Impact of Air Pollution on Asthma Outcomes

Abstract

Asthma is a chronic respiratory disease characterized by variable airflow obstruction, bronchial hyperresponsiveness, and airway inflammation. Evidence suggests that air pollution has a negative impact on asthma outcomes in both adult and pediatric populations. The aim of this review is to summarize the current knowledge on the effect of various outdoor and indoor pollutants on asthma outcomes, their burden on its management, as well as to highlight the measures that could result in improved asthma outcomes. Traffic-related air pollution, nitrogen dioxide and second-hand smoking (SHS) exposures represent significant risk factors for asthma development in children. Nevertheless, a causal relation between air pollution and development of adult asthma is not clearly established. Exposure to outdoor pollutants can induce asthma symptoms, exacerbations and decreases in lung function. Active tobacco smoking is associated with poorer asthma control, while exposure to SHS increases the risk of asthma exacerbations, respiratory symptoms and healthcare utilization. Other indoor pollutants such as heating sources and molds can also negatively impact the course of asthma. Global measures, that aim to reduce exposure to air pollutants, are highly needed in order to improve the outcomes and management of adult and pediatric asthma in addition to the existing guidelines.

External Environmental Pollution as a Risk Factor for Asthma

“…Table 5 shows the effects of outdoor air pollutants on asthma if legal concentrations are exceeded [ 96 ].…”

“…The authors pointed out that the WHO parameters should be outdated and suggest that such a correction probably would describe a more realistic asthma burden incidence. Table 5 shows the effects of outdoor air pollutants on asthma if legal concentrations are exceeded [96].…”

“…Effects of outdoor air pollutants on asthma outcomes if legal concentrations are exceeded (adapted from Tiotiu et al[96])…”

Association between Green Space Structure and the Prevalence of Asthma: A Case Study of Toronto

“…Notwithstanding the complex and genetic characteristics of asthmatics [ 7 ], the development of gene–environment interaction theory from an epidemiologic perspective makes alleviating asthma, as well as asthma-like diseases, via the surrounding environment possible [ 8 ]. Air pollution has been found to have a negative influence on the asthma-related outcomes of children and adults [ 9 ]. For example, higher exposure to nitrogen dioxide (NO 2 ) early in life produces a long-term influence on asthma development across approximately 20 years [ 10 ].…”

Emerging Cell-Based Therapies in Chronic Lung Diseases: What About Asthma?

“…Without a known cause, asthma has a multifactorial background and many risk factors associated with its development. Most of the risk factors are related to early life events, such as genetics, several pathogens, and environmental exposures like tobacco smoke and air pollution (Toskala and Kennedy, 2015;World Health Organisation, 2018;Tiotiu et al, 2020). Asthma is an inflammatory and heterogeneous chronic disease.…”