Tag Archives: Effects of Air Pollution

Air Pollution, Environmental engineering

What are air pollutants? | Types,sources and effects of air pollution

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Most of the times you can’t see it or smell it, but air pollutants kill. As the level of air pollutants in our atmosphere are rising at an alarming rate we must be aware of them. In the previous blogs, we had described the causes and effects of air pollution. Today let’s dive deep into various air pollutants.

Let’s get started.

What are Air Pollutants ?

Air pollutants are substances that can contaminate the air and are hazardous to human and other living species’ health. They can be either primary pollutants like dust, smoke, ammonia etc that are emitted directly from their sources or secondary pollutants.

Secondary Pollutants are formed in the atmosphere by chemical reactions between primary pollutants and the other atmospheric constituents. The common examples include ozone, sulphur trioxide, Peroxy Acetyl Nitrate (PAN), ketones etc.

Air Pollutants Types

The Environmental Protection Agency regulates three types of pollutants:

  • Criteria air pollutants
  • Air Toxics
  • Greenhouse Gases

Criteria air pollutants

Criteria Air pollutants include Particulate matter (PM), photochemical oxidants (e.g., ozone), carbon monoxide, sulphur oxide, nitrogen oxide, and lead. They can have a significant impact on public health and wellbeing, the atmosphere and environment, and neighbouring structures.

Air Toxics

The term “air toxics” consists of a list of over 180 air pollutants such as organic chemicals, volatile organic compounds (VOCs), metals, metal compounds, solvents, mercury, arsenic, asbestos, and benzene etc. Even when existent in trace amounts and emitted by fewer sources than criteria pollutants, they have harmful health and environmental impacts.

Greenhouse Gases

Greenhouse gases (GHGs) are gases such as carbon dioxide, chlorofluorocarbons (CFCs), methane, and ozone. They can harm human health. In addition, they contribute to the acceleration of the greenhouse effect on Earth and the resulting impact on global climate.

Major Air Pollutants – Sources and Effects

The sources of air pollutants can be natural or anthropogenic. Check out our previous blog Air Pollution Causes – A Comprehensive Guide for detailed information on various sources of pollutants. Let me describe each of the air pollutants in detail.

Nitrogen Oxides

  • Nitrogen oxides, notably nitrogen dioxide, are ejected from high-temperature combustion and created by electric discharge during thunderstorms.
  • This reddish-brown poisonous gas has a distinctive sharp, biting stench.
  • They appear as a brown haze above cities or as a plume downwind.
  • High levels of NO2 can irritate and inflame the lining of your airways.
  • This results in asthma or COPD flare-up, as well as symptoms like coughing and difficulty in breathing.

Carbon Monoxide

  • CO is a poisonous gas that is colourless and odourless.
  • It causes a smog-like buildup in the air.
  • CO reacts with haemoglobin in the blood to generate carboxyhaemoglobin when inhaled.
  • CO has a 200-fold higher affinity for haemoglobin than oxygen.
  • The tissues are deprived of oxygen as a result of this situation.
  • When carboxyhaemoglobin saturation levels are about 20%, it affects the heart and destroys tissues by preventing oxygen from reaching them.
  • This has been related to a variety of pulmonary ailments as well as environmental problems.

Sulphur Oxides

  • Sulphur compounds are common in coal and petroleum, and their combustion produces sulphur dioxide.
  • Further oxidation of SO2, usually in the presence of a catalyst like NO2, produces H2SO4, which results in acid rain.
  • It also arises from chemical, paper, and fuel manufacturing plants.
  • People with asthma or emphysema may find it more difficult to breathe after being exposed to sulphur dioxide.
  • It can also irritate the eyes, noses, and throats of people exposed to it.
  • Sulphur dioxide can injure trees and crops, cause structural damage, and impair people’s ability to see over long distances.
sulphur dioxide Pollution- Petroleum refinery
sulphur dioxide Pollution- Petroleum refinery

Volatile Organic Compounds

  • Compounds with high vapour pressure and low water solubility are known as volatile organic compounds.
  • VOCs are man-made substances that are utilised and created in the production of paints, medicines, and refrigerants.
  • Industrial solvents, such as trichloroethylene; fuel oxygenates, such as methyl tert-butyl ether (MTBE); or chlorination by-products, such as chloroform, are examples of VOCs.
  • The aromatic non-methane VOCs such as benzene, toluene, and xylene are suspected carcinogens. They can cause leukaemia in those who are exposed to them for a long time. 

Carbon Dioxide

  • The major greenhouse gas emitted by human activity is carbon dioxide.
  • Fossil fuel combustion, industrial emissions, wildfire etc. are the main sources of CO2 emissions.
  • It traps the solar radiations reflecting from Earth and increases the average temperature of Earth.
  • Due to its contribution to the greenhouse effect and climate change, it is often called the worst climate pollutant
  • It reaches the Earth’s surface as acid rain.

Particulate Matter

Fine particles, also known as atmospheric particulate matter, are microscopic solid or liquid particles suspended in a gas. Volcanoes, dust storms, forest and grassland fires, and sea spray are all sources of particulate matter. Particulate pollution comprises the following:

PM10:  inhalable particles with a diameter of 10 micrometres or less.

