Characterization of Particulate Matter in Urban Environments and Its Effects on the Respiratory System of Mice

Abstract

Aims: To investigate the characteristics of ambient particulate matter (PM) and its impacts on animal respiratory system. Place and Duration of Study: The study was conducted in urban area of Mysore city from 2014 to 2017. Methodology: The elemental composition, image interpretation, and size distribution of particles was analysed using energy dispersive X-ray spectroscopy, scanning electron microscopy, and dynamic light scattering methods, respectively. Bronchoalveolar lavage analysis was performed to determine the differential cell counts of leucocytes and lymphocytes in the mice lungs. Histological and histopathological studies have been demonstrated to observe the effect of PM exposure on the lungs tissue of mice. Results: The particle characterization analysis found that roadside PM was dominated by 56% black carbon and trace amount of metal elements. The analysis also shows that almost 90% of ambient particulate matter collected in the urban traffic roads was fine particles (PM2.5). By using bronchoalveolar lavage fluid, bronchial biopsies studies have found the compositional changes in neutrophils, eosinophils, mast cells, monocytes and lymphocytes after exposure to PM. Elevated expression and concentrations of inflammatory mediators have similarly been observed in the respiratory tract of mice. The pathological change like degeneration of alveolar region, pycnotic nuclei, and intercellular spaces with prominent vacuolization in epithelial cells followed by parenchyma and accumulation of particle laden macrophages was evident. Conclusion: Exposure to PM induces pathological changes, differential cell counts, and inflammatory response in the mice lungs in a dose and duration dependent pattern.