Air Pollution In India

Air Pollution, Pollution Impacts And Air Pollution Remedies ( What, Why & How To Manage ? )

The atmosphere of the earth is vital for life. It creates pressure needed for liquid water which is essential for life. The atmosphere protects living organisms from ultra-violet solar radiation. It warms the earth’s surface by absorbing heat and creates the Greenhouse Effect necessary for supporting life.

The earth’s atmosphere is made up of 78% nitrogen and 20% oxygen with small amounts of carbon dioxide and argon. It also contains traces of water vapour, dust particles, pollen and other gases and compounds. The unique combination of gases in the atmosphere is what makes life on earth possible because it is the combination that is most conducive to life.

However, if for some reason, the percentage of a gas, say carbon dioxide, were to suddenly increase beyond the natural level, it might wreak havoc on earth. This is because the sustenance of life on earth is directly dependent on the fragile balance of the gases in the atmosphere.

Air pollution is a growing concern in India and the world over. It is a health hazard and a threat to the environment. According to the World Health Organization (WHO), every year an estimated 7 million people die prematurely of air pollution-related causes globally. A WHO report stated that in 2012 in India alone around 1.5 million died due to the effects of air pollution.

One of the deadliest repercussions of air pollution has been the depletion of the ozone layer in the outer atmosphere. The ozone layer acts as a shield against harmful UBV ultraviolet rays radiated by the sun. However, due to rampant use of cholofluorocarbons (CFC), a chemical substance used for refrigeration, the layer has been thinning out steadily.

Global warming, also known as climate change, is another side-effect of air pollution. It is caused by fluctuations in the gaseous atmospheric composition and is one of the biggest threats to our planet.

Acid rain is another ramification of air pollution. Air-borne sulphur dioxide molecules react with rain water to form sulphuric acid which then falls down on earth as acid rain. Acid rain is fatal for aquatic life forms. Fish have been seen to perish when water bodies became too acidic due to acid rain. Acid also causes skin diseases in humans and destroys forests.

Air pollution in the Indian is intrinsically related to poor economic conditions. India is the largest consumer of firewood and biomass fuel which are highly polluting fuels. Large parts of the country still lack access to clean cooking fuel. Each year domestic cooking using firewood and biomass generates over 165 million tonnes of combustion products. These products mix with the air we breathe making it extremely unsafe for humans, plants and animals.

According to a 2017 report published by the WHO, 14 of the top 15 most polluted cities in the world based on PM 2.5 concentration are Indian cities. PM 2.5 is a type of microscopic particle called particulate matter (discussed in detail later) with a diameter of less than 2.5 micrometers. It remains suspended in the air and causes severe health issues.

The WHO collected data from 4300 cities and towns in 108 countries. According to the report, Kanpur is the worst hit and the most polluted city with a PM 2.5 level of 173 micrograms per cubic meter which is 17 times higher than the WHO-adjudged safe limit. It is followed by Faridabad, Varanasi and Gaya. New Delhi comes in at sixth position with a PM 2.5 concentration of 143 while Mumbai is the fourth most polluted megacity.

The report further stated that 9 out of 10 people in the world breathe unhealthy polluted air on a regular basis. It also stated that an estimated 4.2 million people died due to pollution-related health complications globally in 2016, of which around 3.8 million perished due to pollution caused by unsustainable and highly-polluting cooking fuels like biomass and firewood. The report also stated that more than 90% of pollution-related deaths were reported in countries with low or moderate per capita income.

In India, the government is taking rigorous steps to cut back on carbon emission and reduce air pollution. The Central Pollution Control Board along with the State Pollution Control Boards keeps a close watch on air quality in 240 cities through 573 monitoring stations. It analyses the concentration of 8 main air pollutants: PM 10, PM 2.5, sulphur dioxide, nitrogen dioxide, nitric acid, carbon monoxide, ozone and lead. India is also a signatory to the Paris Agreement and has pledged to reduce carbon emissions by 33-35% within 2030 compared to 2005 levels.

What is air pollution?

Air pollution may be described as the introduction of certain substances in the atmosphere which makes it detrimental to life. The substances may be chemical compounds, organic matter or particulate matter and they may be present in gaseous, liquid or solid state. When concentration of these substances in the atmosphere exceeds the favorable level, the air loses its life-supporting qualities and becomes unsafe. This is what is known as air pollution.

Pollutants bring about a chemical and physical alteration to the atmosphere and its natural composition. This adversely affects human, animal and plant life. The imbalance in the atmosphere wrought by these substances causes the biosphere to undergo significant, and in most cases, irreversible changes. Such changes in the environment have been found to increase the risk of diseases and abnormalities in human and other life forms.

Air pollution may be due to natural and man-made causes. Let us study these in a little more detail to understand how they work and how it affects us.

Natural causes of air pollution :

Volcanic eruptions :

Volcanic eruptions release massive plumes of ash and smoke into the air. They inject large amounts of water vapour and carbon dioxide, the deadliest known greenhouse gas, into the atmosphere. Volcanic eruptions are a natural cause of acid rain. Gases emitted during eruptions include sulphur dioxide, hydrogen chloride, hydrogen sulphide and hydrogen fluoride. These gases are pumped into the stratosphere (upper atmosphere) which lies about 16-32 km above the earth’s surface.

Air pollution from volcanic erruption

Sulphur dioxide converts to sulphuric acid which condenses in the stratosphere to form sulphate aerosols. Aerosols interfere with the earth’s albedo, increasing it beyond the sustainable level. Aerosols prevent the sun’s rays from penetrating the atmosphere and reflect most of it back into space causing a dip in temperature in the troposphere (lower atmosphere). Sulphate aerosols also interact with atmospheric nitrogen and chlorine and undergo complex chemical reactions to cause ozone layer depletion.

Forest fires :

Air pollution from forest fire

Forest fires or wildfires often start naturally. They mostly occur during extreme hot and dry climate. The major natural causes of forest fires are lightning, spontaneous combustion and volcanic eruptions. Human carelessness may cause forest fires too. Discarded cigarettes, electrical sparks and neglected campfires are some of the leading causes of wildfires. Wildfires release large amounts of smoke and carbon dioxide into the atmosphere. They also inject particulate matter which may cause respiratory and cardiovascular problems in humans.

Radioactive decay of rocks :

Radioactive decay of the earth’s rocks also causes air pollution. It releases a radioactive gas called radon. Radon moves up through the earth’s crust and enters homes  through cracks and gaps in the ground. Radon is fatal for life and is known to cause lung cancer.

Anthropogenic or man-made causes of air pollution :

Combustion of fossil fuel :

Fossil fuels are natural fuels like coal, natural gas and crude oil. Burning fossils fuels or products derived from fossil fuels releases carbon dioxide. It also lowers atmospheric oxygen as oxygen is needed for combustion. Human beings are dependent on fossil fuel for their sustenance.

From cooking to transportation to industrial development, all human endeavors are deeply linked to fossil fuel and its use. Fossil fuels like petroleum and diesel are used for running automobile, mills and factories. For cooking and lighting fuel in rural homes Kerosene is used.

Therefore, it is very difficult to separate human existence from fossil fuels. But it is important to bear in mind that burning fossil fuels directly contributes to air pollution. Apart from carbon dioxide, it releases carbon monoxide, several different oxides of nitrogen, particulates, lead and hydrocarbons into the air, all of which are injurious to health.

