Air pollution killed approximately 1.7 million Indians in 2019, according to a report by the interdisciplinary journal Lancet Planetary Health. The causes of air pollution can be natural or man-made. Breathing fresh and pure air has become nearly impossible due to the increased quantity of contaminants in the air.

All of us are concerned about our health these days due to the rising level of air pollutants. Since the pollutants in the air are invisible to the human eye, we are unaware of the main sources of pollution. To understand the sources of air pollution, we must first identify the fundamental causes of air pollution.

In this blog, l will walk you through some common activities that knowingly or unknowingly are becoming the major causes of air pollution. Now, off we go.

Air pollution causes

Let me list down the 9 major causes of air pollution.

• The Burning of Fossil Fuels
• Agricultural Activities
• Waste in Landfills
• Industrial Emissions
• Mining Operations
• Natural Phenomena
• Indoor Pollution
• Construction and Demolition
• Open Burning of Waste and stubble

Let’s have a look at each of them in detail.

Burning of Fossil Fuels – Chief cause of air pollution

• Millions of diesel and gasoline-powered vehicles run on our roads daily.
• Gasoline is composed mainly of hydrocarbons and trace amounts of nitrogen and sulphur bearing compounds.
• The gasoline doesn’t undergo complete combustion always.
• As a result, the exhaust gases coming out of gasoline-powered vehicles consists of harmful oxides of sulphur ( SO₂, SO₃), nitrogen (NO_X), Particulate matter, carbon monoxide, etc.
• PAHs, or polycyclic aromatic hydrocarbons, are also emitted from automobile exhaust.
• When humans are exposed to large amounts of the same, it can harm their liver and lungs and even permanently destroy them.
• It is not surprising that vehicular pollution contributes about 80% of nitrogen oxides and carbon monoxide in Delhi’s air.

Also read : Electric Vehicles- 5 Types & Advantages Full Guide

Agricultural Activities

• Ammonia is the most common source of agricultural air pollution.
• Heavily fertilised fields and livestock waste emit this gas in large amounts.
• It combines with pollutants from combustion, primarily nitrogen oxides and sulphates from automobiles, power plants, and industrial operations, to form small solid particles known as aerosols.
• They are little larger than 2.5 micrometres in diameter, or approximately 1/30 the width of a human hair.
• These particles can get deep into the lungs and cause heart or lung diseases. 

Waste in Landfills

• Garbage is buried or dumped into sites called Landfills.
• Microbes act on these deposited or buried wastes and generate methane.
• Methane is a significant greenhouse gas that is extremely combustible and dangerous.
• It can form explosive mixtures along with air.

Industrial Emissions

Industrial activities release a variety of pollutants into the atmosphere, affecting air quality in ways we can’t even imagine. Industries that use coal and wood as their principal energy sources release PM 2.5 and 10, nitrogen dioxide, sulphur dioxide, and carbon monoxide.

Also read : Air Pollution Meteorology and Plume Types

Mining

Mining is one of the largest causes of air pollution. Excavations, blasting, and transportation of materials generate particulate matter. Also, Exhaust emissions from mobile sources such as trucks and heavy equipment raise these particulate levels.

Ever thought that there were natural causes of air pollution? Well, let me show you how this happens.

Natural Phenomena

• Climate change is causing not only an increase in wildfires but also an increase in air pollution.
• 0 -90% of wildfire smoke, by mass, lies within the particle size range of 2.5 micrometres in diameter or smaller.
• PM 2.5 in the air combine with other dangerous chemicals, gases and pollen.
• As a result, it causes smog.
• Smog makes the air cloudy, making it difficult for people to breathe.
• On warmer days, trees like Black gum, poplar, oak and willow emit substantial volumes of volatile organic compounds (VOCs) into the environment.
• In addition, these VOCs combine with pollutants like NOx, SO₂, and anthropogenic organic carbon compounds to form a seasonal haze of secondary pollutants.
• Volcanic activity also produces pollutants like sulfur, chlorine, and ash particulates.

For a detailed insight on the major air pollutants, make sure that you go through our blog, What are air pollutants? | Types, sources and effects of air pollution.

Indoor Pollution – A hidden cause of air pollution

Have you ever observed that when you paint your house’s walls, it emits a noxious odour that makes it nearly impossible to breathe? This is due to the VOCs released by paints, perfumes, home decor, cleaning products etc. VOCs including acetone, formaldehyde, xylene, etc are chief causes of air pollution indoors.

Around 3 billion people still cook over open flames using solid fuels such as wood, crop wastes, charcoal, coal, and dung. These inefficient methods of cooking can release CO, CO₂ and soot particles which can penetrate deep into the lungs. Above all, indoor smoke levels can be 100 times higher than permitted values in poorly ventilated houses. Shocking, right?

Here’s the truth. According to WHO, every year, around seven million people die prematurely as a result of the combined impacts of ambient (outdoor) and residential air pollution.

Also read : Waste water treatment – Stages and process

Construction and Demolition

Several construction sites and raw materials such as bricks and concrete produce haze and filthy air. This is endangering people, particularly children and the elderly. For instance, the Central Pollution Control Board (CPCB) recorded the highest number of air pollution complaints in the Delhi NCR due to building and demolition activity.

Open Burning of Waste and Stubble.

• Garbage burning in the open is far more hazardous to your health and the environment than you might believe.
• It is one of the major air pollution causes in Delhi along with the stubble burning by farmers.
• Delhi produces 9500 tonnes of garbage each day, making it India’s second-largest waste dumping city.
• Exposure to open rubbish burning poses a major health risk, including cancer, liver problems, immune system impairment, and reproductive dysfunction.

Causes of Air Pollution in Delhi

• Firstly, the crop stubble burning by farmers of Punjab and Haryana contributes as much as 40% of Delhi’s air pollution in the winter months.
• Secondly, construction activities add a great deal to the city’s pollution load. Dust from construction sites is responsible for 30% of air pollution in Delhi, according to authorities from the Delhi Pollution Control Committee (DPCC).
• Automobile emissions and industrial pollution are also major contributors to poor air quality in Delhi.
• A major source of airborne particulates in Delhi is a fire in the Bhalswa landfill.
• Some other causes include cow dung cake combustion, fires on agricultural land, diesel generator exhaust, waste burning, and illicit industrial activity.

If you wish to dig deep into the pollution levels in Delhi, check out our blog, Air Quality Index in Delhi – AQI categories and Causes.

Conclusion

To sum up, air pollution has a variety of causes, each with its own set of problems. Residential energy for cooking and heating, vehicle emissions, electricity generation, agriculture/waste incineration, and industry are all major sources of air pollution. Integrated policies supporting sustainable land use, energy-efficient housing, power generation, and better municipal waste management can effectively reduce significant sources of ambient air pollution.

The National Green Tribunal has played a key role in delivering effective and timely resolution in cases involving environmental preservation, forest conservation, and air quality management. Let’s all be a part of reducing air pollution and do our bit to protect the air quality.

To know more about air pollution control measures, have a look at our blog, Air Pollution Control measures – Top 9 Air pollution control devices.