Pollution: pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or non point source pollution.

Air pollution is the introduction into the atmosphere of chemicals, particulates, or biological materials that cause discomfort, disease, or death to humans, damage other living organisms such as food crops, or damage the natural environment or built environment.

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.

Indoor air pollution (see Air log) and urban air quality are listed as two of the World’s Worst Toxic Pollution Problems in the 2008 Blacksmith Institute World's Worst Polluted Places report.

Air pollution can result from both human and natural actions. Natural events that pollute the air include forest fires, volcanic eruptions, wind erosion, pollen dispersal, evaporation of organic compounds and natural radioactivity. Pollution from natural occurrences are not very often.

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater), very often by human activities.

Water pollution occurs when pollutants (particles, chemicals or substances that make water contaminated) are discharged directly or indirectly into water bodies without enough treatment to get rid of harmful compounds. Pollutants get into water mainly by human causes or factors.

Water pollution is the second most imperative environmental concern along with air pollution.

Any change or modification in the physical, chemical and biological properties of water that will have a detrimental consequence on living things is water pollution.

Sound is essential to our daily lives, but noise is not. Noise is generally used as an unwanted sound, or sound which produces unpleasant effects and discomfort on the ears.

 

Gadgets like food mixer, grinder, vacuum cleaner, washing machine and dryer, cooler, air conditioners, can be very noisy and injurious to health. Others include loud speakers of  sound systems and TVs, i pods and ear phones. Another example may be your neighbor’s dog barking all night everyday at every shadow it sees, disturbing everyone else in the apartment.

                                 
Land pollution is the deterioration (destruction) of the earth’s land surfaces, often directly or indirectly as a result of man’s activities and their misuse of land resources.
                                               
It occurs when waste is not disposed off properly, or can occur when humans throw chemicals unto the soil in the form of pesticides, insecticides and fertilizers during agricultural practices. Exploitation of minerals (mining activities) has also contributed to the destruction of the earth’s surface.