As industries expand and the number of cars, trains and airplanes increase, the concentration of these substances in the air will also increase. This is bound to cause irreparable harm to the environment and the life forms it sustains.

Industrial activity :

Human civilization and industrial development are deeply interlinked. Over the years, as our society has become more developed, air quality has steadily deteriorated. With the growth of industries, the concentration of carbon dioxide, carbon monoxide and harmful organic compounds in the atmosphere has also increased.

Industrial activity contributing to air pollution

Crude oil contains hydrocarbons which is a pollutant. Refineries process crude oil. Power plants use the processed oil to generate electricity. Both processes produce large amounts of hydrocarbons, sulphur dioxide and particulates as waste products. These wastes are then released into the air, polluting it irreversibly.

Agriculture :

Agriculture is the next big contributor to air pollution. Fertilizers, pesticides, weedicides and fungicides contain high amounts of ammonia which causes air pollution. Also, cattle naturally produce methane which is a greenhouse gas and causes global warming. Methane is produced in the intestines of cows and buffaloes and eliminated from the body through farts. It causes air pollution and ozone layer depletion.

Refrigeration and air-conditioning :

Chlorofluorocarbons or CFCs are a family of hydrocarbons used in refrigeration, air-conditioning, aerosol cans, packing material and insulation. CFCs are carried upwards by air currents and when they reach the stratosphere, they cause severe destruction of the ozone layer. CFCs are banned under the Montreal Protocol and have been gradually phased out of application. However, due to unscrupulous businesses who continue to use CFCs, we have not been able to completely root out CFCs from the environment.

Mining :

Mining involves drilling and blasting the earth’s crust to excavate minerals from deep under the earth’s surface. These types of activities release large amounts of dust and gaseous compounds into the air creating a blanket of dust over the entire area. Mines rely on fossil fuels like petroleum and diesel to run their heavy machinery and that further adds to the problem. People living near mines and quarries are highly susceptible to respiratory issues.

Mining blasts may also cause underground water tables to fracture. The fracture exposes the water to harmful contaminants like methane gas, heavy metals and mine drainage. Mining also leads to soil erosion and loss of biodiversity. However, the people who suffer the most from mining-related air pollution are miners. Coal miners for example often suffer from black lung disease also known as CWP or Coal Worker’s Pneumoconiosis. CWP is caused due to long-term exposure to coal dust. Miners develop silicosis due to constant exposure to fine silica dust deep inside mines. They are also frequently diagnosed with chronic obstructive pulmonary disease, progressive massive fibrosis and dust-related diffuse fibrosis.

Fireworks :

Fireworks increases air pollution very fast

Bursting crackers is one of the biggest causes of air pollution in India and all over the world. Fireworks pump in enormous amounts of sulphur dioxide, cadmium, carbon dioxide, carbon monoxide, copper, lead, magnesium, nitrates and nitrites into the air making it extremely unsafe for breathing. During Diwali, the air quality in India dips dangerously. The respirable suspended particulate matter (RSPM) levels shoot up causing severe respiratory problems in city dwellers. Smoke from crackers aggravates asthma, increases risk of bronchitis and allergies and causes continuous sneezing and wheezing.

Domestic products :

Air pollution is also caused by domestically used products and services. Paint and painting supplies, lacquer, cleaning supplies, perfumes and deodorants, hair sprays, pesticides, glues and plywood contain synthetic substances collectively known as volatile organic compounds or VOCs. VOCs react with air-borne chemical compounds to produce ozone and particulate matter, both of which are responsible for air pollution. VOCs make air unsafe for human health and are a leading cause of urban air pollution. They have been linked with breathing problems and lung disease.

Smoking :

Cigarette smoke releases fine particulate matter into the environment. A study published in the Tobacco Control suggests that particulate matter emitted by cigarettes is ten times greater than automobile smoke. Smoking causes cancer and chronic lung disease. Apart from the smoker, it also affects others who breathe in the smoke through passive inhalation.

Burning biomass and firewood :

Most people in developing and underdeveloped countries live in rural area with scant access to clean sources of fuel for cooking and other domestic purposes. They use natural sources like firewood and homemade biomass fuel. In most Indian villages, people make a concoction of cattle dung, grass, hay, pieces of wood, saw dust and dried leaves which are patted down into thick round saucer-shaped cakes. These are then allowed to bake in the sun for a few days before being stored away for use as cooking fuel. Combustion of dung cakes releases large amounts of harmful air pollutants that are five times greater than those released by coal.

Major pollutants released by biomass burning are PM 10 particulate matter, sulphur dioxide, nitrogen dioxide, carbon monoxide, carbon dioxide, formaldehyde and polycyclic aromatic hydrocarbons, all of which are highly dangerous for humans. Over a 100 million Indian households use biomass and firewood for cooking and heating purposes. This exposes them to a high risk of breathing and cardiovascular problems. Fuel wood and biomass combustion is the biggest cause of indoor air pollution in rural India.

Stubble burning :

During the months of October and November, farmers in Punjab and Haryana burn the crop stubble to clear out fields and prepare it for the next season’s sowing. Stubble burning is common because it is a fast and cheap way of clearing fields, and kills weeds and pests that may otherwise be immune to weedicides and pesticides.

Stubble burning contributes to air pollution in India

However, burning straw stubble causes extensive air pollution. When farmers in Punjab and Harayana burn their crop stubble, the wind blows the smoke in the eastern direction over New Delhi and the national capital region (NCR) causing massive air pollution.

According to a report published in the US journal, Environmental Research Letters, air pollution in Delhi during the peak stubble-burning season is 20 times higher than the safe air levels laid down by the WHO.

The researchers used satellite data from NASA and ran them through complex algorithms to draw a correlation between agricultural fires and winter air pollution in New Delhi. They found that smoke blowing in from Haryana and Punjab mingled with existing vehicular and industrial air pollutants in New Delhi and the NCR to produce a thick blanket of smog over the region.

Stubble burning is prohibited in most developed countries of the world. In India, however, despite the Punjab Pollution Board banning stubble burning, it is still practiced widely all over the state.

Types of pollutants :

Based on their origin and chemical composition, pollutants can be broadly classified into two types: primary and secondary.

Primary air pollutants :

Primary air pollutants are produced by primary sources. They are the original substances that cause air pollution. Carbon dioxide is a primary pollutant. It is produced by burning fossil fuel which is primary cause of air pollution.

Secondary air pollutants :

Secondary air pollutants are created by chemical reactions between primary air pollutants. A classic example of this is smog. Smog is formed when primary air pollutants react in the presence of sunlight to form secondary air pollutants that further react with primary emissions like vehicular and industrial emissions to form photochemical smog. It involves a complex multi-stage reaction of primary pollutants, secondary pollutants and primary emissions. Smog contains sulphur dioxide, ozone, nitrogen dioxide, carbon dioxide and carbon monoxide released by automobiles and factories. It also contains particulate matter, organic matter and water vapour.

