Air Pollution's Deadly Toll: Counting Fatalities

Air pollution is a leading risk factor for death, contributing to an estimated 8.1 million deaths globally in 2021. It is a significant health and environmental issue, impacting people's lives and quality of life worldwide. While indoor air pollution has seen impressive improvements in recent decades, outdoor pollution remains a pressing concern. The burning of fossil fuels, residential energy use, and industrial activities contribute to ambient air pollution, which was responsible for an estimated 4.5 million deaths in 2019. Household air pollution, caused by the use of polluting fuels and technologies, leads to approximately 3.2 million deaths annually. These numbers highlight the urgency of addressing air pollution to protect public health and the environment.

Air pollution causes 8.1 million deaths per year globally

Air pollution is a leading risk factor for death, contributing to about 8.1 million deaths globally in 2021. This figure represents a decline from previous years, with death rates from total air pollution nearly halving since 1990. However, this decrease is primarily driven by improvements in addressing indoor air pollution, while advancements in outdoor pollution have been more modest.

Indoor air pollution, caused by energy poverty, significantly contributes to outdoor air pollution. This means populations suffering from high indoor air pollution are also exposed to high levels of outdoor air pollution. Indoor air pollution was responsible for an estimated 3.2 million deaths per year in 2020, including over 237,000 children under five years old. The main sources of indoor air pollution are the use of polluting open fires or simple stoves for cooking, fuelled by kerosene, biomass, wood, animal dung, crop waste, and coal. These sources of energy contain harmful pollutants, including particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide.

Outdoor air pollution, or ambient air pollution, in both cities and rural areas, is another critical factor. It is caused by residential energy use, vehicles, power generation, agriculture, waste incineration, and industry. In 2019, ambient air pollution was responsible for 4.5 million deaths, an increase from 4.2 million in 2015 and 2.9 million in 2000. The rise in deaths is attributed to increased ambient air pollution and the growing incidence of non-communicable diseases linked to air pollution.

Overall, the combined effects of ambient and household air pollution are associated with approximately 6.7 million premature deaths annually. Women and children, typically responsible for household chores, bear the brunt of the health impact from polluting fuels and technologies. Air pollution's impact extends beyond mortality, as it is also a significant contributor to the global disease burden, affecting the quality of life for millions of people.

Ambient air pollution caused 4.5 million deaths in 2019

Air pollution is a leading environmental risk factor for death and disease globally. It is responsible for approximately 9 million deaths per year, corresponding to one in six deaths worldwide. While the number of deaths from household air pollution and water pollution has decreased, the number of deaths from ambient air pollution has increased by 7% since 2015 and by over 66% since 2000.

In 2019, ambient air pollution was responsible for 4.5 million deaths worldwide. This is an increase from 2015, when ambient air pollution caused 4.2 million deaths, and from 2000, when it caused 2.9 million deaths. The increase in deaths is due to rising ambient air pollution, the incidence of non-communicable diseases (NCDs) linked to air pollution, ageing populations, and increased numbers of people exposed to pollution.

Ambient air pollution is caused by fine particulate matter, which leads to cardiovascular and respiratory disease, and cancers. In 2019, the World Health Organization (WHO) estimated that 68% of outdoor air pollution-related premature deaths were due to ischaemic heart disease and stroke, 14% were due to chronic obstructive pulmonary disease, 14% were due to acute lower respiratory infections, and 4% were due to lung cancers. Women and children in low- and middle-income countries are disproportionately affected by ambient air pollution, as they are typically responsible for household chores such as cooking and collecting firewood, which exposes them to harmful smoke from polluting stoves and fuels.

To reduce air pollution levels and protect populations from health risks, the WHO's Air Quality and Health Unit works in three cross-cutting areas: knowledge, evidence, and measuring progress; institutional capacity building and technical support; and leadership and coordination. Additionally, policies and investments supporting cleaner transport, energy-efficient homes, power generation, industry, and better municipal waste management would help reduce key sources of outdoor air pollution. Access to clean household energy would also significantly reduce ambient air pollution in some regions.

Household air pollution caused 3.2 million deaths per year in 2020

Air pollution is one of the leading risk factors for death and is responsible for about 9 million deaths per year, corresponding to one in six deaths worldwide. It is a combination of outdoor and indoor particulate matter and ozone and is a risk factor for many of the leading causes of death, including heart disease, stroke, lower respiratory infections, lung cancer, diabetes, and chronic obstructive pulmonary disease (COPD).

In 2020, household air pollution was responsible for an estimated 3.2 million deaths per year, including over 237,000 deaths of children under the age of five. This number has declined since 1990, when death rates from indoor air pollution were nearly double what they are now. Household air pollution is caused by the incomplete combustion of solid fuels and kerosene used for cooking, lighting, and heating. Women and children, who are typically responsible for household chores such as cooking and collecting firewood, bear the greatest health burden from the use of polluting fuels and technologies in homes. They are also at risk of injury and violence while gathering fuel.

