Articles | Volume 16, issue 11
Atmos. Chem. Phys., 16, 6901–6911, 2016
Atmos. Chem. Phys., 16, 6901–6911, 2016

Research article 06 Jun 2016

Research article | 06 Jun 2016

Spatial distribution of the persistent organic pollutants across the Tibetan Plateau and its linkage with the climate systems: a 5-year air monitoring study

Xiaoping Wang1,2, Jiao Ren1, Ping Gong1,2, Chuanfei Wang1, Yonggang Xue1, Tandong Yao1,2, and Rainer Lohmann3 Xiaoping Wang et al.
  • 1Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing, 100101, China
  • 2CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China
  • 3Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882-1197, USA

Abstract. The Tibetan Plateau (TP) has been contaminated by persistent organic pollutants (POPs), including legacy organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) through atmospheric transport. The exact source regions, transport pathways and time trends of POPs to the TP are not well understood. Here polystyrene–divinylbenzene copolymer resin (XAD)-based passive air samplers (PASs) were deployed at 16 Tibetan background sites from 2007 to 2012 to gain further insight into spatial patterns and temporal trends of OCPs and PCBs. The southeastern TP was characterized by dichlorodiphenyltrichloroethane (DDT)-related chemicals delivered by Indian monsoon air masses. The northern and northwestern TP displayed the greatest absolute concentration and relative abundance of hexachlorobenzene (HCB) in the atmosphere, caused by the westerly-driven European air masses. The interactions between the DDT polluted Indian monsoon air and the clean westerly winds formed a transition zone in central Tibet, where both DDT and HCB were the dominant chemicals. Based on 5 years of continuous sampling, our data indicated declining concentrations of HCB and hexachlorocyclohexanes (HCHs) across the Tibetan region. Inter-annual trends of DDT class chemicals, however, showed less variation during this 5-year sampling period, which may be due to the ongoing usage of DDT in India. This paper demonstrates the possibility of using POP fingerprints to investigate the climate interactions and the validity of using PAS to derive inter-annual atmospheric POP time trends.

Short summary
Is there any linkage between climate interactions and spatial distribution of persistent organic pollutants (POPs)? To answer this question, we conducted long-term passive air monitoring across the Tibetan Plateau. We found that there are three graphical zones over the Tibetan Plateau that could be classified as a function of POP fingerprints. This study highlights validity of using POP fingerprints as chemical tracers to track the interactions of climate systems.
Final-revised paper