Air pollution refers to the presence of harmful substances in the atmosphere, such as gases like ozone or nitrogen oxides, and tiny particles like soot and dust. It is a global concern, stemming from various sources including industrial processes, vehicle emissions, household combustion, and natural events like wildfires. Breathing polluted air over extended periods poses a significant threat to human health, contributing to a wide range of acute and chronic issues. The World Health Organization (WHO) indicates that almost 99% of the global population breathes air exceeding WHO guideline limits for pollution.
Respiratory System Impacts
Air pollution directly affects the respiratory system, leading to a variety of conditions and exacerbating existing ones. Fine particulate matter (PM2.5), which are particles less than 2.5 micrometers in diameter, can penetrate deep into the lungs, causing irritation and inflammation. Ground-level ozone, another common pollutant, also irritates the airways and can impair lung function. These pollutants contribute to the development and worsening of conditions such as asthma, triggering attacks and increasing their severity.
Prolonged exposure to air pollution can lead to chronic bronchitis, characterized by persistent coughing and mucus production, and emphysema, which involves damage to the air sacs in the lungs. Both of these conditions are components of chronic obstructive pulmonary disease (COPD), with air pollution being a significant contributing factor, accounting for approximately 48% of COPD cases. The irritation and inflammation caused by pollutants also make individuals more susceptible to respiratory infections, including pneumonia and influenza, by weakening the lungs’ natural defenses.
Cardiovascular System Impacts
Air pollution impacts the circulatory system, affecting heart health. Fine particulate matter (PM2.5) can bypass the lungs’ defenses and enter the bloodstream directly due to its small size. Once in the bloodstream, these particles can trigger systemic inflammation and oxidative stress. This widespread inflammation can damage blood vessel linings, making them less flexible and more prone to plaque buildup.
Exposure to air pollution increases the risk of cardiovascular events, including heart attacks and strokes. The inflammation and oxidative stress can promote blood clot formation, which can block arteries leading to the heart or brain. Air pollution is also linked to arrhythmias, irregular heartbeats, and elevated blood pressure. These mechanisms contribute to a higher burden of cardiovascular disease, with ambient particulate pollution (PM2.5) alone accounting for approximately 4.7 million deaths in 2021.
Neurological and Other Systemic Impacts
Beyond the respiratory and cardiovascular systems, air pollution affects other body systems, including neurological functions. Exposure to pollutants has been linked to an increased risk of stroke. Research also suggests connections between air pollution and cognitive decline, with links to neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
Air pollution is also associated with an increased risk of various cancers, most notably lung cancer. The harmful substances in polluted air can damage DNA and promote uncontrolled cell growth, contributing to cancer development. Pregnant individuals exposed to air pollution face risks of adverse birth outcomes, including low birth weight and premature birth. Air pollution can also compromise the immune system, making individuals more vulnerable to illnesses, and has been linked to mental health issues such as depression and anxiety.
Vulnerable Groups
Certain populations are more susceptible to the harmful effects of air pollution. Children are vulnerable because their respiratory and other organ systems are still developing. They also breathe at a faster rate than adults and spend more time outdoors, increasing their exposure. The elderly population is also disproportionately affected due to weakened immune systems and a higher prevalence of pre-existing health conditions.
Pregnant individuals are another sensitive group, as exposure to air pollution can impact both maternal health and fetal development. Individuals with pre-existing respiratory conditions, such as asthma or COPD, or cardiovascular conditions, like heart disease, experience exacerbated symptoms and a greater risk of severe outcomes when exposed to polluted air.