The ingestion of kerosene by accident is the leading cause of childhood poisonings, and a large fraction of the severe burns and injuries occurring in low- and middle-income countries are linked to household energy use. Particulate matter and other pollutants in household air pollution inflame the airways and lungs, impair immune response, and reduce the oxygen-carrying capacity of the blood. Among these 3.2 million deaths from household air pollution exposure, 32% are from ischaemic heart disease, 23% are from stroke, and 21% are due to lower respiratory infection.

To address the negative impact of household air pollution on health, the World Health Organization (WHO) develops guidelines for indoor air quality and household fuel combustion, provides recommendations on the types of fuels and technologies that protect health, and offers strategies for the dissemination and adoption of cleaner household fuels and technologies. It is essential to expand the use of clean fuels and technologies to reduce household air pollution and protect health.

Outdoor air pollution leads to 3.3 million deaths per year

Outdoor air pollution is a pressing issue that significantly impacts global health and the environment. According to the World Health Organization (WHO), outdoor air pollution, caused primarily by residential energy use for heating and cooking, vehicles, power generation, agriculture, waste incineration, and industry, leads to approximately 3.3 million deaths per year. This figure represents a 95% confidence interval ranging from 1.6 million to 4.8 million deaths, with most deaths attributed to particulate matter.

The health consequences of outdoor air pollution are far-reaching. Particulate matter, such as PM2.5, and ground-level ozone contribute to respiratory and cardiovascular issues, including strokes, heart diseases, and acute and chronic respiratory diseases. The impact of outdoor air pollution is particularly pronounced in low- and middle-income countries, where populations often face high levels of both indoor and outdoor air pollution due to energy poverty.

The effects of outdoor air pollution extend beyond physical health. It is a significant contributor to the global disease burden, encompassing not only early deaths but also years lived with poor health. Air pollution diminishes the quality of life for those affected, imposing a substantial burden on healthcare systems, economies, and societies. Furthermore, certain demographics, such as women and children, bear a disproportionate burden due to their involvement in household chores and proximity to polluting activities.

Addressing outdoor air pollution is crucial for mitigating climate change and improving public health. Implementing policies and investments that promote sustainable land use, cleaner household energy, efficient transportation, energy-efficient housing, and better waste management can effectively reduce air pollution levels and their detrimental consequences. Additionally, transitioning to clean sources of energy, such as solar, electricity, and natural gas, can significantly reduce premature mortality associated with outdoor air pollution.

While there have been some improvements in outdoor air quality, particularly in high-income countries, the overall impact of outdoor air pollution remains significant. It is imperative that governments, businesses, and organizations take decisive actions to reduce air pollution, protect vulnerable populations, and safeguard the health and well-being of current and future generations.

Indoor air pollution is a large contributor to outdoor air pollution

Air pollution is responsible for approximately 9 million deaths per year, or one in six deaths worldwide. It is the leading cause of early death and poor health across the globe, with over 90% of pollution-related deaths occurring in low- and middle-income countries. While outdoor air pollution from sources like factories, vehicles, and agricultural activities is a significant contributor, indoor air pollution also plays a large role in this alarming statistic.

Indoor air pollution is caused by various factors, including the use of solid fuels and kerosene for cooking and heating, building materials, and inadequate ventilation systems. Incomplete combustion of solid fuels and kerosene releases particulate matter and pollutants that irritate and damage the airways and lungs, impair immune responses, and reduce the blood's oxygen-carrying capacity. Women and children, who are typically responsible for household chores like cooking and collecting firewood, bear the brunt of the health consequences from indoor air pollution.

Indoor air pollution contributes to outdoor air pollution through the release of toxic gases and particles. For example, mechanical ventilation systems in large buildings are designed to heat and cool the air, as well as circulate outdoor air. However, if these systems are poorly designed or maintained, they can draw in contaminated air from sources like automobile exhaust, boiler emissions, and fumes from dumpsters. Additionally, buildings with specialized purposes, such as restaurants and dry cleaning stores, can release pollutants that circulate into other areas of the same building.

Furthermore, indoor air pollution can lead to an increased risk of developing respiratory infections and lung diseases. High concentrations or prolonged exposure to nitrogen dioxide, a common indoor air pollutant, can contribute to respiratory issues and lung diseases like emphysema. Particles released during the incomplete combustion of fuels can lodge in the lungs, causing irritation or damage. These indoor pollutants can then be released into the outdoor environment, contributing to overall air pollution levels.

The impact of indoor air pollution on outdoor air quality is evident, and addressing this issue is crucial for improving public health and reducing the number of pollution-related deaths. While global death rates from total air pollution have declined in recent decades, the improvement has been driven primarily by advancements in indoor air pollution control. Therefore, continued efforts to enhance indoor air quality, such as expanding the use of clean fuels and technologies, are essential to mitigate the health risks associated with both indoor and outdoor air pollution.

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