Air Pollution: Who's At Risk?

Air pollution is a major cause of disease and premature death worldwide. It is caused by contaminants in the atmosphere, such as dust, fumes, gases, and smoke, which can be harmful to human health. While anyone exposed to air pollution may be at risk, certain groups are more vulnerable to its adverse effects. These include children, adolescents, pregnant women, older adults, and individuals with pre-existing heart and lung diseases. Additionally, low-income communities and minority populations are disproportionately exposed to air pollution and are more susceptible to its health impacts. Other factors, such as genetics, comorbidities, nutrition, and sociodemographic factors, also influence an individual's susceptibility to the health risks associated with air pollution.

Children and adolescents

Outdoor air pollution is unhealthy for everyone, but some groups of people are more vulnerable than others. Children and adolescents are among the most vulnerable groups. Their airways are smaller and still developing, and they breathe more rapidly and inhale more air relative to their size than adults. Children's bodies and organs, including their brains, lungs, and immune systems, are still developing, which further increases the risk of infection. They are also more likely to spend time being active outdoors, which can increase their exposure to air pollution on days when air quality is poor.

Children breathe air closer to the ground where some pollutants, especially from traffic exhausts, are emitted and become concentrated. Their acquired dose of pollution is also elevated since they breathe faster and are often more physically active. Moreover, children inhale a larger fraction of air through their mouths than adults. Due to this increased oral breathing, pollution penetrates deep into the lower respiratory tract, which is more permeable.

Children are affected by ambient air pollutants from the womb through to adulthood. Air pollution damages health during childhood and increases the risk of diseases later in life. It can affect lung function and development, which continues through adolescence. It also negatively affects neurodevelopment and cognitive ability and can trigger asthma, otitis media, childhood cancer, and childhood leukaemia. Children who have been exposed to high levels of air pollution may be at greater risk for chronic diseases, such as cardiovascular disease, later in life.

In 2021, air pollution was the second leading risk factor for death among children under five years old, after malnutrition. It was linked to a total of 709,000 deaths in children under five years old. More than 70 per cent of these deaths were linked to household air pollution due to cooking with polluting fuels. The biggest impacts were seen in Africa and South Asia.

Pregnant women

Outdoor air pollution is unhealthy for everyone, but pregnant women are among the groups that are more vulnerable to its effects. The physical changes that occur during pregnancy already put stress on the body, and exposure to air pollution adds to this stress.

Additionally, air pollution can cause or exacerbate asthma, which can lead to preeclampsia, a condition characterized by elevated blood pressure and decreased function of the liver and kidneys. Untreated asthma can cause the baby to suffer from a lack of oxygen, resulting in poor growth, premature birth, and low birth weight.

The pollutants found in air pollution, such as nitrogen dioxide, sulfur dioxide, and carbon monoxide, can increase the risk of heart and respiratory diseases, lung cancer, and strokes. These pollutants can also cause irritation, inflammation, and damage to the lining of the respiratory tract, putting additional stress on the lungs, heart, and other organs.

To reduce exposure to air pollution, pregnant women can limit their time outdoors on days when the air quality is poor, avoid busy roadways, and use air purifiers indoors to remove pollutants from the air.

Older adults

Outdoor air pollution is unhealthy for everyone, but certain groups of people are more vulnerable than others. Older adults are at an increased risk of harm from air pollution due to various factors. Firstly, the aging process gradually reduces the lungs' breathing ability, making them more susceptible to the detrimental effects of air pollution. The aging process also weakens the immune system, making it less effective at protecting the lungs from inhaled contaminants, including air pollutants. As a result, older adults are more prone to respiratory infections, which increases their risk of developing pneumonia and other serious illnesses.

Additionally, older adults are more likely to have pre-existing chronic illnesses, such as lung and heart disease, which can be exacerbated by exposure to unhealthy air. The cellular injury and inflammation caused by air pollution put additional stress on organs that are already compromised by disease. Fine particle pollution, particularly PM2.5, has been linked to an increased risk of cardiac issues such as arrhythmias and heart attacks, as well as the development of chronic bronchitis. Ozone, even at low levels, can also aggravate respiratory diseases in older adults.