Can you imagine how small is 2.5 micrometre? Consider a single hair on your head. The average human hair is 70 micrometres in diameter, which is 30 times the size of the smallest microscopic particle. I hope this makes it clear how they penetrate deep into our lungs.

Aerosols

Aerosols are produced by human activities such as the combustion of fossil fuels in automobiles, power plants, and numerous industrial processes. Anthropogenic aerosols, or those produced by human activity, currently make up around 10% of our atmosphere. Increased fine particle levels in the air have been related to health risks such as heart disease.

Chlorofluorocarbons

  • CFCs are gases emitted by air conditioners, freezers, aerosol sprays, and other similar devices.
  • CFCs reach the stratosphere after being released into the atmosphere.
  • They interact with other gases here, causing harm to the ozone layer.
  • This allows UV radiation to reach the earth’s surface, which are hazardous.
  • This can result in skin cancer, eye problems etc.
  • As a result, they are currently restricted from usage in products.
Air Conditioners - Source of Chlorofluorocarbons
Air Conditioners – Source of Chlorofluorocarbons

Ammonia

Ammonia is a gas that is emitted primarily by agricultural waste. As a precursor to foodstuffs and fertilisers, it contributes considerably to the nutritional demands of terrestrial species. It is both corrosive and toxic, despite its widespread use. Ammonia combines with nitrogen and sulphur oxides in the atmosphere to generate secondary pollutants.

Ozone 

  • Carbon monoxide (CO), methane (CH4), or other volatile organic compounds (VOCs) are oxidised in the presence of nitrogen oxides (NOx) and sunlight to form ozone.
  • As a result, ozone is most abundant in the summer.
  • Ground-level ozone is a primary component of photochemical smog.
  • It is a significant health hazard connected to breathing issues, asthma, deterioration of lung function, and respiratory disorders.
  • People with asthma may experience more frequent asthma attacks as a result of ozone exposure, as well as sore throats, coughing, and breathing difficulties.
  • It could potentially result in premature death. Plants and crops can be harmed by ozone.

Lead

Lead is a neurotoxin. It was earlier used in petrol as an antiknocking agent. The fine particles emitted through automobile exhausts reaches the lungs and settles down there. At higher levels in the blood, it interferes with haemoglobin production. This results in oxygen starvation and anaemia. Higher levels lead to behavioural disorders.

Cadmium

Cigarette smoking is the main contributor to cadmium in the atmosphere. It can cause hypertension, cardiovascular diseases, kidney and liver damage.

Cigarette Smoke - Source of Cadmium
Cigarette Smoke – Source of Cadmium

Nickel

Finely divided nickel can react with carbon monoxide and forms Nickel Carbonyl. It is also formed in cigarette smoke. When it reaches our lungs it breaks down and deposits finely divided nickel inside our lungs. This is the main cause of lung cancer.

Mercury

Mercury enters the aquatic systems and soil from the atmosphere through acid rain. The adverse effects of mercury poisoning include chromosomal aberrations, neurological damage and even death. It can damage the cerebellum and cortex of brain by penetrating the membranes separating bloodstream from the brain.

So, we had taken a quick trip understanding all the major air pollutants. In case of any doubts, feel free to ask in the comments.

Happy Learning!

Air Pollution, Environmental engineering

Air Pollution Effects and Causes – A complete overview

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Air pollution is one of our era’s biggest scourges, not only because of the impact it causes on climate change but also because it influences public and individual health due to chronic illness and death. The effects of air pollution range from environmental effects like global warming to even financial and health effects like coma and death.

Here’s the truth. According to WHO figures, air pollution-related diseases claimed the lives of 6.5 million people globally in 2012. That’s more than HIV/AIDS, TB, and road accidents combined, accounting for 11.6% of all world deaths. Shocking, right?

In this blog, I will show you the different effects of air pollution in detail. Let’s get started with the classification of the effects.

Also read : Causes of Air Pollution

Classification of Air Pollution Effects

The adverse effects of air pollution can be divided into two classes.

Acute Effects

Acute effects of air pollution appear immediately upon short term exposure to the pollutants at relatively high concentrations.

Chronic Effects

Chronic effects don’t appear immediately, rather become evident only after long term exposure to low levels of air pollutants.

Air Pollution Effects on Environment

Not only does air pollution impair our health, but it also harms the environment in which we live. The following are the most significant environmental effects.

Air Pollution Effects
Global Warming

Global Warming 

One of the most alarming effects for scientists and environmentalists is likely global warming. The greenhouse effect, which is caused by the excessive emission of CO2 and methane into the atmosphere, causes global warming. 

Climate Change

Another effect of global warming is climate change. When the planet’s temperature rises, the typical climatic cycles are disrupted, accelerating the changes of these cycles noticeably.

Acid Rain

Sulphur dioxide (SO2) and nitrogen oxides (NOx) are two gases released into the atmosphere as a result of fossil fuel combustion. When those compounds build up in the atmosphere and react with water, they produce dilute nitric and sulphuric acid solutions. They mix with the rain and reaches the surface of Earth as acid rain.

