Air Pollution: Who Suffers The Most?

Air pollution is one of the most pressing health issues of our time, contributing to over 10% of all deaths worldwide. According to the World Health Organization (WHO), only seven countries met safe air pollution levels in 2023. This article will explore the countries with the highest levels of air pollution, the causes, and the efforts being made to improve air quality. From industrial growth and traffic congestion to transboundary haze, the factors contributing to poor air quality are complex and varied, and they demand urgent attention and action.

Air pollution's impact on health

Air pollution is a familiar environmental health hazard. It is the presence of one or more contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke or vapour, in quantities and durations that can be harmful to human health. According to The Lancet, air pollution is responsible for more than 10% of all deaths worldwide (nearly 4.5 million premature deaths in 2019), making it one of the biggest health problems of modern industrial society.

The main pathway of exposure from air pollution is through the respiratory tract. Fine particulate matter is an especially important source of health risks as these very small particles can penetrate deep into the lungs, enter the bloodstream, and travel to organs, causing systemic damage to tissues and cells. This can lead to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout the body, impacting the lungs, heart, and brain, among other organs, and ultimately leading to disease. Short-term exposure to higher levels of outdoor air pollution is associated with reduced lung function, asthma, cardiac problems, emergency department visits, and hospital admissions.

The World Health Organization (WHO) has classified air pollution as a human carcinogen, and it has been linked to an increased risk of various cancers, including lung cancer, colorectal cancer, and prostate cancer. Long-term exposure to fine particulate matter increases a person's risk for diseases with a longer onset, such as non-communicable diseases like stroke, heart disease, chronic obstructive pulmonary disease, and cancer. Maternal exposure to air pollution is also associated with adverse birth outcomes, such as low birth weight, pre-term birth, and small gestational age births.

In addition to the physical health impacts, air pollution can also have psychosocial effects. There is increasing evidence that non-physical stressors such as poverty, racial or ethnic discrimination, and residency status can amplify the harmful effects of air pollution. Furthermore, air pollution disproportionately impacts communities of colour, with decision-makers often placing sources of pollution, such as power plants, industrial facilities, and highways, in economically disadvantaged communities of colour. This has contributed to high rates of emergency department visits for asthma and other diseases in these communities.

Air pollution's effect on the environment

Air pollution is a pressing issue that significantly impacts the environment, causing a range of harmful effects. It is primarily caused by human activities, particularly the burning of fossil fuels, including coal, natural gas, and oil. This has been a growing concern since the Industrial Revolution, which led to a sharp increase in air pollution due to the extensive use of coal for industrial and domestic purposes.

One of the most concerning consequences of air pollution is its contribution to climate change. Greenhouse gas pollution, which includes carbon dioxide emissions, traps heat energy in the Earth's atmosphere, resulting in the "greenhouse effect." This phenomenon is essential for maintaining the planet's warmth and supporting life. However, human activities have led to excessive greenhouse gas emissions, causing global warming and disrupting the Earth's climate. The energy sector, including heat and electricity generation, is a significant contributor to these emissions.

The impact of climate change due to air pollution extends to various ecosystems. Rising temperatures cause melting ice sheets and warming oceans, threatening marine life. Ocean acidification, resulting from increased carbon dioxide dissolution in seawater, makes it challenging for marine species to develop shells and skeletons. Additionally, the rapid pace of climate change exceeds the adaptation capabilities of many plants and animals, leading to the extinction of numerous species. This disruption in ecosystems can have far-reaching consequences, as even the decline of a few species can topple the balance of entire ecosystems.

Air pollution also affects the environment by reducing visibility and causing acid rain. Haze and smog, for instance, obscure shapes and colours, impacting both human activities and the natural environment. Acid rain, formed by pollutants such as nitrogen and sulfur in the atmosphere, harms forests, wildlife, and agriculture. It leads to acidification and eutrophication of terrestrial and aquatic ecosystems, particularly affecting rivers, lakes, and estuaries.

Furthermore, air pollution poses risks to wildlife and vegetation. Similar to humans, animals can experience respiratory issues, neurological problems, and skin irritations due to pollution. Ozone pollution, specifically, damages the stomata—tiny pores on the underside of leaves—hindering the plant's ability to breathe and reducing crop growth.

Overall, air pollution has far-reaching consequences for the environment, affecting ecosystems, wildlife, and the climate. Addressing this issue requires a collective effort to reduce emissions, transition to cleaner energy sources, and implement policies that prioritize sustainable practices to mitigate the harmful impacts of air pollution on our planet.

The World Health Organization's role in monitoring air pollution

Air pollution is a pressing global health issue, with outdoor and indoor air pollution causing respiratory and other diseases, as well as contributing to morbidity and mortality. According to the World Health Organization (WHO), there are approximately 7 million premature deaths annually due to the combined effects of outdoor and indoor air pollution, with millions more experiencing illness from breathing polluted air. The majority of these deaths, around 89%, occur in low- and middle-income countries, with the greatest burden in the WHO South-East Asia and Western Pacific Regions.

WHO's Role in Monitoring Air Pollution:

The WHO plays a crucial role in monitoring and addressing air pollution as the coordinating authority on international health. It supports countries in protecting public health through evidence-based policies and interventions. WHO's Air Quality and Health Unit works across three key areas: knowledge and evidence, institutional capacity building, and leadership and coordination.