The sensitivity of older adults to air pollution is further heightened during physical activities (PA). Studies have shown that the health risks associated with air pollution are amplified when older adults engage in physical activities, especially in environments with higher pollution levels. Walking, cycle ergometer exercises, and traditional Chinese exercises are among the most commonly investigated physical activities in relation to air pollution and older adults.

It is important to note that the risks associated with air pollution for older adults are not limited to physical health. Research has also linked air pollution to decreased cognitive performance in the elderly. As air pollution continues to worsen due to dirty emissions and a lack of access to clean fuels, it is crucial to prioritize interventions that reduce emissions and improve air quality, thereby mitigating the health risks faced by older adults.

People with pre-existing disease

Outdoor air pollution is unhealthy for everyone, but some groups of people are more vulnerable than others. People with pre-existing diseases are particularly susceptible to the adverse effects of air pollution. The health risks from air pollution vary widely depending on age, location, underlying health, and other factors.

People with asthma or chronic obstructive pulmonary disease (COPD/emphysema or chronic bronchitis) are more vulnerable to the effects of air pollution. Air pollution can make it harder for them to breathe, trigger asthma attacks, or cause wheezing and coughing. It also increases the risk of respiratory infections, heart disease, stroke, and lung cancer, and more severely affects people who are already ill. The cellular injury and inflammation triggered by breathing in air pollution put additional stress on people's lungs, heart, and other organs that are already compromised by disease.

Pregnant women are another group that is susceptible to the effects of air pollution. Exposure to air pollution during pregnancy is associated with adverse birth outcomes, such as premature birth, low birth weight, and an increased risk of preeclampsia. The physical changes and stress of pregnancy already put a strain on the body, and air pollution can further increase the risk of harm to both the mother and fetus.

Outdoor workers are also at higher risk due to the amount of time they spend exposed to air pollution, often engaged in strenuous activity that increases their breathing rate and the amount of polluted air they inhale. Many outdoor workers have limited options for reducing their exposure without impacting their employment.

Lastly, children and adolescents are particularly vulnerable to air pollution as their bodies, organs, and immune systems are still developing. Air pollution can damage their health during childhood and increase the risk of diseases later in life. Growing up breathing in high levels of air pollution can affect how their lungs develop, putting them at greater risk of lung disease as they age.

Low-income communities

Air pollution is harmful to everyone, but low-income communities are disproportionately affected. Low-income communities are regularly subjected to levels of pollutants that are considerably higher than the concentrations deemed unsafe even for short-term exposure. This overexposure to air pollution causes both physical and mental health consequences, as well as impaired cognitive function.

Several factors contribute to the disproportionate impact of air pollution on low-income communities. Firstly, there is a lack of emissions regulations and enforcement in these areas. Additionally, pollution sources, such as industrial facilities and major roadways, are often disproportionately placed near low-income neighbourhoods. The political power of large emitters also plays a role in this disparity. Furthermore, racial and ethnic minorities, who are more likely to live in low-income communities, face higher exposure to pollutants and greater health risks. Research has shown that the greater the concentration of racial and ethnic minorities in an area, the more likely it is to contain hazardous compounds such as vanadium, nitrates, and zinc.

The health risks associated with air pollution in low-income communities include respiratory diseases, heart disease, and adverse birth outcomes. Air pollution can trigger asthma attacks, increase the risk of respiratory infections, and worsen existing lung conditions such as chronic obstructive pulmonary disease (COPD) and emphysema. It can also lead to heart disease, stroke, and lung cancer. The additional stress and inflammation caused by air pollution can also increase the risk of hypertensive disorders during pregnancy, such as preeclampsia.

Addressing the disproportionate impact of air pollution on low-income communities requires a combination of regulatory changes, community organizing, and environmental justice initiatives. Strategies such as reducing emissions from energy, transport, waste management, and industrial sectors can improve air quality and benefit the health and well-being of these communities.

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