Pedestrian exposure to PM2.5, BC and UFP of adults and teens: A case study in Xi’an, China

Abstract

To evaluate the exposure of adults and teens to fine particles (PM2.5), black carbon (BC), and ultrafine particles (UFP) as they walked along urban roads, an investigation was performed using mobile measurement devices on two types of urban roads (arterial and collector) in Xi'an. The inhalation dose model, considering exposure concentration, inhalation rate, and trip time, was employed to estimate the personal inhaled dose of pollutants for adults and teens. Multivariate linear regression was used to explore impact factors that contributed to their exposure variability. Results showed large spatial and temporal pollutant concentration variations along the designed route. Pedestrians experienced higher exposure concentrations on the arterial road than on the collector road. Teens faced higher PM2.5 and BC inhaled doses than adults on all the streets studied, although sometimes being exposed to lower concentrations than adults. In addition, gender-related inhaled dose differences between teens were more significant than those for adults. The overall background concentrations explained the greatest variability in pollutant exposures, from 18.7% for BC to 40.4% for PM2.5. Ambient concentrations and traffic volume as well as pollution hotspots (pedestrian cigarette smokers, restaurants, and open burning) were identified as major factors affecting the pollutant concentrations.