Air Pollution's Global Impact: Who's Warning

Air pollution is a pressing global health and environmental issue. It is the second-leading risk factor for death, causing 8.1 million deaths globally in 2021, and is a major contributor to the global disease burden. According to the World Health Organization (WHO), 4.2 million deaths per year can be attributed to outdoor air pollution. Indoor and outdoor air pollution are caused by sources such as household combustion devices, motor vehicles, industrial facilities, and forest fires, and they result in strokes, heart diseases, lung cancer, and acute and chronic respiratory diseases. WHO data reveals that 99% of the global population breathes air that exceeds its guideline limits, with low- and middle-income countries suffering the highest exposures.

Air pollution is a global health and environmental issue

Air pollution is a pressing global health and environmental issue. It is a threat to both public health and economic progress, with far-reaching implications. According to the World Health Organization (WHO), almost everyone on the planet (99%) breathes air that exceeds the recommended guideline limits and contains high levels of pollutants. This has severe health impacts, with air pollution becoming the second-leading risk factor for death globally in 2021, causing approximately 8.1 million deaths.

The sources of air pollution are diverse and context-specific. Outdoor (ambient) air pollution in cities and rural areas is caused by residential energy use, vehicles, power generation, agriculture/waste incineration, and industry. Common sources of indoor (household) air pollution include cooking with polluting open fires or simple stoves fueled by kerosene, biomass, coal, or solid fuels. In recent years, air pollution has contributed to one in ten deaths worldwide, with low- and middle-income countries suffering the highest exposures and consequences.

The health impacts of air pollution are significant. Outdoor air pollution can lead to strokes, heart diseases, lung cancer, acute and chronic respiratory diseases, and pneumonia. Indoor air pollution is no less harmful, with about 2.4 billion people exposed to dangerous levels, contributing to various health issues. The combined effects of ambient and household air pollution are associated with millions of premature deaths annually. Fine particulate matter, such as PM2.5, is of particular concern as it can enter the lungs and bloodstream, increasing the risk of non-communicable diseases.

Despite efforts to reduce air pollution, certain regions, including Central and Southern Asia and Sub-Saharan Africa, continue to face increasing levels of pollution. The high concentrations in these areas are influenced by factors such as sand and desert dust, with the Sahara being one of the largest sources. While death rates from total air pollution have declined globally in recent decades, the improvement is primarily driven by advancements in addressing indoor air pollution. Outdoor air pollution improvements have been more modest.

Addressing air pollution requires interventions and initiatives that promote healthy sectoral policies. The WHO supports member states by providing technical assistance and guidance to mitigate the risks of exposure and improve air quality. Additionally, the development of tools and models helps policymakers assess the effects of interventions and predict the potential outcomes of proposed policies. While air pollution poses a significant challenge, there is a growing recognition of the issue, and collaborative global efforts are essential to drive sustainable solutions.

Outdoor and indoor air pollution cause diseases and deaths

Outdoor air pollution in both cities and rural areas is caused by residential energy use, vehicles, power generation, agriculture, waste incineration, and industry. It results in fine particulate matter, which can cause strokes, heart diseases, lung cancer, and acute and chronic respiratory diseases. According to WHO, outdoor air pollution was responsible for an estimated 4.2 million premature deaths worldwide per year in 2019. The Global Burden of Disease study (GBD) estimates that this figure was 4.5 million in 2019 and 3.3 million according to another study. The WHO further breaks down the causes of these premature deaths: 68% from ischaemic heart disease and stroke, 14% from chronic obstructive pulmonary disease, 14% from acute lower respiratory infections, and 4% from lung cancers.

Indoor air pollution, on the other hand, is caused by inefficient and polluting cooking methods, such as open fires or simple stoves fueled by kerosene, biomass (wood, animal dung, and crop waste), and coal. Around 2.1 billion people, or a third of the global population, cook using these methods, which generate harmful household air pollution. The combined effects of ambient and household air pollution are associated with an estimated 6.7 million premature deaths annually, according to the WHO. Another source estimates this figure to be 7 million. Among these deaths, 32% are from ischaemic heart disease, 23% from stroke, 21% from lower respiratory infection, 19% from chronic obstructive pulmonary disease, and 6% from lung cancer.

The WHO has recognized the urgency of this problem and supports countries in addressing the health impact of air pollution through evidence-based policies and interventions. These include initiatives for healthy sectoral policies, such as promoting cleaner transport, energy-efficient homes, and better waste management, as well as providing technical support and guidance to member states. Despite these efforts, air pollution remains a significant environmental and health issue worldwide, contributing to one in ten deaths globally.

WHO monitors air pollution and provides technical support

Air pollution is a major public health and environmental issue, causing an estimated 7 million premature deaths annually. It is caused by the contamination of the indoor or outdoor environment by chemical, physical, or biological agents that modify the natural characteristics of the atmosphere. Common sources of air pollution include household combustion devices, motor vehicles, industrial facilities, and forest fires. The pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide.

