Pollution is when something is added to the environment that is harmful or poisonous to living things. Smoke or dust in the air is a type of pollution as it is bad for the lungs when we breath in. Sewage in drinking water is another type of pollution, as it can make people ill because it contains germs and viruses. People living next to a building site where there is too much noise can become sick as they cannot sleep.
As pollution grows, ways to combat it has grown too. Solar energy and wind energy give people other ways to power their homes. When people use these alternative forms of energy, they put less carbon dioxide into the environment. Pollution is of four types; Air, Noise, Water, and Soil or Land pollution.
Here are some ways from which air pollution occurs. Air pollution is caused by poisonous gases, sulphur dioxide, nitrogen dioxide, carbon monoxide and very small particulates. It is also caused by the smoke and harmful gases released by the fires that make vehicles and factories go. Use of coal, wood and kerosene as fuels for fire also causes air pollution. Air pollution may cause breathing problems such as asthma or other health problems. It also causes diseases like cancer.
Water pollution is the presence of harmful materials in water, such as sewage, dissolved metals, waste from farms, factories and crude oil spilled from oil tankers. The three main substances that pollute water are nitrates from fertilizers, sewage and detergents.
Activities such as bathing and washing clothes near lakes, ponds or rivers add nutrients like nitrogen and phosphorous into the water bodies.This leads to excessive growth of algae on the surface of water. It blocks the penetration of sunlight and air, thus reducing oxygen.
Pollution causes harm to organisms living in water and can also harm people's health. In extreme cases it may cause problems such as cancer.
Noise pollution also known as sound pollution is noise which is harmful to humans and animals. This includes the sound of vehicles, loud speakers, etc. Noise pollution can cause ear problems or even permanent deafness, especially to older people.
Soil pollution or land pollution
Soil pollution (also known as land pollution) is when man-made chemicals, such as hydrocarbons, heavy metals, solvents, get into the soil. These chemicals come from industrial activities and from bad waste disposal. Soil pollution may cause health risks. The chemicals can produce harmful vapors, or they can contaminate water supplies underneath the polluted soil.
Plastic pollution is the accumulation of plastic products in the environment that adversely affects wildlife, wildlife habitat, or humans.
A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. This puts back warm water, and so raises the temperature and decreases the oxygen content of the water.
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. An estimated 500 million Indians have no access to a proper toilet, Over ten million people in India fell ill with waterborne illnesses in 2013, and 1,535 people died, most of them children. Nearly 500 million Chinese lack access to safe drinking water. A 2010 analysis estimated that 1.2 million people died prematurely each year in China because of air pollution. The high smog levels China has been facing for a long time can do damage to civilians bodies and generate different diseases The WHO estimated in 2007 that air pollution causes half a million deaths per year in India. Studies have estimated that the number of people killed annually in the United States could be over 50,000.
Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood pressure, stress, and sleep disturbance. Mercury has been linked to developmental deficits in children and neurologic symptoms. Older people are majorly exposed to diseases induced by air pollution. Those with heart or lung disorders are at additional risk. Children and infants are also at serious risk. Lead and other heavy metals have been shown to cause neurological problems. Chemical and radioactive substances can cause cancer and as well as birth defects.
An October 2017 study by the Lancet Commission on Pollution and Health found that global pollution, specifically toxic air, water, soils and workplaces, kill nine million people annually, which is triple the number of deaths caused by AIDS, tuberculosis and malaria combined, and 15 times higher than deaths caused by wars and other forms of human violence. The study concluded that "pollution is one of the great existential challenges of the Anthropocene era. Pollution endangers the stability of the Earth’s support systems and threatens the continuing survival of human societies."
Pollution has been found to be present widely in the environment. There are a number of effects of this:
- Biomagnification describes situations where toxins (such as heavy metals) may pass through trophic levels, becoming exponentially more concentrated in the process.
- Carbon dioxide emissions cause ocean acidification, the ongoing decrease in the pH of the Earth's oceans as CO
2 becomes dissolved.
- The emission of greenhouse gases leads to global warming which affects ecosystems in many ways.
- 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.
- Nitrogen oxides are removed from the air by rain and fertilise land which can change the species composition of ecosystems.
- Smog and haze can reduce the amount of sunlight received by plants to carry out photosynthesis and leads to the production of tropospheric ozone which damages plants.
- Soil can become infertile and unsuitable for plants. This will affect other organisms in the food web.
- Sulfur dioxide and nitrogen oxides can cause acid rain which lowers the pH value of soil.
- Organic pollution of watercourses can deplete oxygen levels and reduce species diversity.
Pollution control is a term used in environmental management. It means the control of emissions and effluents into air, water or soil. Without pollution control, the waste products from overconsumption, heating, agriculture, mining, manufacturing, transportation and other human activities, whether they accumulate or disperse, will degrade the environment. In the hierarchy of controls, pollution prevention and waste minimization are more desirable than pollution control.
Pollution control devices
- Air pollution control
- Thermal oxidizer
- Dust collection systems
- Baffle spray scrubber
- Cyclonic spray scrubber
- Ejector venturi scrubber
- Mechanically aided scrubber
- Spray tower
- Wet scrubber
- Sewage treatment
- Sedimentation (Primary treatment)
- Activated sludge biotreaters (Secondary treatment; also used for industrial wastewater)
- Aerated lagoons
- Constructed wetlands (also used for urban runoff)
- Industrial wastewater treatment
- API oil-water separators
- Dissolved air flotation (DAF)
- Powdered activated carbon treatment
- Vapor recovery systems
Images for kids
Thermal oxidizers purify industrial air flows.
Pollution Facts for Kids. Kiddle Encyclopedia.