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Introduction


The problems of toxic pollution and climate change have traditionally been explored and addressed as separate issues. However, these phenomena interact and overlap in various ways: activities and industries that release greenhouse gases into the atmosphere often also release toxic chemicals, and climate change can change the activity of toxic chemicals in the environment. This article provides an outline of some of these intersections, with the goal of spurring a more holistic understanding of these critical issues.

Carbon as a Pollutant

The definition of "pollutant," in the context of climate change, has been changing. Historically, carbon dioxide, the primary greenhouse gas, was not considered a toxic pollutant because it, as a natural byproduct of respiration as well as combustion, is not harmful to individual organisms in typical atmospheric concentrations. However, due to detrimental global environmental changes caused by increasing concentrations of carbon in the atmosphere, the term "carbon pollution" is now used. Considered as a whole, toxic pollution and carbon pollution can be seen as forces, both largely affected by human activity, that negatively impact both public health and the environment.

Synthetic Chemicals As Greenhouse Gases


Also see: Greenhouse Effect

The greenhouse gases that exist naturally in the atmosphere (though are also released by human activity) are carbon dioxide, methane, water vapor, and nitrous oxide. Synthetic greenhouse gases include these fluorinated gases: chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride, and nitrogen trifluoride. The composition of greenhouse gases created by human activities is as follows (EPA, Student Guide):

  • carbon dioxide, 54.7%
  • methane, 30%
  • other gases, 9.8%
  • nitrous oxide, 4.9%
  • fluorinated gases, 0.6%

Chlorofluorocarbons (CFCs) were created in 1928 and used as refrigerants, propellants, and cleaning solvents. Due to the discovery of their ability to destroy stratospheric ozone, its use was banned globally by the Montreal Protocol on Substances that Deplete the Ozone Layer of 1987. CFCs are still a concern because of their long lifetimes in the atmosphere (some may remain for 100 years), but concentrations are stable or declining (NOAA). Hydrofluorocarbons (HFCs) are used as refrigerants, aerosol propellants, solvents, and fire retardants. The major emissions source of these compounds is their use as refrigerants, such as in air conditioning systems in both vehicles and buildings. Ninety percent of the source of fluorinated gas emissions is the substitution of ozone-depleting substances (EPA, Overview). (Photo: Thomas Midgley Jr., inventor of the first CFC Freon, or dichlorodifluoromethane)

Perfluorocarbons are emitted during primary production for aluminum as byproducts of reactions between molten cryolite (sodium aluminum fluoride) and an anode during the electrolytic process to extract aluminum oxide (EPA, Perfluorocarbon). The two primary perfluorocarbons are tetrafluoromethane (CF4) and hexafluoroethane (CF6). Perfluorocarbons are also used in the electronics sector (for example for plasma cleaning of silicon wafers) as well as in the cosmetic and pharmaceutical industries (EC).

Sulfur hexafluoride is used in magnesium processing and semiconductor manufacturing, and as a tracer gas for leak detection. It is also used in electrical transmission equipment, including circuit breakers. The Global Warming Potential (GWP) of SF6 is 22,800 (compared with 1 for carbon dioxide), making it the most potent greenhouse gas that the Intergovernmental Panel on Climate Change has evaluated (EPA, Overview). (For each greenhouse gas, a Global Warming Potential (GWP) has been calculated to reflect how long it remains in the atmosphere, on average, and how strongly it absorbs energy. Gases with a higher GWP absorb more energy, per pound, than gases with a lower GWP, and thus contribute more to warming. More information on GWP is available from EPA here.)

An additional fluorinated gas is nitrogen trifluoride, which is used as a replacement for perfluorocarbons (primarily hexafluoroethane) and sulfur hexafluoride in the electronics industry. It is used in plasma etching and chamber cleaning during the manufacture of semi-conductors and LCD (Liquid Crystal Display) panels, as well as in the photovoltaic industry for “texturing, phosphorus silicate glass (PSG) removal, edge isolation and reactor cleaning after deposition of silicon nitrate or film silicon” (UNFCC). It is also used in certain types of chemical lasers (hydrogen fluoride and deuterium fluoride lasers). Industrial releases of nitrogen trifluoride increased forty-fold between 1992 and 2007, and are projected to continue increasing (Conniff, WRI). It also has a very high GWP of 17,200. Nitrogen trifluoride was added to the list of targeted greenhouse gases for the second compliance period of the Kyoto Protocol, 2013-2020. The other greenhouse gases targeted by the Kyoto Protocol (since the first compliance period, 2008-2012) are carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.

