Air Pollution: A Slow, Deadly Poison

Air pollution is a serious issue that affects people worldwide and has been linked to a range of negative health outcomes, including respiratory illnesses, heart disease, and even an increased risk of lung cancer and dementia. It is caused by a variety of factors, including electricity generation, commercial and residential emissions, and climate change-fueled wildfires. The fine particulate matter (PM2.5) in air pollution is of particular concern as it can travel deep into the lungs and enter the bloodstream when inhaled, leading to a range of health problems and even premature death. According to a report by IQAir, a company that tracks global air quality, only 13 countries and territories had healthy air quality in 2022, with the remaining 90% of countries exceeding the World Health Organization's air quality guidelines. This has resulted in millions of premature deaths each year, with air pollution remaining a significant health burden and reducing life expectancy.

Air pollution is linked to more than 107,000 premature deaths in the US

Air pollution is a serious issue in the United States, with a significant impact on public health. A study published by CNN in 2018 revealed a startling statistic: air pollution was linked to an astonishing number of premature deaths in the US, exceeding 107,000 in 2011. This issue is not confined to specific regions but affects people across state lines, highlighting the far-reaching consequences of toxic air.

The primary culprit behind these alarming numbers is fine particulate matter, known as PM2.5. This pollutant is minuscule, allowing it to infiltrate deep into the lungs and even enter the bloodstream when inhaled. Its sources include the combustion of fossil fuels, dust storms, and wildfires, which have become increasingly common due to climate change.

The impact of air pollution on health is dire. Short-term exposure to ozone pollution can trigger asthma attacks and chest pain, while long-term exposure can lead to decreased lung function and an elevated risk of lung cancer, even in non-smokers. Alarmingly, air pollution has also been linked to an increased risk of Alzheimer's and other cognitive issues, including a heightened risk of dementia.

Certain communities are disproportionately affected by air pollution. People of color and Hispanics are more likely to reside in areas with unhealthy air quality, suffering the consequences of failing grades in particle and ozone pollution. This disparity underscores the environmental injustice faced by these communities.

As air pollution continues to worsen, the number of people breathing unhealthy air has increased. According to the American Lung Association's State of the Air report, approximately 156 million people in the US, about half of the country's population, are exposed to unhealthy levels of air pollution. This issue extends beyond the US, with a global surge in air pollution in 2022, affecting countries like India, Bangladesh, and Pakistan, where economic growth and industrialization contribute to the problem.

The air quality in 90% of countries exceeds WHO guidelines

Air pollution is a serious issue that affects countries worldwide. According to a report by IQAir, a Swiss firm that tracks global air quality, 90% of 131 countries exceeded the World Health Organization's (WHO) air pollution guidelines for fine particulate matter (PM 2.5) in 2022. This report combined data from official monitoring stations and "citizen science" monitors, utilizing over 30,000 sensors across 7,323 locations. The situation is even more dire when considering that the number of countries monitoring air quality has increased over the years, yet significant gaps in government-operated regulatory instrumentation remain.

PM 2.5 refers to tiny particles in the air, including sulfates, nitrates, black carbon, and ammonium, which pose significant health risks. The updated WHO guidelines recommend that countries maintain an annual average of 5 micrograms per cubic meter or less to safeguard their citizens' health. However, even high-income nations with robust air quality management systems often fall short of this standard. For instance, in the United States, nearly half of the population breathes unhealthy levels of air pollution, according to the American Lung Association's State of the Air report.

The impact of air pollution on human health cannot be overstated. Prolonged exposure to PM 2.5 concentrations above the annual average guideline can lead to severe long-term complications, including heart disease and decreased lung function. Fine particulate matter can infiltrate the lungs and enter the bloodstream, causing irritation and inflammation. This is particularly concerning for vulnerable groups, such as people of color and Hispanics, who are more likely to reside in neighborhoods with unhealthy air quality.

While air quality has shown gradual improvement in high-income countries, the situation in low- and middle-income nations is deteriorating. This disparity is growing, with these countries experiencing rising levels of air pollution due to large-scale urbanization, economic development fueled by the inefficient combustion of fossil fuels, and residential fuel use and industry. As a result, the burden of disease associated with air pollution exposure is increasing, contributing to morbidity and mortality from cardiovascular and respiratory diseases, lower respiratory tract infections, preterm births, and other causes of death in children and infants.

To address this global challenge, the WHO has developed global air quality guidelines to provide quantitative health-based recommendations for air quality. These guidelines serve as a reference for decision-makers in setting legally binding standards and goals for air quality management. Additionally, the guidelines offer interim targets to guide reduction efforts and provide qualitative statements on good practices for managing specific types of particulate matter.

People of colour are more likely to live in areas with unhealthy air

Air pollution is a pressing issue in the United States, with nearly half of Americans living in areas with unhealthy levels of air pollution. This issue disproportionately affects people of colour, who are more likely to reside in neighbourhoods with poor air quality. According to the American Lung Association, people of colour are the group most likely to live in communities with unhealthy air. They are more than twice as likely as White people to be exposed to high levels of particle pollution or ozone pollution. This disparity is even more pronounced for Hispanics, who are three times more likely than White people to live in areas with failing grades for air pollution.

