Indoor Air Pollution: Causes, Sources, Effects & Prevention/Solutions

There’s two main types of air pollution – indoor, and outdoor air pollution.

This guide focuses on indoor air pollution, and specifically in parts of the world where it causes the most harm – which is mostly lower income countries and regions.

We look at some causes, sources, examples, effects, and potential ways to prevent or solve it.


Summary – Indoor Air Pollution

Indoor air pollution happens inside dwellings and buildings (as opposed to the outside atmosphere)

Indoor air pollution might be far more detrimental in developing countries where people don’t have access to safer and more modern electricity and energy production (natural gas or renewable energy, for example).

People in developing regions might use solid fuels (like wood and organic matter) more frequently, as well as kerosene for cooking, cleaning, heating etc.

Particulates and other air contaminants can enter the air as a result of these activities, and especially in smoke

Small particulates like PM10 can be some of the most damaging/harmful air pollutants

Carbon monoxide and VOC’s can also be problematic

A range of health related diseases and illnesses can potentially occur as a result of this, as well as death

Young children and women are some of those most affected in developing regions and low income areas

Encouragingly, deaths from indoor air pollution are mostly on a steady decline

China is one example of a country that has seen a decline in the last decade

Although, some countries like the DRC (Congo) might not be experiencing a decline

Asia and Africa on a regional level, and China and India on a country level, are among the regions and countries with the highest concentration of deaths (and highest mortality rates) from indoor air pollution

Providing cleaner, more modern, and safer indoor systems for heating, cooling and cooking within dwellings might help significantly reduce indoor air pollutants

In developed countries, reducing the use of indoor and outdoor contaminants in products we use (or reducing the use of these products altogether), reducing second hand sources of air contaminants like smoking, and having good ventilation, can all help.


What Is Indoor Air Pollution?

Indoor air pollution is a change in the Indoor Air Quality, usually by the introduction of an air contaminant, that can have an impact on the health of people inside buildings and structures


Indoor Air Pollution In Developed vs Developing Countries

There’s really two distinct types of indoor air pollution – indoor air pollution in developed countries, and indoor air pollution in poorer parts of the world.


Causes, Sources & Examples Of Indoor Air Pollution

In the two examples outlined below:

Developing Countries – Sources

Comes mainly from lacking access to modern cooking and heating systems, and burning solid fuels and kerosene in the open, on open stoves and using inefficient cooking practices


Developed Countries – Sources

Comes mainly from household and outdoor products, and second hand sources like smoking

In both cases, a lack of ventilation can compound the issue.


Developing Countries – Causes

[it’s] usually caused by the inefficient use of solid fuels for cooking and cleaning [and heating]

… smoke and other contaminants [are] released from burning non modern energy sources inside the house like wood, crop residues, dung, charcoal, coal and kerosene.

– OurWorldInData. 


Developed Countries – Causes

[it] is caused by things like mold, household sprays (aerosols for example), cleaning chemicals, garden sprays (insecticides for example) and so on.

[it also comes] from things like second hand tobacco smoke, the use of space heaters and paints/coatings.

– Wikipedia


Main Air Pollutants In Indoor Air Pollution

Developing Countries

Small particulate matter in smoke is one of the main indoor air pollutants [Small particles of less than 10 microns in diameter (PM10), are among the most dangerous] (


Developed Countries

… Particulate matter, carbon monoxide and VOC’s (Wikipedia)


People Affected By Indoor Air Pollution

In 2018, around 3 billion people still cook using polluting open fires or simple stoves fuelled by these types of fuels (


Effects Of Indoor Air Pollution

The effects of indoor air pollution can include health diseases, as well as death.

Young children, and women, might be the ones mainly impacted.

In poorer regions of the world, it’s usually more severe.

Indoor air pollution in developed countries is less severe.


Indoor air pollution can lead to:

… acute lower respiratory disease, chronic obstructive pulmonary disease, cancers, and other illnesses.



In total, 2.6 million people died prematurely in 2016 from illness attributable to household air pollution

– OurWorldInData/Institute for Health Metrics and Evaluation (IHME)


… close to 4 million people die prematurely from illness attributable to household air pollution …

[Deaths are attributable to the following diseases in the following %’s:]

27% are due to pneumonia, 18% from stroke, 27% from ischaemic heart disease, 20% from chronic obstructive pulmonary disease (COPD), 8% from lung cancer.

– World Health Organization (WHO)


Close to half of deaths due to pneumonia among children under 5 years of age are caused by particulate matter (soot) inhaled from household air pollution



It is predominantly women and young children who are killed by indoor air pollution

– OurWorldInData


[Indoor air pollution in developed countries tends not to be anywhere near as severe, and the cumulative effect of indoor air pollution can be more of an issue than short term exposure]

People most at risk might be people who may be exposed to indoor air pollutants for the longest periods of time such as the young, the elderly and the chronically ill, especially those suffering from respiratory or cardiovascular disease [and conditions like asthma]



Indoor Air Pollution Trends

The trends worldwide are that deaths are decreasing in total over the last few decades.


The trends with indoor air pollution is:

Overall, ‘we see a decline in the number of pollution-related deaths since 1990, falling from 3.7 million to 2.6 million in 2016.’

– OurWorldInData


[India and China are two of the countries with the most death attributable to indoor air pollution and have] shown a significant decline in recent years. In the last decade alone the number of deaths from household air pollution in China has approximately halved.’ 

… This is however not true everywhere: the Democratic Republic of Congo appears to still be on the upward slope of this pattern.

– OurWorldInData


Countries & Regions Where Indoor Air Pollution Can Be An Issue

Indoor air pollution mortality rates impact certain regions and countries more than others.

Asia, Africa on a regional level, and on a country level, China and India have some of the highest %’s and totals.


Deaths from air pollution are ‘largely concentrated in Asia and Africa’

Approximately three-quarters of all deaths in 2016 were in Asia, with 22-23 percent in Africa & the Middle East …

At the country level – ‘India followed by China had the highest mortality figures in 2016 with 783,000 and 605,000 respectively.

– OurWorldInData

You can read more about indoor air pollution related death rates, overall trends, and how different countries are affected here (


Potential Solutions For Indoor Air Pollution/How To Prevent It

Three of the biggest solutions might be:

Developed Countries – be mindful of the contaminants being used in the house and outside. Be mindful of second hand sources like indoor smoking. Be mindful of the elderly and those who spend the most time inside

Developing Countries (& Low Income Countries) – introduce cleaner and more modern heating and cooking systems for households. Be mindful of women and children, and in rural and low income areas

Better ventilation can also help in most instances.


In developing countries and poorer countries … switch to modern energy sources which don’t release smoke and other harmful indoor air contaminants.

This involves switching to non solid fuels for heating and cooking such as natural gas, ethanol or electric technologies.

– OurWorldInData


An example of where and how this might be occurring is with the AKON Lighting Africa Project, which is replacing solid fuels with clean and affordable electricity in the form of solar panels/solar energy.

Improved design of stoves and ventilation systems can also reduce indoor air pollution in many poor communities, as well as raising more awareness about the issue to those most at risk



Read more about potential solutions to air pollution in this guide.




2. Max Roser and Hannah Ritchie (2018) – “Indoor Air Pollution”. Published online at Retrieved from: ‘’ [Online Resource]






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