationships between household, community, and global risks that arise throughout the development process. FIGURE 3-1 The environmental health risk transition. SOURCE: Smith and Ezzati, 2005.
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 57 If It Doesnât Take Fifty Years, It Isnât Worth Doing Smith noted that monumental health changes do take a while, and establishing the risk, even conclusively, is insufficient by itself to influence change. The First Royal Commission on Air Pollution in London in 1315 recommended banning coal burning in the city, but this recommendation was not taken up until the 1950s after the infamous âLondon Smogâ of 1952. In 1854, the work of John Snow supported the use of adequate sanitation and water for disease prevention; yet, one- third of the worldâs population still has inadequate water and sanitation today. Additionally, Sir Ronald Ross received the Nobel Prize in 1902 for showing conclusively the causes of malaria, but the world still has hundreds of millions who suffer from it today. Thus, the relatively recent recognition that household air pollution is a serious risk cannot be expected, by itself, to fix the problem, and Smith proposed that considerably more work is needed. DISCUSSION A discussion followed the presentations and the remarks are summarized in this section. Lynn Goldman noted that all of the speakers, in one way or another, made points about nuclear power, which may diverge with the views of many environmentalists. Goldman highlighted that nuclear plants require enormous investments for building and maintenance, and asked the speakers to describe ways in which they would persuade people to support allocating the required resources. Additionally, she asked about the sustainability of nuclear energy given what is known about the limitations in the supply of nuclear materials to fuel the plants and how expanding nuclear power would impact the supply of the fuel. Daniel Schrag noted that people talk about the limitations of uranium, but in fact, the price of uranium has little impact on the price of nuclear power. For instance, he said, if the price of uranium is increased 10-fold, the price of nuclear power would likely increase by less than 1 percent. Among environmentalists, said Schrag, there appears to be a split in the environmental community on nuclear energy. Schrag stated that nuclear plants are likely not being built in the United States because of price; the current price of natural gas counters the economic argument for investing in nuclear energy. Additionally,
58 PUBLIC HEALTH LINKAGES WITH SUSTAINABILITY Schrag noted that the focus should not be on teaching people to be unafraid of nuclear energy; instead, the lesson should be that just because it can be measured, this does not mean it is dangerous. He highlighted that more may be known about the risk of nuclear radiation than any other environmental risk factor, but it is difficult for the public to understand the importance of dose or orders of magnitude of exposure. Paul Wilkinson addressed the questions by stating that even though he does not advocate for nuclear energy, he would like to see the issue debated properly. He emphasized that in order to be serious about climate change mitigation, large-scale choices need to be considered, and nuclear energy is one of them. Wilkinson noted that the health argument is often not adequately represented in these debates and more should be done to address this. Wilfried Kreisel joined the discussion, sharing his experience with leading a WHO program on the health effects of the Chernobyl accident that occurred in the Ukraine in 1986. Kreisel noted that at the time, conservative estimates were produced for radiation- induced death, cancer, leukemia, and so on. He stated that when the results were published in 1996, the public confused the number of radiation-induced diseases and the total number of diseases related to non-radiation causes. For example, Kreisel said, in the Chernobyl accident, only 50 people had been killed initially by radiation, but there were hundreds of thousands of people who suffered from mental disorders and alcohol consumption because they believed they received a lethal dose of radiation. Smith agreed that there were major health impacts of the Chernobyl accident because of fear, disruption, anger, loss of jobs, and so forth; but, he asked, was that due to the accident or the poor information people received about the accident? Additionally, he asked about the role of the environmental health community in these situations, noting that efforts should likely focus on making people less afraid if in fact there is no imminent damage. Martin Philbert provided a comment and question to the group around the issue of why the environmental health community has been unsuccessful in influencing energy policy changes. Philbert noted that the discussions appear to no longer be about the science, and at least in the system in the United States, they have become inextricably bound with politics (not policy, but politics). Because of the politics, he stated, science-based regulatory agencies in the United States often have to chart a new course every 2 years. Philbert asked the speakers to comment on ways of moving forward to substantively address the kind of problems
LINKS BETWEEN ENERGY, AIR QUALITY, AND HUMAN HEALTH 59 outlined in this session. Schrag stated that understanding the U.S. political system with respect to energy can be challenging. He noted that the politics in the United States with respect to coal are quite difficult, given that there is bipartisan support for coal in the Senate; this complicates passing climate change legislation that includes reducing coal use. Schrag suggested that a change in coal policies may likely come from the politics surrounding natural gas and hydraulic fracturing, in that states like Pennsylvania are transforming from coal states to natural gas states. Schrag continued to say that in some ways the debate is no longer about the environment and more about industry; but, if the natural gas industry can push for a climate bill that puts a price on carbon, coal use will likely still be reduced. Goldman joined the discussion by noting the importance of constituent concerns in political discourse. She stated that voters often do not recognize that climate change is occurring, nor do they sense the urgency of the problem; if they felt it was an urgent problem, she said, the politics would likely take care of themselves. Juli Trtanj added a comment about value and perceptions, noting that the climate debate can be framed in terms of helping people adapt and respond, rather than just focusing on the environmental or public health connection. Trtanj also said that there are adaptation options across time scales, with adaptation bordering on mitigation in the long term and adaptation on shorter time scales on the individual level. The point about short-term political realities in the United States is well taken, stated Trtanj, and we need to be more strategic in articulating what we mean by adaptation for what audiences and time scales, and including specific value-oriented win-win scenarios in the discussion. Trtanj noted that this will help the public health community move forward a little faster in the political process. Carlos CorvalÃ¡n made one final comment during the discussion about inequalities and climate change. CorvalÃ¡n noted that to simplify the climate change argument there are two phenomena. The first includes areas similar to Queensland, Australia, where the cost of bananas, for instance, increases but those who do not have the money find alternative food options. The second includes droughts taking place in areas of Africa, where people are not able to eat anything at all. CorvalÃ¡n stated that we cannot say we are all equally vulnerable, and the issue of inequality is an inherent component of climate change.
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