Effects of Air Pollution on Human Health

When encountering a car that emits many smoke fumes, what is your initial reaction?

It is to cover mouths and noses with a handkerchief, or at least our hands for many of us. We know that the coughing fits we can get if we inhale that smoke is only a minor consequence if we don’t.

You know that this emission coming from vehicles is just one of the contributors to air pollution. You may not be aware of its other sources, with some of them even more hazardous than vehicle emissions.

And because of these different sources, it can be expected that there will also be various effects on human health.

You must be informed of both the sources and their effects and other necessary information. Prevention is indeed better than cure. The best way to prevent the health effects is to understand what causes it in the first place.

blue sky

What is it?

Everyone knows that air pollution exists, but not all of them are aware of it. Most people think it only involves the dark smoke from vehicles and factories, especially smog. Still, they are unaware that it goes beyond that. It is one of those concepts that people think they are very familiar with, only to discover that they still have much to learn about.

Ideally, the air in the atmosphere should contain mostly nitrogen and some oxygen. It should maybe contain a mix of other trace gases to be considered completely clean and healthy for us to breathe in. But with air pollution, the essential nitrogen and oxygen are lessened. Harmful pollutants in the air increase simultaneously. Because of this, the air quality is compromised.

Since these pollutants also have toxic chemicals or compounds, air pollution is detrimental to humans and the environment. It includes plants and animals alike. And unlike what most people think, it is present both indoors and outdoors and in urban and rural areas.

And because air easily circulates, it can also easily transfer to and affect other areas.


There is a lot of misconception about air pollution. That is why it is important to know the most important facts. It includes why everyone should take this environmental issue seriously.

  • It is due to multiple sources and not just the smoke coming from cars. The most dangerous ones are those that are invisible to the naked eye.
  • This type is considered more dangerous than other forms because of the pollutants involved. Being mostly invisible means that we are constantly exposed to them without our notice. Also, they generally contain toxic substances.
  • The amount produced annually is believed to be greater than the total amount of water, ground, and land pollutants.
  • These particles can cover large distances. Scientists have found out that air pollution coming from Asia has been affecting the western region of the US for the past two decades.
  • In a recent report, China and India were discovered to be collectively responsible for more than half of the deaths worldwide due to air pollution.
  • Exposure can affect anyone, from a simple cough or eye irritation to lung cancer.
girl wearing mask
  • It happens both indoors and outdoors.
  • Urban areas generally have the worst air quality due to the amount of traffic present.
  • The US only ranks 10th worldwide in terms of having the best air quality. Among its states, California has consistently topped the list of states with the worst air quality in the entire US.
  • It indirectly affects the global economy, with the average loss amounting to billions of dollars. Productivity is lessened because of illnesses and death related to this problem, resulting in companies’ loss of income.
  • Certain types worsen air pollution and exacerbate other global problems, like climate change.
  • It has long been considered responsible for claiming many lives each year. It is now considered the 4th leading cause of death worldwide.
  • While occurring both indoors and outdoors, indoor types are generally considered more dangerous. It is more concentrated.
  • More people die from a stroke caused by air pollution, followed by heart disease and cancer, and lung diseases.

To sum it up, it has become a worldwide problem affecting not just us humans. A single factor does not cause it. And unless we continue to find ways to address this problem, it is bound to worsen.

What Causes It?

You may be aware that there are different causes. You will be surprised to know that the most common ones you can think of are not the only ones. You are probably unaware of other sources, especially those invisible to the naked eye.

Excessive amounts of pollutants cannot be absorbed by the environment or broken down. They’re composed mainly of gases and liquid aerosols. They are not always present in the atmosphere and are also mostly invisible.

The sources can either be man-made, also called anthropogenically. Otherwise, they can be naturally occurring. But with air pollution, the main cause is attributed to anthropogenic causes.


Any activity that involves the use or burning of fossil fuels is seen as the biggest culprit. Industrial processes use up the largest amount of fossil fuels. They are considered the major cause of the problem. Facilities and equipment are at the forefront of generating power, such as power plants. Those that use coal are especially concerning.

