Air pollution, pollens and childhood asthma – is there a link?

While the interplay between ambient air pollutants and their role in the development of asthma continues to remain a subject of detailed study, a link appears to be postulated between ambient air pollutants and airborne pollens in the increasing prevalence of allergic airway disease. With an increasing focus on climate change and the effects of global warming, pollen allergy has become the focus of recent studies looking at the interrelationship between ambient air pollutants and pollen exposures in individuals with allergic respiratory disease. At the population level, little is known about the potential synergistic effects between pollen allergens and air pollutants since this type of association poses challenges in uncontrolled real-life settings. The current knowledge of the pathogenesis of allergies and asthma due to the combined exposure to biological agents such as pollens and air pollutants has been based primarily on animal or in vitro studies. This article highlights possible mechanisms involved in the interrelationship between air pollutants and pollen allergens with asthma, and summarises the evidence on the independent and/or co-effect of multiple environmental exposures (ambient air pollutants and pollens) on childhood asthma.National Research Foundation (South Africa