Traffic-related air pollution and black carbon in sputum macrophages: a “silent” lung disease?

Abstract

AIMS: To describe two case reports with significant black carbon deposition in sputum macrophages in healthy young adults from an urban city, showing mild airway obstruction in lung function tests. The role of black carbon deposition by air pollution in the airways and the development of indolent chronic lung disease in populations living in larger cities is not clear and may be a potential world health problem. CASES DESCRIPTION: We report two cases of voluntary adults living in a South American large city who have undergone clinical examination, lung function and analysis of inflammation and black carbon deposition in macrophages from induced sputum. Two Caucasian, previously healthy, nonsmokers, male adults, living in the same city of southern Brazil, with no respiratory symptoms presented with normal physical exams, but with lung function demonstrating mild obstructive lung disorder, with no bronchodilator response. In particular, one of the subjects works daily in delivery services as a motorcycle driver. Induced sputum of both patients showed no signs of cellular inflammation. However, a large number of black carbon content was detected inside macrophages of the sputum sample in both patients. CONCLUSIONS: In summary, significant daily air pollution exposure may play a role in long-term silent disease in adults, potentially leading to clinically relevant chronic lung diseases later in life, particularly in populations of urbanized large cities from developing countries. The development of better, more directly and less invasive, methods for air pollution exposure are required, along with longitudinal studies, in order to measure the real impact of air pollution in chronic lung diseases of susceptible populations.