Smog Formation 

Smog is a type of air pollution that makes it difficult to see. In the early 1900s, environmental scholars coined the term “smog” to describe a mixture of smoke and fog. Coal burning is the main cause of this pollution. Smog was frequent in industrial regions and has now extended to the cities.

The majority of the pollution we see nowadays is photochemical haze. The reaction of nitrogen oxides with volatile organic compounds (VOCs) in the presence of sunlight produces photochemical smog. 

Car exhaust, coal power stations, and manufacturing pollutants emit nitrogen oxides. Gasoline, paints, and a variety of cleaning solvents all emit VOCs. These compounds produce airborne particles and ground-level ozone, sometimes known as smog when exposed to sunlight.

Formation of Smog

The amount of pollutants produced by burning and exploiting fossil fuels, known to cause severe health impacts, is particularly concerning. The source of smog is also a significant concern, especially for human health, because much of its presence is in cities with substantial populations.

Ozone, one of the most important elements, is produced by chemical interactions between sunlight and some contaminants. Similarly, chemical reactions can form particulate matter, the other fundamental constituent in smog. 

However, the latter is also introduced to the atmosphere through other means. Wind can spread these particles across the land, reducing their concentration in a given area. Rainfall may also wash these contaminants out of the local atmosphere. This might also lead to unintended consequences, such as acid rain. 

Smog can persist for an extended period. During this time, it reaches an inversion layer (produced by warm areas in the upper atmosphere), exposing people to its effects for longer.

Major Components of Smog

In industrial areas and large cities, two types of smog pollute the air. They are:

• Industrial Smog
• Photochemical Smog

Components of Industrial Smog

When pollutants from coal-burning companies interact with fog, the original smog – a mixture of smoke and fog – arises. It is known as industrial smog, and it is also called London smog because it was originally seen in London.

Sulphur dioxide is a significant contributor to the haze in London. It is a by-product of coal-burning, and on cloudy days, it interacts with the wet air to form an acidic, caustic soup. Unburned particle matter that wafts into the air when burning coal is a part of industrial smog. 

Industrial pollution can be thick enough to impair eyesight on misty days, and authorities blame it for thousands of deaths.

Components of Photochemical Smog

Since the 1940s, a new sort of smog has plagued the communities near the mountains. The emissions from automobiles and fossil-fuel-burning power plants on sunny, hot days create this photochemical smog. People first noticed it in Los Angeles.

A complicated process produces the contaminants in photochemical smog. It starts with nitrogen oxide and volatile organic compound (VOC) emissions from automobile tailpipes. 

These main ingredients react with both moisture and oxygen in the air to make ozone. Subsequent reactions produce a range of organic gases, including peroxyacyl nitrates (PANs), which cause severe eye irritation at high concentrations.

Effects of Smog

Particulate matter (PM) comprises solid and liquid particles that vary in size and composition. Most PM is caught in the nose and throat and does not make it to the lungs. On the other hand, smaller particulates can reach the lungs, called “respirable PM.” These microscopic particles can penetrate deep into the body and cause harm. 

PM causes the most damage to the cardiorespiratory (heart-lung) system, leading to infections, asthma, bronchitis, emphysema, black lung, and other diseases.

Ozone (O3) is a powerful irritant and a severe health hazard that can harm the eyes, nose, throat, and lungs. It causes respiratory difficulties like coughing and wheezing and lowers lung function.

Sulphur dioxide (SO2) causes irritation of the eyes, shortness of breath and reduced lung function. It can enter deep into the lungs and, when coupled with water, produces sulfuric acid, which the body is sensitive to. It is also one of the primary causes of tiny PM development.

Carbon monoxide (CO) is an atmospheric contaminant with health consequences and is fatal in high amounts. It attaches to haemoglobin in the blood, limiting its ability to deliver oxygen and depriving essential tissues of oxygen. 

High CO levels have the greatest impact on people with weakened immune systems and a history of health problems.

Conclusion

The health effects of smog and its constituents can be severe, and they depend on many factors. When inhaled, smog is damaging. 

The severity of the impact depends on the amount inhaled, the types of pollutants present, and the individual’s age, weight, activity level, and overall health.