Properties of Fluorinated Gases

Fluorinated GasLifetime in AtmosphereGlobal Warming Potential, 100-Year (GWP)
Hydrofluorocarbons (HFCs)1-270 years12-14,800
Perfluorocarbons (PFCs)2,600-50,000 years7,390-12,200
Sulfurhexafluoride (SF6)3,200 years22,800
Nitrogen trifluoride (NF3)740 years17,200

While stability and low flammability make the fluorinated gases useful as industrial chemicals, their high global warming potentials pose a significant threat to increased warming of the atmosphere. 

Reducing Emissions of Fluorinated Gases

  • refrigerants: use substitutes with lower global warming potential, reduce leakage from vehicle air-conditioning systems
  • electricity transmission and distribution (sulfur hexafluoride): detect and repair leaks, use recycling equipment, train employees in appropriate emissions reductions methods
  • industrial users: adopt fluorinated gas recycling and destruction processes, optimize production to minimize emissions, and replace these gases with alternatives (EPA, Overview)

The European Commission offers helpful information on climate friendly alternatives to chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs); the European Union has regulations in place that aim to reduce emissions of fluorinated gases by two-thirds by 2030 (EC). While flourine may be used as a substitute for nitrogen trifluoride, it poses the challenge of being highly toxic and reactive, and difficult to transport (UNFCC). In Japan and Taiwan, hexafluorobutadiene has been tested as a possible replacement for nitrogen trifluoride etching agent, and remote plasma cleaning is an alternative technology that can reduce the fraction of nitrogen fluoride released from 16% to 2% (UNFCC).

Volatile organic compounds (VOCs) also have a small direct impact as greenhouse gases. VOCs include non-methane hydrocarbons (NMHC) and oxygenated NMHCs (alcohols and organic acids), and their largest source is natural emissions from vegetation. However, there are some anthropogenic sources such as vehicle emissions, fuel production, and biomass burning. Though measurement of VOCs is extremely difficult, it is expected that most anthropogenic emissions of these compounds have increased in recent decades (NOAA). Also see: Solvents

Energy Production, Climate Change, and Toxic Pollution


Also see: Introduction to the Health Effects of Air Pollution, Polycyclic Aromatic Hydrocarbons, Solar Power

 

Total U.S. Greenhouse Gas Emissions by Economic Sector in 2014


 

Total Emissions in 2014 = 6,870 Million Metric Tons of CO2 equivalent
* Land Use, Land-Use Change, and Forestry in the United States is a net sink and offsets approximately 11% of these greenhouse gas emissions.
All emission estimates from the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014 (Image: EPA)


Global Greenhouse Gas Emissions by Economic Sector, 2010

 

 

Source: IPCC (2014);based on global emissions from 2010.

Details about the sources included in these estimates can be found in the Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change . (Image: EPA)

 


As seen in the graphic above, 30% of US greenhouse gas emissions in 2014 was from the electricity economic sector. This includes electricity generation, transmission, and distribution. Carbon dioxide makes up the vast majority of greenhouse gas emissions from the sector, but smaller amounts of methane and nitrous oxide are also emitted. These gases are released during the combustion of fossil fuels, such as coal, oil, and natural gas.

Fossil Fuels

Coal combustion is generally more carbon intensive than burning natural gas or petroleum for electricity. Although coal accounts for about 77% of carbon dioxide emissions from the sector, it represents about 39% of the electricity generated in the US. About 27% of electricity generated in 2014 was generated using natural gas, an increase relative to 2013. Petroleum accounts for approximately 1% of electricity generation. The remaining generation comes from nuclear (about 19%) and renewable sources (about 13%), which includes hydroelectricity, biomass, wind, and solar (EPA, Sources). (Photo: Bełchatów Power Station in Poland, one of the world's largest coal-fired power stations)

Power plants are currently the dominant emitters of mercury (50%) and many toxic metals (20-60%) in the United States. While newer, and a significant percentage of older, power plants already control their emissions of mercury and heavy metals, approximately 40% of current plants still do not have advanced pollution control equipment (EPA, Cleaner Power Plants). According to the UN Environment Programme, on a global scale, up to 95% of mercury emissions from power plants can be reduced. (Image below right: EPA, Cleaner Power Plants) Also see: Mercury

The burning of coal also releases sulfur dioxide, nitrogen oxide, and particulate matter (soot or fly ash). These are considered “criteria” air pollutants by the EPA (of which there are six), meaning that they are common air pollutants that are monitored under the Clean Air Act’s National Ambient Air Quality Standards (NAAQS). Below are brief facts on these air pollutants (EPA, Criteria Air Pollutants):

  • Sulfur dioxide: The largest sources of sulfur dioxide emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%). Sulfur dioxide is linked with a number of adverse effects on the respiratory system.
  • Nitrogen dioxide: Nitrogen dioxide forms quickly from emissions from cars, trucks and buses, power plants, and off-road equipment. In addition to contributing to the formation of ground-level ozone and fine particle pollution, nitrogen dioxide is linked with a number of adverse effects on the respiratory system.
  • Particulate matter: "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.