Types of air pollution :

Air pollution can be classified into two categories: outdoor and indoor

Outdoor air pollution :

Outdoor air pollution refers mainly to pollution of air by smog. One of the most toxic components of smog is ground-level ozone, a compound comprising of three oxygen atoms. Ozone causes respiratory problems in human beings. Smog not only causes health hazards but also reduces visibility in cities, affecting air and road traffic. The biggest causes of smog are vehicular and industrial emissions. Today, major cities of the world are reeling under an acute smog crisis. Beijing, New Delhi, Athens and Madrid are among the worst-affected cities.

Mining, volcanic activity and wildfires also play a role in smog formation. Smog caused by bush fires and volcanic eruptions can last for days, weeks and sometimes months. They wreak havoc over vast areas of the neighboring region causing mass evacuations and immeasurable destruction of life and property.

Outdoor air pollution is a cumulative effect of all the outdoor sources and causes of air pollution. Apart from smog, other common outdoor air pollutants include carbon monoxide, carbon dioxide, sulphur dioxide, nitrogen oxide, particulate matter and VOC. They are all directly or indirectly produced due to combustion of fossil fuel, agricultural activities, mining and natural causes of air pollutions.

Ozone layer depletion and acid rain are two clear indicators of outdoor air pollution. Poor air quality reduces visibility, produces foul odors and damages and discolors historical monuments.

Indoor air pollution :

Indoor air pollution refers to pollution inside a house or building. The air inside our homes is often mixed with air-borne chemicals, particulate matter and synthetic VOCs released by cooking and heating appliances, cleaning supplies, paint, perfumes, adhesives and cigarette smoke. Radon gas is another cause of indoor air pollution.

Due to restricted air movement in closed living spaces, there pollutants remain trapped inside our homes. It causes a spike in indoor air pollution. Contrary to popular belief, indoor air pollution can be far more dangerous than outdoor air pollution. An estimate published by the California Air Resources Board states that indoor air pollution is 25% to 62% higher than outdoor air pollution and can lead to severe health problems.

Burning of incense sticks, oil lamps and aromatic candles are a major cause of indoor air pollution in India. Most Indian homes have a temple or place of worship attached to the house. Regular use of lamps and incense for religious purposes increases the risk of respiratory and skin problems.

Carpets, rugs and heavy drapes also cause indoor air pollution. They absorb dust, lint, pet hair and sand making the air inside the house unsafe for breathing. Floor rugs are also a breeding ground for small insects like bed bugs and microscopic organisms like bacteria, protozoa and fungi. These pollutants and their spores are released into the air during vacuuming and dusting. This may cause severe allergies and breathing problems.

Use of plastics and cosmetics also increase indoor air pollution. Plastics like synthetic carpets, synthetic clothing and certain cosmetics release a substance known as micro-plastics which are tiny bits of plastic with diameters ranging from 0.1 micron to 5mm. Micro-plastics are incredibly harmful for health and a growing concern worldwide.

Major air pollutants :

Any substance can become a pollutant if its atmospheric concentration exceeds the natural limit and reaches levels capable of causing serious harm to life and property. What matters is not the substance itself, but rather its quantity in the air, and that can make all the difference between harmless and harmful. For instance, the atmosphere contains about 1% carbon dioxide and that is fine.

However, if the concentration increases sharply, the air becomes unsafe for breathing and cause health issues. Similarly, the atmosphere contains pollen in trace amounts. But pollen released in large quantities by coniferous forests can pollute the air and cause allergic reactions in human beings.

Let us now study some of the top air pollutants.

Sulphur dioxide :

Arguably one of the deadliest air pollutants, sulphur dioxide is a toxic pungent gas that causes irritation when inhaled. It is a chemical compound comprising of two atoms of oxygen and one atom of sulphur. It is produced when sulphur or any substance containing sulphur is burnt. High concentration of sulphur dioxide in the air has huge implications on the environment. It affects human health and destabilizes flora and fauna.

According to the Department of Environment and Energy, Government of Australia, more than 90% of sulphur dioxide comes from industrial and vehicular emissions. Combustion of fossil fuels is the biggest contributor of sulphur dioxide in the air with coal-based thermal power plants being the worst culprits. Sulphur dioxide is also produced in large quantities by natural causes like volcanic eruptions and forest fires. The gas reacts with other air pollutants in the presence of sunlight to produce smog and acid rain.

Inhalation of air rich in sulphur dioxide causes shortness of breath, coughing, sneezing, wheezing and persistent irritation of the nose and throat.

Carbon monoxide :

Carbon monoxide is another major cause of air pollution in India. It is a colorless, odorless and tasteless toxic gas. It can be fatal if inhaled in large amounts in closed rooms. Carbon monoxide severely affects the blood’s ability to transport oxygen to various tissues and organs of the body. It also causes heart pain, fatigue, headache, lack of concentration and giddiness.

According to a 2017 report in the Financial Times, carbon monoxide is one of the biggest causes of air pollution in New Delhi. It is produced due to incomplete combustion of fossil fuels like coal, petrol, diesel, CNG and PNG. New Delhi’s carbon monoxide pollution is also aggravated by the low inversion height.

Inversion height is the level beyond which pollutants cannot move upwards to the upper stratum of air. It is caused due to absence of wind and low temperature. It is the reason why carbon monoxide levels are highest at night.

Excessive exposure to carbon monoxide can lead to death. Burning fossil fuels indoors without proper air circulation can cause indoor air pollution. It is a combination of poor ventilation and unsafe heating and fuel burning practices. There have been reports of people dying in their sleep due to carbon monoxide poisoning caused by naked coal fire in closed unventilated rooms.

Carbon dioxide :

Carbon dioxide is naturally present in the atmosphere. It makes up less than one percent of the total atmospheric volume. However, if its concentration rises above the natural level, it poses a health risk. This is because carbon dioxide is a greenhouse gas. Greenhouse gases trap heat by absorbing infrared radiation from the earth’s surface and keep surface temperatures warm. This phenomenon is called the greenhouse effect and it gives the atmosphere its life-supporting quality.

However, if the concentration of greenhouse gases exceeds their natural limit, it makes the earth’s temperature unduly warm and causes global warming. Too much carbon dioxide in the air can cause an imbalance in the atmosphere and harm the ecosystem and biodiversity of the planet.

The biggest source of carbon dioxide is combustion of fossil fuels like natural gas, crude oil, coal and firewood. Cement manufacturing also generates carbon dioxide. Since the beginning of the industrial revolution, carbon dioxide content in the air has seen a sharp rise. This is because fossil fuels are burnt for production of electricity, transportation and industrial manufacturing.

Oxides of nitrogen :

Nitric oxide (NO), nitrogen dioxide (NO2) and nitrous oxide (N2O) are harmful gases that cause air pollution. They are a group of gases consisting of nitrogen and oxygen atoms in various combinations. They are produced by the burning of fossil fuels in thermal power plants, industrial plants and automobile engines. Industrial processes like welding, smelting, engraving, electroplating and dynamite explosions in mining produce huge amounts of nitrogen oxides.

Combustion of biomass and firewood for domestic cooking and heating purposes also emits nitrogen oxides. Nitrogen oxides react with water vapour and volatile organic compounds (VOC) in the atmosphere in the presence of sunlight to produce ground-level ozone (a greenhouse gas) in the troposphere. Hence, they are also classified as indirect greenhouse gases.