Other industrial causes include:

  • Emission comes from production and manufacturing facilities, like factories and other industrial plants.
  • Mining activities, like drilling and extracting
  • Facilities that produce chemical products and metals.
  • Diesel generators
  • Plastic manufacturers and facilities that process them.
  • Gas and oil refineries
  • Smelting
  • Industrial heating devices that require fossil fuel.
  • Waste incineration and use of landfills
vintage generator


Not many people know that certain household activities also contribute to air pollution. Those that also involve the use of fossil fuels and household products are particularly bad.

Did you know that you also release pollutants while you cook? The amount depends on your heating source. Whether you use electricity or gas, these sources will contribute to your home’s pollution. They can produce formaldehyde and carbon monoxide. The cooking ingredients themselves may also release complex particles as they are heated.

When you use the following household products, certain problematic particles are also released:

  • Solvents
  • Cleaning products, especially disinfectants
  • Air fresheners
  • Laundry products
  • Paint
  • Glue and other chemical adhesives
  • Personal care products, such as deodorant sprays and hairsprays
  • Tobacco products, such as cigarettes
  • Pest or insect sprays

Home construction or renovation is also known to contribute because of the materials involved. Old homes are even more dangerous to work with. They may release lead and asbestos, also known pollutants.


Another major cause is the transport sector, especially those that emit carbon dioxide. As you know, cars are also one of the major sources of exhaust fumes. Diesel-powered cars are known to be the biggest culprit of vehicle emissions. The bigger trains and planes also use fossil fuel. The smaller cars pollute the air the most because these cars greatly outnumber other modes of transport. It means they collectively use up more fossil fuel.


The agriculture industry is also known to contribute to air pollution. It has been discovered to be the biggest contributor. Most particles come from using various agricultural products like fertilizers and pesticides. It’s especially those containing ammonia. Not only that, but various farm equipment also use fossil fuels in their operations. Crop dusting and burning is another farming activity known to release complex particles.

Natural Causes

While natural causes have less impact, they still add to the overall probæem. Some of them may be preventable, while others occur instantaneously and give us no chance to prevent them.

Among the natural causes are:

  • Volcanic eruptions
  • Radioactive decay
  • Decomposition of plants and other organic matter
  • Forest fires
  • Whirlwinds
  • Dust and sand storms
  • Mold
  • Pollen and other natural allergens
  • Animal droppings
  • Wind erosion
  • Sea-salt spray
  • Animal digestion that produces methane, particularly involving cattle
  • Plants that produce volatile organic compounds
  • Hot springs
  • Fog and mist
  • Soot
  • Certain gases, such as ozone and radon
  • Release of gas due to natural processes

Man-made causes produce more air pollutants than natural ones. They contribute to the overall problem every day.

What is the Biggest Source?

You may have noticed that we mentioned fossil fuels plenty of times in the previous section. It should come as no surprise that the biggest source of the problem is any activity that involves its combustion.

People are not aware that plenty of our daily activities involves using these fossil fuels, directly or indirectly. It has detrimental consequences to the environment, especially when left unchecked.

In particular, the biggest source is our use of automobiles. Transportation uses up a lot of fossil fuels. It disturbs pollutants on the ground that can easily become airborne, such as road dust. Also, cars are responsible for both primary and secondary sources.

Cars are considered a primary source of toxic gases and particles. While other means of transport also produce these particles, cars vastly outnumber their volume. It is why they collectively produce the most pollutants. Some of these will react with other particles or even themselves. It results in secondary pollutants like ozone and acid rain.

Primary air pollutants that are emitted by cars and other modes of transport include:

Most of them come from cars. Different car manufacturers have been trying to cut back on their use due to the burning of fossil fuels. It is why they are now developing more eco-friendly cars, such as hybrid and electric cars. They hope to lessen their contribution.

