Industry is a major polluter of air, water, and land. People rely on air, water, and land to remove and disperse waste from factories as well as from other human activities. Pollution occurs when more waste is added to air, water, and land than those resources can handle.
Key Issue 3: Why Do Industries Face Pollution Challenges?
Air Pollution Pollution occurs when more waste is added than air, water, and land resources can handle. At ground level, Earth’s average atmosphere is made up of about 78 percent nitrogen, 21 percent oxygen, and less than 1 percent argon. The remaining 0.04 percent includes several trace gases. Air pollution is a concentration of trace substances at a greater level than occurs in average air. These high concentrations of trace gases in the air can damage property and negatively affect the health of people, other animals, and vegetation. Most air pollution is caused by factories and power plants, in addition to motor vehicles. Factories and power plants produce sulfur dioxides and solid particulates, principally from burning coal. Carbon monoxide, hydrocarbons, and nitrogen oxides are released into the atmosphere when motor vehicles burn petroleum.
Local-Scale Air Pollution At the local scale, air pollution is especially severe in places where emission sources are concentrated, such as urban areas. Urban air pollution has three basic elements:
· Carbon monoxide Breathing carbon monoxide reduces the oxygen level in blood, impairs vision and alertness, and threatens those with breathing problems.
· Hydrocarbons Hydrocarbons and nitrogen oxides in the presence of sunlight form photochemical smog, which causes respiratory problems, stinging in the eyes, and an ugly haze over cities.
· Particulates These pollutants include dust and smoke particles. The dark plume of smoke from a factory stack and the exhaust of a diesel truck are examples of particulate emission.
Regional-Scale Air Pollution Air pollution may damage a region’s vegetation and water supply through acid deposition. Acid deposition is the accumulation of acids on Earth’s surface. Sulfur oxides and nitrogen oxides enter Earth’s atmosphere through the burning of fossil fuels, combine with oxygen and water to form sulfuric acid and nitric acid, and are deposited on Earth’s surface. Acid precipitation is the conversion of sulfur oxides and nitrogen oxides to acids that return to Earth as rain, snow, or fog. Acid precipitation damages lakes, killing fish and plants. On land, concentrations of acid in the soil can injure plants by depriving them of nutrients and can harm worms and insects. Buildings and monuments made of marble and limestone have suffered corrosion from acid rain. Geographers are particularly interested in the effects of acid precipitation because the worst damage is not experienced at the same location as the emission of the pollutants.
Global-Scale Air Pollution: Climate Change Between 1880 and 2014, the average temperature of Earth’s surface increased by 0.89°C (1.6°F). An international team of U.N. scientists has concluded that this temperature increase is directly linked to human actions, particularly the burning of fossil fuels in factories and vehicles. Carbon dioxide is released into the atmosphere when fossil fuels are burned. According to U.N. scientists, the level of carbon dioxide in the atmosphere has increased by more than one-fourth during the past 200 years. A concentration of trace gasses in the atmosphere can block or delay the return of some of the heat leaving the surface heading for space, thereby raising Earth’s temperature. When fossil fuels are burned, one of the trace gases, carbon dioxide, is discharged into the atmosphere. The anticipated increase in Earth’s temperature, caused by carbon dioxide trapping some of the radiation emitted by the surface, is called the greenhouse effect. As a country’s per capita income increases, its per capita carbon dioxide emissions generally increase.
Global-Scale Air Pollution: Ozone Damage Geographers can examine air pollution at three scales: global, regional, and local. Climate change and ozone damage are both global-scale issues.
Ozone Damage The stratosphere contains a concentration of ozone gas. The ozone layer absorbs dangerous ultraviolet rays from the Sun. Were it not for the ozone in the stratosphere, ultraviolet rays would damage plants, cause skin cancer, and disrupt food chains. Earth’s protective ozone layer is threatened by pollutants called chlorofluorocarbons.
Water Pollution Water pollution is a widespread problem because it is easy to dump waste into a river and let the water carry it downstream, where it becomes someone else’s problem. Water can decompose some waste without negatively affecting other activities, but the volume of waste often exceeds the capacity that many rivers and lakes can accommodate.
Demand for Water Humans use approximately 3.6 trillion cubic meters (950 billion gallons) of water per year, or around 500 cubic meters (132,000) per capita. The most demand is for electricity, followed by agriculture and municipal sewage systems. Water usage is either nonconsumptive or consumptive. Nonconsumptive water usage is use of water that is returned to nature as a liquid. Most industrial and municipal uses of water are nonconsumptive because the wastewater is primarily discharged into lakes and streams. Consumptive water usage is use of water that evaporates rather than being returned to nature as a liquid. Most agricultural uses are consumptive because the water is used primarily to supply plants that transpire it and therefore it cannot be treated and reused.