Various oxides of nitrogen also react with moisture and sulphuric acid in the air to form acid rain. They mingle with dust and other air pollutants to form smog in urban areas. Nitrogen oxides hinder photosynthesis in plants and destroy leaves and foliage. In humans, it causes nausea, indigestion, bronchitis and shortness of breath.

Volatile Organic Compounds or VOCs :

VOCs are organic carbon-based chemicals that easily evaporate at room temperature and normal pressure conditions to convert to gaseous state. VOCs can be made up of various elements, principal among which are carbon, hydrogen, oxygen, nitrogen, sulphur, bromide, chlorine and fluorine. They are primarily used as solvents in waxes, paints, thinners, lacquers, glues, varnishes, air fresheners, aerosol sprays and dry cleaning spirits. They are released into the air from automobile exhaust pipes and industrial plants.

Combustion of fossil fuels like gasoline, coal and firewood is the biggest source of VOCs. They also enter the air through evaporation from solvents. VOCc are hazardous air pollutants because of their volatile nature. They can rapidly turn to gases and enter the human body through respiration.

Depending on the toxicity of the chemical, the degree of exposure and the duration of exposure, VOCs can cause a lot of harm to human, plant and animal life. Sustained exposure to VOCs can cause irreversible harm to the central nervous system and cause kidney and liver failure. They can also cause irritation in the eyes, nose and throat, and induce dizziness, nausea, headache and fatigue. VOCs play a central role in formation of smog and ground-level ozone. They contribute to climate change and global warming. Common examples of VOCs are petrol, diesel, benzene and formaldehyde. Solvents used in dry cleaning such as perchloroethylene and styrene and industrial solvents like xylene and toluene are other examples of VOCs.

Methane and other hydrocarbons :

Hydrocarbons are chemical compounds consisting only of hydrogen and carbon atoms. They are mainly found in fossil fuels. In fact, all forms of fuel derived or blended from fossil remains contain hydrocarbons. Coal, natural gas, crude oil, wax, etc all contain hydrocarbons in huge proportions.

When we burn fossil fuels, we release hydrocarbons into the air and this causes air pollution. Methane is the most commonly found hydrocarbon. It is also a greenhouse gas and causes global warming. It is fundamental component of natural gas and leaks into the atmosphere during extraction, processing, refining and distribution of natural gas.

According to the Environmental Protection Agency (EPA) of the United States, around 60% of the world’s total methane production comes from human activities. One of the key sources of methane gas is livestock farming. Methane is produced in the intestine and stomach of ruminants like cows, buffaloes, goats and sheep which is then released into the air through farts. The third largest generator of methane is landfills. When garbage decomposes, it emits methane into the environment. Methane is also produced naturally in the environment in marshy wetlands. Other hydrocarbons that contribute towards air pollution are butane, benzene, formaldehyde, propane, ethane and hexane. Inhaling hydrocarbon vapours can cause irritation of the eyes and allergic reactions.

Ozone :

Ozone is found in two layers in the atmosphere: stratosphere and troposphere. Stratospheric ozone is good ozone as it protects life on earth from harmful solar radiation. Tropospheric ozone is bad ozone as it causes air pollution. Ground-level ozone is created when pollutants from automobile and industrial emissions reacts with each other in the presence of heat and sunlight. Oxides of nitrogen and VOCs undergo complex chemical reactions aided by sunlight to form ozone which leads to global warming.

Inhalation of ozone causes coughing, wheezing and irritation of the throat and nose. It is a major reason behind diminished lung activity. Prolonged exposure to ozone can cause lung scars and inflammation of the tissue lining the lungs. Ozone is also bad for patients of bronchitis, asthma and emphysema. In plants, ozone destroys vegetation and reduces agricultural output. It hinders healthy plant growth and makes them vulnerable to blights, rots and pests.

Particulate matter or total suspended particulate matter :

Particulate matter refers to microscopic air-borne solid, liquid or gaseous substances. They occur in varying sizes and are denoted by the acronym PM followed by a number which indicates its size. For instance PM 2.5 refers to particulate matter with a diameter of 2.5 micrometer.

Particulate matter may be produced naturally or anthropogenically (through human action or inaction). Natural sources of particulate matter are volcanic eruptions, forest fires, sea sprays and dust storms. Anthropogenic sources include combustion of fossil fuels, garbage disposal and smoking. Examples of common particulates are mineral dust, pollen, fly ash, soot, smog, oil smoke, viruses, bacteria, spores, cat allergens, suspended atmospheric dust, heavy dust and tobacco smoke.

Particulates are one of the deadliest causes of air pollution. The smaller their size, the more dangerous they are. Particulate matter with sizes of 10 micrometer or less are known as repsirable particulate matter or RPM as they penetrate deep into the lungs. For instance, particulates less than 10 micrometer in size infiltrate the lungs and get deposited in the bronchi of lungs causing massive lung disorder.

Particulates smaller than 2.5 micrometer enter the lung’s alveoli and affect other organs. PM 10 and PM 2.5 are the deadliest forms of RPM. Needless to say, particulates cause chronic respiratory problems, severe asthma and in extreme cases, lung cancer. They have also been linked with premature delivery and birth anomalies.

Particulate matter abets gradual disintegration of historical monuments and statues. Due to their tendency to settle to the ground, they cause discoloration of forts and ancient structures.


Aerosol is a suspension of fine particulate matter in air or another gas. Fog is a naturally occurring aerosol. Dust and geyser steams are also natural aerosols. Man-made aerosols like smoke and haze, however, have dangerous impacts on the environment.

Aerosols are used in deodorants, perfumes, room fresheners, insect sprays and other household products. They pollute the air inside the house and cause skin irritations. Aerosols with a diameter of 10 micrometer or less enter the bronchi of lungs and have the potential to cause chronic lung disease.

Aerosols reflect solar radiation back into space and lower the earth’s temperature. They also lead to warming of the earth’s surface due to absorption of solar energy. Aerosols are one of the key factors behind air pollution and climate change.

Chlorofluorocarbons or CFCs

CFCs are non-inflammable anthropogenic chemical compounds made of fluorine, carbon and chlorine atoms. They have been used since the 1930s as cooling chemicals in refrigeration and air-conditioning, as propellant gas in aerosol cans, as solvents in household cleaning supplies and as blowing agent in fire extinguishers for producing foam. CFCs are extremely harmful for the environment.

Along with other pollutants like hydrochlorofluorocarbons (HCFCs) and halons, it destroys stratospheric ozone and heats up the lower atmosphere triggering global warming and climate change. Rampant use of CFCs and HCFCs in the earlier days created massive holes in the ozone layer. The holes allow dangerous solar radiation to start penetrating the earth’s atmosphere.

These holes were first discovered in the 1980s over Antarctica. It got the whole world excited and led to the signing of the Montreal Protocol in 1987 by 46 countries (although currently close to 197 countries have ratified it). The agreement pledged to phase out production and use of ozone depleting substances (ODS), principally CFCs and HCFCs.

Lead (Pb)

Lead is a poisonous metal. It affects the central nervous system and induces hallucinations. Lead is emitted into the air due to burning of leaded gasoline in automobile engines. It is also found near lead smelters, ore and metallurgical plants, waste incinerators and factories manufacturing lead-acid batteries.

