Hearths and Health
Evidence of the Global Impact of Household Air Pollution on Health
Introduction
Exposure to household air pollution (HAP) from cooking with solid fuels and kerosene over open fires and inefficient stoves contributes up to 4 million deaths per year. The detrimental impacts of household air pollution go beyond the home – toxic pollutants and climate warming gases escape from the home and contribute to poor outdoor air quality and climate change. Increasing access to clean cooking solutions is critical to improving the health of both people and the planet.
This story map highlights the latest key data related to the impact of household air pollution on human health.
Putting HAP into Context
PM2.5 is a pollutant that scientists commonly measure while examining the health impacts of HAP.
Continue scrolling to learn more about PM2.5 and its role in HAP.
PM2.5 consists of particulate matter 2.5 microns (µm) or less in diameter. For reference, a human hair is between 50-70 µm in diameter.
Due to its microscopic size, PM2.5 can be easily inhaled, bypass our body’s natural defenses, penetrate deep into the lungs, and even enter the bloodstream.
PM2.5 concentration is measured in micrograms per cubic meter of air (µg/m³).
To contextualize PM2.5 levels, let's look at wildfires and the World Health Organization (WHO)'s Air Quality Guidelines.
WHO recommends annual mean PM2.5 concentrations less than 35 µg/m³ to help protect human health, and less than 5 µg/m³ to maximize health benefits.
In 2020, California experienced a devastating record-setting year of wildfires, wreaking havoc and destroying 4 million acres. During the height of the fire season in September 2020, PM2.5 levels averaged at 120 µg/m³ in Yosemite National Park, which is well above the WHO recommendations.
Kitchen PM2.5 concentrations above 750 ug/m³ per day are not uncommon in solid fuel using households, well over the average level recorded during the height of the California wildfire season in Yosemite National Park and the WHO guidelines.
Exposure to PM2.5 leads to numerous negative health outcomes.
Click through the interactive image to learn how HAP exposure impacts various aspects of human health.
HAP and Global Air Quality
HAP is not only confined to the home -- it is also a major source of ambient air pollution (outdoor air pollution) worldwide, which contributes to poor air quality in both urban and rural areas that can be dangerously high.
The following map shows what percentage of ambient air pollution (measured as PM2.5) comes from the burning of residential biomass in each country.
Continue scrolling to learn about how residential biomass combustion contributes to ambient air pollution, in terms of PM2.5, across the globe.
Globally, the residential burning of biomass accounted for over 15% of ambient PM2.5 in 2019.
In many countries, such as Nepal, this percentage exceeds 30%.
As such, all sources of air pollution, including household air pollution, must be addressed to improve air quality and ensure that everyone can breathe clean air.
Hover over the map, or click on specific countries, to see the residential biofuel combustion contribution (%) to ambient PM2.5, population weighted annual average PM2.5, and PM2.5 from residential biofuel combustion in each country.
HAP-Related Deaths
The burden of household air pollution is not borne equally across the world. Low- and middle-income countries are especially vulnerable.
The following map shows the death rate attributable to HAP, which is # of deaths per 100,000 people.
Continue scrolling to learn about how the health burden of HAP is distributed globally.
Exposure to household air pollution from the burning of solid fuels and kerosene contributes up to 4 million deaths annually. The healthcare costs associated with household reliance on polluting cooking technologies amounts to USD 1.4 trillion per year.
Over 60% of these deaths occurred in just two regions: sub-Saharan Africa and South Asia. This is partially because the proportion of the population cooking with solid fuels is higher in South Asia (60%) and sub-Saharan Africa (85%) compared to other regions of the world.
Reducing household air pollution exposure by increasing access to clean cooking solutions can help unlock health benefits for vulnerable and marginalized communities, and ensure an inclusive energy transition.
Interact with or hover over the map to see the number of Household Air Pollution Deaths and the resulting Death Rate (2016) per country.
HAP-Related Deaths By Cause
Long-term exposure to household air pollution is associated with an increased risk for lung cancer, chronic obstructive pulmonary disease, lower-respiratory infections (e.g. pneumonia), ischemic heart disease, stroke, type 2 diabetes, and adverse birth outcomes.
In addition, research is emerging that suggests household air pollution increases the risk for poor cognitive outcomes, such as increased risk for developing dementia. Universal access to clean cooking solutions is needed to saves lives from these smoke-related illnesses.
The following chart shows the breakdown of household air pollution related deaths by specific cause. Interact with the chart to see the number of deaths by cause and percentage of deaths by cause.
Vulnerable Populations
Household air pollution has uniquely devastating impacts on newborns and children under 5 . In 2019, lower respiratory infections, like pneumonia, caused over 650,000 deaths in children under five. HAP from solid fuel use for cooking is tied to over one third of these deaths.
The Clean Cooking Alliance (CCA) and others have also found that air pollution is linked with increased risk of low birth weight and preterm births. For example, a CCA-funded research study showed that babies born to mothers who cooked with ethanol were born approximately one week later and 88 grams heavier than babies born to mothers cooking with polluting fuels.
While 88 grams weighs less than a deck of cards and may seem trivial, babies born even marginally smaller have worse development outcomes. If babies who are born too small or too early survive infancy, they are still at higher risk for infectious diseases and major chronic illnesses throughout life, greatly reducing their quality of life.
The following chart shows what number and percentage of total child deaths (under 5 years old) are caused by HAP-related lower respiratory infections. Interact with the chart to see the number and percentage of child deaths caused by HAP-related lower respiratory infections.
Policy Actions
A growing number of countries have cooking-related policies in place, which can play a key role in reducing exposure to household air pollution and unlocking health benefits. However, more countries need to integrate clean cooking into national energy policies and strategies to tackle this major source of air pollution and health burden.
Interact with or hover over the following map to see which countries have cooking-related policies in place, and of those policies, if any mention health impacts.
Number of Policies Related to Cooking in Each Country
Clean Cooking Saves Lives
In order to improve air quality and save lives from smoke-related illnesses, we need to accelerate access to clean cooking.
Over the last decade, steady progress has been made in scaling clean cooking access: since 2010, over 400 million people have gained access to clean cooking fuels and technologies and are, in theory, exposed to less air pollution. In a recent Nature article , it was shown that 53% of the global population relied on mainly polluting cooking fuels in 1990, which decreased to 36% in 2020, and is projected to further decrease to 31% in 2030.
However, we need to greatly increase this momentum to achieve universal access by 2030. Public and private investment levels need to be ramped up to achieve clean cooking for all - an estimated USD 4.5 billion per year is needed to reach universal access. Current investments fall far below this - estimated at only USD 131 million in 2018.
By reducing exposure to dangerous pollutants, clean cooking can play a critical role in drastically lowering the global health burden of air pollution. Interact with the following figure to see how the population relying on polluting fuels and technologies has decreased over time, but simultaneously demonstrates the 2.6 billion people waiting for access.
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