A hazardous byproduct of coal combustion is coal ash, which is one of the largest types of industrial waste generated in the United States. According to EPA, coal ash contains contaminants like mercury, cadmium, and arsenic, which can pollute waterways, groundwater, drinking water, and the air without proper management (EPA, Coal Ash Basics). Fly ash, bottom ash and boiler slag from coal-fired power plants contain small amounts of naturally occurring radioactive material. Generally, these wastes are only slightly more radioactive than the average soil in the U.S. (EPA, Natural Radiation).

Natural gas is much more clean burning than coal, but still releases nitrogen oxides (in addition to carbon dioxide). However, the drilling, extraction, and transport of natural gases results in leakage of methane (the main constituent of natural gas), which is about 20 times as potent as carbon dioxide, into the atmosphere (EIA). An additional concern is the environmental release of various toxic chemicals used in the extraction process known as hydraulic fracturing, or fracking. A related issue to consider is the use of oil dispersants in the event of oil spills. (Photo: Currant Creek Gas-Fired Power Plant, Mona, UT, USA) Also see: Fracking, Oil Dispersant

 

Fossil-Free Energy Sources

Nuclear power plants may release little in the way of greenhouse gases, but result in the formation and accumulation of nuclear wastes including uranium mill tailings (which contain radium, which decays to radon) and spent reactor fuels. Mill tailings are characterized as low-level nuclear waste while spent fuels are characterized as high-level nuclear waste (EIA). Spent reactor fuel rods can be stored in water, or encased in dry storage casks (USNRC).

As mentioned above, nitrogen trifluoride is used in the production of thin-film photovoltaic cells. The production of silicon solar panels also involves the use of various corrosive chemicals used to clean semiconductor materials (hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride), and sulfur hexafluoride, also mentioned above, is also used to clean the reactors used in silicon production (Mulvaney, 2013). Silicon production also results in waste silicon tetrachloride, which can be recycled into the production process but must be handled carefully as it reacts violently with water and poses acute health threats (Mulvaney, 2013). Thin-film PV cells, of which there are many varieties, may contain gallium arsenide, copper indium gallium selenide (CIGS), and cadmium telluride (NEF). Gallium arsenide is listed as a carcinogen by the State of California (under Proposition 65 or the Safe Drinking Water and Toxic Enforcement Act of 1986); copper indium gallium selenide cells were found to leach significant amounts of cadmium in one study (Zimmermann); and cadmium telluride is considered less toxic than elemental cadmium but may still pose toxicity concerns. Research is underway to develop thin-film PV cells that do not contain toxic or rare elements (Mulvaney, 2014). Also, lead is often used in electrical circuits, and fugitive air emissions from PV production facilities include trichloroethane, acetone, ammonia, and isopropyl alcohol (Mulvaney, 2013). It is therefore important for appropriate workplace safety standards to be enforced in production facilities, for chemical emissions to be managed and reduced, and for PV cells to be properly recycled at end-of-life. (Image credit: AleSpa)

Use of PCBs and Mercury in Electronic Equipment

Also see: Polychlorinated Biphenyls, Mercury

An additional issue to consider is the use of various chemicals in products used to conduct, store, or emit energy. In the past, polychlorinated biphenyls (PCBs), which are persistent toxic chemicals, were used in electronic equipment including transformers, capacitors, light ballasts, insulation materials, and as lubricants. Mercury is another toxic chemical that can be found in various types of electronic equipment, such as thermostats, switches, button or mercury oxide batteries, and fluorescent light bulbs. (Other types of batteries may also contain toxic chemicals, such as cadmium in nickel-cadmium batteries and lead in lead-acid batteries.)

