22 Mar 24
Despite progress and current policies for sustainability, air quality in the most populous cities is still low and, according to WHO, around 99% of the global population breathes air that exceeds WHO guideline limits.
The impact of pollution on respiratory health has been analyzed in a variety of studies, showing how particle exposure can lead to several issues, such as inflammation of the airways, respiratory infections, bronchial hyperreactivity, decreased lung function in children or loss of pulmonary function in adults, acute reaction and asthma development or symptom exacerbation. In addition, several studies are evaluating the possibility of a connection between fine particle exposure and lung cancer.
According to WHO, air pollution is “contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere”. That being said, several harmful or poisonous substances in outdoor or indoor air can be considered air pollution, with articulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide being the ones causing major public health concerns.
Household combustion devices, motor vehicles, industrial facilities and forest fires are the common sources of pollution.
The good news: our respiratory system shows high resilience to air pollution, thanks to its repeated mobilization of defense and repair mechanisms. A series of studies conducted in the late 1980s and early 1990s on the inhabitants of the Utah Valley showed how hospital admissions for bronchitis and asthma decreased by almost 50 percent during the time a local steel mill – responsible for 90% of local particle pollution emissions – was out of operation.
On the other hand, however, the impact of pollution on respiratory health cannot be overlooked, and implementing strategies to reduce exposure may be a necessary step for both healthy and sensitive people, especially when they are young. Epidemiologic studies conducted in several countries highlighted associations between long-term exposure to fine particles and decrements in lung function growth in children, as well as increased respiratory symptoms.
By inhaling polluted air, particles and contaminants enter the airways and can deposit in the respiratory tract inducing inflammation, the extent of which may vary according to particle dose and composition.
Inflamed airways can respond more violently to irritants like cold air, allergens or gases, leading to a higher risk of cellular damage and compromising the integrity of the alveolar-capillary barrier. On a long-term scale, repeated exposure to air pollutants means chronic inflammation.
Asthma is a chronic condition that can cause the airways to narrow because of swelling or excessive mucus production, with consequential breathing difficulties and symptoms like cough, wheezing or chest tightness. The impact of pollution on respiratory health can therefore be significant for people suffering from the disease.
Although sensitivity to environmental triggers varies between individuals, particle pollution exposure is a higher risk factor if compared to healthy patients, especially when it comes to children, who seem to be more affected by particle pollution than adults with asthma.
Airway hyper-reactivity and bronchoconstriction in patients with asthma can affect particle deposition – since deposition can be augmented in peripheral regions as a result of obstruction and poor ventilation – resulting in inflammatory mechanisms. Moreover, the intensity of bronchial responsiveness can increase during times of high-allergen exposure, leading to symptom exacerbation.
Reducing exposure to air pollution is crucial for protecting respiratory health. This can happen through regulatory measures, lifestyle changes, and sustainable practices. Global-scale action like promoting cleaner energy sources, reducing vehicle emissions, and implementing air quality regulations to limit pollutant levels in the atmosphere are viable ways to get to the goal, though public awareness and education are essential to encourage individuals to take steps to minimize their contribution to air pollution.
