The menace of Air pollution arises when harmful gases or excessive amounts of suspended particles including concentrations of biological molecules get mixed Earth's atmosphere. This phenomenon can lead to uncontrollable spread of diseases, increased allergic reactions and can also end serving death to human beings. Air pollution can also cause immense harms to other forms of living beings that can include animals as well as food crops, and therefore can potentially damage both the natural as also the man made environment. Air pollution can result from reckless human activities as well as from several natural processes and events.
Pollutants affecting the quality of Indoor air along with the polluted air of several urban areas and industrialized cities count among the worst cases of pollution and toxicity problems in the world as identified by several reports. Based on a report by the World Health Organization or WHO in 2014, it was noted that air pollution in the year of 2012 resulted in the deaths of roughly seven million people across the globe. This estimate went in line with what was later put forth by the International Energy Agency IEA as part of their estimates. This suggests that mankind is in the urgent need of finding a solution to curbing and controlling air pollution if they hope of continuing to live a healthy life along with sustaining a suitable environment for the biotic factors and the animal and plant species, they are dependent on. For example, humans if consume animals or crops affected from pollution can start suffering from new kinds of diseases which can even lead to death for the vulnerable ones.
Air pollutants are materials floating in air which can adversely affect humans and the ecosystem as the living beings including man depend on it to stay alive. Humans and animals breathe in air to gain oxygen required for their bodily functions and similarly plants and crops depend on air to get carbon dioxide. The pollutants affecting the quality of air are commonly found to be dust, solid as well as liquid particles including disease molecules and toxins and even gases. These pollutants may get formed through natural events and process and fuelled by mankind and can be classified on the basis of primary pollutants and secondary pollutants. Primary pollutants refer to those that typically generates from natural events for example as ash and pyroclastic cloud formed from volcanic eruptions. Depending on the severity of the eruption and the components present in the magma the pollutants and toxic gases released in the process can vary and depending on the magnitude of the eruption the eruptions can end up significantly changing the face of the ecosystem. An example of a catastrophic volcanic eruption that ended up affecting the lives of thousands of people in multiple countries as also damaging the associated cattle and marine life was the Krakatoa volcanic eruption of Indonesia in the 20th century. The enormous landslides of Mount Krakatoa triggered massive tsunamis that went several kilometres inland killing countless people of Indonesia as well as those in the surrounding countries and islands. The toxic gases and plumes along with the pyroclastic cloud rose high up in the atmosphere filling it with ash, sulphur dioxide, carbon monoxide and this resulted in forming holes in the ozone layer as also contributing to sudden rise in global temperature through the greenhouse effect thus fuelling global warming. As for manmade pollution, the examples are countless. These can be the emission of carbon monoxide gas from combustions inside motor vehicles, sulphur dioxide releases from numerous factories. Since the 20th century the world has noticed a dramatic rise in industrialization which grossly depends on non-renewable fossil fuels for their energy needs. Be it coal, natural gas or petroleum products, they are to burn to generate the energy requirements of the industries and this has resulted to substantial rise in concentrations of carbon monoxide and sulphur dioxide in the atmosphere which are poisonous gases and prolonged exposure to these gases can even kill humans, animals and plant life. Not only that the increase in concentrations of sulphur dioxide in the atmosphere is resulting in acid rains which is leading damages to people, their property and the environment. Secondary pollutants however do not get emitted to the atmosphere directly. Instead, these kinds of pollutants are formed in air as the primary pollutants interact with themselves or react with other elements and compounds to form these secondary pollutants. Among the major examples of these secondary pollutants are smog and ground level ozone. Then comes another kind of pollutants which can be primary as well as secondary in nature and these result from direct emissions as also can be generated from reactions of other primary pollutants already existing in the earth’s atmosphere.
The list of air pollutants that get emitted due to human activity is quite long. The gas that tops the list is Carbon Dioxide (CO2). Since this one is an important greenhouse gas, carbon dioxide serves as a leading air pollutant and among the worst pollutants contributing to climate change. Carbon Dioxide forms as a natural component of the earth’s atmosphere and is inhaled by plants but exhaled by human being. Due to unchecked burning of fossil fuels coupled with the booming population of mankind, the concentration of CO2 is steadily rising in the atmosphere. Next in the list comes the oxides of sulphur or SOx. Mostly involving sulphur dioxide or SO2, these are produced by volcanoes as well as from several industrial plants and factories. This is because coal and petroleum usually comprise of sulphur compounds which after combustion releases sulphur dioxide as gas. Further down the list comes NOx or the nitric oxides. Mostly involving nitrogen dioxide or NO2, which get formed from combustions at very high temperatures as also from thunderstorms due to the resultant electrical discharge from lightning strikes. Concentrations of these gases can appear as brownish haze above and plumes downward of cities. This gas is toxic in nature, among the leading air pollutants, is characterized by a reddish-brown appearance and a sharp biting smell. Next in the list comes carbon monoxide or CO. This one is a colourless gas that also lacks in odour, does not cause irritations yet it is toxic in nature and this makes people more vulnerable to it as the presence of this gas is hard to recognize. This gas gets formed as a result of consumption of fossil fuels for example coal, petroleum, natural gas and even wood. Most of the carbon monoxide emissions are generated from vehicular exhausts. High concentrations of carbon monoxide result in formation of smog in air. Smog has resulted in numerous illnesses especially lung disorders as also disruptions in the life of animals. In 2013 half of the total carbon monoxide emissions to the earth’s atmosphere resulted through exhausts from vehicular combustion of petrol and diesel. Another pollutant in this list are volatile organic compounds or VOC. VOCs are among the major outdoor air pollutants. These compounds can be of two types which are methane (CH4) and non-methane volatile organic compounds or NMVOCs. Methane constitutes as highly efficient when it comes to causing the greenhouse effect and as a result speeds up global warming.
VOCs based on other hydrocarbons play an equally significant role in the greenhouse effect as they generate ozone in the atmosphere which in turn prolongs the presence of methane in the air. One of the most important air pollutants are suspended particulate matter or SPM. These are particles that are present in the air and can vary in terms of size. They are solid or liquid particles suspended in gases. Similar to particulate matter (PM) exist aerosols which refer to combined formations of particles and gas. Many of the particulate matter get formed through natural events like forest fires, volcanoes dust storms among others. Substantial quantities of aerosols are also generated from human activities such as burning of fuel in vehicles, homes, power plants. Currently aerosols generated from these human activities constitute 10% of the entire atmosphere and as a result is leading to diseases like asthma among the children as well as the elderly. A direct link with aerosols and lung cancer is also being noticed by various healthcare facilities. Further down the line are Chlorofluorocarbons or CFC which are harmful to the ozone layer. These are gases that would get emitted from refrigerators, air conditioners, aerosol sprays and more. As these CFCs rose through the atmosphere and into the stratosphere, they would react with other gases and damage the ozone layer letting harmful ultraviolet UV rays to penetrate the atmosphere and reach the earth’s surface. Known damages from these rays would include cause of skin cancers, eye diseases and also damages to plant life. The products which would emit these gases have been banned from use as of today. There are several other manmade pollutants but the one that stands out is radioactive pollutants. They are produced by nuclear explosions and events, meltdowns in nuclear power plants and testing sites like the Fukushima disaster in Japan and the Chernobyl fallout in Ukraine.