While fluorescent light bulbs are popular for using less energy, it is important to recycle the bulbs to properly extract and contain the mercury, and if bulbs break during use, appropriate cleanup techniques must be used to reduce exposure to toxic mercury vapor. Other light bulbs that are more energy efficient than traditional incandescents include LEDs (light emitting diodes) and halogen incandescents. Halogen incandescents use less energy than standard incandescents but are less efficient than LEDs and fluorescents. One 2011 study found lead, arsenic, and other toxic chemicals in LEDs (Lim). LEDs may still be a better choice than fluorescent bulbs from both toxicity and energy efficiency standpoints, but there is a need for energy-efficient bulbs that contain no toxic components.

 

Transportation, Climate Change, and Toxic Pollution

In 2014, 26% of greenhouse gas emissions in the US were from the transportation sector. The largest sources of these emissions include passenger cars and light-duty trucks, including sport utility vehicles, pickup trucks, and minivans. These sources account for over half of the emissions from the sector. The remainder of greenhouse gas emissions comes from other modes of transportation, including freight trucks, commercial aircraft, ships, boats, and trains as well as pipelines and lubricants. On a global scale, as stated by the UN Environment Programme, "transport gobbles up over half of the planet’s liquid fossil fuels and is responsible for almost a quarter of energy-related greenhouse gas (GHG) emissions".

Between 1990 and 2014, greenhouse gas emissions in the US transportation sector increased more in absolute terms than any other sector (i.e. electricity generation, industry, agriculture, residential, or commercial). Greenhouse gas emissions from transportation sources include carbon dioxide, methane, nitrous oxide, and various hydrofluorocarbons (HFCs). Carbon dioxide, methane, and nitrous oxide are all emitted via the combustion of fuels, while HFCs are the result of leaks and end-of-life disposal from air conditioners used to cool people and/or freight. Additional air pollutants released are carbon monoxide, particulate matter, polycyclic aromatic hydrocarbons (PAHs), and sulfur dioxide. Some of these pollutants react in sunlight to cause the production of ground-level ozone, which is also one of EPA's criteria air pollutants (sulfur dioxide, nitrogen oxide, particulate matter, lead, ozone, and carbon monoxide). Also see: PAHs

Use of leaded gasoline, treated with tetraethyl lead to reduce engine knock, dispersed vast amounts of lead into the environment. In the US, leaded gasoline was available from the 1920s through the '80s; the World Bank called for a ban on leaded gasoline in 1996 and the European Union banned leaded gasoline in 2000. It is estimated that 7 million tons of lead were released into the atmosphere from gasoline in the United States alone. Leaded fuel is still used in small piston-engine aircraft (FAA). Also see: Lead

Another link between air pollution and climate change is that the deposition of soot onto glaciers located near urban areas can cause increased glacial melting due to decreased reflectivity of glacial surfaces. This phenomenon has been observed in the European Alps as well as the Himalayas.

Agriculture, Climate Change, and Toxic Pollution


Also see: Pesticides, Meat Production and Environmental Health

Farming emissions come from a variety of sources that differ depending on the type of farm. Image credit: IPCC

 

While the impacts of agriculture on climate change, due directly to the release of methane (CH4, primarily from cows) and nitrous oxide (N2O, primarily from fertilizers and animal wastes), and indirectly due to deforestation to clear land for agricultural use, are well established, knowledge on the impacts of climate change on agriculture is in development. Changes in precipitation and weather patterns will affect farm productivity and cultivation methods, but in the realm of toxic pollution, will there be an effect on the use and action of synthetic fertilizers and pesticides? Studies suggest the following possibilities:

  • Changes in temperature and precipitation will increase pest infestations and related pesticide use, including new pesticides; while the majority of pesticides used today are herbicides, the use of insecticides and fungicides may increase
  • Pesticides will generally break down more quickly in the environment due to increased moisture and temperature, but due to increased volatilization, may travel farther through air; however, in heavy rainfall, leaching and runoff will increase, and in drought, breakdown will be inhibited
  • Delayed autumn spraying of pesticides (due to longer growing seasons) may increase the winter leaching of pesticides in wet-winter regions
  • Pesticide varieties and applications will be affected by changes in land use, crop rotation, and the introduction of new crop varieties

 

A May 2016 report by the UN Environment Programme states that severe weather can alter the levels of natural toxicants in food crops. Drought and high temperatures can cause the accumulation of nitrates (due to slowed breakdown of nitrates into amino acids) in certain food crops including wheat, corn, barley, and millet. Nitrates consumed in large enough quantities inhibit red blood cells’ ability to carry oxygen, and acute nitrate poisoning in animals can cause miscarriage, asphyxiation, and death. Another toxicant of concern is hydrogen cyanide, also called prussic acid, which may accumulate to dangerous levels in crops including flax, corn, sorghum, arrow grass, cherries, and apples when heavy rains follow prolonged drought. Finally, aflatoxins, released by a fungus (Aspergillus flavus) that commonly infects various crops including grains, nuts, and seeds, are expected to be increasingly problematic in higher latitudes, including Europe, due to rising temperatures. Aflatoxins cause liver damage and cancer.

