Difference Between Conventional pollutants And Unconventional pollutants
Air pollutants include unwanted smoke particles and gases. Examples of specific gases are carbon monoxide, sulfur oxides, gaseous hydrocarbons, nitrogen oxides, and ozone. Some of the pollutants react with one another to form irritating substances. When heated by the Sun, the ingredients combine to form smog (from “smoke” and “fog”). Smog is a serious health concern, especially for people with upper respiratory conditions. Similarly, when sulfur and nitrogen oxides react with water vapor in the atmosphere, the resulting precipitation falls to Earth as acid rain, changing the balance of both land and water environments. Ultimately it kills forests, poisons lakes, and affects organisms from the smallest plankton to the largest mammals.
Air pollution is a relatively recent phenomenon, traced back to the smoke plumes of the Industrial Revolution. But gases released in automobile and airplane exhaust fumes are now among the major contributors. Billions of metric tons of such pollutants are discharged into the air worldwide each year.
A particularly potent source of air pollutants are nuclear and industrial accidents. For example, toxic gas from a chemical plant operated by Union Carbide escaped into the atmosphere in Bhopal, India, in 1984. The fumes killed more than 2,000 local residents and injured an estimated 150,000. Two years later, in 1986, a fire broke out at the Chernobyl nuclear power plant located near Kiev, Ukraine. It discharged massive amounts of radiation into the atmosphere. The catastrophe caused millions of dollars of damage to crops and livestock and highlighted the worldwide environmental threat posed by nuclear fallout.
In general, water pollutants are hazardous materials that have found their way into surface water, groundwater, or waterways and oceans. Some may be introduced directly into water sources: industrial chemicals and metals released from factories into rivers; sewage and detergents flowing through sewers into streams and lakes; or oil spilled into the ocean during transport. Other pollutants may find their way into water indirectly. For instance, agricultural fertilizers can be carried by wind, or percolate through soil and into water sources after rain storms. Rains can also flush mineral deposits exposed by mining projects into topsoil and, ultimately, into nearby streams and rivers. In the process, such pollutants also contaminate the soils of the land.
There are many other causes of land pollution. The fertility of surface soil can be changed by erosion from wind or water. The eroded sediments can be deposited in unwanted places, where they must be cleaned out. Contaminants entering the soil system and into groundwater may end up in the food chain. Additionally, they may directly harm organisms living in and on the soil. Thus the impact of land pollution goes far beyond the soil itself.
Noise, light, and visual blight—all relatively recent in origin—can also be regarded as pollution. Environmental noise is most often associated with urban settings—street traffic, sirens, alarms, construction, radios, and loudspeakers, to name just a few. Evidence has shown that noise-related stress causes a wide range of health problems, from hearing loss to irritability.
Cities and towns alike have innumerable lights that illuminate the night sky. Streetlights, advertising signs, windowed buildings, and vehicle headlights create an orange haze known as “sky glow” that fills the night sky and obscures the stars. Light pollution can be hazardous to humans and nocturnal wildlife. Drivers and pedestrians can be momentarily blinded by glare. Artificial light confuses creatures such as migrating birds and hatchling turtles, sometimes leading to their demise. Few studies have been directed to what other ecological disruptions might be caused by the human ability to light up the night sky.
While not usually a serious health threat, visual or aesthetic pollution must also be mentioned. In cities, the jumble of advertising signs, dingy factories, garbage, litter, abandoned buildings, and empty lots are considered to be “eyesores.” Beyond city limits, equally offensive are vast acres of tree stumps left from lumbering; monotonous suburban housing developments on once-verdant farmland; and the unsightly maze of deep pits left from strip mining. Even highway billboards and power lines can ruin beautiful landscapes.