Air Pollution Definition | Causes | Effects | Smog and Soot | GreenHouse Gases | Prevention and Control

Air Pollution

Our atmosphere is a homogeneous mixture of many gasses. The second most abundant gas in our atmosphere is oxygen, the life-giving gas. When this air mixture is contaminated with some chemical, biological or physical factors that are harmful for us and the environment too, it is called air pollution. These factors that make our air polluted are called pollutants. Ground level Ozone gas, Particulate matters, Carbon Dioxide, Oxides of Nitrogen and Sulfur are some major pollutants.  

 When we were younger, we felt more free. We didn’t have to cover our faces with masks or some clothes because of the exhaust of traffic. Well something was right about our environment specially the atmosphere was healthier. We hear the term air pollution once in a blue moon and these days due to many human activities we listen to this term more frequently. Air pollution isn’t a new concept, it’s just now the time when people should set all the alarm bells ringing about it because it is increasing day by day exponentially. 


Definition of Air Pollution 

Air pollution is an imbalance and modification of the natural concentrations of gasses present in the atmosphere or addition of some harmful factors that are detrimental for our and earth’s health. These factors that cause air pollution are called pollutants. Some pollutants like soot, carbon dioxide, sulfur oxides, particulate matter (PMs) are pollutants.

According to the World Health Organization 99 percent of the world’s population breathes in air that is considered as polluted as per the set limits and guidelines. The maximum population of the low and middle income countries is suffering the most due the high levels of pollutants in the air. In India the Air (Prevention and Control of Pollution) Act was established in 1981 and amended in 1987 to abate, prevent and control air pollution in India. The Central Pollution Control Board (CPCB) a statutory body was established under the water (prevention and control of pollution) act, 1974 in 1974 to take action in monitoring, prevention, control and improving air quality. 


Types of Air Pollutants:-

Air pollutants are classified into two main types:

1. Primary Pollutants:

These are pollutants that are directly emitted into the air, causing immediate air pollution. Examples include:

– Sulphur Dioxide: Emitted from factories and industrial processes.
– Nitrogen Oxides: Produced by burning fossil fuels in vehicles and power plants.
– Particulate Matter (PM): Solid or liquid particles suspended in the air from sources like construction sites and vehicle emissions.
– Carbon Monoxide: Released during incomplete combustion of fossil fuels in vehicles and heating systems.

2. Secondary Pollutants:

These pollutants form in the air as a result of chemical reactions between primary pollutants. Examples include:

– Smog: A mix of smoke and fog, often caused by the reaction of sunlight with pollutants such as ozone and nitrogen oxides.
– Ground-level Ozone: Formed by the reaction of nitrogen oxides with volatile organic compounds (VOCs) in the presence of sunlight.



What causes air pollution? | Sources of Air Pollution 

Main cause of air pollution is the combustion process. In this process oxygen is decreased and pollutants are increased to break the balance of the atmosphere. Natural combustion process of fossil fuels or wood, utilizes oxygen to create pollutants like carbon dioxide, oxides of nitrogen and sulfur and particulate matters like soot and smoke.

There are many ways through which our atmosphere becomes polluted. In which man-made sources are main contributors in air pollution which are called anthropogenic sources. Travel contributes a huge share in destroying quality of air. From private vehicles like scooters, cars to public transports like buses and airplanes, from delivering goods through ships to protecting the countries with jets in each way combustion of fossil fuels and other materials lead to making air more and more polluted. 

Exhaust of chimney’s from large factories and chemical plants make air quality drop significantly in the local area. According to the World Health Organization, developing and poor countries’ air quality is worse than large cities in developed countries. For instance Karachi Pakistan New Delhi India Beijing China Lima Peru and Cairo Egypt are capital cities of some developing and poor countries that have poor air quality. Although some cities of developed nations like Los Angeles, California have polluted air. Even Los Angeles is called smog city. List of types of Pollutants:


Pollutant Type Examples Sources Impact on Environment Impact on Human Health
Heavy Metals Lead, mercury, cadmium, arsenic Industrial runoff, mining activities, fossil fuel combustion Neurological damage, organ failure, developmental issues
Pesticides DDT, glyphosate, organophosphates Agricultural runoff, urban pest control Neurological damage, cancer, reproductive disorders
Persistent Organic Pollutants (POPs) PCBs, dioxins, furans Industrial processes, burning of waste, pesticide use Cancer, reproductive disorders, immune system impairment
Particulate Matter (PM) PM2.5, PM10 Industrial emissions, vehicle exhaust, dust Respiratory problems, cardiovascular diseases
Noise Pollution Traffic noise, industrial machinery noise Transportation, industrial activities Hearing loss, stress, sleep disturbances
Thermal Pollution Increase in water temperature Industrial cooling water discharge Disruption of aquatic ecosystems, decreased oxygen levels
Pathogens Bacteria (e.g., E. coli), viruses Sewage discharge, animal waste, contaminated water sources Gastrointestinal diseases, infections
Algal Blooms Cyanobacteria, dinoflagellates Nutrient runoff, warm temperatures Harmful to aquatic life, toxin production
Invasive Species Zebra mussels, Asian carp Human activities, accidental introductions Disruption of ecosystems, decline in native species


Major Causes of Air Pollution:-

Air pollution is caused by a variety of human and natural activities:

– Burning of Fossil Fuels: The combustion of fossil fuels in vehicles, power plants, and factories releases harmful pollutants like carbon monoxide and sulfur dioxide.

– Automobiles: Emissions from vehicles contribute significantly to air pollution and greenhouse gas levels.

– Agricultural Activities: Ammonia from farming, as well as the use of pesticides and fertilizers, releases harmful chemicals into the air.

– Factories and Industries: Industrial processes emit pollutants like carbon monoxide, VOCs, and particulate matter.

– Mining Activities: The extraction of minerals can release dust and chemicals into the air, affecting local air quality.

– Domestic Sources: Household products like paints and cleaning agents release toxic chemicals, affecting indoor air quality.



Effects of Air Pollution:-

Air pollution is becoming one of the top most factors of diseases and death in humans and animals in today’s world. According to a report by State of Global Air Report 2020 4.5 million people died due to the air pollution and around 2.2 million people died due to indoor air pollution in 2019. Highest people died were from the two most populous countries of the world India and China. Here’s some major effects of air pollution on man and the environment. 


Effects On The Environment

Air pollution has its huge impact on the environment. For instance, climate change is a main issue these days. Happiness more frequently is because of air pollution. Air pollutants have increased the  temperature of earth drastically. Due to the new variations in global temperature now seasons are changing. Unpredictable rains, heat strokes, flooding and drought are the result of climate change due to the pollution. Ozone layers get depleted due to the chloro-fluoro carbon or CFCs now being controlled with use of HFCs. Due to this more ultraviolet radiation coming on the earth surface making it warmer. Many biological factors like fungi and certain disease carrying insects population increases significantly due to higher temperatures. Due to climate change some trees with infectious pollen grains now have a longer pollen season. Wildfires incidents are increasing around the globe due to the drought and dry conditions even in rain forests of the Amazon. 


Smog and Soot

Smog is made up of two words smoke and fog. When pollutants like group level ozone, oxides of nitrogen and sulfur, and other hazardous pollutants get mixed with fog it becomes smog. Smog reduces visibility, causes eye infections, creates problems in the respiratory system specially lungs. Smog in Delhi NCR is a famous issue from September to almost the whole winter season. Soot is unburnt hydrocarbons released after combustion of fossil fuels which is very harmful for health.


Hazardous air pollutants

Some air pollutants are fatal and cause severe damage to health when come in contact even in small quantities. For instance lead, mercury, benzene and dioxins etc. They’re released after the combustion of fossil fuels. They cause eye, lungs, skin allergies and even disorders related to blood and vital organs. Most of these are carcinogenic and harm the nervous, immune and endocrine system. Low IQ and learning ability in children is Associated with Mercury, which harms the Central Nervous system. Polycyclic aromatic hydrocarbons (PAHs) are connected with the lung, liver, blood and eye diseases and even cancer. If exposed during pregnancy can cause ADHD in hampered brain development in infants. Here’s a list of air pollutants according to their effects and level of severity. 