Effects of a Changing Climate on Toxic Chemicals in the Environment


Climate Change Negatively Impacts Air Quality

According to the National Climate Assessment, climate change will increase ground-level ozone and/or particulate matter air pollution in some locations. Ground-level ozone (a key component of smog) is associated with many health problems, including diminished lung function, increased hospital admissions and emergency department visits for asthma, and increases in premature deaths. More and larger wildfires linked to climate change could also significantly reduce air quality and affect people’s health in a number of ways. Smoke exposure increases acute (or sudden onset) respiratory illness, respiratory and cardiovascular hospitalizations, and medical visits for lung illnesses. The frequency of wildfires is expected to increase as drought conditions become more prevalent. Finally, the increase in air pollutants may exacerbate the effects of increased allergens, primarily pollen, also associated with climate change. When sensitive individuals are simultaneously exposed to allergens and air pollutants, allergic reactions often become more severe. (CDC) (Image credit: Fidel Gonzalez)

 

The Intergovernmental Panel on Climate Change (IPCC) projected “declining air quality in cities” into the future as a result of climate change. Further, EPA concluded in 2009 that GHG emissions “may reasonably be anticipated both to endanger public health and to endanger public welfare," stating that climate change could have the following impacts on national air quality levels:

• Produce 2-8 ppb increases in summertime average ground-level ozone concentrations in many regions of the country
• Further exacerbate ozone concentrations on days when weather is already conducive to high ozone concentrations
• Lengthen the ozone season
• Produce both increases and decreases in particle pollution over different regions of the US (EPA, Climate Change and Air Quality)

 

One study published in 2014 suggests that climate change will lead to increased air stagnation: "by the late 21st century more frequent air stagnation will affect areas covering approximately 55 percent of the current global population, with some regions potentially experiencing an increase of up to 40 stagnation days per year" (Horton).

Melting Glaciers and Permafrost Release Toxic Chemicals and Greenhouse Gases

Studies have found that persistent toxic chemicals such as dioxins, PCBs, and organochlorine pesticides that are trapped in glaciers are being released into the environment as the glaciers melt. This phenomenon has been observed in the European Alps and in Antarctica (PSI, New Scientist). Also see: Persistent Environmental Contaminants

Also, as the ice in melting glaciers gets thinner, pockets of methane trapped beneath it are released. Studies also predict that melting permafrost will release significant amounts of methane into the atmosphere (NSIDC).

Recent studies also show that Arctic Sea ice contains levels of microplastics at "several orders of magnitude greater than those that have been previously reported in highly contaminated surface waters," and suggest that the potential for these plastics to be released as ice melts requires investigation (Obbard). (Image: Permafrost peatbog border. Storflaket, Abisko, Sweden. Credit: Dentren at English Wikipedia )

Other Effects on Chemical Distribution, Activity, and Exposure

Various studies have explored the toxicology of climate change, and how climate change affects the distribution and activity of toxic pollutants in the environment, as well as exposure. One review study (Noyes) summarizes some of the possible changes, focusing on changes in temperature, precipitation, and salinity of water bodies, and these classes of chemicals: persistent organic pollutants, air pollutants, and pesticides. Possible changes include:

  • Increased temperatures will increase the toxicity of pollutants and the development of ground-level ozone; it may also speed the degradation of pollutants
  • Increased temperatures will make wildlife more vulnerable to the effects of toxic exposures
  • Levels of persistent organic pollutants in water, air, and soil will increase
  • Volatilization of pesticides and other pollutants will increase in regions affected by drought
  • Air pollution will worsen in areas affected by drought; air pollution will decrease in areas with heavy precipitation, but surface deposition of airborne persistent contaminants and pesticide run-off will increase
  • Storm events may lead to severe episodes of increased chemical contamination of water bodies
  • Changes in salinity may alter the bioavailability and toxicity of chemicals to aquatic life, including increased toxicity in some cases

Also, ocean acidification (due to increased amounts of atmospheric carbon dioxide dissolving in the oceans) may alter bioavailability of sediment-bound chemicals, potentially exposing marine life to higher concentrations of certain chemicals (Roberts).

