A Meta-analysis of Studies of Air Pollution in Urban Areas along Highways/Major Streets and Lung Diseases including Asthma among Children

Background Asthma affects more than 23 million people in the United States of which a third of those are children. Air pollution plays a role in asthma, especially among children due to the vulnerability of their lung function. Objective 1) To investigate, using meta-analysis, the relation between the traffic-related air pollution and lung diseases that include asthma in children. 2) To determine the effect of air pollution in children. Method Articles from 1999-2009 related to highway air pollution were retrieved from Highwire, Pubmed and Medline search engines. Confidence interval related to individual air contaminants (PM2.5, CO, O3, NO2) was obtained. Results were stratified on the following inclusion criteria – a) air pollution, b) asthma, c) children and d) case control studies. Meta-analysis was conducted and random effect models were generated. Results As per the metaanalysis – (OR – 1.041, CI – 1.027- 1.056, Z – 143.627, P – 0.000) indicates that air pollutants are triggering factor for asthma exacerbation and allergies. Exposure to particulate matter (PM2.5, PM10) and carbon monoxide are associated with decreased pulmonary functions and hospital admission among asthmatic children. Conclusion Meta-analysis of 20 case control studies suggest that there is a considerable association between proximity to highways and results in adverse respiratory health effects in children. High ambient levels of PM 10, PM2.5, NO2 and O3 are associated with increased risk of childhood asthma symptoms. Therefore we can infer that highway air pollutants have a major effect on the development of asthma in young children.