Gas Effects Severity
Carbon Monoxide (CO) Highly harmful to humans, can cause death in high concentrations Severe
Sulfur Dioxide (SO2) Irritates respiratory system, contributes to acid rain and smog Severe
Nitrogen Dioxide (NO2) Causes respiratory issues, contributes to smog formation Moderate to Severe
Particulate Matter (PM2.5/PM10) Causes respiratory issues, cardiovascular problems, and lung diseases Moderate to Severe
Ozone (O3) Causes respiratory issues, eye irritation, and exacerbates asthma Moderate to Severe
Methane (CH4) Contributes to global warming and climate change Moderate
Hydrocarbons Contribute to smog formation and air pollution Moderate
Benzene Carcinogenic, causes leukemia and other cancers Severe
Mercury Highly toxic to humans and ecosystems, causes neurological damage Severe
Polyaromatic Hydrocarbons (PAHs) Carcinogenic, can cause respiratory issues and DNA damage Severe
Hydrofluorocarbons (HFCs) Potent greenhouse gases, contribute to global warming and ozone depletion Severe
Carbon Dioxide (CO2) Major contributor to global warming and climate change Moderate


Greenhouse gasses

Greenhouse gasses do not harm the human body directly but they help in increasing the mean temperature of the earth and lead to global warming. Some greenhouse gasses are methane, carbon dioxide hydrofluorocarbons (HFCs) etc. Global warming leads to climate change and melting of glaciers, increase in sea level that causes the over flooding in shore-cities. Around 140 countries signed the Kigali Agreement in October 2016 to curtail the use of greenhouse gasses that are used in refrigerator and air conditioners and invent more safer Alternatives in the meantime.  


Some Other Effects of Air Pollution:-

Air pollution has several harmful effects on both the environment and human health:

– Diseases: Air pollution can cause respiratory disorders, heart disease, and lung cancer. It is especially harmful to children and the elderly.

– Global Warming: Greenhouse gases contribute to rising temperatures and climate change, leading to melting glaciers and rising sea levels.

– Acid Rain: Pollutants like sulfur and nitrogen oxides combine with water vapor to form acid rain, which can harm plants, animals, and infrastructure.

– Ozone Layer Depletion: Chemicals like chlorofluorocarbons (CFCs) contribute to the thinning of the ozone layer, allowing harmful UV rays to reach the earth.

– Effect on Animals: Pollutants can accumulate in water bodies, harming aquatic life and forcing animals to relocate, impacting biodiversity.



Air Pollution Control and Environmental Justice:-

In India to mitigate air pollution and reduce its impacts on environment and people the Air (Prevention and Control of Pollution) act, 1981 was enacted. Under which the Central Pollution Control Board (CPCB) was set up. It is a statutory body which functions to control, prevent, and abate air pollution and improve air quality in the country. The CPCB monitors air quality under the National Air Monitoring Programme (NAMP). To monitor air quality CBCB has installed Automatic Monitoring Station in Delhi which measures concentration of nitrogen dioxide, sulfur dioxide, respirable suspended particulate matter (RSPM), suspended particulate matter (SPM), Ozone, carbon monoxide etc. Also air quality index has been launched online and displayed in the main crossroads of the country. Along with the efforts made by the government various awareness programs and rallies are organized. Awareness and understanding the issue helps mitigate the problem from its roots. Efforts from the top level are as necessary as the small efforts and equally important by people in everyday life. 



Air Pollution Control Measures:-

Controlling air pollution requires a combination of government regulations and individual actions:

– Avoid Using Vehicles: Opt for public transportation or carpooling to reduce emissions from private vehicles.

– Energy Conservation: Use energy-efficient appliances and turn off electrical devices when not in use to reduce the demand for fossil fuel-generated power.

– Use of Clean Energy Resources: Adopt renewable energy sources like solar, wind, and geothermal to reduce reliance on fossil fuels.

– Minimize Fire Usage: Reduce the use of open fires and fire products, as they can release harmful pollutants.

– Fuel Substitution: Switch to cleaner fuels like compressed natural gas (CNG) for vehicles and industrial processes.


Other Air Pollution Control Measures:-

– Industrial Emission Control: Implement emissions controls and process modifications in factories to minimize pollutants.

– Process Control Equipment: Use equipment like scrubbers and filters to capture and remove pollutants from emissions.

– Dilution of Pollutants: Increase ventilation and use air purifiers to dilute indoor pollutants.

– Tree Plantation: Planting trees helps absorb carbon dioxide and other pollutants, improving air quality.

– Awareness and Education: Promote awareness about air pollution and encourage practices to reduce it.


By implementing these measures, individuals and organizations can work together to combat air pollution and protect the environment and public health.


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