In 2010, the Stockholm Convention on Persistent Organic Pollutants produced the study "Climate Change and POPs Inter-Linkages,” investigating the impact of climate change on the release of POPs into the environment, their long range transport and environmental fate, and human and environmental exposure. The study concludes that “global warming increases emissions of POPs and exposure of humans and wildlife via the food chain and will also affect biodiversity, ecosystems and vulnerability.” For example, marine mammals in the Arctic are expected to be exposed to increasing concentrations of persistent toxic chemicals, and extreme weather events and floods are expected to release stockpiled obsolete pesticides into the environment. In 2013, the Convention adopted a guidance outlining the need to account for these expected effects in its work. Also see: Obsolete Pesticides, Stockholm Convention, Persistent Environmental Contaminants

Summary and Conclusion

Activity/IndustryGreenhouse Gases EmittedToxic Pollutants Emitted
Energy: Coal CombustionCarbon dioxide, nitrogen oxide, sulfur dioxideNitrogen oxide, sulfur dioxide, particulate matter, heavy metals
Energy: Natural Gas CombustionCarbon dioxide, methane (through leakage of gas), nitrogen oxideNitrogen oxide, methane, fracking chemicals
Energy: NuclearMinimalSpent nuclear fuel
Energy: SolarNitrogen trifluoride, sulfur hexafluoride (if not captured)Various chemicals used in silicon and PV cell production (if not captured); some chemicals may leach at end-of-life if not properly recycled
Transportation (primarily combustion of gasoline)Carbon dioxide, methane, nitrous oxide, sulfur dioxide, various hydrofluorocarbons (HFCs, through leakage from refrigerant systems)Carbon monoxide, particulate matter, polycyclic aromatic hydrocarbons (PAHs), sulfur dioxide
AgricultureMethane, nitrogen oxide, carbon dioxide (if output exceeds input)Fertilizers, pesticides
Industry/ManufacturingVarious, including fluorinated gases with very high global warming potentials Various, including persistent bioaccumulative toxicants

 

While toxic chemicals are often perceived as primarily being synthesized in laboratories or emitted from manufacturing processes, large-scale combustion of fossil fuels releases vast quantities of toxic chemicals into the air, water, and soil. As such, it is clear that clean energy is necessary for a clean and climate-stable environment, and that the issues of toxic pollution and carbon pollution are, in some cases, inextricably linked. The history of fluorinated gases, which have very high global warming potentials, reveals that chemicals turned to as substitutes for those that are found to be problematic may still pose significant harm, echoing the history of certain other toxic chemicals such as flame retardants or pesticides. While our knowledge of the health and environmental effects of chemicals and processes is always in flux, it is paramount to embrace a precautionary approach and to invest resources into exploring and developing the safest possible alternatives.

Changing Perspectives on Environmental Health

The discipline and practice of environmental health explores and aims to manage aspects of public health that are affected by environmental factors, typically soil, air, and water pollution and chemical hazards in the workplace. In light of increasing knowledge about the effects of climate change on the environment and human health, environmental health is broadening its scope to include the effects of climate change. This definition of environmental health by the National Environmental Health Association (NEHA) presents a broad and holistic perspective: "Environmental health and protection refers to protection against environmental factors that may adversely impact human health or the ecological balances essential to long-term human health and environmental quality, whether in the natural or man-made environment."

It is clear that climate change is already disrupting ecological balance on a global scale, and compromising long-term human health and environmental quality. Also, in some cases, climate change directly or indirectly causes an increase in the levels and distribution of toxic chemicals in the environment–whether in air, water, or soil–and a corresponding increase in exposure and in some cases, susceptibility. The effects of toxic pollution and carbon pollution can both be felt in regions far removed from emissions sources, and greenhouse gases and persistent toxic chemicals both continue to pose harm for many years. While the issues are complex, it is clear that there are opportunities to address both issues in an integrated way, especially in the areas of energy and transportation. For example, in May 2016 the EPA issued three final rules for its Oil and Natural Gas Pollution Standards in response to both the President's Climate Action Plan: Strategy to Reduce Methane Emissions and the Clean Air Act; the rules aim to reduce emissions of methane, smog-forming VOCs, and toxic air pollutants such as benzene. Finally, further research is needed to illuminate the full effects of climate change on toxic pollution so we can prevent or avoid adverse impacts to the greatest extent possible. Also see: Green Chemistry, Precautionary Principle , Tragedy of the Commons , Ethical Considerations, Environmental Justice