Different Types

Most people have no clue that there are different types, namely indoors and outdoors. They believe that air pollution only happens outdoors where all the smog is present. Stay inside a confined space protects them from all the particles, like their home.

criteria pollutants OutdoorIndoor
Carbon monoxideCigarette smokeBuilding materials
Ground-level ozoneGround-level ozoneCooking
LeadParticulate matterGases
Nitrogen DioxideSmogHousehold and personal care products
Particulate matterToxic gasesTobacco smoke
Sulfur Dioxide Various allergens

Why air pollution is not limited outdoors has to do with the different types present. If you recall, these can either be primary or secondary. It means they may be pollutants themselves and, at the same time, be responsible for the creation of other air pollutants.

The EPA has identified the following as the “criteria pollutants” or those that are most common in the United States:

  • Ground-level ozone
  • Lead
  • Particulate matter
  • Nitrogen Dioxide
  • Sulfur Dioxide
  • Carbon monoxide
sign saying no science, no coffee

Aside from these six common variants, the agency has also identified 187 hazardous air pollutants. They are monitored through the Clean Air Act. All these can easily be transferred from one place to another. Their minuscule sizes mean they can easily pass through the smallest of gaps.

You already know that activities involving burning fossil fuels are the major source, with cars being at the forefront. It is generally responsible for most of the air pollutants. Most of these activities are done outdoors. That is why we get the highest amounts of exposure when outside. If you recall, most of the causes are also found outdoors.

Aside from most of the natural and man-made causes we mentioned earlier, outdoor air pollution also includes the following:

  • Cigarette smoke
  • Particulate matter is produced from activities involving burning.
  • Toxic gases, especially those produced by industrial processes and facilities
  • Ground-level ozone
  • Smog

What makes outdoor air pollution the most familiar to most people is it is associated with smog. This is the most visible sign formed by reactions between various pollutants. Because smog appears in a dark haze or cloud, people immediately associate it. This visibility of smog makes people aware of the problem outside.

On the other hand, smog does not form inside any house or building. It lets people think there is no such thing as indoor air issues. After all, the sources seem to be less than outdoor air ones. Any visible smoke inside the house is not seen as air pollution but simply a nuisance that will disappear in a few. Smoke due to cooking is an example.

Here are sources of indoor air problems, mostly due to indoor activities. They include:

  • Building materials
  • Household and personal care products and chemicals
  • Gases
  • Various allergens are found indoors and outdoors, such as mold and fungal spores.
  • Tobacco smoke
  • Cooking

However, this does not mean you should not take indoor air quality seriously. While it may be smaller in volume, it is more concentrated than outdoor air pollution. It makes it more dangerous. It happens because air ventilation is poorer indoors than outdoors. It prevents the problematic particles from moving around freely, leading them to have a higher buildup indoors. Because we spend most of our time indoors, we get more exposure.

These two types pose different dangers, with higher amounts for outdoor exposure and higher concentrations for indoor exposure. Exposure to any of these two types is dangerous. It is even more amplified because most of them are invisible to the naked eye, which makes it a challenge.

PM2.5 Pollution

People tend to associate smog with air pollution the most. They don’t know that there is a much more hazardous enemy in the form of PM2.5. Particulate matter comes in two general categories, PM10 and PM2.5. The latter is considered more dangerous, which we’ll talk more about. Scientists agree that it is the most lethal among air pollutants.

Also called fine particles, PM2.5 is named because of its size. It measures only 2.5 microns or less. To put it into perspective, the average strand of human hair has a diameter of 50 to 70 microns. It means you need an electron microscope to see PM2.5. Because of its size and weight remain airborne longer, anyone can get exposed to it much easier and in higher amounts.

PM2.5 is produced through combustion of any kind. Since the burning of fossil fuels is the biggest contributor to the problem, PM2.5 is also abundant in the atmosphere. Since they can also react to other air pollutants, they can produce even more dangerous compounds.

All these characteristics put everyone at risk of PM2.5 pollution. What makes it even worse is that the particles are so small when inhaled. They immediately penetrate the lungs and settle there, leading to all sorts of illnesses. Not only that, but they can also affect soil and water quality. It can even compromise our food supply.

