What is SMOG and how it is harmful for us?

Smog is derived from two words i.e. smoke and fog which is also described as a mixture of various gases with dust and water vapour and makes breathing difficult. In 17 years such an alarming situation raised in Delhi which raised health emergency. In this article we will discuss about the sources of smog, how it affects our health and how it is formed; what are the necessary precautions that we can take etc.
Nov 8, 2017 12:02 IST
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What is Smog and how it is harmful for us
What is Smog and how it is harmful for us

Smog is derived from two words i.e. smoke and fog which is also described as the type of fog having smoke or soot particles in it or a mixture of various gases with dust and water vapour and makes breathing difficult. It is a yellowish or blackish fog mainly formed by a mixture of air pollutants like nitrogen oxides, sulphur oxides and some other organic compounds that combine with sunlight to form ozone.

In certain other cities, such as Delhi, smog severity is often aggravated and in 17 years such an alarming situation raised called it as health emergency. The atmospheric pollution levels of Los Angeles, Beijing, Delhi, Tehran etc. are increased by inversion that traps the pollution close to the ground. In Delhi due to smog visibility is poor, children are preferred to remain indoor as it is highly toxic to humans and can cause severe sickness, even shortened life. Let’s see the sources of smog, how it affects our health and how it is formed; what are the necessary precautions that we can take etc.

Sources of Smog are: emissions from vehicles, construction, open burning, incinerators, factories, lawnmowers, coal-fired power generation stations, diesel & gasoline vehicles, solvents, cleaners & oil paints, pesticides and through winds which carries pollutants.

Do you know how smog got its name?


During early 1900’s the term ‘smog’ was first used in London to describe the combination of smoke and fog that often covered the whole city. And according to various sources the term was first coined by Dr. Henry Antoine des Voeux in his paper “Fog and Smoke”, at Public Health Congress meeting in July 1905. He said that smog is a combination of smoke and sulphur dioxide.

Before going in to deep first we will see what Ozone (O3) is

Naturally, Ozone is colourless, odourless gas, present in the Stratosphere layer high above the earth which protects us from incoming solar radiations i.e. from UV rays and act as a sheet. On the other hand, ground-level ozone is basically trapped near the ground by some weather conditions or heat inversions and results in to burning of eyes, respiratory distress which act as an important component of smog & is not only harmful for humans but also for plants, animals and man-made materials.


What is Green Muffler and how it is related with pollution

How Smog is formed?

We can say that 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 and nitrogen oxides which are also known as precursors.

During winters when pollution level increases in the atmosphere due to heavy traffic, high temperatures etc. and the speed of the wind are low, it helps the smoke and fog to become stagnate at a place forming smog and increases pollution level near the ground closer to where people are respiring. It hampers visibility and disturbs the environment.

How smog affects our health?

Why smog is harmful for health

Smog is not only harmful to humans but also to plants, animals and the nature as a whole. Exposure to it can lead to various health problems which include:

- Symptoms of Asthma will become worse and can lead to asthma attacks.

- Cardiovascular (heart) disease. Due to bronchial disease many people are dying.

- Production of natural element vitamin D will be less which will lead to rickets among people.

- Chest irritation, coughing, pneumonia and throat cancer or infection

- Breathing problem, pain when breathing, irritation in eyes and pulmonary disease like lung cancer will increase.

- Feeling unusually tired, headache, low energy, wheezing.

- It will cause immense damage to crops and forests. Vegetables and crops mainly soya beans, wheat, tomatoes, peanuts and cotton are subject to infection when they are exposed to smog.

- Various animal species and green life are also affecting by it.

So, on smoggy days it is important to note that children, seniors and people with asthma need to be especially careful. They should take proper precautions.

Who are at most risk?

Although smog affects each and every one of us, it is especially harmful to:

- Children: As children lungs are still in developing stage and in summers they spend lot of time outdoors while playing which will increase their risk of inhaling more polluted air.

- People those who have lung disease like asthma problem etc.

- People those who have heart problem and diabetic patients are also more sensitive because they are more likely to have heart disease.

- Seniors are also at higher risk not only because of their age but also due to their weaker heart, lungs and immune system.

- People with allergies, pregnant women and smokers need to be careful.

Now the question arises that how we can protect ourselves from smog?

- It is necessary to inform your family and others about the EPA (Environment Protection Agency) report on Air Quality Index (AQI) basically known as Pollutant Standards Index i.e. about the ozone levels in your area. And also check the ozone level wherever you are traveling.

- To check ozone levels in a particular region; national, state and local air agencies have tools to look up the ozone level and understand the negative health effects of smog.

-  The AQI ranks air quality from zero to 300. Levels above 150 are considered unhealthy for anyone and levels above 200 are considered unhealthy. And these exposure levels correspond to red and purple colours on the index.


These precautions will help us to survive properly when ozone levels are high.

- Limit your outdoor activities as much as you can.

- On smoggy days keep your activities gentle i.e. reduce running or biking, walking which will help in reducing respiratory problems.

- Avoid using gas-powered engines, pesticides, and oil-based paints.

- Stay hydrated.

- Consider exercising indoors in a smoke-free, air-conditioned environment.

- Drive less

These precautions will help you to sustain properly in the city.

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