Effects of Air Pollution - Smog
Effects of Air Pollution – Smog

Smog

  • The smog effect, sometimes known as the beret effect, occurs when a dense dark fog forms over cities and fields. This fog is made up of pollutants.
  • There are two varieties of smog: sulphurous smog and photochemical smog.
  • The smog of both forms is a result of industrial and urban activity.
  • When nitrogen oxides and volatile organic compounds (VOCs) combine with sunlight, photochemical smog is created, resulting in a brown cloud above cities.
  • Sulphurous smog, on the other hand, is mostly caused by the usage of coal in numerous industrial operations.

Deterioration of Crop Fields

  • The Earth’s surface is degraded by acid rain, climate change, and smog.
  • Polluted water and gases infiltrate into the ground, altering the soil’s makeup.
  • This has a direct impact on agriculture, as crop cycles change and the composition of the food we eat changes.
  • In India, it was reported in 2014 that air pollution from black carbon and ground-level ozone had cut crop yields in the most impacted areas by nearly half in 2011 compared to 1980 levels in the most afflicted districts.

Extinction of animals

  • Many animal species that rely on oceans and rivers for existence are threatened as the poles’ ice melts and sea levels rise.
  • Because currents, ocean temperatures, and migratory cycles fluctuate, many creatures are driven to seek food in unfamiliar environments.
  • Ecosystems and habitats are also disappearing as a result of deforestation and low soil quality. And, without a doubt, this leads to the extinction of many wild animals.

Deterioration of construction materials

Because air pollutants degrade and modify the composition of building materials, many structures and infrastructure are weakened, degraded, or destroyed at a faster rate over time. The air pollution has been turning the Taj Mahal yellow-brown.

Destroys Vegetation

The pollutants penetrate the inner leaf tissues through stomata and destroy the chlorophyll. This disrupts photosynthesis. The damages caused ranges from chlorosis, necrosis, epinasty to the death of the plant. Cement dust deposits along with mist or rain cause incrustations in the leaves. 

Air Pollution Effects on Materials

Pollutants in the air have the following effects on materials, resulting in economic losses.

  • Abrasion
  • Materials deposition
  • Chemical attack 
  • Corrosion 

Sulphuric Acid mist in the atmosphere leads to the deterioration of structural materials like marble and limestone. Leather readily absorbs sulphur dioxide and gets disintegrated. Ozone causes the weathering of fabrics like acetate, cotton, nylon and polyester. At atmospheric levels of 0.01 to 0.02 ppm, it can cause the cracking of synthetic rubber. Particulates erode the exposed surface of materials and accelerate their corrosion.

Air Pollution Effects on Human Health

Air pollution has a variety of negative health consequences. Even on days when air pollution is low, vulnerable and sensitive people’s health can be harmed. COPD (Chronic Obstructive Pulmonary Disorders), cough, shortness of breath, wheezing, asthma, and respiratory disease are all linked to short-term exposure to air pollution.

Let me describe the health effects caused by each of the major air pollutants.

Oxides of Sulphur

  • When people are exposed to an atmosphere with sulphur dioxide concentrations above permissible levels, they get respiratory ailments.
  • At higher temperatures, their visibility is also affected.
  • Even at low concentrations of 1.6 ppm, it can cause bronchoconstriction in healthy individuals.
  • At higher concentrations, it leads to throat and eye irritation and immediate coughing. 

Carbon Monoxide

  • Carbon monoxide is released as a result of incomplete combustion of fuels in petrol engines, industrial operations, and other sources.
  • When CO is inhaled it mixes with the haemoglobin in the blood and forms carboxyhaemoglobin.
  • The affinity of CO towards haemoglobin is 200 times that of oxygen.
  • This condition deprives the tissues of oxygen.
  • When carboxyhaemoglobin saturation levels are about 20%, it affects the heart and also damages tissues by restricting oxygen.
  • Since the blood supply to vital organs including the brain is obstructed it can lead to mental impairment, visual acuity and even fatal coma at higher COHb levels in the blood. 

Oxides of Nitrogen

When NO2 is inhaled it reaches the moist alveoli of the lungs. There it is converted to nitrous and nitric acids which are highly irritating. They can damage the lung tissues. Long term exposure leads to symptoms resembling emphysema and biochemical alterations in blood.

Particulate Matter

  • Particulate matter of size less than 0.5 micrometres gets deposited in the alveoli and damage the respiratory tissues.
  • They can also act as carriers of toxic gases such as SO2 and produce synergistic effects.
  • Long-term exposure to PM2.5 raises the risk of non-accidental mortality by 6% for every 10 micrograms/m3 increase in concentration.
  • PM2.5 exposure was also linked to an elevated risk of lung cancer mortality ranging from 15% to 21% per 10 micrograms/m3 increase.

Shall we wrap up?

Conclusion

To sum up, air pollution affects not only humans but also our mother nature and other living beings. The effects of air pollution include environmental, economical and health effects. So it’s our responsibility to keep air pollution in check for a better tomorrow.