Air Pollution wreaks havoc on human health. It is a global threat to the health of all human beings.

We often happen to see in the news, how a thick layer of smog envelops the skyline of our capital city, New Delhi.

Not only Delhi, but other Indian cities (Kanpur, Lucknow, Agra, Gurgaon, etc.) also dominate the list of World’s most polluted cities!

Studies reveal that every year, around 7 million people die of Air Pollution.

So, we can say, “Air Pollution, literally takes our breath away!”

In this article, we’ll discuss how does air pollution put our life on peril.

Why India’s Air Is So Bad to Breathe?

Dozens of Indian cities are dealing with air pollution.

It has been noted that the iconic white marble walls of Taj Mahal are now turning green.

Delhi has also been described as a “gas chamber”.

The smoke also whirls over the other major cities like Chennai and Mumbai.

Traffic exhausts, factory emissions, construction dust, are the main sources of air pollution in the cities.

2/3rd of India’s population still lives outside the cities. Most of these people rely on biomass like wood, dung for cooking.

‘Chulhas’ contribute to 25% of the outdoor pollution.

Crop burning is another source of pollution in rural areas.

Poor waste management in some cities is another major reason.

Which Are the Most Dangerous Air Pollutants In India?

1. Sulphur Dioxide (SO2)

Sulphur Dioxide is a colourless gas. It has a nasty and sharp smell. It reacts easily with other substances and forms sulphuric acid and sulfate salts. These are harmful to health.

Sources of SO2

  • Burning of Fossil Fuels like coal, wood, natural gas.
  • Industrial processes such as refining, pulp making, etc.
  • Metal extraction.
  • Vehicle Emissions, etc.
  • Effects of SO2 on Health

Short-Term Exposure to SO2 causes chest-tightness, coughing and wheezing.

While, long-term exposure leads to shortness of breath, fatigue, lungs diseases like Bronchitis, etc.

It is more dangerous to children and Asthma patients.

2. Nitrogen Dioxide (NO2)

Nitrogen Dioxide is an irritant gas. It is produced when Nitrogen Oxide (NO) and other oxides of Nitrogen (NOX) react with other chemicals in the air.

It is a major air pollutant.


  • Combustion of fossil fuels (coal, petroleum, natural gas).
  • Emissions from cars, trucks, buses, etc.
  • Power Plants.
  • Road transport is the major contributor to the increase in NO2 levels in the air.
  • Effects of NO2 on Health

It mainly affects the respiratory system of the body.

Long-term exposure can decrease lung functions and increase the body’s response to allergens.

It may cause Emphysema, Fibrosis and Bronchitis.

London Smog and Los Angeles Smog

‘Smog’ is a fusion of the words ‘smoke’ and ‘fog’. It is a type of severe air pollution.

The term was first used to describe the air conditions in the British towns.

London Smog

It is also called ‘Great Smog of London’ or ‘The Killer Smog of 1952’. It was first observed in December, 1952. It was a period of cold weather and windless conditions which lasted for 5 days in London.

A thick fog formed over the city and caused deaths of 4,000-6,000 people.

This type of smog forms in the months of winter, especially in the morning hours when the temperature is low.

Los Angeles Smog

This type of smog was first seen in Los Angeles in 1950. It is also known as Photochemical smog.

It forms due to the photochemical reaction in the presence of NO2 and hydrocarbons in the air.

It is seen in the months of summer during the afternoon.

These two types of smog are the results of pollution caused by sulphur and nitrogen oxides.

3. Carbon Monoxide (CO)

Carbon Monoxide has no smell or taste. This gas is a silent killer. It is a by-product of combustion.


  • Vehicular and Industrial Emissions.
  • Blocked furnaces and chimneys.
  • Cigarette smoke.
  • Incomplete burning of fuels, etc.


Our blood contains Haemoglobin (Hb), which carries oxygen from the lungs to the tissues and brings CO2 back from the tissues.

