Air pollution

Air pollution is a chemical, physical (e.g. particulate matter), or biological agent that modifies the natural characteristics of the atmosphere. The atmosphere is a complex, dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems.

Worldwide air pollution is responsible for large numbers of deaths and cases of respiratory disease. Enforced air quality standards, like the Clean Air Act in the United States, have reduced the presence of some pollutants. While major stationary sources are often identified with air pollution, the greatest source of emissions is actually made up by mobile sources, mainly the automobiles. Gases such as carbon dioxide, which contribute to global warming, have recently gained recognition as pollutants by some scientists. Others recognize the gas as being essential to life, and therefore incapable of being classed as a pollutant.

There are many substances in the air which may impair the health of plants and animals (including humans), or reduce visibility. These arise both from natural processes and human activity. Substances not naturally found in the air or at greater concentrations or in different locations from usual are referred to as 'pollutants'.

Pollutants can be classified as either primary or secondary. Primary pollutants are substances directly produced by a process, such as ash from a volcanic eruption or the carbon monoxide gas from a motor vehicle exhaust.

Secondary pollutants are not emitted. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone - one of the many secondary pollutants that make up photochemical smog.

Note that some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants.

Environmental science

Environmental science is the study of the interactions among the physical, chemical and biological components of the environment; with a focus on pollution and degradation of the environment related to human activities; and the impact on biodiversity and sustainability from local and global development. It is inherently an interdisciplinary field that draws upon not only its core scientific areas, but also applies knowledge from other non-scientific studies such as economics, law and social sciences. Physics is used to understand the flux of material and energy interaction and construct mathematical models of environmental phenomena. Chemistry is applied to understand the molecular interactions among natural systems. Biology is fundamental to describing the effects within the plant and animal kingdoms.

While the concept of environmental science has existed for centuries, it came alive as a substantive, active field of scientific investigation in the 1960s and 1970s driven by (a) the need for a large multi-disciplined team to analyze complex environmental problems, (b) the arrival of substantive environmental laws requiring specific environmental protocols of investigation and (c) the growing public awareness of a need for action in addressing environmental problems.

Environmental science encompasses issues such as climate change, conservation, biodiversity, groundwater and soil contamination, use of natural resources, waste management, sustainable development, air pollution and noise pollution. Due to the inherent interdisciplinary nature of environmental science, teams of professionals commonly work together to conduct environmental research or to produce Environmental Impact Statements, as required by the U.S. National Environmental Policy Act (NEPA) or under state laws. There are professional organizations that engender work in environmental science and aid in communication among the diverse sciences.

Atmospheric sciences examines the new phenomenology of the Earth's gaseous outer layer with emphasis upon interrelation to other systems. Atmospheric sciences comprises meteorological studies, greenhouse gas phenomena, atmospheric dispersion modeling of airborne contaminants,[1][2] sound propagation phenomena related to noise pollution, and even light pollution

Taking the example of the global warming phenomena, physicists create computer models of atmospheric circulation and infra-red radiation transmission, chemists examine the inventory of atmospheric chemicals and their reactions, biologists analyze the plant and animal contributions to carbon dioxide fluxes, and specialists such as meteorologists and oceanographers add additional breadth in understanding the atmospheric dynamics.

Ecology studies typically analyze the dynamics among an interrelated set of populations, or a population and some aspect of its environment. These studies could address endangered species, predator/prey interactions, habitat integrity, effects upon populations by environmental contaminants, or impact analysis of proposed land development upon species viability.

An interdisciplinary analysis of an ecological system which is being impacted by one or more stressors might include several related environmental science fields. For example one might examine an estuarine setting where a proposed industrial development could impact certain species by water pollution and air pollution. For this study biologists would describe the flora and fauna, chemists would analyze the transport of water pollutants to the marsh, physicists would calculate air pollution emissions and geologists would assist in understanding the marsh soils and bay muds.

