Assessing the impact of individual exposure to air pollution via biomarkers in sputum of children in Ho Chi Minh city, Vietnam

Understanding the impact of exposure to air pollution on children's health is critical for developing effective child health protection policies. Alveolar macrophage black carbon (AMBC) provides an indicator of personal exposure to air pollution. Hence, we aimed to examine air pollution exposure and its effects on children by measuring AMBC area and inflammatory cytokines in sputum. Sputum induction was attempted in 120 children aged 13-14 years, but samples of sufficient volume and quality for analysis were only obtained from 47 (39.2%). Alveolar macrophages (AMs) were visualized, and black carbon (BC) area quantified by microscopy. Participants completed questionnaires, recording air pollution exposure and respiratory symptoms. Univariable associations between AMBC area and respiratory symptoms, exposure variables, cytokines, and pulmonary function were examined. Multivariable regression was conducted, adjusting for potential confounders. The median AMBC area was 0.23 μm² (range: 0.09-0.77 μm²). Most participants (87%) reported a history of respiratory symptoms. AMBC area was related to the distance from home to school, living on the main road, and the habit of opening windows for ventilation. No significant associations were seen between AMBC area and respiratory symptoms, lung function, or inflammatory markers (IL-8, TNF-α, IFN-α). Our findings support the use of AMBC area as a biomarker of individual air pollution exposure. The lack of associations between AMBC area and health outcomes is likely due to a lack of study power, indicating more extensive studies are required.