The contamination of air due to the presence of compounds in the atmosphere that are hazardous to human & other living beings’ health or impair the climate or materials is referred to as air pollution. Air pollutants include gases such as sulphur dioxide, ammonia, nitrous oxides, carbon monoxide, carbon dioxide, methane and chlorofluorocarbons, as well as particles (both organic and inorganic) and biological molecules. Air pollution can harm humans by causing diseases, allergies, and even death; it can also harm other living species including animals and food crops, as well as the natural environment (like ozone depletion, climate change and habitat degradation) and the built environment (for example, acid rain). Human activity & natural processes both have the ability to pollute the air.
What is a particulate matter?
Particulate matter is a mixture of solids and liquids suspended in the air, including carbon, complex organic chemicals, sulphates, nitrates, mineral dust, and water.
The size of the PM varies. Some particles are large or dark enough to be seen with the naked eye, such as dust, soot, dirt, or smoke. The most dangerous particles, however, are the smaller particles known as PM10 and PM2.5. PM10 particles have a diameter of less than 10 microns (10m), which is 100 times smaller than a millimetre. PM2.5 particles have a diameter of less than 2.5 microns and are classified as fine particles. Ultrafine particles are the smallest fine particles, measuring less than 0.1 micron in diameter.
Particulate pollutants
- Particulate pollutants are airborne particles such as dust and soot.
- Industries, vehicles, power plants, construction activities, oil refineries, railway yards, market places, industries, and so on are major sources of SPM (suspended particulate matter).
- Their diameters range from 0.001 to 500 micrometres (m).
- Particles with a diameter of less than 10 m float and move freely with the air current.
- Particles with diameters greater than 10 m settle.
- Persistent aerosols are formed by particles smaller than 0.02 m in size.
- According to the Central Pollution Control Board (CPCB), particulates with a diameter of 2.5 m or less (PM 2.5) are the most dangerous to human health.
What are Chlorofluorocarbons?
Chlorofluorocarbon (CFC), any of a group of organic compounds made up of carbon, fluorine, and chlorine. When CFCs contain hydrogen in addition to one or more chlorines, they are referred to as hydrochlorofluorocarbons, or HCFCs. CFCs are also known as Freons, which is a trademark of E.I. du Pont de Nemours & Company in Wilmington, Delaware. CFCs were first developed as refrigerants in the 1930s. Some of these compounds, particularly trichlorofluoromethane (CFC-11) and dichlorodifluoromethane (CFC-12), have found applications as aerosol-spray propellants, solvents, and foam-blowing agents. They are well suited for these and other applications because they are nontoxic and nonflammable, and they can easily transition from a liquid to a gas and vice versa. Despite their commercial and industrial value, CFCs were eventually discovered to be a serious environmental threat. CFCs accumulate in the stratosphere after being released into the atmosphere, according to research, particularly that of American chemists F. Sherwood Rowland and Mario Molina and as well as Dutch chemist Paul Crutzen. Stratospheric ozone protects life on Earth from the Sun’s ultraviolet radiation; even a small decrease in stratospheric ozone concentration can result in an increased incidence of skin cancer in humans and genetic damage in many organisms. The dissociation of CFC molecules in the stratosphere is caused by ultraviolet radiation, which produces chlorine atoms and radicals (i.e., chlorodifluoromethyl radical; free radicals are species that contain one or more unpaired electrons).
Carbon monoxide
Carbon monoxide is colourless and odourless, but it is extremely poisonous. While it is commonly thought of as an indoor hazard, it is also a major source of outdoor air pollution.
Air Pollutant Examples
Most air pollutants are invisible and cannot be seen or smelled. However, this does not mean that they do not exist in sufficient quantities to pose a health risk! A number of gases are also linked to the so-called “greenhouse effect,” which means that they retain more heat and thus contribute to overall global warming. Carbon dioxide, which is emitted by many industrial processes, is the most common example of a greenhouse gas. Methane, another explosive gas, is another example.
Conclusion
Air pollutant is the contamination of air caused by the presence of substances in the atmosphere that are harmful to human and other living beings’ health or cause damage to the climate or materials. Air pollution can cause diseases, allergies, and even death in humans; it can also harm other living organisms such as animals and food crops, and it can harm the natural environment (such as climate change, ozone depletion, or habitat degradation) or the built environment. Particulate matter is a mixture of solids and liquids suspended in the air, including carbon, complex organic chemicals, sulphates, nitrates, mineral dust, and water. A number of gases are also linked to the so-called “greenhouse effect,” which means that they retain more heat and thus contribute to overall global warming.