Environmental chemistry is the study of chemical alterations in the environment. Principal areas of study include soil contamination and water pollution. The topics of analysis involve chemical degradation in the environment, multi-phase transport of chemicals (for example, evaporation of a solvent containing lake to yield solvent as an air pollutant), and chemical effects upon biota.

an example study, consider the case of a leaking solvent tank which has entered the soil upgradient of a habitat of an endangered species of amphibian. Physicists would develop a computer model to understand the extent of soil contamination and subsurface transport of solvent, chemists would analyze the molecular bonding of the solvent to the specific soil type and biologists would study the impacts upon soil

The natural environment

The natural environment, commonly referred to simply as the environment, is a term that comprises all living and non-living things that occur naturally on earth or some part of it (e.g. the natural environment in the United States). This term includes a few key components:

Complete landscape units that function as natural systems without massive human intervention, including all plants, animals, rocks, etc. and natural phenomena that occur within their boundaries.
Universal natural resources and phenomena that lack clear-cut boundaries, such as air, water and climate.
Natural features which occur within areas heavily influenced by man (such as wild birds in urban gardens).

The natural environment is contrasted with the built environment, which comprises the areas and components that are heavily influenced by man. A geographical area is regarded as a natural environment (with an indefinite article), if the human impact on it is kept under a certain limited level (similar to section 1 above). This level depends on the specific context, and changes in different areas and contexts. The term wilderness, on the other hand, refers to areas without any human intervention whatsoever (or almost so).

Challenges in the natural environment
It is the common understanding of natural environment that underlies environmentalism—a broad political, social, and philosophical movement that advocates various actions and policies in the interest of protecting what nature remains in the natural environment, or restoring or expanding the role of nature in this environment. While true wilderness is increasingly rare, wild nature (e.g., unmanaged forests, uncultivated grasslands, wildlife, wildflowers) can be found in many locations previously inhabited by humans.

Goals commonly expressed by the environmentalists include: reduction and clean up of man-made pollution, with future goals of zero pollution; reducing societal consumption of non-renewable fuels, development of alternative, green, low carbon or renewable energy sources; conservation and sustainable use of scarce resources such as water, land and air; protection of representative or unique or pristine ecosystems; preservation and expansion of threatened or endangered species or ecosystems from extinction; the establishment of nature and biosphere reserves under various types of protection, and, most generally, the protection of biodiversity and ecosystems upon which all human and other life on earth depends.

More recently, there has been a strong concern about climatic changes such as Global warming caused by anthropogenic releases of greenhouse gases, most notably carbon dioxide, and their interactions with human uses and the natural environment. Efforts here have focused on the mitigation of greenhouse gases that are causing climatic changes (e.g. through the Climate Change Convention and the Kyoto Protocol), and on developing adaptative strategies to assist species, ecosystems, humans, regions and nations in adjusting to the Effects of global warming.

A more profound challenge, however, is to identify the natural environmental dynamics in contrast to environmental changes not within natural variances. A common solution is to adapt a static view neglecting natural variances to exist. Methodologically this view could be defended when looking at processes which change slowly and short time series, while the problem arrives when fast processes turns essential in the object of the study.

Pollution and its effect effect on ecosystems

Sulfur dioxide and oxides of nitrogen can cause acid rain which reduces the pH value of soil.
Soil can become infertile and unsuitable for plants. This will affect other organisms in the food web.
Smog and haze can reduce the amount of sunlight received by plants to carry out photosynthesis.
Invasive species can out compete native species and reduce biodiversity. Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species competitiveness.

Effects on human health and pollution

Adverse air quality can kill many organisms including humans. Ozone pollution can cause respiratory disease, cardiovascular disease, throat inflammation, chest pain and congestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of drinking water by untreated sewage in developing countries. Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood pressure, stress and sleep disturbance.

