What are the major sources of outdoor air pollution?

Air pollution has many sources. On a global basis, major sources include residential, commercial, and industrial combustion of coal and other fossil fuels for heating and power generation, agricultural practices, residential burning of biomass (wood, dung, and peat) for heating and cooking, and traffic, among others. 

However, the contributions that these sources make to human exposure and health burden vary by region, country, and among — and even within — cities. Taking action to reduce the burden of disease from air pollution therefore begins with identifying the high-priority sources.

The Health Effects Institute has now conducted two studies to identify the major sources of air pollution in China and in India. The air pollution–related health burden in these two countries accounts for about 50% of the air pollution health burden worldwide.

Major sources of outdoor air pollution and health burden in China

The study in China found that coal-burning — by industry, by power plants, and for residential (home) heating — was the most important contributor to outdoor air pollution. Coal-burning from these three sectors combined accounted for 40% of population-weighted outdoor PM2.5 concentrations and an estimated 366,200 deaths in 2013, the baseline year for this study (see figure).

For more information see HEI Special Report 20Burden of Disease Attributable to Coal-Burning and Other Air Pollution Sources in China

Source contributions to deaths attributable to ambient PM2.5 in China in 2013.

[Figure L, © HEI]


Major sources of outdoor air pollution and health burden in India

In India, the largest source of fine particle air pollution and health burden was burning of biomass for residential (home) cooking and heating (see figure). It contributed to 267,700 deaths, or nearly 25% of all deaths attributable to PM2.5. For those cooking and heating with biomass of various forms, direct exposure to household air pollution adds a considerable additional health burden.

Coal combustion for energy generation by power plants and by industry was the next biggest source of outdoor air pollution in India. 

For more information, see HEI Special Report 21Burden of Disease Attributable to Major Air Pollution Sources in India.

Source contributions to deaths attributable to ambient PM2.5 in India in 2015.

[Figure M, © HEI]