Because of all these, various government agencies are now keeping a closer eye on PM2.5 more than any other air pollutants. The Air Quality Index (AQI) also measures the amount of PM2.5 present and PM10.

What are the Effects on Human Health?

Everyone knows that it has various effects on human health, but many are unaware that these are just coughing fits. Anyone can get exposed to these harmful particles. Still, no one is more vulnerable to them than the children and the elderly.

Children spend the most time outdoors, where the exposure is abundant. Because they are still small, their bodies are not yet fully equipped to handle these particles. They are still in the development stage. They also get exposed to ground-level particles more than adults, especially those emitted by cars.

The elderly are also among the most vulnerable, but only next to children. While their bodies can defend themselves better against these particles, age plays a factor. The older the adults are, the less capable they handle exposure and other environmental hazards. If they already have pre-existing conditions, it can increase the symptoms they experience or aggravate their conditions.

Some of the health effects anyone can experience or acquire due to exposure to air pollution include:

  • Eye, nose, and throat irritation
  • Lethargy, weakness, or constant fatigue
  • Issues with the reproductive organs
  • Damage to the cardiovascular system
  • Diabetes
  • Allergic reactions
  • Various respiratory diseases
  • Mobility issues

You may have noticed that many of these health issues are not related to the respiratory system. It’s contrary to what most people would expect. It proves how dangerous it is, with death being its worst consequence.

How Does It Affect the Environment?

It affects not only humans but also the environment. How it does so mainly has to do with the pollutants present. These can either cause harmful environmental conditions or worsen existing ones, just like how they affect health.

Air pollution is seen as the cause of the following environmental hazards and effects:

  • Acid rain is due to sulfur dioxide and nitrogen oxides. They cause a reaction with various chemicals and compounds in the atmosphere. Acid rain can fall as rain and snow, and fog can damage vegetation. It can affect water quality by making it acidic and harmful to aquatic life and those who drink from it.
  • Damage to crops and forests – it can directly cause damage to vegetation, not just acid rain. Ground-level ozone can affect the growth and yield of plants. It can reduce their lifespans because it can make them more susceptible to pests and diseases.
  • Harm to wildlife – just like humans, wildlife can also acquire health problems due to air pollution. It includes issues such as reproductive issues and birth defects.
  • Eutrophication – nitrogen, and phosphorus from various sources will promote harmful algal bloom that can kill off marine life.
  • Haze – just like smog, haze is a form of fog. It is made up of particles that remain suspended in the air and block sunlight, affecting visibility.

Aside from causing the above conditions, it is also known to contribute to global warming and ozone layer depletion. The greenhouse gases are attributed to global warming, and certain particles are also considered ozone-depleting substances.

When it affects the environment, humans are also affected. We consider the plants and animals as our food supply may be lessened or compromised because of air pollution. If we consume animals that have eaten and drank contaminated plants and water, this contamination may also affect us.

What are the Global Effects?

Because the pollutants can easily travel once airborne, the effects can be felt globally. The issue in one country may be blown away in another country. It means the problem in one country can worsen due to moving from another country.

Unfortunately, developing countries are the most affected because they use more fossil fuels than developed countries. It’s particularly when cooking and heating their homes. These countries also have many of the world’s industrial facilities and engage in agricultural activities the most. It exacerbates their problem.

Most of those on the top 50 list of cities with the world’s worst air pollution belong to countries that include India and Pakistan. Bangladesh and China are high up on the list, too. These countries are also known as the world’s industrial facilities hub. That is why they are expectedly on the top of the list of countries with the highest annual concentrations of PM2.5. Bangladesh and India are the top countries, while China is now in 12th place. It’s a vast improvement.

The top 10 countries with the highest PM2.5 concentrations are:

  1. Bangladesh
  2. Pakistan
  3. India
  4. Afghanistan
  5. Bahrain
  6. Mongolia
  7. Kuwait
  8. Nepal
  9. United Arab Emirates
  10. Nigeria

These countries have poor air quality due to the PM2.5 concentrations present. The countries worldwide exceed the global standards set. It is the reason why the whole world seems to experience its effects.