 

"Climate change, primarily attributed to a rise in greenhouse gases produced by burning fossil fuels, strikes at the pillars of what keeps us healthy: adequate food, safe and sufficient fresh water, clean air, and freedom from infectious diseases that may intensify in the wake of natural catastrophes.
- Harvard School of Public Health Center for Global Health and the Environment


"If you want to learn about the health of a population, look at the air they breathe, the water they drink, and the places where they live."
- Hippocrates

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Source: CDC)

Resources and References

Synthetic Chemicals 

Conniff, Richard. The Greenhouse Gas that Nobody Knew. Yale Environment 360, November 13 2008 (accessed June 15, 2016)

European Commission: Climate-friendly Alternatives to HFCs and HCFCs (accessed June 15, 2016)

European Commission: Fluorinated Greenhouse Gases (accessed June 22, 2016)

European Environment Agency: Potent greenhouse gases – fluorinated gases in the European Union (accessed June 15, 2016)

EPA: Overview of Greenhouse Gases (accessed June 15, 2016)

EPA Center for Corporate Climate Leadership: Reducing Supply Chain GHG Emissions from LCD Panel Manufacturing Webinar (accessed June 15, 2016)

Encyclopedia Britannica Blog: New Greenhouse Gas Threat (The Rise of Nitrogen Trifluoride – NF3) (accessed June 15, 2016)

EPA: A Student's Guide to Global Climate Change (accessed June 15, 2016)

EPA: Overview of Greenhouse Gases (accessed June 15, 2016)

EPA: Perfluorocarbon Generation During Primary Aluminum Production (accessed June 19, 2016)

Greenhouse Gas Protocol: Required Greenhouse Gases in Inventories, Accounting and Reporting Standard Amendment, February 2013 (accessed June 15, 2016)

NOAA: Greenhouse Gases (accessed June 15, 2016)

United Nations Framework Convention on Climate Change: Compilation of technical information on the new greenhouse gases and groups of gases included in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (accessed June 22, 2016)

World Resources Institute Blog: Nitrogen Trifluoride Now Required in GHG Protocol Greenhouse Gas Emissions Inventories, May 22, 2013 (accessed June 15, 2016)

 

Energy Production

EPA: Cleaner Power Plants (accessed June 16, 2016)

EPA: Criteria Air Pollutants (accessed June 16, 2016)

EPA: Natural Radiation in Wastes From Coal-Fired Power Plants (accessed June 16, 2016)

EPA: Sources of Greenhouse Gas Emissions, Electricity (accessed June 16, 2016)

Lim, Seong-Rim et al. "Potential Environmental Impacts of Light-Emitting Diodes (LEDs): Metallic Resources, Toxicity, and Hazardous Waste Classification." Environmental Science & Technology. 2011, 45 (1), pp 320–327 (accessed June 22, 2016)

Mulvaney, Dustin. Hazardous Materials Used in Silicon PV Cell Production: A Primer. Solar Industry Magazine, Volume 6 Number 8, September 2013 (accessed June 22, 2016)

Mulvaney, Dustin. Solar Energy Isn’t Always as Green as You Think. IEEE (Institute of Electrical and Electronics Engineers) Spectrum. 26 Aug 2014 (accessed June 22, 2016)

National Energy Foundation (UK): Types of Photovoltaic Cells (accessed June 22, 2016)

Physicians for Social Responsibility: Coal Ash, Toxic and Leaking (accessed June 22, 2016)

Sierra Club: Coal Waste in America (accessed June 16, 2016)

Sierra Club: Coal Plant Water Pollution (accessed June 22, 2016)

Union of Concerned Scientists: Environmental impacts of coal power: air pollution (accessed June 22, 2016)

Union of Concerned Scientists: Environmental Impacts of Solar Power (accessed June 22, 2016)

UN Environment Programme: Mercury Control from Coal Combustion (accessed June 22, 2016)

US Department of Energy: How Gas Turbine Power Plants Work (accessed June 22, 2016)

US Energy Information Administration: How much carbon dioxide is produced when different fuels are burned? (accessed June 22, 2016)

US Energy Information Administration: Natural Gas Explained (accessed June 22, 2016)

US Energy Information Administration (EIA): Nuclear Power and the Environment (accessed June 22, 2016)

US Nuclear Regulatory Commission (NRC): Storage of Spent Nuclear Fuel (accessed June 22, 2016)

