Alveolar deposition of inhaled fine particulate matter increased risk of severity of pulmonary tuberculosis in the upper and middle lobes

To the Editor:
The chest X-ray (CXR) is still an important examination in the diagnosis of pulmonary tuberculosis in low- and middle-income countries [1]. The degree of abnormalities on the CXR reflects the overall disease severity in culture-positive pulmonary tuberculosis patients and is independently predicitve of outcome [2]. Previous studies have shown that exposure to ambient air pollution was associated with an increase of risk of Mycobacterium tuberculosis infection
[3, 4]. However, the association between inhaled particulate matter (PM) deposition in the lungs and the severity of pulmonary tuberculosis at the lung lobar level is still poorly understood. We investigated the association between lung lobe-deposited dose of inhaled fine particulate matter, PM2.5 (particle size less than 2.5 µm in aerodynamic diameter) and CXR abnormalities in different lung lobes of pulmonary tuberculosis patients.