Deposition modeling of ambient particulate matter in the human respiratory tract

Abstract

In this study, the generation-specific, lobar, regional, and total deposition of Particulate matter (PM) in the human respiratory tract (HRT) and its clearance was quantified using the Multiple Path Particle Dosimetry Model (MPPD-V3.04). The visualizations of the deposited PM are also shown. The study area was a technical institute of national importance, highly affected by PM pollution. Ambient PM particles (PM1, PM2.5 and PM10) were measured in three seasons (i.e., monsoon, winter and summer). Different age groups, viz. adults (18 and 21 years), adolescents (14 years), children (8 years), toddlers (28 months) and Infants (3 months) were considered. Deposited mass (Dm) in the winter season was significantly higher than the monsoon for all the three PM sizes (PM10 (60%), PM2.5 (45%) and PM1 (43%)), mainly due to the greater PM levels witnessed in the winters. The deposition of PM10 was maximum in the head region (81%), and it increases with the age of individuals. The fine fraction (PM1 and PM2.5) was predominantly deposited in the pulmonary region. The maximum pulmonary deposition of fine fraction lies in children (49.5%). The variation in deposition percentage was mainly because of airway geometries, PM sizes, and deposition mechanisms. In lobar region, maximum deposition occurred in the lower lobes (65.9%). Concerning clearance, about 54.5% and 1.8% of the submicron particles deposited in the pulmonary and TB region, respectively, were retained even at the end of one year. Present study results may help analyze potential health risks in different age groups and targeted drug delivery.