Children are especially vulnerable to the negative effects of air pollution because of their unique behaviours and physiology. Children often play in the dust or crawl on the ground. They spend much more time outdoors than adults do, increasing their exposure to air pollutants, and they also have fewer biological defences compared to adults.

Evidence suggests[i] that current levels of ambient air pollutants may cause deficits in lung function growth in children.  Ambient air pollution has been associated with increased respiratory symptoms among non-asthmatic children, as well as increased respiratory hospital admissions and paediatric visits to the emergency department.

Less well-known but as important are the effects of air pollution on allergic rhinitis in children. Allergic rhinitis is a very common disease in children and adolescents which is often undervalued and underdiagnosed. It is an inflammatory disease of the nasal mucosa caused by exposure to allergens, most commonly domestic dust mites, pollens and pet dander. Viral infections are also an important trigger. At face value allergic rhinitis may seem to be a trivial disease, however it does cause a lot of morbidity and affects the quality of life of the individual. When untreated, it can limit physical activity, and intellectual and social life. Paediatricians do not only have a role in evaluating, investigating and treating children with allergic rhinitis, but also in advocating for cleaner air, both indoors and outside.

The symptoms can occur minutes after exposure and last for days. The treatment consists of avoidance of allergens and risk factors, like tobacco smoke or air pollution, drug relief therapy with oral antihistamines and/or intranasal steroids or allergen immunotherapy. It is important that paediatricians know how to evaluate pediatric patients with rhinitis, investigate the pattern of allergens sensitisation and initiate appropriate therapy. This control will not only improve the quality of life but also prevent possible comorbidities, like allergic conjunctivitis, ear infections, sleep disturbances and asthma. Active and passive exposure to tobacco smoke is related not only to worsening but also to the onset of rhinitis symptoms. Anti-smoking policies, as reviewed in our previous blog about tobacco, are essential to protect and improve the prognosis of these hyper-reactive patients.

Air pollution including cigarette smoke compromises natural pulmonary defence mechanisms by disrupting both mucociliary function and macrophage activity. Exposure to cigarette smoke therefore increases the risk for pneumonia in infants younger than one year of age. According to WHO, approximately a million children die from pneumonia each year worldwide. Half of these are linked to air pollution. There is a growing body of evidence that second-hand smoke exposure is also associated with the development of asthma.

Clean air is critical for children′s health and well-being. Many samples from children populations are showing an array of adverse short and long-term health outcomes, which include some of the most detrimental effects on brain development . However, most of current research and policy efforts link air pollution to respiratory and cardiovascular disease, and the effects on children’s central nervous system are still not broadly recognised.