There are many reasons for air pollution, both natural and man-made.

Air pollution refers to the emissions of harmful gas and dust into the atmosphere. The main pollutants that cause air pollution are carbon monoxide, sulfur dioxide, ozone and nitrogen dioxide. Many human activities create air pollution in both developed and developing nations. But humans are not the only source of air pollution. Air pollution happens due to natural activities as well, although human activities are the greatest sources of air pollution on the planet.

Transportation

• Cars, buses, trains, planes and ships emit exhaust into the atmosphere. This exhaust contains a toxic brew of carbon monoxide, gaseous oxide and nitrous oxide that erodes air quality. The result is smog that suffocates many urban environments.

Housing

• Many homes and office buildings create air pollution because fossil fuels must be burned to generate energy to heat or cool the space. Burning things like coal and oil for homes and offices contributes to smog almost as much as transportation.

Agriculture

• Farming as well is a major source of air pollution. The release of nitrous oxide into the atmosphere is primarily the result of farming because bacteria in the soil break down nitrogen through a process called denitrification. In addition, the use of artificial fertilizers and pesticides adds more pollution and contaminants to the air, including methane, nitrogen oxides and ammonia.

Electricity Generation

• Electrical plants that burn coal emit a large amount of mercury into the atmosphere. The U.S. Environmental Protection Agency found that coal-producing power plants emit almost a third of all mercury air emissions found in the atmosphere.

Industry

• Industry is another major contributor to air pollution. Factories not only emit air pollution, but they also emit substances that don’t directly contribute to poor air quality, but instead combine with other elements to create air pollutants. A major source of air pollution from industry comes from volatile organic compounds, or VOCs, which are released into the atmosphere on a large scale.

Consumption

• Consumers also contribute to air pollution. The use of many end products is obvious, such as driving a car; however, their constant consumption demands more industrial activities, which compounds the release of air pollutants into the atmosphere. Think of the person who must have a new car every year. If the average car lasts 10 years, this person will have created a demand for nine more cars unnecessarily. Now imagine 1 billion people with the same lifestyle, applied to every product imaginable. Consumption is the major driver of air pollution.

Livestock

• The raising of livestock contributes to air pollution as well. Animals raised for food release large amounts of methane gas into the atmosphere.

Contribution of Developing Countries

• In developing countries, while factories and other industry may not contribute as much to air pollution, the burning of wood and animal feces for fuel and cooking contributes to air pollution.

Natural Air Pollution

• Nature also creates air pollution. Volcanic eruptions are one source, while others include pollen, insects, bacteria, yeast, fungi and algae. Volcanoes release tons of gases, dust and ash into the atmosphere. These substances make their way around the planet and lower air quality.

Forest Fires

• Forest fires, both natural and those caused by human activities, create air pollution. The burning of forests releases gases, ash and dust into the atmosphere.

Since the discovery of some of the adverse effects of indiscriminant pesticide usage in the 1970s, alternatives to total dependence on chemicals to control pests have been adopted by farmers. A guiding philosophy known as “integrated pest management” (IPM) underlies most strategies to reduce pesticide use. In IPM an agricultural field is viewed as an ecosystem containing pest populations that are influenced by many interacting natural forces. IPM makes use of several types of techniques to minimize damage caused by pests, including biological controls, cultural practices, genetic engineering, and judicious use of chemicals. A biological control can include introducing or enhancing populations of natural predators. The use of natural substances to interfere with pest life cycles, such as the use of sex attractants to draw pests to traps, is another type of biological control. Cultural practices are farming techniques, such as planting patterns, that interfere with pest life cycles. Genetic engineering can be used to develop pest-resistant crop varieties. Under this integrated approach, farmers use chemicals only when necessary, rather than as the first and primary line of attack.

One of the central principles of IPM is that pest populations must be maintained at some minimal level in order to maintain populations of predators. Traditional methods of pest control, on the other hand, aimed to eradicate pest populations entirely. Successful eradication, however, also reduced predator populations, thereby creating an ecologically unstable situation in which the pest when excessive amounts of a crop are lost.

Governmental programs encouraging the adoption of IPM were initiated in the 1970s. As of 1984, IPM programs supervised by the U.S. Department of Agriculture Extension Service were underway for nearly 40 crops and collectively covered 11 million hectares, about 8% of the nation’s harvested cropland. During the period 1971-1982, for example, U.S. pesticide applications on fields of sorghum, cotton, and peanuts declined 41%, 75%, and 81%, respectively (Postel 1987).

Successful application of IPM requires knowledge and ingenuity. The pest’s life cycle, behavior, and natural enemies; the influence of planting patterns and chemical use on pest and predator populations; and many other aspects of the agricultural ecosystem must be understood in depth. IPM offers several benefits, including a decreased reliance on costly chemicals, reduced health risk from exposure to chemicals (either during pesticide application or by contamination of groundwater supplies), and diminished impacts on nontarget wildlife populations. Farmers adopting IPM have been shown to spend less money on pest control. For example, the Texas cotton farmers mentioned previously had net returns per hectare averaging $282 higher than other cotton farmers (Postel 1987).

Similar efforts to develop creative solutions could eliminate or reduce the severity of all of the pollution problems faced by modern society.

Pollution can be defined as the human alteration of chemical or physical characteristics of the environment to a degree that is harmful to living organisms. Some forms of pollution exert a destructive influence on wildlife by killing or impairing the health of individuals. Synthetic chemicals, oil, toxic metals, and acid rain are included in this category of toxic pollutants. Other forms of pollution affect wildlife in a more indirect manner by altering or destroying wildlife habitat. Examples include the obliteration of canyons, marshes, and grasslands with solid waste landfills; the destruction of the ozone layer by chlorofluorocarbons, which may lead to widespread damage due to the effects of excessive ultraviolet radiation on wildlife and their food sources; and carbon dioxide accumulation in the atmosphere, which may lead to global changes in climate and the distribution of wildlife habitats. Although both of these categories of pollutants pose significant threats to wildlife, this chapter focuses on toxic pollutants because of their specific effects on wildlife.