Knowledge and Evidence:

WHO regularly integrates scientific evidence on the health impacts of air pollution and monitors countries' air quality progress. The organization has developed the WHO Global Air Quality Guidelines (AQG), which offer guidance on thresholds and limits for key air pollutants that pose health risks. These guidelines are based on rigorous scientific evaluation and consultation with experts worldwide. The AQG also provides interim targets to promote a gradual shift towards lower pollutant concentrations, reducing health risks.

Institutional Capacity Building and Technical Support:

WHO assists its member states by providing technical support and authoritative advice on health issues related to air pollution. This includes the development of normative guidance and tools. The WHO Household Multiple Emission Sources (HOMES) model, for instance, helps policymakers understand household air pollution levels and their impacts.

Leadership and Coordination:

WHO has implemented a strategy to raise awareness about the risks of air pollution and the available solutions. Through digital outreach and partnerships, WHO engages with various stakeholders, including health and environment ministries and city governments, to emphasize the importance of addressing air pollution.

By providing global guidance, evidence-based recommendations, and coordination, the WHO plays a vital role in helping countries tackle air pollution and protect public health. The organization's efforts are crucial in addressing the significant health burden caused by air pollution, particularly in low- and middle-income regions.

The sources of air pollution

Air pollution is a significant health risk, causing more than 10% of all deaths worldwide (approximately 4.5 million premature deaths in 2019). It is a particular problem in emerging and developing countries, where global environmental standards are often not met.

There are four main types of air pollution sources: mobile, stationary, area, and natural. Mobile sources, such as cars, buses, planes, trucks, and trains, are responsible for more than half of the air pollution in the United States, with automobiles being the primary contributor. Stationary sources include power plants, oil refineries, industrial facilities, and factories, which emit large amounts of pollution from a single location. Area sources consist of smaller pollution sources that can collectively have a significant impact, such as agricultural areas, cities, and wood-burning fireplaces. Natural sources include wind-blown dust, wildfires, and volcanoes, which can release large amounts of harmful gases and smoke, increasing pollution levels even in distant areas.

Road traffic is a significant contributor to air pollution, with vehicles like cars, vans, buses, and lorries releasing pollutants from their exhausts. Near busy roads, the main pollutants are nitrogen oxides, carbon monoxide, and particulate matter, with larger vehicles emitting more pollution. Industrial processes, such as oil and gas development, also contribute to elevated ozone concentrations. Power plants, in particular, can increase smog levels in nearby areas.

Particulate matter is another important pollutant, encompassing everything in the air that isn't gas. It includes natural sources like pollen, sea spray, and desert dust, as well as human-made sources like smoke and dust from exhausts, brakes, and tyres. Particulate matter can travel long distances and has been known to affect air quality in other countries. Domestic burning, such as wood-burning stoves and open fires, is the UK's largest source of particulate matter air pollution.

To improve air quality and reduce the impact of these pollution sources, various measures can be taken. For example, individuals can turn off their car engines when parked or stationary, use cleaner fuels and more efficient appliances, and stay away from busy traffic when walking or cycling. Local authorities can also play a role by monitoring air quality and issuing penalties to drivers who leave their engines running unnecessarily.

The most polluted countries and cities

Air pollution is a pressing issue that poses a significant threat to global health. According to the World Health Organization (WHO), air pollution is responsible for approximately seven million premature deaths annually worldwide. It is a problem that affects almost everyone, with 99% of the global population breathing air that exceeds WHO guideline limits and contains high levels of pollutants. Developing and emerging countries often suffer the highest exposures, with indoor air quality contributing significantly to the issue.

Sources of air pollution are varied and include household combustion devices, motor vehicles, industrial facilities, and forest fires. Outdoor air pollution, or ambient air pollution, is influenced by residential energy use, vehicles, power generation, agriculture, waste incineration, and industry.

While air pollution is a global issue, some countries and cities experience more severe pollution levels than others. The World Air Quality Index (AQI) provides real-time data on air pollution levels in over 80 countries, helping to identify areas with the worst air pollution. Here is a list of some of the most polluted countries and cities:

Most Polluted Countries:

According to IQAir's World Air Quality Report in 2024, several countries stood out for their high levels of air pollution. Bangladesh, Pakistan, and India were among the countries with the worst air quality, often exceeding recommended limits by several times.

Most Polluted Cities:

• Delhi, India: Delhi consistently ranks among the most polluted cities globally, with high levels of PM2.5 and other pollutants. Vehicle emissions, industrial activities, and crop burning contribute to the poor air quality.
• Dhaka, Bangladesh: Dhaka faces severe air pollution, particularly from traffic congestion and the large number of brick kilns in the city's vicinity.
• Lahore, Pakistan: Lahore experiences high levels of air pollution due to industrial emissions, vehicle exhaust, and the burning of crops and solid waste.
• Beijing, China: Beijing has struggled with air pollution for years, often experiencing smog and haze. Coal burning, vehicle emissions, and industrial activities are major contributors.
• Los Angeles, United States: While air quality has improved, Los Angeles still faces challenges with smog and ozone pollution due to vehicle emissions and geographic factors.

These countries and cities have implemented various interventions and initiatives to improve air quality and mitigate the health risks associated with air pollution.

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