Air Pollution Data: Who's Watching?

Air pollution is a pressing global issue that poses a significant threat to human health and the environment. It is caused by a combination of outdoor and indoor particulate matter and ozone, with natural and man-made sources contributing to the problem. WHO collects and monitors air pollution data, tracking exposure levels and health impacts at the national, regional, and global levels. This data is crucial for understanding the risks and impacts of air pollution, which include an increased risk of heart disease, stroke, respiratory infections, lung cancer, and other serious illnesses. With almost the entire global population exposed to dangerous levels of air pollution, addressing this issue is essential for protecting public health and reducing the global disease burden.

Indoor air pollution

The World Health Organization (WHO) defines indoor air pollution as the incomplete combustion of solid fuels and kerosene used for cooking. This is caused by the widespread use of polluting fuels and stoves for cooking, which results in the release of a range of health-damaging pollutants, including small particles that penetrate deep into the lungs and enter the bloodstream.

WHO has issued guidelines for indoor air quality, offering practical evidence-based guidance on clean fuels and technologies for household fuel combustion. These guidelines include recommendations on the types of fuels and technologies that can be considered clean, such as solar, electricity, biogas, liquefied petroleum gas (LPG), natural gas, alcohol fuels, and biomass stoves that meet emission targets.

WHO monitors exposure to indoor air pollution and its health impacts at the national, regional, and global levels. The organization has developed tools and resources to support countries in developing clean household energy policies and programs. For example, the Air Pollution Data Portal includes Burden of Disease statistics, air quality databases, and modelled exposure estimates for both ambient and household air pollution.

To address indoor air pollution, interventions focus on transitioning from traditional cooking and heating methods to modern, cleaner alternatives. This includes promoting access to clean fuels and technologies, such as non-solid fuels like natural gas and electric cooking technologies. Additionally, initiatives aim to raise awareness about the risks of indoor air pollution and provide solutions to mitigate exposure.

Outdoor air pollution

The WHO has developed the Global Air Quality Guidelines (AQG) to provide global guidance on thresholds and limits for key air pollutants that pose health risks. These guidelines are developed through a transparent, evidence-based decision-making process and offer qualitative statements on the management of certain types of particulate matter. Additionally, the guidelines provide interim targets to promote a gradual shift towards lower pollutant concentrations, highlighting the associated health benefits. For example, achieving interim target one (35 µg/m3) is estimated to save around 300,000 lives worldwide each year.

The WHO also maintains an air quality database, which was last updated in April 2022. This database compiles data on ground measurements of annual mean concentrations of nitrogen dioxide (NO2) and particulate matter of varying diameters (PM10 and PM2.5). The data is collected from over 600 human settlements in more than 100 countries and is used to derive the Sustainable Development Goal Indicator 11.6.2, with WHO serving as the custodial agency. While efforts are made to ensure comprehensive monitoring, some geographical areas have little to no monitoring capabilities, highlighting the need for additional data to produce high-resolution global estimates.

Addressing outdoor air pollution is crucial for protecting public health, particularly in low- and middle-income countries, where the burden of air pollution is disproportionately higher. Implementing policies and investments that support cleaner transport, energy-efficient homes, improved power generation and industrial practices, and better municipal waste management can significantly reduce key sources of outdoor air pollution. Additionally, improving access to clean household energy can also contribute to reducing ambient air pollution in certain regions.

Energy consumption

The World Health Organization (WHO) monitors air pollution exposure levels and their health impacts, such as deaths and DALYs, at the national, regional, and global levels. WHO's data includes both ambient (outdoor) and household air pollution. The data is used for official reporting, such as world health statistics and Sustainable Development Goals.

WHO's Household Energy Database monitors household energy use and contains nationally representative data from surveys and censuses on cooking, heating, and lighting fuels. The database is used to calculate estimates at the national, rural, and urban levels for the share of the population using clean fuels and technologies. This information is reported for Sustainable Development Goal Indicator 7.1.2.

