The Effects of Air Pollution on Asthma in Children

In Brief The harmful effects of ambient air pollution have been extensively studied in recent decades. Most studies have been designed to investigate the detrimental effects of pollution on asthmatic patients. However, there are very little data to support the role of air pollution in the inception of asthma. Although the traditional form of air pollution due to combustion of fossil fuel is disappearing, traffic exhaust has become the most important source of pollution in the urban setting. Therefore, there have been many recent cross-sectional and longitudinal studies investigating the harmful effects of traffic-related pollution. Many epidemiological studies in children and adults have confirmed the association of ambient air pollution and various respiratory health outcomes such as asthma exacerbations, visits to accident and emergency departments, hospitalization, deterioration in lung function, and increased use of asthma medications. The role of ambient air pollution in the inception of asthma remains to be determined. Current levels of ambient air pollution in many countries are associated with increased morbidity in asthmatic children. However, whether outdoor air pollution has a causative role in the development of childhood asthma remains unclear. The gaseous component, particulate matter, as well as the microbial component in the ambient air are all important in inducing inflammation in the asthmatic airways. To minimize the overall burden of asthma care in children, further reduction of the current level of ambient air pollution is necessary.