International monitoring

The Kyoto Protocol[7] is an amendment to the United Nations Framework Convention on Climate Change (UNFCCC), an international treaty on global warming. It also reaffirms sections of the UNFCCC. Countries which ratify this protocol commit to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emissions trading if they maintain or increase emissions of these gases.[7] A total of 141 countries have ratified the agreement. Notable exceptions include the United States and Australia, who have signed but not ratified the agreement. The stated reason for the United States not ratifying is the exemption of large emitters of greenhouse gases who are also developing countries, like China and India.[8]

Monitoring in China

China's rapid industrialization has substantially increased pollution. China has some relevant regulations: the 1979 Environmental Protection Law, which was largely modelled on U.S. legislation. But the environment continues to deteriorate.[5] Twelve years after the law, only one Chinese city was making an effort to clean up its water discharges.[6] This indicates that China is about 30 years behind the U.S. schedule of environmental regulation and 10 to 20 years behind Europe.

Monitoring in The United Kingdom

In the United Kingdom, it took until the 1840s to bring onto the statute books legislation to control water pollution. It was extended to all rivers and coastal water by 1961. However, currently the clean up of historic contamination is controlled under a specific statutory scheme found in Part IIA of the Environmental Protection Act 1990 (Part IIA), as inserted by the Environment Act 1995, and other ‘rules’ found in regulations and statutory guidance. The Act came into force in England in April 2000.

Within the current regulatory framework, Pollution Prevention and Control (PPC) is a regime for controlling pollution from certain industrial activities. The regime introduces the concept of Best Available Techniques ("BAT") to environmental regulations. Operators must use the BAT to control pollution from their industrial activities to prevent, and where that is not practicable, to reduce to acceptable levels, pollution to air, land and water from industrial activities. The Best Available Techniques also aim to balance the cost to the operator against benefits to the environment. The system of Pollution Prevention and Control is replacing that of Integrated Pollution Control (IPC) (which was established by the Environmental Protection Act 1990) and is taking effect between 2000 and 2007. The Pollution Prevention and Control regime implements the European Directive (EC/96/61) on integrated pollution prevention and control.

Monitoring in Europe

Noticeable pollution in BordeauxGenerally the European countries lagged significantly behind the United States in meaningful environmental regulation, including air quality standards, water quality standards, soil contamination cleanup, indoor air quality and noise regulations.[4] Despite this, European pollution output is far lower than that of the USA. In the year 2000, UK Air Quality Regulations were established and they were further amended in 2002. There has also been British harmonization with EU regulations.

The EU is presently entertaining use of the (possibly carcinogenic) MTBE as a widespread gasoline additive, a chemical which has been in the process of phaseout in the U.S. for over a decade.

Monitoring in United States

To protect the environment from the adverse effects of pollution, many nations worldwide have enacted legislation to regulate various types of pollution as well as to mitigate the adverse effects of pollution.

The United States Environmental Protection Agency (EPA) established threshold standards for air pollutants to protect human health on January 1, 1970. One of the ratings chemicals are given is carcinogenicity. In addition to the classification "unknown", designated levels range from non-carcinogen, to likely and known carcinogen. Some scientists have said that the concentrations which most of these levels indicate are far too high and the exposure of people should be less. In 1999, the United States EPA replaced the Pollution Standards Index (PSI) with the Air Quality Index (AQI) to incorporate new PM2.5 and Ozone standards.

The United States Congress passed the Clean Air Act in 1963 to legislate the reduction of smog and atmospheric pollution in general. That legislation has subsequently been amended and extended in 1966, 1970, 1977 and 1990. Numerous state and local governments have enacted similar legislation either implementing or filling in locally important gaps in the national program. The national Clean Air Act and similar state legislative acts have led to the widespread use of atmospheric dispersion modeling[3] in order to analyze the air quality impacts of proposed major actions.

Passage of the Clean Water Act amendments of 1977 required strict permitting for any contaminant discharge to navigable waters, and also required use of best management practices for a wide range of other water discharges including thermal pollution.

Passage of the Noise Control Act established mechanisms of setting emission standards for virtually every source of noise including motor vehicles, aircraft, certain types of HVAC equipment and major appliances. It also put local government on notice as to their responsibilities in land use planning to address noise mitigation. This noise regulation framework comprised a broad data base detailing the extent of noise health effects.

