Deposition modeling of ambient aerosols in human respiratory system: Health implication of fine particles penetration into pulmonary region

Abstract

In this study, we have monitored 1-h (afternoon) ambient concentrations of size-segregated particles by means of 12 channels aerosol spectrometer (PALAS; welas® 2000) over 130 days in one year (2015/2016) from a highly polluted and populated region (Kanpur) in central Indo-Gangetic Plain (IGP). Average mass concentrations of PM2.5 (fine) and PM10-2.5 (coarse) varied from ∼40–160 and 30–67 μg m−3, respectively. PM mass size distribution analysis revealed multi-modal peaks in monsoon (tri-modal: < 0.5; 1.4–1.8; 7.8 μm), post monsoon (tetra-modal: < 0.5; 1.4–1.8; 3.2; 7.8 μm), winter (tri-modal: < 0.5; 1.4–1.8; 5.8 μm) and summer (tetra-modal: < 0.5; 1.4–1.8; 3.2; 7.8 μm). The MMAD ± GSD were found to be 2.1 μm ± 3.0 (monsoon), 1.0 ± 3.0 μm (post monsoon), 1.1 μm ± 2.7 (winter) and 2.4 μm ± 2.9 (summer). A computational model (Multiple Path Particle Dosimetry: MPPD, v 2.11) analysis revealed total PM mass deposition in human respiratory airways (test subject: male adult) was 34.1 μg in monsoon, 64.5 μg in post monsoon, 40.6 μg in winter and 34.4 μg in summer. Coarse particles exhibited higher mass deposition fraction (84%) in HEAD (extrathoracic), whereas fine particles deposited significantly (33%) in PUL (pulmonary region). Intensification of biomass and biofuel burning emissions during post-monsoon and wintertime have implications to deeper penetration and higher mass deposition fraction of fine-particles in the PUL region. High PM concentration and its significant deposition in PUL region calls for immediate measures to be taken to improve regional air quality to reduce health hazards and disease burden for exposed population.