Article in Press  PDF(1.18 MB)
Supplementary MaterialPDF (115 KB)
Characteristics of Particulate-Phase Polycyclic Aromatic Hydrocarbons (PAHs) in the Atmosphere over the Central Himalayas
Pengfei Chen1, Chaoliu Li2, Shichang Kang1,3, Maheswar Rupakheti4, Arnico K. Panday5, Fangping Yan1, Quanlian Li1, Qianggong Zhang2,3, Junming Guo1, Zhenming Ji2, Dipesh Rupakheti2, Wei Luo6
1 State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China
2 Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, CAS, Beijing 100101, China
3 CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100085, China
4 Institute for Advanced Sustainability Studies, Potsdam 14467, Germany
5 International Centre for Integrated Mountain Development, Kathmandu, Nepal
6 State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, CAS, Beijing 100085, China
- TSP and PAH concentrations decreased remarkably northwards along both transects.
- High TSP and PAH concentrations were observed in the non-monsoon season.
- Similar PAH profiles were found at remote sites on both sides of the Himalayas.
- The northern Himalayas were affected by pollutants transported form the IGP.
PAH concentrations were measured in total suspended particle (TSP) samples collected from six sites along two south-north transects across the central Himalayas from April 2013 to March 2014. The annual average TSP and PAH (especially 5- and 6-ring compounds) concentrations were found to decrease noticeably northwards along both transects. At rural and urban sites, the TSP and PAH concentrations showed clear seasonal variations, with the lower concentrations around the mid-monsoon season and the higher values in the winter season. Meanwhile, at the remote sites (e.g., Nyalam and Zhongba), these pollutants generally remained constant throughout the year but with relatively higher levels during the pre-monsoon season. Both IndP/(IndP + BghiP) and Fla/(Fla + Pyr) ratios suggested that atmospheric PAHs from urban and rural sites were mainly associated with emissions from biomass burning, coal burning and petroleum combustion. However, the contribution of biomass burning increased at remote sites. Similar compositions of PAHs were found at three remote sites located on both sides of the Himalayas (Jomsom, Zhongba, and Nyalam), suggesting that the northern side of the Himalayas may be affected by anthropogenic emissions from the Indo-Gangetic Plain (IGP) via long-range atmospheric transport. This work provides a database of PAHs in central Himalayas for further assessing environmental risk of air pollution in the remote regions.
Polycyclic aromatic hydrocarbons; Total Suspended Particles; Source; Himalayas.