The reasons for this disparity are complex and multifaceted. One significant factor is residential segregation, which has resulted in people of colour, especially African Americans, living in areas with greater exposure to air pollution. Additionally, socioeconomic factors play a role, as low-income communities and those with less education are also more likely to be exposed to higher levels of pollution. Multiple large studies have found a link between low socioeconomic status and increased risk of adverse health effects from air pollution. For example, a 2016 study of New Jersey residents revealed a higher risk of premature death from long-term particle pollution exposure in communities with larger African American populations and lower income levels.

The sources of air pollution that disproportionately impact people of colour vary. According to a US EPA study, people of colour experience greater than average exposures from source types that contribute to 75% of overall exposure to PM2.5 pollution. These sources include industry, agriculture, vehicles, construction, and road dust. The study found racial-ethnic disparities in almost all major emission categories.

The health consequences of air pollution are significant, with particle pollution causing irritation, inflammation, asthma attacks, chest pain, and decreased lung function. Long-term exposure can even lead to premature death. People of colour, who are more likely to live in polluted areas, bear the brunt of these health risks. This inequity underscores the urgent need for effective policies and interventions to improve air quality and protect the health of vulnerable communities.

Air pollution can cross state lines and cause health issues elsewhere

Air pollution is a pervasive issue that knows no borders, and its health implications can be far-reaching. A study published in the journal Nature in 2020 revealed that air pollution generated in one state can readily cross state lines, impacting the health and well-being of people living far from the pollution's source. This phenomenon is not limited to a single state or region but extends across the United States, with deadly consequences.

The study found that northern Midwest states are the largest net "exporters" of pollution-related premature deaths outside their borders. This is due to a combination of factors, including low local populations, high emissions, and the presence of large populations downwind, who bear the brunt of the pollution's impact. Of the 48 contiguous states studied, New York had the highest percentage of premature deaths attributed to out-of-state pollution for all three years examined.

The deadly impact of cross-state air pollution is akin to "secondhand smoke but on a national scale," as described by Steven Barrett, a co-author of the study and director of the Laboratory for Aviation and the Environment at the Massachusetts Institute of Technology. The fine particulate matter, or PM2.5, can originate from various sources, including the combustion of fossil fuels, dust storms, and wildfires, posing a significant threat to public health.

While the US Environmental Protection Agency (EPA) has implemented regulations to curb cross-state air pollution, these rules primarily target pollution from power generation. Barrett emphasizes the need to expand the scope of these regulations to encompass other sectors, such as commercial, residential, and automotive emissions, which have become the leading contributors to premature deaths from air pollution since 2018.

The issue of air pollution extends beyond national borders, with global cities facing similar challenges. The list of the world's most polluted cities in 2024 and 2025 predominantly featured Asian cities, with 13 of them located in India. However, it's important to note that the cities with the worst pollution in North America were all in California, underscoring the pervasive nature of air pollution and the urgent need for comprehensive solutions.

Climate change-fuelled wildfires are worsening air quality

According to a report by the American Lung Association, nearly half of Americans live in areas with unhealthy levels of air pollution. The problem is only getting worse, with air pollution levels increasing for more people in the US. One of the main contributors to poor air quality is wildfires, which are becoming more frequent and severe due to climate change.

The World Meteorological Organization (WMO) has highlighted the vicious cycle of climate change, wildfires, and air pollution, which is having a spiralling negative impact on human health, ecosystems, and agriculture. The WMO Air Quality and Climate Bulletin found that the first eight months of 2024 saw intense heat and persistent droughts that fuelled the risk of wildfires and air pollution. As a result, eastern Canada and the northeastern United States, particularly New York City, experienced worsening air quality in early June 2023. The smoke from these wildfires was carried across the North Atlantic Ocean, reaching as far as southern Greenland and Western Europe.

Wildfires release greenhouse gases and aerosols, such as carbon dioxide, methane, and black carbon, into the atmosphere. While the plants that recolonize burned areas can remove carbon from the atmosphere, the increased frequency and intensity of wildfires due to climate change may lead to a net increase in greenhouse gas emissions if the plants are unable to reach maturity or are less efficient at carbon uptake.

The impact of wildfires on air quality can be significant, with smoke causing eye and respiratory illnesses, especially among children and the elderly. Wildfires can also melt plastic water pipes, leading to contamination of water systems with known carcinogens. The economic costs of wildfires can be substantial, with NOAA estimating the total costs of wildfires in 2017 and 2018 to be over $40 billion.

The chemical species that lead to a degradation in air quality are typically co-emitted with greenhouse gases. Fine particulate matter, or PM2.5, is one of the smallest and most dangerous pollutants. It is produced by the combustion of fossil fuels, dust storms, and wildfires. Exposure to ozone pollution, a component of PM2.5, can cause asthma attacks and chest pain in the short term, and decreased lung function and premature death in the long term.

Frequently asked questions