  • CO can bind to Hb 200 times easily as compared to the Oxygen.
  • It provides no benefit but deprives the body of oxygen.
  • If a pregnant woman inhales CO, it may cause premature delivery.
  • It affects the health of the newborn as well.

4. Lead (Pb)

Lead is a heavy metal found naturally in the environment. It is like a poison to the body.


  • Copper Smelters.
  • Metals processing.
  • Iron and Steel Foundries.
  • Waste Incinerators.
  • Glass manufacturers, etc.

Effects of Lead on Health

Once taken into the body, lead finds its way into the blood throughout the body. It gets accumulated in the bones.

It adversely affects the nervous system, kidney function, immune system and reproductive system.

Children and pregnant women are at greater risk. If a pregnant woman inhales lead, it may increase the demand of Calcium during pregnancy.

Lead decreases the ability of the blood to carry oxygen. It can cause Anaemia.

5. Volatile Organic Compounds (VOCs)

VOCs are a variety of organic chemicals that may have short and long-term effects on health. They are emitted as gases from certain compounds. It is a pollutant we find in every home.


  • Burning of Fossil Fuels in industries and homes.
  • Vehicular emissions.
  • Gas leaks from stoves.
  • Household appliances that use coolant gases, for example, AC units.
  • Mosquito coils, perfumes, camphor, etc.

Effects of VOCs on Health

  • It causes irritation of eyes, nose, throat, headaches, nausea.
  • It may cause damage to liver, kidneys and nervous system.
  • It creates smog and reduces visibility.

Also, VOCs play a major role in the creation of ground-level Ozone.

6. Particulate Matter (PM)

It is a mixture of solid particles and liquid droplets present in the air. Some particles like dust, dirt, soot can be seen through the naked eyes. Whereas, some particles are too small to be seen.


  • Pollen, fungi, bacteria.
  • Powdering, crushing, cracking of metals.
  • Burning of fuels.
  • Construction and public works, etc.
  • Effects of Particulate Matter on Health

PM of size 2.5 micrometres sticks inside the lungs and alveoli. It causes respiratory disorders.

PM smaller than 2.5 micrometres can find their way to the bloodstream. It can cause cardiovascular problems.

They complicate the pre-existing heart and respiratory problems.

7. Ozone (O3)

Ozone is the main component of smog.

High up in the atmosphere, ozone acts as a protective blanket to save earth from the UV rays.

However, ground-level ozone is a pollutant.

It is the main component of smog.


Chemical reactions between Nitrogen oxides and VOCs create ozone.

NOx + VOCs + Sunlight and Heat = Ozone.

Ozone reaches the most unhealthy levels on hot sunny days. But, it can reach the harmful level in winters also.

Effects of Ozone on Health

Headaches, cough, chest discomfort are the effects of Ozone.

If we get exposed to high levels of ozone, it may cause inflammation in the lungs.

Our body becomes sensitive to pulmonary bacterial infections.

8. Benzene (C6H6)

Benzene is a chemical with sweet odour. It is colourless or light yellow coloured liquid.

It is a proven cancer-causing pollutant.


  • Crude oil, gasoline, cigarette smoke.
  • Motor vehicle and industrial smoke.
  • Dyes, drugs, pesticides, etc.
  • Effects of Benzene on Health

Dizziness, headaches, irregular heartbeat, anxiety, etc. are the effects of long-term exposure to benzene.

It can also cause genetic changes.

High levels of benzene can also cause cancer in kidney, brain, stomach, bladder and uterus.

What Can We Do To Deal With The Problem?

Air is all around us. We need it every moment.

If a water body is polluted, we can opt to stay away from the source of water. We can also choose a water purifier.

But, Air Pollution is hard to escape.

No matter, how posh an area you live in, it is all around us.

Luckily, we can control the indoor air quality. Thanks to the Air Purifiers!

Air filters such as HEPA filters can remove smallest of the impurities present in the air. It is the best way to control air pollution at our level.