June 6, 2023

Air Pollution: History, causes and its effects on humans' health

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ir pollution has been an environmental and health issue for a long time now. It does affect not only humanity but plant and animal life as well. Pollution results from suspended solid or liquid particles from cars, factories, dust, pollen, or mold spores. 

Polluted air has been linked to respiratory diseases, heart problems, certain types of cancer, asthma attacks, and a host of other health issues. It is also responsible for climate change and global warming.

Notable increases in air pollution due to human activity began in the late 18th and early 19th century during the rise of the industrial revolution and continued to climb after the wide availability of affordable cars in the 20th century. For context, the amount of carbon dioxide suspension in air has risen over 50% since the industrial revolution. Carbon dioxide is one of the main causes of air pollution and has resulted in average global air and ocean temperature rises.

This article highlights details about air pollution, that include causes, different types, their effects on human health, and how to reduce them.

Table of  Contents

What Is Air Pollution?

Air pollution is the introduction of harmful substances to the environment by physical, biological, or mechanical agents. It primarily results from burning fossil fuels, some Industrial activities, mass farming, transportation, other combustion devices, forest fires.

Up to 99% of the population breathes air that exceeds the WHO guideline limits for pollutants, making air pollution one of the leading contributors to deaths worldwide. Air pollution was labeled by the UN as one of the world's worst environmental health risks, and it affects everyone in low, middle, and high income countries.

Causes of Air Pollution

Different activities cause air pollution and affect health, water, and soil quality. The common air pollution to look out for are:

Coal and Natural Gas Power Plants  

The burning of fossil fuels is the biggest contributor to air pollution. Be it the thick smog that covers the cities or the acid rain destroying fragile ecosystems, burning fossil fuels has had the most adverse impact on the worsening global climate. Coal, and natural gas power plants release significant amounts of particulate matter, carbon dioxide, methane, heavy metals, nitrogen dioxide, and sulfur dioxide into the air. 

Petroleum Usage 

The burning of petroleum fuels in industrial applications and transportation such as buses, planes, and cars, releases pollutants such as carbon dioxide, carbon monoxide, volatile organic compounds, sulfur dioxide, and nitrogen dioxide.

These pollutants cause irritation in the eyes, throat, and respiratory systems, and may lead to chronic diseases.

Agricultural Activities

Various agricultural activities can also cause air pollution. Chemicals such as synthetic pesticides and fertilizers can release toxic chemicals into the environment, affecting the air quality. Some fertilizers or pesticides also produce harmful fumes that blend with the air, affecting oxygen levels.

Burning Waste

Another common practice that leads to air pollution is burning waste products. This can include waste products from the house or industries. Garbage burning is common in cities with poor waste management practices and results in high levels of soot and carbon in the air. 


Wildfires can result from climatic conditions such as heat waves and lightning, poorly maintained electrical infrastructure such as the California Camp Fire in 2018, campfires, discarded cigarettes, malfunctioning equipment, and so on. 

Carbon monoxide, carbon dioxide,volatile organic compounds, particulate matter are the most common pollutants released by wildfires. 

Types of Air Pollutants and Their Health Implications

According to the World Health Organization (WHO) air pollution contributes to many health issues including, lung cancer, heart disease, stroke and respiratory diseases. They are also estimating that annual premature death rates of 6.7 million people are related to air pollution.  

Here are the most common types of air pollution that have adverse effects on the environment and human health where they come from:

Greenhouse Gases

Greenhouse gases such as carbon dioxide and methane stay present in air for a long duration and have resulted in the increase of air and ocean temperatures by trapping solar heat in the atmosphere. High Carbon dioxide levels are caused by fossil fuel combustion or industrial activities like oil or gas drilling, and wildfires. 

According to guidelines released by the US Department of Agriculture, compared to other air pollutants, carbon dioxide has a relatively low toxicity level when inhaled. However, mild exposures can result in headaches and drowsiness while high levels of exposures cause shortness of breath, heart palpitations, and high blood pressure.  

Nitrogen Dioxide and Sulfur Dioxide

Nitrogen and sulfur dioxides are both water soluble molecules that once released into air, produce particulates that decrease visibility. Both compounds also react in air to form nitric and sulfuric acid contributing to the formation of acid rain which contribute to soil and water pollution. 

These gases are mainly produced by internal combustion engines primarily used in transportation, industrial facilities using petroleum fuel, and coal burning power plants. Other household equipment like furnaces, fireplaces, and ovens can produce nitrogen oxides as well. 

Both sulfur, and nitrogen oxides can irritate the respiratory system and aggravate asthma attacks. They can also contribute to the development of asthma and vulnerability to respiratory diseases.  

Carbon Monoxide

The odorless and colorless gas is produced after the incomplete combustion of wood, coal, or natural gas. However, carbon monoxide is most commonly released by vehicles. 