You are aware of the numerous health effects on humans and why it is becoming one of the leading causes of worldwide death. The WHO even reports that more than 7 million people die annually due to indoor and outdoor air particles. Most of these deaths occur in developing countries in Asia and Africa. This number does not include those who acquired symptoms and illnesses and survived, which is expected to be higher.

Climate change has become a global issue recently, with its effects felt worldwide. Unbeknownst to many, air pollution and climate change are closely linked. The pollutants can cause various reactions in the atmosphere that directly affect temperatures. Climate change is associated with greenhouse gases. By lessening the sources, climate change is also reduced.

This scenario also applies to the depletion of the ozone layer. The hole in the ozone layer gets bigger with the increase of ozone-depleting substances released into the atmosphere. Many of these compounds that cause the depletion are also known as complex particles. They include things such as volatile organic compounds and hydrochlorofluorocarbons. If these are lessened, ozone layer depletion is also lessened.

The environmental effects mentioned earlier are also felt in various parts of the world. It’s especially acid rain that results in vegetation and marine life deaths. Because the pollutants needed to produce it can travel long distances by wind, acid rain can happen anywhere. One example is that Norway experiences acid rain due to pollutants coming from the United Kingdom.

The widespread reach has been a cause of global concern for years now. There have been signs of improvement in air quality in some countries. The consensus is that there is still much to be done. Different countries have made their legislation and adopted universal policies to solve this.

Lessening the global effects is still a work in progress. Still, we are slowly starting to see improvements that affect everyone.


To better understand the seriousness of the problem, here are other important statistics you need to know:

  • More than 90% of the people worldwide live in places with poor air quality. It means it exceeds the standards of the World Health Organization.
  • As many as two billion children are believed to be severely exposed to outdoor air pollution. And in 2016, 600,000 children reportedly died due to acute lower respiratory infections.
  • 1 out of 10 children under the age of 5 years old died because of illnesses.
  • In the US, as many as 11 million people reside in counties where the air quality also fails to meet the national standards.
  • In 1952, the problem in London was so bad that almost all modes of transportation had to be stopped. People were unable to see their own feet while walking. This incident became known as the Great Smog of London of 1952. It was responsible for thousands of deaths that are said to range from a total of 4,000 to 10,000.
  • Around 800 people per hour or 13 people per minute die because of it. It means 1 out of 8 or a total of 7 million lives are now lost annually. Almost all of these deaths happen in developing countries.
  • Out of the 7 million average premature deaths, 4 million are due to outdoor air pollution, and 3 million are due to indoor air issues.
  • People breathe in an average of 20,000 liters a day. Just imagine the exposure you inhale, depending on where you live.
  • Crop production has also been affected by it. As much as 50 million tons worth of yield is lost annually.

These figures are enough to alarm scientists and world leaders to move quickly and develop ways to address the problem. With numerous legislations and calls to action over the years, we are now reaping its benefits. The best proof of this is the improving overall air quality condition throughout the world.

The world had come a long way if we were to compare the figures now to those in the past before any intervention occurred. However, the battle is not yet won. Millions of people are still dying because of it every year.

How to Reduce It

Surprisingly, it does not require fancy machinery or many resources to reduce the issue. Most people are unaware that the simplest measures go a long way when dealing with this problem.