Impact on Aquatic Life Polluted water can harm aquatic life. A commonly used measure of water pollution is biochemical oxygen demand (BOD), which is the amount of oxygen required by aquatic bacteria to decompose a given amount of organic waste. Aquatic plants and animals consume oxygen and so does the decomposing organic waste that humans dump in the water. If too much waste is discharged into water, the water becomes oxygen starved and the fish die. Many factories and power plants use water for cooling and then discharge the warm water back into the river or lake. Fish adapted to cold water, such as salmon or trout, might not be able to survive the warmer water.
Point Source Pollution The sources of pollution can be divided into point sources and nonpoint sources. Point source pollution enters a body of water at a specific location. Nonpoint source pollution comes from a large, diffuse area. Point source pollutants are usually smaller in quantity and much easier to control than nonpoint source pollutants. Water-using manufacturers and municipal sewage are the two main point sources of water pollution.
Nonpoint Source Pollution Nonpoint sources usually pollute in greater quantities and are much harder to control than point sources of pollution. The principal nonpoint source is agriculture. Fertilizers and pesticides spread on fields to increase agricultural productivity are carried into rivers and lakes by irrigation systems or natural runoff.
Solid Waste Pollution The average American generates about 2 kilograms (4 pounds) of solid waste per day. Residences generate around 60 percent of the solid waste, while businesses account for the remaining 40 percent. Paper products account for the largest share of solid waste in the United States, especially among residences and retailers. Manufacturers throw away large quantities of metals as well as paper.
Sanitary Landfill Solid Waste Disposal Using a sanitary landfill is by far the most common strategy for disposal of solid waste in the United States. Thousands of small-town “dumps” have been closed and replaced by a small number of large regional ones. Given the shortage of landfills, alternatives have been sought to dispose of solid waste. A rapidly growing alternative is incineration. Burning releases some toxins into the air and some toxins also remain in ash. Thus, solving one pollution problem may increase another.
Hazardous Waste Disposing of hazardous waste is especially difficult. Hazardous waste includes heavy metals (including mercury, cadmium, and zinc), PCB oils from electrical equipment, cyanides, strong solvents, acids, and caustics. These may be unwanted by-products generated in manufacturing or waste to be discarded after usage. If poisonous industrial residuals are not carefully placed in protective containers, the chemicals may leach into the soil and contaminate groundwater or escape into the atmosphere.
Recycling and Remanufacturing Recycling is the separation, collection, processing, marketing, and reuse of unwanted material. Remanufacturing is the rebuilding of a product to specifications of the original manufactured product using a combination of reused, repaired, and new parts.
Recycling Recycling has increased in the United States from 7 percent of all solid waste in 1970 to 34 percent in 2013. As a result of recycling, about 87 million of the 254 million tons of solid waste generated in the United States in 2013 did not have to go to landfills and incinerators, compared to 34 million of the 200 million tons generated in 1990. The percentage of materials recovered by recycling varies widely by product: 50 percent of paper products and 24 percent of yard trimmings are recycled, compared to less than 10 percent for other sources of solid waste.
Remanufacturing Recycled materials can be remanufactured into new products. Four major manufacturing sectors accounted for more than half of the recycling activity: paper mills, steel mills, plastic converters, and iron and steel foundries. Common household items that contain remanufactured materials include newspapers and paper towels; aluminum, plastic, and glass soft-drink containers; steel cans; and plastic laundry detergent bottles.
11.3
Acid deposition The accumulation of acids on Earth's surface.
Acid precipitation Conversion of sulfur oxides and nitrogen oxides to acids that return to Earth as rain, snow, or fog.
Air pollution Concentration of trace substances, such as carbon monoxide, sulfur dioxide, nitrogen oxides, hydrocarbons, and solid particulates, at a greater level than occurs in average air.
Biochemical oxygen demand (BCD) The amount of oxygen required by aquatic bacteria to decompose a given load of organic waste; a measure of water pollution.
Chlorofluorocarbon (CFC) A gas used as a solvent, a propellant in aerosols, a refrigerant, and in plastic foams and fire extinguishers.
Consumptive water usage The use of water that evaporates rather than being returned to nature as a liquid.
Nonconsumptive water usage The use of water that is returned to nature as a liquid.
Nonpoint-source pollution Pollution that originates from a large, diffuse area.
Ozone A gas that absorbs ultraviolet solar radiation and is found in the stratosphere, a zone 1 5 to 50 kilometers (9 to 30 miles) above Earth's surface.
Photochemical smog An atmospheric condition formed through a combination of weather conditions and pollution, especially from motor vehicle emissions.
Point-source pollution Pollution that enters a body of water from a specific source.
Pollution Concentration of waste added to air, water, or land at a greater level than occurs in average air, water, or land.
Recycling The separation, collection, processing, marketing, and reuse of unwanted material.
Remanufacturing The rebuilding of a product to specifications of the original manufactured product using a combination of reused, repaired and new parts.
Sanitary landfill A place to deposit solid waste, where a layer of earth is bulldozed over garbage each day to reduce emissions of gases and odors from the decaying trash, to minimize fires, and to discourage vermin.