High concentrations of Carbon monoxide affects the body's ability to absorb oxygen. Low levels of oxygen in the body leads to improper function of the cardiovascular and nervous system. Though unlikely to occur outdoors, inhalation of carbon monoxide at very high concentrations can lead to death.


Lead can be present in our homes through paints, ceramics, plumbing materials, or pipes. It is also found in fuel exhaust, ammunition, lead acid batteries, or cosmetics. 

According to a report published by the EPA, children and pregnant women are most sensitive to the effects of lead. In Pregnant women, lead can result in several birth defects, increased risk of miscarriage, and premature childbirth. In Children low levels of lead can lead to IQ deficiencies, slow growth, behavioral issues, anemia, and hearing problems. 

Depending on the amount of exposure, when lead enters the body, it can negatively affect the functional systems of the human body such as the immune system, nervous system, and kidney function. It can also decrease the oxygen transport capabilities of the blood.  


While ozone protects the planet from high levels of harmful sun rays such as radiation when it is present at the atmospheric levels, when occurring at ground-level ozone is problematic. Ozone that is present in the air we breathe is part of the smog that forms after reacting with other pollutants like carbon monoxide or nitrogen dioxide released from internal combustion engines and other industrial activities. High ozone levels or smog form when nitrogen dioxide reacts with other air pollutants known as volatile organic compounds(VOCs). Ozone can be identified by the orange, brown haze and is a health risk to humans.

This pollutant affects the eyes, throat, and lungs in kids and the elderly. It can also cause worse allergic reactions in those with allergies or asthma. 

Particulate Matter

Particulate matter, also known as soot, consists of tiny particles such as sulfates, nitrates, Polycyclic Aromatic Hydrocarbons (PAHs), Volatile Organic Compounds(VOCs), dust, and other allergens. Soot can either be gaseous or solid in the air. It comes from combustion of petroleum fuels, coal power plants, wildfires, certain industrial plants, certain types of paint, and permanent markers. 

Particulate matter can cause serious health issues including heart palpitations, heart attacks, and early death in people with heart or lung disease. 

From an environmental standpoint, particulate matter contributes to acid rain which results in degraded water quality in all waterways, and causes nutrient depletion in soil. 

Pollen and Mold

Mold and pollen can come from trees around homes. Some are present in the air we breathe. Despite not being directly related to human actions, this type of air pollution affects human health in a big way. Mold growth happens because of high moisture concentration of different surfaces. 

However, pollen from various plants spreads through the atmosphere because of wind. Pollen-producing plants like ragweed increase production if there is a high carbon dioxide presence.

Mold and pollen can lead to cardiovascular complications, respiratory problems, or stroke. It also makes individuals suffer from allergic reactions like itchy eyes, runny noses, and fevers. 

Air Pollution World Map: The Cleanest Places on Earth and the Most Polluted

The World Health Organization has air quality guidelines containing low to medium or high limits. Various countries have set laws to help them achieve the highest air quality limits. For example, the USA has the Clean Air Act, which allows the Environmental Protection Agency (EPA) to uphold public health by reducing the emissions of air pollutants. 

However, some countries, especially in the Third World, are also struggling with high limits of pollutants that cause high deaths globally. People in such regions breathe dirty air and experience adverse effects of climatic changes as pollution continues to worsen. 

The cleanest places on earth to live in and experience clean air are: 

  • Zurich, Switzerland

Zurich has the cleanest air in the world. The city has an annual PM2.5 limit of 0.51μg/m3, the lowest in the world. 

  • Reykjavik, Iceland

This is another city with clean air you can stay in or visit. Its annual PM2.5 level is at 1.9μg/m3. Reykjavik focuses on using alternative energy sources, and that's why it's cleaner.

  • Launceston, Australia

The Australian city also has clean air, which is good for human health. Launceston has low air pollution activities. Its annual PM2.5 levels are 3.68μg/m3.

  • Honolulu, Hawaii

Honolulu, Hawaii, is another city with clear air. It was among the popular tourist destinations with the cleanest air in 2022. Its annual PM2.5 level is around 4.04μg/m3.

The most polluted place in the world:

India is one of the most polluted places in the world, as most of its cities have a higher annual PM2.5 level. Cities in India like Kanpur, Delhi, Gaya, and Agra have higher concentrations of lead in air pollution. 

Other cities are Xi’an, China, with a PM2.5 level of 48.11 μg/m3. Kampala, Uganda, with 44.99μg/m3, and Bamako, Mali, with 44.88 μg/m3.

How can we reduce air pollution?

