Articles | Volume 16, issue 5
https://doi.org/10.5194/acp-16-2971-2016
https://doi.org/10.5194/acp-16-2971-2016
Research article
 | 
08 Mar 2016
Research article |  | 08 Mar 2016

Size distributions of polycyclic aromatic hydrocarbons in urban atmosphere: sorption mechanism and source contributions to respiratory deposition

Yan Lv, Xiang Li, Ting Ting Xu, Tian Tao Cheng, Xin Yang, Jian Min Chen, Yoshiteru Iinuma, and Hartmut Herrmann

Abstract. In order to better understand the particle size distribution of polycyclic aromatic hydrocarbons (PAHs) and their source contribution to human respiratory system, size-resolved PAHs have been studied in ambient aerosols at a megacity Shanghai site during a 1-year period (2012–2013). The results showed the PAHs had a bimodal distribution with one mode peak in the fine-particle size range (0.4–2.1 µm) and another mode peak in the coarse-particle size range (3.3–9.0 µm). Along with the increase in ring number of PAHs, the intensity of the fine-mode peak increased, while the coarse-mode peak decreased. Plotting of log(PAH / PM) against log(Dp) showed that all slope values were above −1, suggesting that multiple mechanisms (adsorption and absorption) controlled the particle size distribution of PAHs. The total deposition flux of PAHs in the respiratory tract was calculated as being 8.8 ± 2.0 ng h−1. The highest lifetime cancer risk (LCR) was estimated at 1.5  ×  10−6, which exceeded the unit risk of 10−6. The LCR values presented here were mainly influenced by accumulation mode PAHs which came from biomass burning (24 %), coal combustion (25 %), and vehicular emission (27 %). The present study provides us with a mechanistic understanding of the particle size distribution of PAHs and their transport in the human respiratory system, which can help develop better source control strategies.

Download
Short summary
The study focused on size-resolved PAHs in urban aerosols at a megacity Shanghai site. The results provide us with a mechanistic understanding of the particle size distribution of PAHs and their transport in the human respiratory system; this can help develop better source control strategies.
Altmetrics
Final-revised paper
Preprint