Indoor air pollution is by far the biggest environmental problem of the world. Every year, 4.3 million people die due to the exposure to household air pollution caused by indoor open fire. To bring this in perspective: This is 45-times the number of the global annual deaths from natural catastrophes (±95,000 in the 2010s). And more than twice the number of people dying because of AIDS (1.5 million in 2013). It might be the most unreported of the world’s big problems.
It is predominantly women and young children who are killed by indoor air pollution.
The World Health Organization estimates that “4.3 million people a year die prematurely from illness attributable to the household air pollution caused by the inefficient use of solid fuels (2012 data).”1
According to the WHO these deaths are attributable to the following diseases:
- 12% are due to pneumonia
- 34% from stroke
- 26% from ischaemic heart disease
- 22% from chronic obstructive pulmonary disease (COPD), and
- 6% from lung cancer.
# Empirical View
The burning of solid fuels fills the houses and huts in poorer countries with smoke that kills the world’s poor by causing pneumonia, stroke, heart disease, chronic obstructive pulmonary disease, and lung cancer. The solid fuels responsible for this include wood, crop residues, dung, charcoal, and coal. The solution for this problem is straightforward: shift from solid fuels to modern energy sources.
And the following chart shows that the world is making progress in this direction. In 1980 almost two thirds of the world’s population used solid fuels for their cooking. 30 years later this is down to 41%. The chart also shows that it is a problem associated with poverty: In richer Europe and North America the share is much lower than in the rest of the world; and in the high income countries of the world the use of solid fuels is entirely a thing of the past.
The use of solid fuels is going down in all of the world’s regions. But the success rapidly developing South East Asia is particularly impressive: Here the share fell from 95% to 61%.
Regional trends for the percentage of population using solid fuels as the main cooking fuel, 1980-20102Full screen view Download Data
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World map of the indoor air pollution indicator from the environmental performance index (EPI), 2006 – SEDAC (NASA)3
Share of population without access to modern fuels in developing countries, 2007 – UNDP & WHO (2009)4
# Type of Fuel used in Households
Share of population relying on different types of solid fuels for cooking by developing regions, 2007 – UNDP & WHO (2009)5
# Difference within Countries – By Income and by Location
Percentage of population using solid fuels in some of the world’s largest countries by income quintiles in urban (top) and rural (bottom) locations, 2003 – WHO (2006)6
Share of population with access to modern fuels in rural and urban areas of developing countries (DCs), least developing countries (LDCs) and Sub-Saharan Africa (SSA), 2007 – UNDP & WHO (2009)7
# Correlates, Determinants & Consequences
# Effects on Health
The effects of indoor air pollution are wide and impact our health in a variety of ways, leading to both morbidity and mortality.
Health impacts of indoor air pollution – WHO (2006)8
# The death rate from indoor air pollution over time
In the chart below we see that, at the global level, the death rate (per 100,000 people) from diseases related to indoor air pollution has declined significantly since 1990. There are large differences in the risk of indoor air pollution globally: in high-income nations, the likelihood is typically zero; in low- to middle-income nations, it can be the dominant form of air-pollution related deaths. This risk is, however, continuing to fall at the global level and in most low- to middle-income economies.
This disparity in death rates from indoor air pollution based on economic development is also reflected in the absolute number of related deaths. These are primarily concentrated in low- to middle-income countries as the following chart shows:
Number of deaths attributable to indoor air pollution from solid fuel use by diseases, 2004 – UNDP & WHO (2009)9
Number of DALYs attributable to indoor air pollution from solid fuel use by disease, 2004 – UNDP & WHO (2009)10
# World map of the number of deaths per 1000 capita per year attributable to indoor air pollution from solid fuel use, 2004 – UNDP & WHO (2009)11
# Share by gender of COPD and lung cancer deaths attributable to solid fuel use in adults older than 30 years – UNDP & WHO (2009)12
# Other Consequences of Indoor Air Pollution and the Use of Solid Cooking Fuels
Daily hours that women spend collecting fuel in different African geographical settings by country, 1990-2003 – WHO (2006)13
# Development Correlates of Cleaner Indoor Air
# The energy ladder – the link between household energy and development – WHO (2006)14
Percentage of population using solid fuels as main cooking fuel versus gross domestic product (GDP) per capita, 2010 – Bonjour et al. (2013)15
# Data Quality & Definition
The US Environmental Protection Agency publishes a glossary related to indoor air here.
# Data Sources
The WHO publishes data related to household air pollution with respect to exposure and the burden of disease here. Information on the issue is published by the WHO here.
The US Environmental Protection Agency publishes information on indoor air quality here.
The IHME, GBD project publishes global data on exposure and death rates related to air pollution here.
The FAO database on Forestry is online here. It includes data on wood fuel for countries and world regions since 1961.
Research on the issue can be found at the academic research journal ‘Indoor Air‘ published by Wiley.