The state of California's Office of Environmental Health Hazard Assessment (OEHHA) has maintained an independent list of substances with product labeling requirements as part of Proposition 65 since 1986.

The U.S. has a maximum fine of US$25,000 for dumping toxic waste. However, many large manufacturers decline to dispute violations, as they can easily afford the fine.

Pollution in Middle Ages II

Since travel and widespread information were less common, there did not exist a more general context than that of local consequences in which to consider pollution. Foul air would have been considered a nuissance and wood, or eventually, coal burning produced smoke, which in sufficient concentrations could be a health hazard in proximity to living quarters. Septic contamination or poisoning of a clean drinking water source was very easily fatal to those who depended on it, especially if such a resource was rare. Superstitions predominated and the extent of such concerns would probably have been little more than a sense of moderation and an avoidance of obvious extremes.

Pollution in Middle Ages

The dark ages and early Middle Ages were a great boon for the environment, in that industrial activity fell, and population levels did not grow rapidly. Toward the end of the Middle Ages populations grew and concentrated more within cities, creating pockets of readily evident contamination. In certain places air pollution levels were recognizable as health issues, and water pollution in population centers was a serious medium for disease transmission from untreated human waste.

Pollution in Ancient cultures

The first advanced civilizations of China, Egypt, Persia, Greece and Rome increased the use of water for their manufacture of goods, increasingly forged metal and created fires of wood and peat for more elaborate purposes (for example, bathing, heating). Still, at this time the scale of higher activity did not disrupt ecosystems or greatly alter air or water quality.

Prehistory of pollution

Humankind has some effect upon the natural environment since the Paleolithic era during which the ability to generate fire was acquired. In the Iron Age, the use of tooling led to the practice of metal grinding on a small scale and resulted in minor accumulations of discarded material probably easily dispersed without too much impact. Human wastes would have polluted rivers or water sources to some degree. However, these effects could be expected predominantly to be dwarfed by the natural world.

Causes of pollution

Motor vehicle emissions are likely the leading cause of air pollution. China, United States, Russia, Mexico, and Japan are the world leaders in air pollution emissions; however, Canada is the number two country, ranked per capita. Principal stationary pollution sources include chemical plants, coal-fired power plants, oil refineries,[2] petrochemical plants, nuclear waste disposal activity, incinerators, large animal farms, PVC factories, metals production factories, plastics factories, and other heavy industry.

Some of the more common soil contaminants are chlorinated hydrocarbons (CFH), heavy metals (such as chromium, cadmium--found in rechargeable batteries, and lead--found in lead paint, aviation fuel and still in some countries, gasoline), MTBE, zinc, arsenic and benzene. Ordinary municipal landfills are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU.

Pollution can also be the consequence of a natural disaster. For example, hurricanes often involve water contamination from sewage, and petrochemical spills from ruptured boats or automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produce widespread and potentially hazardous releases when accidents occur.

In the case of noise pollution the dominant source class is the motor vehicle, producing about ninety percent of all unwanted noise worldwide.

What is pollution?

Pollution is the introduction of substances or energy into the environment, resulting in deleterious effects of such a nature as to endanger human health, harm living resources and ecosystems, and impair or interfere with amenities and other legitimate uses of the environment.[1] The major forms of pollution include:

Air pollution, the release of chemicals and particulates into the atmosphere. Common examples include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs), and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight.

Water pollution via surface runoff and leaching to groundwater.

Soil contamination occurs when chemicals are released by spill or underground storage tank leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons.

Radioactive contamination, added in the wake of 20th-century discoveries in atomic physics. (See alpha emitters and actinides in the environment.)

Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar.

Light pollution, includes light trespass, over-illumination and astronomical interference.

Visual pollution, which can refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash or municipal solid waste.

Thermal Pollution, is a temperature change in natural water bodies caused by human influence.