Carbon particles in airway macrophage as a surrogate marker in the early detection of lung diseases.

BACKGROUND It has been shown that inhalation of carbonaceous particulate matter may impair lung function in children. OBJECTIVE Using the carbon content of airway macrophages as a marker of individual exposure to particulate matter derived from fossil fuel, we sought direct evidence for this association. METHODS 300 children from puffed rice industrial areas and 300 children from population living in green zone were selected randomly. Airway macrophages were obtained from healthy children through sputum induction, and the grading of ultrafine carbon particles in airway macrophages was measured. Pulmonary function was also measured by spirometry. RESULTS Pulmonary function tests showed that in industrial area 42.6% and 20.3% of children had moderate obstructive airway disease and restrictive airway disease, respectively. In the green zone area, 7% of children had obstructive airway disease and 6% had restrictive airway disease. Evaluation of airway macrophages for ultrafine carbon particles revealed that in industrial area there were ultrafine carbon particles of grade 2 in 23% of subjects and grade 3 in 8.33% of individuals with obstructive airway disease. In the green zone area, the rates were 1.67% and 0.7%, respectively. CONCLUSION The study provides a first evidence of the strong association between air pollution and development of airway diseases. Carbon particles in the sputum can be used as a marker for air pollution.