Age-specific and seasonal deposition of outdoor and indoor particulate matter in human respiratory tract

Abstract

Particulate matter (PM), a crucial air pollutant is related with range of human health effects. PM having aerodynamic diameter ≤10 μm enter the human airways due to its smaller size and gets deposited in various regions of lungs. However, age-specific seasonal deposition under various sampling environments and site locations are not addressed in the Indian context. Hence this study aims to estimate the PM deposition during monsoon, winter, and summer seasons in outdoor and indoor environments of traffic and residential sites for different age groups at Vellore city, India. PM was collected using nine-stage impactor. PM2.5 and PM10 deposition in infants, children, adults, and elderly were estimated using Multiple Path Particle Dosimetry (MPPD) model. Total, regional, lobar, and generation-specific PM deposition were estimated and discussed in the study. Results showed that annual average of PM2.5 and PM10 concentrations exceeded the Indian and World Health Organization standards. Total deposition of PM10 was consistently larger than PM2.5 across all age groups. Children and elderly experienced highest total PM2.5 and PM10 deposition, respectively during summer in traffic outdoor environment. Regional results showed that head and alveolar regions were dominated by PM10 and PM2.5 depositions, respectively. The deposited mass rate was found highest in elderly followed by adults, children, and infants irrespective of size. Lower lobes received maximum deposition than other lobes. Also, the trend of increased PM deposition fraction after 20th generation was found. PM pollution and deposition in residential site and indoor environment were comparable to traffic site and outdoor environment, respectively.