Tiny particles of lead remain suspended in the air as dust and enter our body through breathing. It circulates in our bloodstream and gets deposited in bones. Lead impairs the overall growth of vertebrates and plants. In humans, it affects the nervous system, the immune system, the reproductive system, endocrine system and cardiovascular system. Infants and children are especially susceptible to lead poisoning.

Long-term exposure to even small amounts of lead can cause neurological damage, developmental defects and lowered IQ in children. When lead mixes with soil it leads to stunted growth in plants and decreases agricultural output.

Other metals

Other metals found in polluted air are vanadium, cadmium, nickel, copper and magnesium. Inhaling air rich in vanadium can cause irritation of the nose, esophagus and skin, chest pain, wheezing, coughing and diarrhea.

Cadmium is found in firecrackers. Inhalation of cadmium fumes can damage the kidneys and nervous system and cause anemia. Air-borne nickle impacts cardiovascular activity and causes heart disease. Copper concentration in ambient air is fairly negligible.

However, settlements close to smelting plants that process copper ore into metal are exposed to high levels of copper in the air. This may cause metal fume fever with atrophic alteration of the nasal mucous membrane.

Effects of air pollution

Air pollution has harmful implications on the environment as well as plant and animal life. Let us now go through the effects of air pollution.

Ozone Depletion

The troposphere is the bottom-most layer of the atmosphere just above the earth’s surface. The stratosphere is the layer of atmosphere adjacent to the troposphere and spans from 20 to 50 kilometers above the earth’s crust. The stratosphere contains ozone, a compound made of three atoms of oxygen. Ozone protects the earth from harmful ultraviolet radiation from the sun and outer universe.

However, due to man-made chemicals like Chlorofluorocarbons or CFCs, like hydrochlorofluorocarbons (HCFCs) and halons, the ozone layer has witnessed a rapid thinning out. These chemicals are hydrocarbons by composition and are collectively known as Ozone Depleting Substances or ODS. They are used as coolants in refrigerators and air-conditioners, as propellants in aerosol cans, as blowing agents for making foam in fire-extinguishers and as solvents in paints and dry-cleaning.

ODSs emitted into the tropospheric air are carried upward by the wind. When they reach the stratosphere, they release chlorine and bromine atoms through photodissociation. These atoms react with ozone and break it down into oxygen (O2) resulting in the disappearance of ozone.

Depletion of the ozone layer was first speculated in the late 1960s by Dutch scientist Paul Crutzen and in the 1970s by American scientists Mario Molina and F Sherwood Rowland. Their work got the attention of the entire world and culminated in the signing of the Montreal Protocol which pledged to phase out the production and use of CFCs and other ODSs.

Ozone depletion has created a hole over Antarctica which experts believe will take many more years to heal completely. As the ozone layer gets thinner and thinner, life on earth will progressively be exposed to greater amounts of harmful UV radiation leading to skin cancer, skin allergies and cataracts.

Studies have shown a strong connection between UV radiation and squamous cell carcinoma, basal cell carcinoma and malignant melanoma, all of which are different types of skin cancer. UV radiation has also been linked with cortical cataracts. Ozone depletion is said to be the biggest contributor to this health risk.

Excessive exposure to UV rays is also bad for plants and cash crops like rice. It affects cyanobacteria residing in the roots of plants. Cyanobacteria are responsible for fixing nitrogen in the soil. Therefore, destroying them can cause irreparable harm to crops and lead to stunted growth and lowered crop yield.

The good news is, due to the relentless efforts of most leading economies of the world, the production of ODSs has seen a steady decline. Latest studies have reported a marginal increase in the thickness of the ozone layer and a reduction of the size of the Antarctic hole. Scientists predict the ozone layer will continue to recover in the coming years.

Global Warming and Greenhouse Effect

The terms global warming and climate change can be used interchangeably. They refer to the observed and recorded gradual increase in average surface temperature of the earth and its effects on the climate and ecosystem, over the last century. Climate change is predominantly an anthropogenic phenomenon. It is caused by greenhouse gases like water vapour, carbon dioxide, methane, ozone, nitrogen oxides and fluorinated gases, all of which are released into the air by automobile exhaust pipes and industries.

Greenhouse gases create the greenhouse effect by absorbing and emitting infrared radiation which results in the cooling of the lower atmosphere closest to the earth’s surface. It is a natural process that keeps the earth’s surface warm and is necessary for sustaining life on earth.

In the absence of greenhouse effect, the earth’s temperature will plummet below the freezing point of water and become unable to support most life forms. However, man-made greenhouse effect has been a growing concern. It has increased the earth’s mean surface temperature causing irreversible harm to the environment.

Climate change has led to large-scale melting of arctic and Antarctic ice plates and glaciers. It has had a direct impact on polar bear population and the livelihood of people living in arctic regions. Climate change has caused the sea level to rise, leading to floods in coastal regions. It is also linked to extreme climatic-induced events like droughts, forest fires, floods, hurricanes and heat waves.

The National Aeronautical Society of America (NASA) website states that by 2100, sea levels around the world will have risen by 1 foot to 4 feet. It further predicts that arctic sea ice will disappear by the year 2050 and hurricanes will steadily become more intense as the years go by.

Climate change has lowered biodiversity of the ecosystem and caused extinction of endangered species. It has been linked to bleaching of coral reefs and decline of marine life due to increase in acidity of sea water.

Acid rain

Acid rain is a direct result of polluted air. Combustion of fossil fuels emits nitrogen oxides and sulphur dioxide into the air. These molecules react with moisture in the upper strata of the atmosphere and form suphuric acid and nitric acid which then falls down to earth as acid rain.

Acid rain leads to acidification of water bodies and deeply impacts aquatic life. It changes the PH level of lakes, seas and oceans and makes them more acidic. Acidic water is harmful for fish and other marine life forms. Acid rain destroys the PH balance of soil and affects vegetation in forests. Acid rain also corrodes statues and monuments made from marble, limestone, copper, iron, steel and bronze.

Effects of air pollution on human health

Effects of air pollution on human, animal and plant health depends on the nature of the pollutant, the intensity and duration of the exposure, and the health of the organism.

According to a report published in the journal Elsevier’s Process Safety and Environmental Protection, in 2016 air-borne fine dust particles (PM 2.5) led to the premature death of approximately 14,800 people in New Delhi, 10,800 in Mumbai, 7,300 in Kolkata and 4,800 each in Chennai and Bangalore. Beijing and Shanghai recorded some of the worse numbers with 18,200 and 17,600 deaths respectively. The study analyzed data from 13 megacities in Asia. The report stated that particulate pollution was the major reason behind a series of ailments afflicting the heart, lungs, kidneys, eyes, nose, throat and skin.

In light of this, let us try to understand how air pollution affects us and what its implications are on our health and well-being.

Respiratory system

Air pollution causes respiratory problems in humans. It is especially evident in urban areas where the number of vehicles and factories is higher. Smoke produced due to burning of fossil fuel like gasoline and oil mixes with the air we breathe and enters our lungs through our nasal passage and mouths. It causes coughing, wheezing, irritation of the nose and esophagus.