Zimmermann , Y-S et al. "Thin-Film Photovoltaic Cells: Long-Term Metal(loid) Leaching at Their End-of-Life." Environmental Science & Technology, 2013, 47 (22), pp 13151-13159.     (accessed June 22, 2016)

 

Transportation

EPA: Sources of Greenhouse Gas Emissions, Transportation (accessed June 21, 2016)

EPA: US Transportation Sector Greenhouse Gas Emissions, 1990-2014, June 2016

Federal Aviation Administration: Aviation Gasoline (accessed June 21, 2016)

ClimateCentral.org: Pollution Melted Alps’ Glaciers, Not Rising Temperatures, September 22, 2013 (accessed June 22, 2016)

ClimateChangeNews.com: India pollution linked to Himalaya glacier melt  , October 3, 2014 (accessed June 22, 2016)

Union of Concerned Scientists: Cars, Trucks, and Air Pollution (accessed June 22, 2016)

UN Environment Programme Climate Change Mitigation: Transport (accessed June 22, 2016)

 

Agriculture

EPA Sources of Greenhouse Gas Emissions: Agriculture (accessed June 23, 2016)

Swedish University of Agricultural Sciences: Climate Change and Pesticides (accessed June 15, 2016)

UK Groundwater Forum: Predicted Impact of Climate Change: Pesticides in Groundwater (accessed June 15, 2016)

UNEP Climate Change Mitigation: Agriculture (accessed June 22, 2016)

UNEP Press Release (May 20, 2016): Toxic Crops and Zoonotic Disease: UNEP Identifies the Emerging Environmental Issues of Our Time (accessed June 16, 2016)

World Resources Institute: Everything You Need to Know About Agricultural Emissions (accessed June 15, 2016)

 

Effects of a Changing Climate on Toxic Chemicals

Air Quality

CDC and APHA Fact Sheet: Climate Change Decreases the Quality of the Air We Breathe  (accessed June 22, 2016)

Horton, Daniel E. et al. "Occurrence and persistence of future atmospheric stagnation events." Nature Climate Change 4, 698–703 (2014) (accessed June 22, 2016)

EPA Report Our Nation's Air: Climate Change and Air Quality (2011) (accessed June 22, 2016)

Tibbetts, John H. "Air Quality and Climate Change: A Delicate Balance" Environmental Health Perspectives Volume 123 Issue 6, June 2015 (accessed June 22, 2016)

Melting Glaciers and Permafrost

Obbard, R. W., et al. "Global warming releases microplastic legacy frozen in Arctic Sea ice." Earth's Future, 2: 315–320 (2014) (accessed June 22, 2016)

Lusher et al "Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples" Scientific Reports 5, Article number: 14947 (2015) (accessed June 22, 2016)

Weinhold, Bob. PERSISTENT ORGANIC POLLUTANTS: Melting Glaciers Release Frozen Toxicants, Environ Health Perspect. 2009 Dec; 117(12): A538. (accessed June 22, 2016)

NewScientist.com: Melting Glaciers Release Toxic Chemical Cocktail, May 7, 2008 (accessed June 22, 2016)

Paul Scherrer Institute: When Melting Glaciers Release Pollutants, October 31, 2014 (accessed June 22, 2016)

Phys.Org: When thawing glaciers release pollutants, November 3, 2014 (accessed June 22, 2016)

National Snow and Ice Data Center: Methane and Frozen Ground (accessed June 22, 2016)

 

Other Effects

Beyond Pesticides News Blog: Climate Change Increases Storm Severity and Toxic Chemical Hazards (November 13, 2013) (accessed June 22, 2016)

Doney, Scott et al. “Climate Change Impacts on Marine Ecosystems.” Annual Review of Marine Science. Vol. 4: 11-37 (Volume publication date January 2012) (accessed June 22, 2016)

EPA report: America’s Children and the Environment, 3rd edition, Environments and Climate Change (2013) (accessed June 22, 2016)

Nikinmaa, Mikko. "Climate change and ocean acidification—Interactions with aquatic toxicology" Aquatic Toxicology Volume 126, 15 January 2013, Pages 365–37 (accessed June 22, 2016)

Noyes PD et al. “The toxicology of climate change: environmental contaminants in a warming world.” Environ Int. 2009 Aug;35(6):971-86. (accessed June 22, 2016)

Roberts DA et al. "Ocean acidification increases the toxicity of contaminated sediments." Global Change Biology. 2013 Feb;19(2):340-51. (accessed June 22, 2016)

Stockholm Convention Press Release: Climate Change and POPs Focus of New International Study (March 12, 2010) (accessed June 22, 2016)

 

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