Smog refers to a noxious mixture of gases & particles that often appears as a haze in the air. This is caused by excessive air pollution. The term “SMOG” was coined in the early 1900s in London to describe the combination of smoke & fog that often covered the whole city. And according to various sources, the term was coined by Dr. Henry Antoine des Voeux in his paper “Fog and smoke”, at the Public Health Congress meeting in July 1905. He said that “smog is a combination of smoke & Sulphur dioxide”.

It contains harmful gasses like nitrogen oxide, sulfur oxide, unburned hydrocarbons & carbon monoxide. Smog is mainly composed of ozone so it is also called ground-level ozone. Ozone is another gas that causes health problems. It has a yellowish color or it can be blackish. In certain other cities such as Delhi, smog severity is often aggravated & in 17 years such an alarming situation raised called it is a health emergency.

Smog is classified into two types-

1)Sulfurous smog: It results from a high concentration of sulfur oxides in the air & is caused by the use of sulfur-bearing fossil fuels, particularly coal.

2) Photochemical smog: It occurs most prominently in urban areas that have large no of automobiles, and requires neither smoke nor fog.  This type of smog has its origin in the nitrogen oxides & hydrocarbon vapors emitted by automobiles & other sources which are undergoing photochemical reactions in the lower atmosphere.

Smog is purely caused by air pollution. When fuels are burnt, the atmospheric pollutants or gases released in the air react with sunlight and its heat in the atmosphere, smog is formed. And also due to complex photochemical reactions between VOC, Sulphur dioxide, ozone, coal combustion, vehicular emissions, forest & agricultural fires, nitrogen oxides which are also known as precursors, and also other particulates in the air that combine with moisture.

Today, we are primarily seeing photochemical smog. Sulfurous smog was first observed in London on December 5, 1952. It arose as a result of the high concentration of Sulphur in the air. The atmospheric pollution levels of Los Angeles, Beijing, Tehran, etc. are increasing by inversion that traps the pollution close to the ground.

Ozone is the main ingredient in smog which is one of the most widespread air pollutants & among the most dangerous. Smog is harmful & it is evident from the components that it affects what can happen from it. It is harmful to humans, animals, plants & nature as a whole.  Long-term health effects from air pollution include heart disease, lung cancer, and respiratory diseases such as emphysema. It can also cause long-term damage to people’s nerves, brain, kidneys, liver, and other organs. There are many more effects like- burning eyes, throat, irritated mucous, membranes, shortness of breath, wheezing, coughing, and asthma attacks. It can be the reason for chest pain when inhaling. It also increased the risk of heart attacks & pulmonary inflammation. It can also affect the reproductive system. The smog results in mortifying impacts on the environment by killing innumerable animal species & green life as it takes time to adapt to breathing & surviving in such a toxic environment. So we should fight the forceful impacts of smog for reducing its effects.