Respirable particulate matter PM 10 and PM 2.5 are two of the deadliest air pollutants that cause chronic lung disease like lung cancer. Air pollution aggravates asthma and bronchitis. It is particularly bad for small children and aged people. Air pollution due to mining causes silicosis and Coal Worker’s Pneumoconiosis in humans. Air containing carbon monoxide fumes can be fatal if inhaled inside poorly ventilated rooms.

Cardiovascular system

Air pollutants can cause serious heart problems in people of all ages. It can lead to thickening of the cardiovascular and pulmonary tissues causing heart attacks and heart pain. It can increase blood pressure and affect the nervous system. Studies have shown that pollution-induced cerebrovascular dysfunction and neuroinflammation directly impact the central nervous system.

Central Nervous system

Poor air quality affects the central nervous system in humans. It causes headache, fatigue, restlessness and lack of concentration. Air pollution is linked with Alzheimer’s disease and Parkinson’s disease. In infants and small children, it can cause neurological disorders like impaired mental development and lowered IQ. In pregnant woman, it can lead to premature delivery. Prolonged exposure to air polluted by fine lead particles can induce hallucinations.

Endocrine system

The kidneys take one the worst beatings due to air pollution. VOCs and aerosols which pollute our air have the potential to do serious renal harm. Cadmium fumes present in the air can also impact the kidney’s natural ability to filter out impurities from the body.


Air pollution causes ozone depletion which results in sunburns, skin allergies, and in extreme cases, cancer of the skin. Studies have proven that long-term exposure to ultra violet rays increases the risk of squamous cell carcinoma. It is the commonest form of skin cancer. UV radiation also causes malignant melanoma, basal cell carcinoma and other skin diseases.


Smog, dust and chemical fumes can severely hamper your eyesight. Chronic eye irritation characterized by itchiness, burning and watering are the result of poor air quality. Depletion of the ozone layer has also been linked to eye disease like cortical cataract in humans.

Digestive system

Prolonged inhalation of toxic fumes emanating from car exhausts and factories can lead to abdominal cramps and diarrhea. People living near landfills, industrial estates and busy streets are most in danger of developing these symptoms.

Air Quality Index

Air Quality Index or AQI is a number that denotes the level of air pollution in an area. It is a tool used by government agencies to communicate to the public how polluted the air in their town or city is. It contains important facts about air quality along with concentration of various air pollutants on a daily basis.

In India, the National Air Quality Index was introduced under the Swachh Bharat Abhiyan in September 2014. It comes under the National Air Monitoring Programme (NAMP) which is joint effort between the Central Pollution Control Board and all the state pollution control boards. As mentioned already, at present the NAMP operates around 573 monitoring stations in around 240 towns and cities in India.

The national AQI has six categories – Good, Satisfactory, Moderately polluted, Poor, Very Poor, and Severe. Each of these categories has a unique color to indicate the level of pollution. The categories are adjudged based on ambient concentration values of air pollutants and their possible health implications, also called health breakpoints. The AQI has sub-indices of eight air pollutants. They are PM 10, PM 2.5, NO2, SO2, CO, O3, NH3, and Pb. It prescribes the short term (up to 24 hours) National Ambient Air Quality Standards for each of these eight pollutants and also mentions the health breakpoints of each pollutant.

Sub-indices are defined by concentration or density of ambient pollutants. This metric is a linear function of pollutants. Generally the air quality index of a specific location is marked by the worst performing sub-index in that locality.

The following table data captured from the Central Pollution Control Board website shows the AQI categories, pollutants and their corresponding health breakpoints.

Air Quality Index For Different Pollutants

Air Quality Index for couple more pollutants

Anything beyond 400 is considered to be extreme situation and categorized as severe. The following table shows the different AQI categories and the corresponding health implications.

Different health impacts with decreasing Air Quality Index

How is AQI calculated in India?

In India there are two methods of calculating AQI – manual and automated. The manual system requires the monitoring station to manually feed data into the AQI calculator to come up with the AQI for that location. The automated method is a web-based system that calculates AQI on real time basis. It gathers data from 24-hour monitoring stations to calculate AQI based on running average values. For instance, AQI for a location at six in the morning is based on data from 6am of the previous day to 6am of that day.

Currently, 10 Indian cities have web-based continuous air quality monitoring stations. Plans are underway to extend automated air monitoring to 20 state capitals and 46 cities with populations of over a million.

At any given air monitoring location, the AQ sub-index of a particular air pollutant is the 24-hour average concentration value and the associated health breakpoint concentration range, except for CO and O3, for which the average is taken every 8 hours. The worst sub-index is the AQI for that location.

All monitoring locations in India do not record all eight pollutants. But for calculation of AQI for any location, data of at least three pollutants must be available out of which one should mandatorily be either PM 10 or PM 2.5. Otherwise, data are deemed to be insufficient for determining AQI for that area. Likewise, data should be available for at least 16 hours for accurate calculation of AQ sub-indices.

However, even if data are inadequate for calculating overall AQI, the available sub-indices for those pollutants that were monitored are calculated and shared with the public. It reveals the concentration of those pollutants in the air but not the overall AQI.

How the monitoring network works?

Monitoring air quality is a complex undertaking. The air quality in a city cannot be judged based on data from a single monitoring station. This is because different localities will have different levels of pollution due to local activities. For example, in a greenery-covered park the air will be much cleaner than near a busy industrial estate.

Therefore, to get a genuine picture of air pollution in a town or city, its air must be monitored at multiple microenvironments. In a large city, for instance, air quality must be monitored in urban, suburban, residential, commercial, industrial, high-traffic and airport locations.

Steps taken by the Indian government to tackle air pollution in India

The law governing air pollution in India is laid out in the Air (Prevention and Control of Pollution) Act, 1981. The Act seeks to prevent, control and abate air pollution through the setting up of air monitoring stations across the Indian heartland. It paved the way for the establishment of the Central Pollution Control Board and the State Pollution Control Boards. The main function of the boards is to implement laws enacted for the prevention and control of air pollution in India.

In 2010, the centre passed the National Green Tribunal Act which laid down provisions for the setting up of a special tribunal for handling urgent environmental cases. The National Green Tribunal (NGT) is an express quasi-judicial body with a mandate to dispose of cases within six months.

In April 2014, The NGT said that construction of recreational facilities along the Yamuna river will hamper the river’s already suffocating ecosystem. It further advised the government to declare a 52km stretch of the river as a conservation zone.

The NGT cancelled the clearance issued by then Union Minister for Environment and Forest, Jairam Ramesh to private industrialists for mining coal in the forests of Chattisgarh. In July 2018, the NGT asked automobile giant Volkswagen to explain why it failed to recall cars causing air pollution. In other words, the NGT functions as a watchdog for the environment and works towards curbing all forms of environmental pollution.

Early in 2018, the central government formulated the National Clean Air Programme (NCAP) to tackle growing air pollution in India. Its primary aim is to develop and use an effective air quality monitoring network across India to prevent, control and reduce air pollution in rural and urban areas. It will be a collaborative effort between the centre and the states, local bodies and private organizations. The key objectives of the NCAP are as follows:

  • The NCAP proposes to increase the number of manual air quality monitoring station from 691 at present to 1000 with 50 additional stations in rural areas.
  • It proposes to increase the number of Continuous Ambient Air Quality Monitoring Stations (CAAQMS) from 84 at present to 268.
  • It also proposes to augment the number of stations monitoring PM 2.5 pollution from 67 at present to 1000.
  • The NCAP has identified 100 cities as non-attainment cities whose air quality is worse than the National Ambient Air Quality Standards (NAAQS). The NCAP aims to reduce air pollution in these cities by 35% in the next three years and by 50% in the next five.
  • Air pollution data is to be disseminated to the public on a regular basis. The NCAP also has provisions for public participation. It plans to set up Air Information Center. The center will analyse, interpret and disseminate air quality data through GIS platforms.
  • The NCAP further aims to develop a sophisticated forecasting model which will predict the following day’s air pollution level. It also plans to create an updated national emission inventory.

