Smog - Causes of Atmospheric Pollution

Atmospheric pollution is highly harmful to life; when it comes to the survival of all living organisms, the air has more importance than food. Atmospheric pollution is thus a matter of great concern on this planet for life to survive. The most common type of air pollutant that affects a large portion of the globe is smog. The blend of two words, smoke, and fog, contributes to the development of the word smog.

It lowers visibility and creates breathing troubles. As it is made of very minute particles, smog comes under particulate pollutants. The types of smog are discussed briefly below.


Air Pollutants

Carbon monoxide is an invisible, odourless gas produced as a result of incomplete combustion. The primary source is gasoline-powered highway vehicles, while large quantities of this gas are also emitted by residential heating systems and some industrial processes. Power plants produce very little carbon monoxide because, to optimize combustion efficiency, they are carefully engineered and controlled. As it quickly displaces oxygen in the bloodstream, exposure to carbon monoxide can be acutely detrimental, leading to asphyxiation at sufficiently high concentrations and exposure periods.

Sulfur dioxide: During the combustion of coal or oil containing sulfur as an impurity, a colourless gas with a strong, choking odour, sulfur dioxide, is produced. Much of the emissions of sulfur dioxide come from plants that produce power; very little comes from mobile sources. This pungent gas, when inhaled, can cause irritation of the eye and throat and damage lung tissue. 

Sulfur dioxide also reacts in the air with oxygen and water vapour, creating a sulfuric acid mist that reaches the ground as an acid rain portion.

Nitrogen dioxide, a pungent, unpleasant gas, is of most concern among the other types of nitrogen oxides. In the atmosphere, nitrogen dioxide also reacts to form nitric acid, leading to the acid rain crisis. Nitrogen dioxide also plays a role in the creation of photochemical smog, a reddish-brown haze that is frequently seen in many urban areas and formed in the lower atmosphere by sunlight-promoted reactions.

Ozone: In the presence of sunlight, ozone is a key component of photochemical smog, created by a complex reaction between nitrogen dioxide and hydrocarbons. It is known to be a tropospheric pollutant, i.e., in the lowest layer of the atmosphere, but not in the upper layers of the atmosphere, where it occurs naturally and is used to block the Sun's harmful ultraviolet rays.


How Is the Smog Formed?

Smog is produced when certain chemicals interfere with the sunlight in our atmosphere, which in turn contributes to visible air pollution that we call smog. It is primarily produced by the emission of vehicle nitrogen oxides, but also by the use of solvents or paints to release volatile organic compounds.


Causes of Smog

  1. Overpopulation

  2. Fossil fuels

  3. Private cars

  4. Long transportation distances

  5. Industrial processes

  6. Excessive consumption

  7. Excessive waste production

  8. Fireworks

  9. Burning of agricultural material

  10. Construction activities

  11. Volcanoes


Smog and Its Type

We have two major types of smog and they are as follows

  1. Classical Smog

When there is a high concentration of sulfur dioxide and particulate matter produced due to fuel combustion, classical smog is created. This happens in humid and cold climates. It is also known as Sulphurous smog, or London smog, and causes the atmosphere to be dark brownish in colour. This smog has a high reducing agent concentration, so it is also known as reducing smog.

  1. Photochemical Smog

In dry and sunny areas of the world, this form of smog is prevalent. Automobiles and factories emit smoke containing hydrocarbons and nitrogen dioxide, which becomes the main component of photochemical smog under the action of sunlight. This smog has a high oxidizing agent concentration, so it is also known as oxidizing smog.


Effects of Photochemical Smog in Points:

There are various harmful effects of photochemical smog.

The harmful effects of photochemical smog are discussed below.

  1. Pulmonary Health Issues: It can contribute to many different respiratory diseases because smog is made up of many particles and elements that are detrimental to our health. This may include health conditions including COPD or bronchitis. The greater the concentration of toxic compounds in the air, the greater the risk of problems with lung health.

  2. Lung Damage: Due to smog, our lungs can also be impaired. For example, these substances can remain in our lungs for quite a long time if we breathe air that is highly polluted with particles and other harmful substances. These substances can cause many physical problems in the lungs during this period of time.

  3. Lung Cancer: When it comes to the consequences of smog, lung cancer is another key concern. Lung cancer is a major problem, particularly in countries where high concentrations of toxic gases and particles can enter the air due to inadequate regulations, because people have no choice but to breathe polluted air. Many of these individuals, which further exacerbates the problem, do not even wear masks or other protection.

  4. Long-Term Health Issues: A variety of chronic diseases related to damage to our lungs can also be caused by smog. When it comes to contamination with toxic chemicals, our lungs are normally very susceptible. Thus, if our lungs are contaminated with smog-related pollutants, the risks of long-term complications grow significantly.

  5. Allergies: While it is difficult to verify, several scientists have also concluded that the probability of allergies can also be increased by a substantial level of air pollution and smog. Researchers have found that allergies are more prevalent in these areas, especially in regions with high smog concentrations.

  6. Irritation of Eyes: These individuals can also suffer from eye irritations, particularly for individuals who respond very sensitive to environmental conditions, as smog contains tiny particles that could irritate our body's mucosae.

  7. Birth Defects: This is especially true in countries where people do not wear protective masks against smog and where air cleaning systems are not sophisticated enough to filter out harmful particles. Therefore, unborn children may suffer or die due to smog and related adverse issues.

  8. Effect on Flora and Fauna: Animals can suffer because smog can contaminate their respiratory systems, which can in turn lead to many kinds of diseases and even death. 

Also, plants may suffer because they are typically very sensitive to their natural conditions and their growth actions, and because of smog, crop yields may also be adversely affected.

  1. It also causes Asthma, Lower life expectancy, Accidents due to bad visibility, Breathing issues, Lower quality of life, and Accidents due to bad visibility.


Do You Know?

  • 92% of people across the world do not breathe fresh air.

  • The cost of atmospheric pollution to the global economy is around USD 5 trillion every year.

  • Approximately 7 million people die prematurely every year from atmospheric pollution, with maximum deaths taking place in Asia- Pacific.


Solved Examples

Example 1: What Are the Smog Solutions? 

By modifying a few habits, such as: Driving less, everyone can do their part to minimize smog. Whenever possible, walk, ride, carpool, and use public transit. Take control of equipment.


Example 2: Why Will Smog Be Dangerous? 

Smog irritates our airways when inhaled, raising our risk of severe heart and lung diseases. Such health threats are why smog levels are tracked by many cities. On a high ozone-alert day, for example, eyes and throat may burn, and may cause cough and wheeze.


FAQs (Frequently Asked Questions)

1. What are the major sources of the toxicity of the air?

Air pollution is caused by solid and liquid particles and some gases which are dissolved in the air. The exhaust from cars and trucks, factories, dust, pollen, mold spores, volcanoes, and wildfires can result in these particles and gases.

2. What are the emission effects?

High levels of air pollution can result in an increased risk of heart disease, wheezing, problems with coughing and breathing, and inflammation of the skin, nose, and throat. Air pollution can also lead to a worsening of heart problems, asthma, and other lung complications.

3. What are the smog components?

Smog mainly comprises tropospheric ozone (O3), primary particulate matter such as pollen and dust, and secondary particulate matter such as sulfur oxides, volatile organic compounds, nitrogen oxides (NOx), and ammonia gases, produced predominantly over urban centers.