Additionally, the database is used to estimate the percentage of the population using polluting fuels and stoves, such as those that burn wood, charcoal, animal dung, coal, and kerosene. These estimates serve as a proxy for exposure to household air pollution and form the basis for further assessing the burden of diseases attributable to it.

Furthermore, introducing or strengthening mandatory vehicle efficiency standards is an effective way to reduce pollution within cities. The US Clean Air Act of 1970 is an excellent example of how stringent vehicle emission standards can deliver long-term reductions in air pollution.

Health impacts

Air pollution is a major environmental health problem, posing a threat to almost the entire global population (99% of people). This includes indoor and outdoor pollution, with sources ranging from household combustion devices to motor vehicles, industrial facilities, and forest fires. The pollutants of major concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide. These pollutants have severe health impacts, causing about 4.2 million premature deaths worldwide each year. The World Health Organization (WHO) estimates that in 2019, 68% of these premature deaths were due to ischemic heart disease and stroke, 14% to chronic obstructive pulmonary disease, 14% to acute lower respiratory infections, and 4% to lung cancers.

The health impacts of air pollution are not limited to mortality but also include respiratory and other diseases, with vulnerable groups such as seniors, children, and people with pre-existing heart and lung conditions being at higher risk. Low-income communities are particularly vulnerable, with higher rates of uninsured residents and a greater reliance on solid fuels for cooking, leading to increased indoor pollution.

Recognizing the urgency of addressing air pollution, WHO Member States approved resolution A68.8, "Health and the Environment: addressing the health impact of air pollution," at the World Health Assembly in 2015. WHO supports countries in tackling air pollution through evidence-based policies, institutional capacity building, and coordination.

To quantify the health effects of exposure to air pollution, tools like AirQ+ are used to calculate the reduction in life expectancy and other health impacts. Additionally, models such as WHO's Household Multiple Emission Sources (HOMES) help policymakers understand household air pollution levels and make informed decisions.

The health impacts of air pollution are not limited to a specific region or country but are seen worldwide. Data from 43 European countries between 1990 and 2019 showed that air pollution was the fourth greatest overall risk factor for health, contributing to mortality, disability-adjusted life years (DALYs), and years of life lost (YLL). Similarly, in Minnesota, it was estimated that reducing fine particle pollution levels by 10% could prevent up to 500 deaths, 50 hospitalizations, and 60 emergency room visits, highlighting the significant public health impact of air pollution reduction strategies.

Disease burden

Air pollution is a major concern and has serious toxicological effects on human health. According to the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year. WHO data also shows that 99% of the global population breathes air that exceeds WHO guideline limits and contains high levels of pollutants, with low- and middle-income countries suffering the highest exposures.

The disease burden attributed to air pollution is expressed in terms of deaths and disability-adjusted life years (DALYs). DALYs refer to the number of years lost due to ill health, disability, or early death. The calculation of DALYs helps to quantify the health burden due to air pollution and guide decision-making to improve air quality and promote health.

Several diseases have been linked to air pollution exposure, with the strongest evidence for the following:

• Lower respiratory infections
• Trachea, bronchus, and lung cancer
• Chronic obstructive pulmonary disease (COPD)
• Ischemic heart disease
• Stroke

The burden of these diseases due to air pollution varies by region. For example, the Western Pacific and South-East Asia regions have had the highest rates of COPD deaths attributable to air pollution. Additionally, low- and middle-income countries bear a significant burden of household air pollution due to the burning of solid fuels, which contributes to ambient air pollution as well.

To reduce the disease burden attributed to air pollution, aggressive air quality management programs are necessary. These programs should focus on major sources of air pollution, such as coal combustion, household burning of solid fuels, vehicle emissions, power generation, agriculture, and industry. By addressing these sources, countries can lower the disease burden and improve the health and life expectancy of their populations.

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