Other efforts by the Indian Government to fight air pollution

  • In 2015, the Ministry of Health and Family Welfare set up a Steering Committee on Air Pollution and Health Related issues. In its report submitted to the Centre, it enlisted the implications of air pollution on human health in India. It proposed dispensing with firewood and biomass as cooking fuel and pushed for the use of cleaner cooking energy. It also proposed the creation of vehicle-free zones and cycle lanes, increasing fuel tax and parking fee, and levying congestion charges.
  • In 2013, Veerabhadran Ramanathan, professor of Atmospheric and Climate Sciences at Scripps Institution of Oceanography at University of California, San Diego, entered into collaboration with the Air Resources Board, California, and the Energy and Resources Institute, India, to launch an India-California Air Pollution Mitigation Programme. The programme emphasizes that much of India’s pollution can be brought under control if Indian villages had access to clean cooking stoves.
  • To mitigate air pollution, the Ministry of Environment & Forests and Climate Change (MoEFCC) introduced the BS IV norms of emission for automobile engines. The norms are meant to regulate and reduce release of harmful fumes from the internal combustion engines of automobiles. The drive, launched in 2010 in 13 big cities across India is now enforced successfully across the entire nation. In 2016, the centre announced that it will skip BS V norms and directly adopt BS VI by 2020.
  • In December 2015, the MoEFCC notified thermal power plants to follow strict anti-pollution standards. The coal-based power plants were directed to lower their consumption of water and emission of particulate matter, nitrogen oxides, sulphur dioxide, carbon monoxide and mercury by December 2017. However, due to non-compliance, the deadline was extended to 2022. The Central Pollution Control Board, working under the aegis of the MoEFCC, continues to tighten emission rules for thermal power plants, and has issued them strict instructions to adopt clean and green technologies.
  • Delhi and the NCR have extremely poor air quality. While the healthy limit is 100 micrograms per cubic meter, many localities in Delhi have registered AQI of 448 out of 500 which is dangerously toxic and falls in the ‘severe’ category. In light of this, the Delhi state government introduced the odd-even traffic rule in early 2016. Under this rule, between 8am and 8pm private vehicles were allowed to ply only on alternate days with odd-number vehicles plying on odd days and even-number vehicles playing on even days. This drive was instrumental in reducing smog over the city, with residents witnessing a clear improvement in air quality.
  • In an attempt to encourage public transport and carpooling, and dissuade people from driving their own cars and therefore reduce vehicular emissions, the Delhi government has quadrupled the parking fees for private non-commercial vehicles.
  • In 2017, the Delhi Metro Rail Corporation announced that it will introduce 186 additional train trips to increase passenger capacity and cater to a wider travelling public. The Delhi Transport Corporation was directed by the government to hire 500 extra buses on short-term basis while the DMRC was directed to expand its fleet by 300 buses to handle rush-hour traffic during the odd-even rule.

Comparative study of AQI by country

While it is not easy to calculate AQI at an individual country level due to lack of sufficient reliable data, the WHO reports serve as guiding beacons for understanding air pollution in different countries. To compile its Ambient (Outdoor) Air Pollution in Cities database for 2014, the WHO team collected and studied PM 10 and PM 2.5 concentration data from 92 countries using 1622 monitoring stations. Each country’s average concentration was weighted by the number of inhabitants in each city to plot the country’s data.

This database only covers urban areas as the monitoring stations were almost always located in cities. So the pollution data revealed by the report refers to the pollution in the cities and not in the rural areas.

The WHO recommends maintaining PM 10 concentration at 20 micrograms per cubic meter of air and PM 2.5 concentration at 10 micrograms per cubic meter of air. This is the healthy limit with least possible implications on health. The following table shows the levels of pollution based on micrograms of PM 10 and PM 2.15 per cubic meter of air.

Air Quality Guidelines based on PM2.5 and PM10

In 2016, the WHO and the International Energy Agency published air quality data from 135 countries. The study ranked countries based on their PM 2.5 levels. The following tables show the top 10 least and most polluted countries.

Top nations with highest and lowest air pollution

Vulnerable groups – People most affected by air pollution

Poor air quality affects everyone. But the ones who suffer the most are:

  • Children
  • Old people
  • Pregnant women
  • Asthmatics
  • People suffering from respiratory issues
  • People suffering from cardiovascular disease
  • Diabetics
  • People suffering from skin disease
  • Human with neurological issues
  • People who exercise outdoors

How to protect your family from air pollution?

If you are an Indian living in a city, you are already exposed to air pollution. If your house is on a busy street or close to an industrial area, you are in greater peril still. However, there are things you can do to protect yourself and your family from the ill-effects of air pollution. In the following points we will take you through some of the steps you can take to curb air pollution in your home and keep your family safe and healthy.

Indoor protection

The air inside your house contains pollutants from the following sources:

  • Burning of fossil fuels like oil, gas, wood fire, coal, kerosene and wax
  • Smoke from cigarettes
  • Dust mites, pet hair and dander trapped in carpet, rugs, cushions, soft toys and heavy drapes
  • Aerosols emitted from deodorants, perfumes, room fresheners and insecticide sprays
  • Household cleaning supplies
  • Personal care products
  • Asbestos
  • Furniture made from processed pressed wood or plywood
  • Paint, varnishes and glue
  • Radon (in rare cases)

In order to improve indoor air quality you can do the following:

  • Remove the pollutant

If you know what’s causing the air quality in your house to deteriorate, the first thing to do is to remove the pollutant.  The carpet probably needs to go, if crawling on it in the living room is making your toddler sneeze constantly and is giving him rashes. If incense sticks are giving you a headache and making you feel nauseous, you should look for a healthier alternative.

  • Improve ventilation and air circulation

The next thing you need to do to improve indoor air quality is increase the air circulation in your house. Air Outlets and well ventilation is essential for all rooms. Open doors and windows for at least an hour everyday. It helps to let out the stale indoor air and let in fresh air (provided the outdoor air is clean).

  • Install an air purifier

Installing an air purifier in your home is the smart thing to do considering the amount of pollution we have to deal with. Air purifiers clean the indoor air and eliminate harmful pollutants up to 99%. They remove impurities like pet dander, dust mites, pollen, fungi spores, VOCs, asbestos and smoke. We will discuss different air purifying technologies later in the article.

  • Clean AC and heater filters regularly

Air conditioner and heater filters trap impurities which need to be cleaned from time to time. Wash or vacuum the Filter panels once every 30 days. In case they are too grimy, you can use a mild detergent.

