Air Pollution: A Slow Poison For Your Health

Air pollution is a major environmental health risk, causing an estimated seven million deaths globally each year. It is caused by the presence of contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke or vapour, in quantities that can be harmful to human health. These pollutants can enter the body through the respiratory tract, leading to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout the body, impacting the lungs, heart, and brain, among other organs. Fine particulate matter, such as PM2.5, is of particular concern as it can penetrate deep into the lungs, enter the bloodstream, and travel to organs, causing systemic damage to tissues and cells. This can lead to a range of health issues, including respiratory diseases, lung cancer, heart disease, strokes, and premature death.

Particulate matter (PM) can enter the bloodstream and cause systemic damage to tissues and cells

Particulate matter (PM) is a core component of air pollution, consisting of microscopic solids and liquid droplets. These particles are so small that they are often invisible to the naked eye, but when their levels are high, they cause a noticeable haze in the air.

PM can enter the body through the respiratory tract, leading to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout the body. The particles that are smaller than 10 micrometers in diameter, especially those that are 2.5 micrometers or smaller, pose the greatest risk as they can penetrate deep into the lungs and even enter the bloodstream. Once in the bloodstream, these particles can travel to other organs, causing systemic damage to tissues and cells.

Scientific research has linked exposure to PM to a variety of health problems, including premature death in people with heart or lung disease, increased respiratory symptoms such as irritation of the airways, coughing, and difficulty breathing, as well as aggravated asthma. The smallest particles, known as ultrafine particles, are of particular concern as they can pass through the lungs and into the bloodstream just like essential oxygen molecules.

The sources of PM are varied and include the combustion of carbon-based fuels, such as wildfires, agricultural fires, and residential wood-burning, as well as emissions from factories, power plants, and diesel- and gasoline-powered vehicles. While air quality has improved in recent years due to stricter emissions regulations, far too many people still live with unhealthy levels of particle pollution, and the emerging evidence shows that fine particles are more dangerous than previously understood.

Carbon monoxide (CO) and other pollutants in tobacco smoke are known to cause cancer

Air pollution is the presence of one or more contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke, or vapour, in quantities that can be harmful to human health. These contaminants are inhaled through the respiratory tract, leading to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout the body, impacting the lungs, heart, and brain, among other organs. Fine particulate matter, such as PM2.5, is of particular concern as it can penetrate deep into the lungs, enter the bloodstream, and travel to organs, causing systemic damage to tissues and cells.

Carbon monoxide (CO) is one of the key pollutants of concern for human health. It is a colourless, odourless, and toxic gas that is harmful when inhaled. CO is produced by the incomplete combustion of fossil fuels, including gasoline, wood, coal, natural gas, and propane. Exposure to CO can lead to serious health issues, including headaches, dizziness, weakness, nausea, and even death in extreme cases.

Tobacco smoke is a significant source of carbon monoxide, and exposure to it can have detrimental effects on health. Cigarettes, cigars, and pipe tobacco contain dried tobacco leaves, along with added chemicals for flavour and enhanced smoking pleasure. When burned, they release over 7,000 chemicals, including at least 70 known carcinogens, which are compounds that cause cancer. These carcinogens, such as tobacco-specific nitrosamines (TSNAs), damage DNA, increasing the risk of cancer.

In addition to carbon monoxide, tobacco smoke contains other harmful pollutants, including nitrogen oxides, ammonia, tar, and radioactive materials. These pollutants contribute to the development of various types of cancer, as well as heart and lung diseases. The health risks associated with tobacco smoke exposure are not limited to direct smokers but also extend to those exposed to secondhand smoke.

The impact of tobacco smoke on health is significant, and it is essential to understand the dangers posed by carbon monoxide and other pollutants present in tobacco smoke. Quitting smoking and reducing exposure to secondhand smoke are crucial steps in mitigating the health risks associated with these pollutants.

Ozone (O3) irritates the lungs, causing inflammation and reducing lung function

Ozone (O3) is a colourless gas molecule composed of three oxygen atoms. While the ozone layer found high in the upper atmosphere shields us from much of the sun's ultraviolet radiation, ozone at ground level is a dangerous pollutant. Ground-level ozone is formed when gases from tailpipes, smokestacks, factories, and other sources react with sunlight.

Ozone is a powerful oxidant and lung irritant. When inhaled, it reacts with the lining of the airways, causing inflammation and other damage that can impact multiple body systems. This inflammation has been compared to the skin inflammation caused by sunburn. Visible redness of the airways can be seen during bronchoscopy, and the release of inflammatory mediators can attract polymorphonuclear leukocytes (PMNs) into the lungs, further contributing to inflammation.