The World Health Organization (WHO) plays a crucial role in monitoring air pollution and providing technical support to address this global issue. WHO recognizes the significant health risks associated with air pollution and has developed various initiatives to mitigate its impacts. WHO monitors air pollution exposure levels and health impacts, including deaths and disability-adjusted life years (DALYs), at the national, regional, and global levels. This data is used for official reporting, such as world health statistics and the Sustainable Development Goals. WHO also provides technical support to its member states, offering guidance, tools, and authoritative advice on health issues related to air pollution and its sources.

WHO has developed the Household Multiple Emission Sources (HOMES) model to assist policymakers in understanding household air pollution levels and making informed decisions. Additionally, the Air Quality, Energy, and Health Science and Policy Summaries (SPS) provide concise overviews of current knowledge and evidence on topics related to air quality, energy, and health. WHO also promotes interventions and initiatives for healthy sectoral policies, addressing key risks from indoor and outdoor air pollution, and contributing to the co-benefits of climate change mitigation policies.

Furthermore, WHO emphasizes the importance of air quality monitoring as the foundation for tackling air pollution. The organization has published reports comparing different measurement and modelling methods, including emerging techniques like machine learning and geostatistical data fusion. These reports help policy-makers and government officials assess their country's baseline air quality levels and develop effective plans for air quality monitoring and data management. WHO encourages countries to employ a mixture of approaches to address their unique air quality problems, considering their national priorities, resources, and local conditions.

By leveraging its technical expertise, WHO actively monitors and tracks progress on health indicators related to Sustainable Development Goals 3 (good health and well-being), 7 (affordable and clean energy), and 11 (sustainable cities and communities). WHO's efforts in monitoring air pollution, providing technical support, and promoting sustainable initiatives are crucial steps towards protecting public health and mitigating the adverse effects of air pollution on a global scale.

Air pollution levels are impacted by income levels

Air pollution is one of the world's most pressing health and environmental issues, with 99% of the global population exposed to air pollution levels that put them at risk of severe health issues. According to the World Health Organization (WHO), low- and middle-income countries suffer the highest exposures, and income levels play a significant role in determining air pollution levels and their impacts.

Income levels influence air pollution through various factors. Firstly, in low-income countries, indoor pollution rates tend to be high due to a reliance on solid fuels, such as wood, animal dung, and coal, for cooking and heating. These traditional fuels, along with inefficient cooking stoves, contribute to poor indoor air quality. Additionally, energy poverty, characterized by a lack of access to clean and reliable energy sources, disproportionately affects low-income households. This results in the use of polluting open fires or simple stoves, leading to increased exposure to harmful pollutants.

Furthermore, as countries industrialize and transition from low to middle incomes, outdoor air pollution tends to increase. Industrialization often involves the burning of fossil fuels, such as coal, oil, and gas, which release pollutants into the atmosphere. Motor vehicles, power generation, agriculture, waste incineration, and industrial facilities are significant sources of outdoor air pollution. Lower-income households may also reside in areas with higher traffic exposure, proximity to industrial sites, or inadequate waste management, exacerbating their exposure to outdoor air pollution.

The health impacts of air pollution are also influenced by income levels. People in low- and middle-income countries are typically more vulnerable to the health risks associated with air pollution due to higher exposure levels and the prevalence of diseases sensitive to air pollution, such as asthma. Additionally, within low- and middle-income countries, specific populations bear a disproportionate burden. These include people living in slums or near busy highways, lacking access to clean cooking fuels, or engaged in certain occupations.

Moreover, income-related disparities exist within countries as well. In the United States, for example, low-income communities, people of color, and certain ethnic groups are more likely to live in areas with higher air pollution levels. Studies have found that non-Hispanic blacks, Hispanics, and Asians have a higher risk of premature death from particle pollution compared to whites. These disparities are attributed to factors such as discriminatory practices, lack of access to healthcare, and poorer job opportunities, which contribute to increased exposure to air pollution for these vulnerable groups.

Air pollution is caused by various sources

Air pollution is a pressing health and environmental issue worldwide, with almost the entire global population (99%) breathing air that exceeds the WHO's guideline limits for pollutants. It is the leading cause of death, contributing to about one in ten deaths worldwide.

Outdoor air pollution, on the other hand, is caused by a range of sources, including residential energy use, vehicles, power generation, agriculture, waste incineration, and industry. Mobile sources, such as cars, buses, planes, trucks, and trains, are a significant contributor to outdoor air pollution, especially in developed nations. Stationary sources, like power plants, oil refineries, and industrial facilities, emit large amounts of pollution from a single location. Area sources, such as agricultural areas, cities, and wood-burning fireplaces, also contribute to air pollution when considered collectively. Natural sources, including wind-blown dust, wildfires, and volcanoes, play a role as well.

The major outdoor pollution sources and their impacts vary based on the context and level of development of a country or region. For example, as countries industrialize and transition from low to middle incomes, outdoor air pollution tends to increase. The combustion of fossil fuels is a common denominator in both indoor and outdoor air pollution, contributing to the release of greenhouse gases and climate change.

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