  • Use apps to track air pollution

Track the air pollution level in your city regularly to stay up to date on pollution levels. It’s an effective way to preempt exposure to outdoor polluted air. Use the forecast data as a guide while making your weekly plans. Avoid shopping and outdoor exercise on days predicted to have high levels of pollution. You can access AQI data through mobile apps like AirVisual, BeezoMeter, Insdio and Safar Air. The Central Pollution Control Board and the State Pollution Control Boards also publish AQI data on a daily basis. Just visit the website and know what the AQI is for your area.

  • Do not smoke indoors

Smoking indoors is a grave mistake. It fills the air with fine particulates that infiltrate our lungs’ alveoli and cause serious harm. Say no to indoor smoking (and outdoor too) if you want yourself and your family to be healthy.

  • Avoid using carpet and rugs

Carpets, rugs and heavy curtains absorb and retain dust. If not vacuumed regularly, they may harbor dust mites, pet hair and tiny insects. If kept in damp conditions, rugs and drapes can develop molds which release spores into the air causing allergic reactions. It is best not to use carpets, if your house is already located in a high-pollution zone.

  • Wash soft toys regularly

Soft toys absorb dust and grime. If your child is constantly coughing and sneezing while playing with her teddy bear, maybe it is the teddy bear. Keep an eye out for such signs and yes, wash soft toys regularly.

  • Use clean cooking fuel

Use of unclean cooking fuel like fire wood, oil, biomass, kerosene, etc is one of the biggest reasons for indoor air pollution in India. Therefore, make sure you use only safe and clean fuel like LPG.

  • Minimize use of aerosols

Aerosol cans emit harmful pollutants that can cause respiratory problems. Minimize your use of deodorants, mosquito repellants and room fresheners. Try and look for alternatives that are not aerosol-based and do not cause air pollution.

  • Wear a mask when cleaning the house

Wear a face mask while engaging in cleaning activities like dusting, vacuuming, sweeping, mopping, scrubbing and washing. It helps keep out harmful contaminants that get released into the air during the cleaning process.

  • Vacuum regularly

Vacuum your house regularly. It eliminates dust, cobwebs, pet hair and dander, and keeps your indoor air clean and safe.

  • Wipe off mold and mildew from books and wooden surfaces

During monsoons, books, wood and fabric become coated with a layer of mildew. Wipe off the layer and clean regularly to keep the fungi from spreading and contaminating the air with its spores. Fungi spores aggravate asthma and other allergies.

  • Check your house for presence of Radon

If you live in a basement or ground floor apartment, it is advisable to check your house for radon poisoning. Radon gas is emitted by rocks. It passes through cracks in the floor and mixes with the air we breathe. Excessive exposure to radon can cause lung cancer.

  • Go for natural wood furniture

Furniture made from processed and pressed wood like plywood causes air pollution. Natural wood furniture and construction material are better substitutes as they do not cause air pollution.

  • Use unscented personal care products and cleaning supplies

Perfumes used in products like soaps, shampoos, moisturizers, detergents, fabric softeners and surface cleaners. They contain harmful chemicals that may cause eye, nose and throat irritation. Keep your family safe and your house free of chemicals by using unscented products.  

  • Air-purifying indoor plants

Decorate your house with air-purifying indoor plants. For example Aloe Vera, Broad-leaf lily palm, Spider Plant, Red-edged dracaena, Peace lily, Lily turf and English Ivy. These plants remove toxic pollutants like formaldehyde, ammonia, benzene and trichloroethylene from the indoor air.

  • Eat healthy

Eat plenty of fruits and vegetables to get anti-oxidants into your body. Anti-oxidants protect your body from air-borne free radicals. Jaggery flushes out disease-causing foreign particles from your lungs. Vitamin C in citrus fruits strengthens blood vessels. Selenium, found in eggs, onions, garlic, etc., protects your lungs and liver from harmful pollutants. Herbal tea infused with the goodness of tulsi and ginger helps fight the ill-effects of air pollution. Apart from these, incorporate foods rich in Vitamin A, beta-carotene, Vitamin E and Omega fatty acids in your family’s diet to make sure everyone stays strong and healthy.

Outdoor protection

  • Check AQI regularly

As mentioned earlier, it is advisable to check your area’s AQI before planning a family outing. It is safe to remain indoors on days that are extremely polluted. Children especially should not be allowed to play outdoors on such days.

  • Use face masks

Use N95/99 face masks every time you step outdoors. It filters out large pollutants and helps you breathe more easily.

  • Avoid exercising outdoors

Do not exercise or go on walks, jogs and cycle rides in the morning or when the smog cover is the worst. Avoid exercising in parks located near busy traffic junctions. It will expose you to ground-level ozone, carbon monoxide and a host of other pollutants ejected from automobile exhausts.

  • Use a car air purifier and set fan on re-circulate

Install a car air purifier if you spend a lot of time commuting. It will enable you to breathe clean air even while being stuck in traffic. Also, put the AC in your car on re-circulate/recycle mode to keep the air inside the car clean.

  • Avoid peak traffic hours

Beat the traffic by leaving for office a little early every day. It will minimize your and family’s exposure to outdoor air pollution.

  • Carpool/shared taxi

Always go for shared cabs as they help ease up congestion on roads and also reduce air pollution.

Technology used in air purification 

Air filters can primarily be divided into 2 types: active and passive. Active purifiers use ionization technology to release negatively charged particles which attract air pollutants. Therefore they are pulled by an electrostatically charged plate and removed from the air. The downside of this technology is that it may release trace amounts of ozone which is harmful for health.

Passive air purifiers use filters to remove air pollutants. They are of various kinds. The latest ones use High-efficiency Particulate Air or HEPA filters. HEPA is a sophisticated air purifying technology and remove close to 99.97% contaminants of size 0.3 micron and larger. It is highly effective and removes even PM 2.5 pollutants from the air. HEPA filters pass the air through fine sieves or filters which trap the pollutants and prevent them from floating in the air. The more the air passes through the filters, the cleaner it gets.

Another technology used in air purification is Ultraviolet germicidal irradiation. In this process, air is forcibly passed through a powerful UV lamp. In this way it destroys germs like viruses, bacteria, protozoa and fungi, leaving the air purified.

Air purifiers also use carbon filters and pre filters. Carbon filters remove VOCs and odors while pre filters remove most of the PM 10 substances from the air.

Another technology used to destroy air-borne microbes and other harmful pollutants is Thermodynamic sterilization. The process involves heating a ceramic cone with micro capillaries up to a temperature of 200ᵒC and passing air through the cone. It helps to kill bacteria, fungal spores, pollen and viruses. The cone uses heat sterilization to burn the microbiological particles.


Finally, to conclude, we can say that air pollution is a serious issue ailing our planet right now. It impacts humans, animals, plants and the entire ecosystem. We need to be sensitive about the environment and take effective steps to curb air pollution before it’s too late.

2 thoughts on “Air Pollution In India

  1. Very Helpful Reviews! Given detailed info about air pollution and its effects. I was looking for this kind of article for a long time. I loved your post especially the air purification technology and protection. Thank you so much for such a great info…

    • Dheepika, Thanks for reading our air pollution research section. In India air pollution is a very concerning problem which is contributing tremendously in average temperature increase across tier – I and tier – II cities and this will affect the overall climates in decades to come. Recent study in IPCC is quite concerning in this regard – .

Leave a Comment