Environmental inequality: air pollution and asthma in children

Abstract

Whether you benefit from high-quality urban environments, such as those rich in green and blue spaces, that may offer benefits to allergic and respiratory health depends on where you live and work. Environmental inequality, therefore, results from the unequal distribution of the risks and benefits that stem from interactions with our environment. Within this perspective, this article reviews the evidence for an association between air pollution caused by industrial activities, traffic, disinfection-by-products and tobacco/e-cigarettes and asthma in children. We also discuss the proposed mechanisms by which air pollution increases asthma risk, including environmental epigenetic regulations, oxidative stress, and damage, disrupted barrier integrity, inflammatory pathways, and enhancement of respiratory sensitization to aeroallergens. Environmental air pollution is a major determinant of childhood asthma, but magnitude of effect is not shared equally across the population, regions, and settings where people live, work, and spend their time. Improvement of the exposure assessment, a better understanding of critical exposure time windows, underlying mechanisms, and drivers of heterogeneity may improve the risk estimates. Urban conditions and air quality are not only important features for national and local authorities to shape healthy cities and protect their citizens from environmental and health risks, but they also provide opportunities to mitigate inequalities in the most deprived areas where the environmental burden is highest. Actions to avoid exposure to indoor and outdoor air pollutants should be complementary at different levels – individual, local, and national levels – to take effective measures to protect children who have little or no control over the air they breathe.

Environment and the development of severe asthma in inner city population

“…Higher VOC concentrations were associated with increased asthma exacerbations [8]. Multiple mechanisms have been proposed, including disruption of the integrity and immunoregulatory function of the bronchial epithelium, induction of allergen sensitization, and promotion of airway reactivity in individuals with preexisting allergens sensitivities [10].…”

“…Higher air pollutant concentrations are found in urban settings. Multiple longitudinal cohort and epidemiologic studies have demonstrated increased asthma prevalence and symptoms, decreased lung function, and increased airway inflammation in individuals living in areas of lower air quality, cumulating in higher numbers of ED visits [10,21]. Particulate matter (PM) is a mixture of solid and liquid particles that are suspended in the air.…”

“…High maternal exposure to PM 2.5 during weeks 6-26 of pregnancy (the pseudo-glandular and canalicular stages of embryology during which the tracheobronchial tree elongates and develops smooth muscles, connective tissue, and respiratory bronchioles) was significantly associated with increased incidence of childhood asthma [24]. Increased PM 2.5 exposure in childhood was associated with a greater risk for developing asthma [10,24]. High environmental NO 2 levels during prenatal period and in the first year of life were associated with greater asthma prevalence in preschool children [25].…”

“…Elevated ambient PM 2.5 levels are associated with greater asthma symptoms and outpatient visits [27]. Children who reside in areas with more air pollution experience higher numbers of ED visits compared to children living in areas with low levels of PM 2.5 [10,21]. Komisarow and Pakhtigian [28 & ] found that a 1 mg/m 3 increase in average annual PM 2.5 concentrations was associated with around an 11% increase in ED visits for asthmarelated conditions.…”

Editorial to the special issue “Environmental influences on childhood asthma”

“…Paciencia et al 12 investigated the association and mechanisms between air pollution and asthma in children along with the precautions that should be taken to reduce the burden of air pollution on asthma. Environmental conditions are not shared equally across the populations, regions, and settings where people live, work, and spend their time.…”