Ozone exposure can lead to a range of respiratory symptoms, including chest tightness, coughing, and shortness of breath. It can also cause a decrease in maximal inspiration, making it difficult to inhale to total lung capacity. These effects can be particularly harmful to people with existing lung diseases, such as asthma, and those who are more vulnerable, including children, older adults, and people who are active outdoors.

The health risks associated with ozone exposure include a higher risk of premature death, especially when combined with other risk factors. Long-term exposure to ozone is linked to aggravating asthma and may even contribute to its development. Repeated episodes of damage, inflammation, and repair induced by years of recurrent short-term ozone exposures may result in adverse health effects beyond the acute effects, although further research is needed to confirm this.

Nitrogen dioxide (NO2) and sulphur dioxide (SO2) can cause asthma, bronchial symptoms, and lung inflammation

Nitrogen dioxide (NO2) and sulphur dioxide (SO2) are two of the most important air pollutants that can lead to adverse health outcomes. These pollutants are primarily emitted from burning fuels, with trucks, buses, and cars being the largest sources of NO2 emissions, while power plants and industrial boilers are the main contributors to SO2 emissions.

Elevated levels of NO2 and SO2 in the atmosphere can have detrimental effects on human health, particularly in the development of asthma, bronchial symptoms, and lung inflammation. Scientific evidence suggests that exposure to NO2 is strongly linked to an increased risk of asthma, especially in children. Short-term exposure to peak levels of SO2 can also cause breathing difficulties for people with asthma when they engage in outdoor activities.

The respiratory tract is the primary pathway through which these pollutants enter the body, leading to inflammation and damage to the delicate lining of the airways. This inflammation can impact multiple body systems and organs, including the lungs, heart, and brain. The small size of particulate matter allows it to penetrate deeply into the lungs, enter the bloodstream, and travel to other organs, causing systemic damage to tissues and cells.

Long-term exposure to NO2 and SO2 has been associated with various health issues, including lung and heart disease, diabetes, and an increased risk of cancer. Additionally, NO2 exposure during pregnancy can negatively affect birth outcomes, contributing to low birth weight, pre-term birth, and small gestational age births.

Reducing emissions of NO2 and SO2 is crucial to mitigate their health impacts. While progress has been made in improving air quality through stricter regulations and cleaner technologies, continued efforts are necessary to ensure that fewer people are exposed to unhealthy levels of these pollutants.

Air pollution is a leading cause of premature births, low birth weight, and adverse health effects in children

Air pollution is a pressing issue that poses significant risks to human health, particularly in the case of children and pregnant people. The presence of contaminants in the atmosphere, such as dust, fumes, gases, and smoke, can have detrimental effects on the respiratory tract, leading to inflammation, oxidative stress, and even mutagenicity in cells throughout the body. These pollutants can enter the bloodstream through the lungs, impacting almost every organ and leading to systemic inflammation and disease.

One of the most vulnerable groups affected by air pollution is pregnant people. Studies have consistently shown a link between air pollution and adverse birth outcomes, including premature births, low birth weight, and small for gestational age births. For instance, a study in Guangdong, China, found that exposure to air pollutants such as PM2.5, PM10, SO2, NO2, CO, and O3 was associated with an increased risk of preterm birth and low birth weight. The risk of premature birth was higher with increased exposure to these pollutants during the first and third trimesters.

Moreover, air pollution has been linked to an increased risk of various health problems in children, including respiratory infections such as pneumonia, upper respiratory infections, and otitis media (ear infections). Short-term exposure to air pollution can also exacerbate allergies in children, including allergic rhinitis, eczema, and conjunctivitis. Ozone, nitrogen dioxide (NO2), and fine particles (PM2.5) have been identified as particular contributors to adverse health effects in children.

Additionally, air pollution has been suggested to impact neurological development in children. While the evidence is still emerging, there are indications that air pollution may affect neurological development and contribute to conditions such as diabetes. Children and adolescents are more susceptible than adults to adverse environmental factors, and their developing bodies, organs, and immune systems make them especially vulnerable to the harmful effects of air pollution.

It is important to note that the impacts of air pollution on health can vary depending on the specific pollutants, the levels of exposure, and individual factors. However, the available evidence strongly suggests that air pollution is a leading cause of premature births, low birth weight, and adverse health effects in children, underscoring the urgency of implementing measures to improve air quality and protect vulnerable populations.

Frequently asked questions