The meaning of air pollution.
To pollute means to make dirty. So, air pollution is anything which contaminates the air. When it originally came into English, from the Latin word for ‘to contaminate’, the word ‘pollute’ had connotations of moral contamination and sin. It was not until the 19th century that the word ‘pollute’ would come to specifically mean ‘contaminating the environment’, and it is no coincidence that this coincided with the Industrial Revolution, when the increasing numbers of factories began polluting the air with soot, smoke, and fumes.
What counts as air pollution may depend on the context. The air that we breathe needs to have a certain minimum safety level so that we do not get sick, and this means not exceeding certain levels of polluting gases. However, in other contexts, more stringent tests will need to be applied: if we are treating a hospital patient with pure oxygen, for example, that oxygen must not be contaminated with other gases that are currently found in the air – even though this mixture would be safe to breathe in the outside world.
Now that we know what air pollution is, this article will explain the key types of air pollution.
Types of air pollutants.
As we explore this list of the key types of air pollutants, it will quickly become apparent that the vast majority of air pollutants on the planet is caused by human beings. And, just as we are the ones who cause air pollution, we are also the ones who should act right now to halt it in its tracks – and hopefully reverse its damaging effects.
1. Greenhouse gases: sulphides and nitrous oxides are very harmful pollutants which are produced in a variety of ways. The plastic manufacturing industry, the shipping industry, and factories that burn fossil fuels are all key sources of greenhouse gases. These gases form a thick layer in the atmosphere which traps the sun’s rays. They are called greenhouse gases because this layer acts like the glass of a greenhouse, building up heat inside the earth’s atmosphere and causing catastrophic climate change caused by the overall warming of the earth and sea.
2. Soot: this pollutant is a carbon based, black substance. You will see it in your household chimney, and it is produced in large amounts by exhausts and chimneys in vehicles, boats, factories, and various kinds of industrial chimneys. The polluting nature of soot is partly visual: it forms a thick black layer on everything it touches which can be hard to clean off. But, when it enters the human lungs or touches the delicate membranes of the nose, mouth, and eyes, it can also cause irritation and (in severe cases) respiratory illnesses.
3. Carbon dioxide: this pollutant is produced when fossil fuels are burned. It can cause respiratory illnesses including lung cancer and bronchitis. Carbon dioxide also contributes to the greenhouse effect and global warming. There are currently tonnes of carbon being released into the atmosphere as a result of human manufacturing, and the shipping and aviation industries (to name but a few causes) and this is causing the earth’s temperatures to rise at an alarming rate.
4. Acidic compounds: sulphur, hydrogen, and nitrogen gases in the air can mix with rain and turn the rain acidic. This is the phenomenon known as ‘acid rain’ and it can dissolve the stone in buildings (sadly, for instance, its effects have been seen in the Taj Mahal), poison rivers and lakes, and kill plant, fish, and animal life.
5. CFCs: these are very dangerous substances which were found in most aerosols prior to the 1970s and 1980s. CFCs were causing a dramatically large hole in the ozone layer to appear, and this was increasing the amount of radiation from the sun that was reaching earth, harming human bodies and causing droughts and scorching temperatures. When CFCs were banned over the following decade or so, the hole in the ozone layer began noticeably to repair itself. The story of CFCs is thus ultimately a positive one as it demonstrates how when human beings realise the ways in which they are polluting the air and take concrete steps to stop pollution at its source, the damaging effects of air pollution can start to reverse themselves.
6. Smog: smog is a type of visual as well as health based pollution. It is a mixture of everyday fog with ozone, nitrous and sulphuric compounds, and sooty smoke. It often occurs in big cities – and the smog in London is famously known as a pea souper. Smog makes it hard to see even a short way in front of you, so it pollutes the air visually as well as being filled with compounds that are dangerous both to the environment and to human health. In a way, smog shows us the extent of pollution in a very immediate form: CFCs and acidic compounds in the air can be pretty much invisible until we see their effects on the environment. When a city suffers from smog, this usually means that it is very polluted, and there are more, invisible, types of pollution in the air over and above the thick discoloured smog which we can actually see.
Air pollution is a serious problem. It harms the environment worldwide and also damages human health. As we can see, human activity is the main cause of air pollution, which also means that humans are able to stop polluting the air.