To reduce the amount of carbon monoxide, nitrogen dioxide, and other pollutants in our air, we need to invest back in the planet that gave us oxygen in the first place. Here are some key initiatives that WHO and others in the health and climate change space are encouraging to decrease air pollution:

Clean Energy

As we’ve said, one of the biggest contributors to our global air quality crisis is the burning of fossil fuels. This means that clean energy is a solution we can’t ignore. Unlike power generated from coal or natural gas, energy sources such as wind, water, sun, and biofuel emit little to no air pollution.

Clean energy tends to be more of an investment, but companies like WattBuy, Inspire Clean Energy, and Green Mountain Energy can help you find affordable options for your home.

Practice Energy Conservation

If you’re not in a position to use clean energy, that doesn’t mean you can’t assist in reducing our dependence on fossil fuels. As of 2022, the residential sector took up just under 20% of the energy used in America. Practicing energy conservation is something we can all do to lower this figure further and help reduce air pollution from fossil fuels. 

Putting your water heater on a timer so that it’s not using power during the day, programming your thermostat to be more efficient, and making sure to switch lights off when they’re not needed are all ways you can reduce your energy usage. A company like Arcadia is also a great option to help you tap into the data of your power usage and automate things in your home so that you’re only using the energy you need.

Adopt Eco-Friendly Transport

The US Environmental Protection Agency estimates that about 27% of US greenhouse gas emissions are made up of emissions from transport. This contributes to the smog you’ll often see over big cities like LA and has serious implications for our air quality and health.

The impact of car fumes is significant enough that many European cities have introduced tax cuts for those who switch to hybrid and electric vehicles. Changing your car isn’t the only option though. 

Carpooling, using public transport, or switching to a bicycle when you can, are all ways that you can be more eco-friendly in your transport choices. If you’re able to, it’s a good idea to connect with colleagues or people you know who do the same commute so that you can share rides or bike together. That way you’re not just shifting your own impact but bringing your community along for the ride too.

Excitingly, many public transport systems are trying to make their systems even more eco-friendly. Public trains in the Netherlands are not only electric but have relied mainly on wind power since 2017.

Green Buildings and Green Walls

“Green buildings” are structures designed to be more environmentally conscious, especially in their energy usage. They reduce reliance on fossil fuels and help ease air pollution in the process by implementing clean energy solutions, low-energy use appliances, and more efficient heating and cooling systems. 

Green walls are another structural shift that can improve the impact that buildings have on air pollution as they create large walls of greenery that help absorb carbon dioxide and other pollutants. For urban environments where space is scarce, it’s a great way to add greenery that helps not only regulate the temperature of the buildings they’re attached to by shading them, but also reduces particulate matter in the air. 

Urban Gardens

Another way to introduce air-cleaning plants into cities is by planting up more urban gardens. These gardens are great ways to reclaim abandoned spaces like the old railway line that became the High Line Park in NYC so that they’re no longer eyesores, but beautiful, air-purifying oases instead.

If you’d like to create your own personal garden to improve air quality, palm plants, rubber plants, and flowers such as Gerberas or Chrysanthemums are all considered to be particularly good at filtering harmful chemicals in the air.

Composting Garden Waste 

Landfills are a major culprit when it comes to air pollutants. Whether the waste is burnt, or left to ferment and break down on its own, large garbage sites are often releasing toxic air pollutants. The less that ends up at the dump, the better, which is why composting your garden waste is so important.

Grass cuttings, fallen leaves, and trimmed branches can be composted on their own or added to food scraps. The great thing about compost is that it not only lessens how much you send to landfills, it also provides you with a great addition for your own plants. Compost can help increase soil nutrients and encourage the growth of more plants which only helps our air quality more.

Reduce Plastic Bags

About 40% of the world’s garbage is burned, causing all kinds of toxic fumes to enter our air. Plastic is one of the worst to cause this, which is why reducing your use of things like plastic bags can actually help decrease air pollution. 

Many countries, including Kenya and Australia, have successfully banned plastic bags to help ease this issue. The next step? Reducing all single-use plastics so there’s less to burn on our landfills and fewer toxins polluting our air as a result.

Encourage Forest Conservation & Planting Trees

Forests are often referred to as the “lungs” of the planet because of their ability to absorb carbon dioxide and release clean oxygen. As it happens, they also act similarly to our liver by filtering toxins in the air. Through photosynthesis and their leaf structures, trees not only operate as carbon sinks, but trap pollutants like nitrogen dioxide and prevent them from circulating further.

Because of this, encouraging forest conservation and tree planting is highly effective at reducing the impact of air pollution. While we need to be reducing the harmful toxins being released, we also need to ensure that what does infect our air is being removed wherever possible.

Planting more trees, especially in places with lots of buildings and hot surfaces can also help with air pollution simply by providing shade and reducing temperatures as a result. Lowered temperatures mean less energy wasted on cooling systems while also reducing ground-level ozone pollutants.

As it turns out, the best way to protect our health and air quality is to invest back into the greenery that’s been trying to take care of us all along.