If you are wondering how you can be part of the solution, here are some of the best ways for you to do so:

  • Cut back on using anything that requires power and switch off electrical appliances and equipment. Conserving energy means fewer fossil fuels are needed to produce the needed energy.
  • Use appliances with an Energy Star label, as they are confirmed to use power more efficiently. Consider installing alternative energy sources, such as solar panels.
  • Go places using mass transport or simply walking.
  • Ensure that your car and any other engine-powered machinery are regularly maintained to prevent fuel spills. Ensure fuel efficiency, and prevent tailpipe smoke from coming out. Overweight cars and tires in poor condition will also cause an increase in fuel combustion.
  • Refuel during the evening because the temperature is cooler and will lessen the number of pollutants that can be produced. This principle also applies to using any gas-powered equipment, such as those for gardening.
  • If possible, switch to eco-friendly or hybrid cars and equipment. It’s especially great for those that are manually powered.
  • Choose paints and other personal and household products that are labeled environment-safe. It’s especially those that have little to no VOC present.
  • Avoid idling your car for long periods.
  • Use household appliances and equipment only with a full load to conserve electricity.
  • Instead of backyard-burning biodegradable material, create a compost pit or mulch them.
  • Lessen your use of wood, whether in cooking or any other activities that require it to be burned.
  • Ensure that your household products are properly sealed, especially those that contain VOCs. Prevent these compounds from evaporating.
  • When driving, stay within speed limits to lessen fuel combustion. The faster your car runs, the more fuel is needed, and the more particles are released.
  • Have a garden and grow plants that are known to purify the air.
  • Stop smoking, whether indoors or outdoors
  • Participate in local initiatives.

You may be familiar with many of these tips. You may not be aware of the impact these small changes can bring to the entire world. If we all do our share, there is a 100% guarantee of good results that everyone will benefit from.

But since having zero air pollution is not going to happen anytime soon, minimize your exposure to it simultaneously. It’s especially on days when the AQI levels are forecasted to be high.

Here are some of the ways you can keep yourself protected to avoid experiencing its health effects:

  • Keep yourself updated with the AQI to learn when the levels are forecasted to be elevated.
  • Avoid staying outdoors and doing intensive physical activities during the times when levels are high.
  • If exposure is inevitable, wear face masks.
  • Cover your mouth and nose when dealing with smoke, even those coming from cigarettes. If a suitable mask is unavailable, wear it.
  • Install air purifiers in your home, especially those that are capable of filtering even the smallest PM2.5 particulates. You can also place purifying plants to help improve indoor air quality.
  • Ensure proper ventilation by installing air vents and exhaust systems in your home, especially in the kitchen and bathrooms. Add filters that can block air pollution.
  • Air out your home every now and then to prevent pollutants from settling and lessen the concentration present. It is advisable to do it between 3 to 5 pm when the PM2.5 levels are generally lowest.
  • Remove any mold and mildew present.

Doing these measures will protect you, but it will also help lessen the levels present. That way, the time when we will all constantly breathe clean air may happen sooner than later.


What is pollution? The short answer.

Pollution refers to the after-effects seen in the environment when contaminants are introduced into it. Air pollution refers to contaminated air with energies, particles, or gases.

What are the four types of pollution?

The four types of pollution are air pollution, land pollution, water pollution, and noise pollution. All are considered equally harmful to the earth as well as humans.

Why is pollution such a big problem today?

Pollution is causing irreparable damage to our ecosystems and ozone layers. They’re problematic whether you’re at sea or on land. Also, it is causing an unprecedented amount of premature deaths and diseases. 9 million people worldwide die due to air or water pollution.

Why is pollution a world problem?

Because of globalization, humanity is now more linked than ever before. A setback in our ecosystems means setbacks to food security and health. Therefore, pollution sets off a domino effect globally. It leads to major global threats to humankind.

AQI, or the Air quality index, measures air pollution. Here’s how it’s done:

How do you measure air pollution?

  1. Satellites collect information.

    Satellites like NOAA-GOES-R and JPSS collect information about pollutants in the air. It includes gases like Nitrogen dioxide, sulfur dioxide, and ground-level ozone.

  2. Information on aerosols

    These are suspended liquid or solid particles that are very harmful to the air quality. It includes particles from construction sites and wildfires. It can also be caused by car exhausts, volcanoes, and factories.

  3. Satellites process information.

    Using formulae, the information regarding AQI is calculated and distributed. AQI is measured on a scale of 0-500, and anything about 150 is considered poor air quality. AQI from 200- 300 is very unhealthy, while 300-500 is considered hazardous.