Different species vary in their sensitivity to toxic pollution. For example, populations of fish living in lakes in the northeastern U.S. have proven to be extremely intolerant of the increased acidity caused by acid rain. On the other hand, fish populations in naturally acidic Florida lakes thrive under conditions that would kill fish from northeastern lakes. Why are some fish populations sensitive to the effects of acidity while others are tolerant? The process of evolution allows species to optimize their chances of survival by adapting to the biological, chemical, and physical characteristics of their environment. Evolution, however, occurs over the course of many generations. Over thousands of years fish populations have evolved a tolerance of the conditions in the naturally acidic Florida lakes. Fish in northeastern lakes have evolved to survive under very different conditions, and have no mechanism for coping with high levels of acidity.

In recent times humans have released thousands of synthetic chemicals into the environment and altered the distribution of many naturally occurring substances, thereby creating conditions that wildlife species had never experienced before. In many instances these new conditions have disrupted the delicate biological machinery evolved by organisms over thousands of years.

The word pollution implies a negative impact on our environment. When a reference is made to polluting the environment we commonly think of land, air and water pollution. The types of images we conger up are the dumping of chemicals into our environment, toxic smoke being released into the air, litter lining our streets and parks, poisonous chemicals flowing into our ponds & rivers, toxins and heavy metals penetrating our ground water supplies. But not all forms of pollution are toxic or physically harmful. Visual pollution offends our eyes and impacts our overall well-being. It can damage the economic health of a town or city; ruin a community’s “curb appeal.”Our first impression of a community, rural, suburban or urban, is generally visual. What we are seeing is the visual environment. Natural and built components that reflect design, architecture, art and natural processes combine to create a mosaic of images we rarely think about, yet experience constantly. Change due to natural causes or human intervention such as development or agriculture is a constant feature of this environment. The visual environment is as much an important part of the fabric of our communities as clean water and animal habitat.

Imagine you are on a commercial street in a suburban community. Signs of all sizes, shapes and colors fight for your attention. There are signs on the buildings, signs in front of the buildings and billboards towering above the buildings. Overhead stretches a web of utility wires. Parking lots, expansive areas of asphalt and franchise architecture, housing a number of easily recognizable fast food restaurants and stores, greet your vision in every direction. This is referred to as visual clutter. Visual clutter occurs on many of our suburban and urban commercial streets. These visually cluttered areas are often the gateways to our communities; the roadways which lead into the commercial, tourist or economic centers. The visual impact of these sprawling strip commercial zones create a lasting image of the community; they over shadow the community’s individuality; its sense of place. Isn’t this a form of pollution – visual pollution?

How often do we simply look at and examine what it around us? How often do we question what is happening to the visual environment within our community? When we use the term visual pollution we are suggesting that the portion of the built and natural environment we are viewing has been downgraded. It has been made less attractive to us. Visual pollution is usually the result of design out of context or out of character with already existing elements. It results from failure to consider the relationship between new and existing components of the visual environment. Visual clutter, poor signage, out-of-context architecture, franchise architecture, excess use of poles and wires are just some examples of visual pollution.

Individuals determine differently what is attractive about their environment, based upon their own aesthetic senses, expectations and experiences. The visual environment is integral to our daily experience of the built and natural worlds. Yet, the altering of this visual environment is often taken for granted. There is an assumption that things change as time goes on, yet often little thought is given to designing and planning the changes in a way that positively, instead of negatively, impacts the visual environment. The introduction of cell towers into an area is a good example. To simply function, a cell tower is a tall wire metal structure. You can stick it any where – along a roadside, in the middle of a lush country field, along side the historic town hall. But the same cell tower will function just fine if it is blended into the environment by encasing it in an existing structure such as a bell tower or placing it on top of an already existing structure such as a barn silo or water tower. A little planning and good design can go a long way in preserving scenic beauty.

Visual pollution results in the homogenization of our communities and our loss of sense of place. Many regions and communities today are struggling to maintain a unique identity; that sense of place. When you pass that strip mall with the fast food chains, supermarkets and discount stores can you tell whether you are in the Midwest, Northeast or the South? Our current culture of mass buying and marketing, along with increased mobility subsidizes a growing tendency to substitute commonality for diversity. Franchise commercial architecture is an example of this trend. For economy, building designs are mass-produced for locations in every community creating a sameness about our commercial streets in every region, regardless of significant differences in context. Highways, signage, recreational facilities, schools, community architecture, building materials, utility poles and cell towers have also become homogenized from one area to the other. This homogenization impacts community values – what communities have described as their sense of self-worth, and the identify as distinctive places in which to live, work, recreate and call home. To retain regional identity, and for communities to retain their character, communities need to work towards keeping growth and development in character rather than letting economic pressures and the values of auto-bound consumers shape their viewscapes.

Identifying visual pollution and its appearance in the community is an important step in becoming visually literate and conserving community character across our country. Change in our landscapes and cityscapes is an inevitable and continual process. It can happen, however, without eroding the unique and individual character of America’s cities, towns and countryside, without erasing the result of history, culture and geography. A healthy visual environment promotes the values of those who live, work and play in that community; it promotes civic pride and economic health. Individuals and communities who care about their physical environment can make a difference in how growth impacts what we see. A community’s appearance should express uniqueness while reflecting its history, present vitality and future potential. It should be coherent and vibrant, not cluttered with visual pollution.