Research Progress on the Atmospheric Persistent Organic Pollutants in Indochina Peninsula by Guangzhou Institute of Geochemistry of CAS

Monitoring and Risk Assessment of Toxic Chemicals in the Air, MORATOXA

28 09, 2023

Recently, led by Professor Zhang Gan of Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (hereinafter referred to as GIG), the project team of the Alliance of International Science Organizations (ANSO) joint research cooperation project " Monitoring and Risk Assessment of Toxic Chemicals in the Air, MORATOXA " , significant progress has been made on atmospheric persistent organic pollutants (POPs) in the Indo-China Peninsula region of Asia. The paper entitled "Mapping the Contribution of Biomass Burning to Persistent Organic Pollutants in the Air of the Indo-China Peninsula Based on a Passive Air Monitoring Network" was published online on January 19, 2023 in Environmental Science & Technology and was selected as the supplementary cover story.

Biomass burning (BB) could re-emit POPs into the atmosphere originally present in vegetation and soil. Due to the geographical limitations of emission factors, the difficulty of satellite data to capture indoor biomass combustion events and small fire points, and the limitations of existing pollutant transport models, the contribution of BB to global atmospheric POPs is still unknown. Few regional studies have been reported on the secondary emissions of POPs caused by BB. Indochina Peninsula is a hotspot of biomass combustion worldwide, which is ideal for empirical research on this issue.

Under the guidance and project support of the ANSO international cooperation framework, postdoctoral researcher Jiang Haoyu and Associate Professor Zhao Shizhen from the GIG, in collaboration with Associate Professor Zhang Ruijie from Guangxi University, Dr. Wanwisa Pansak from Naresuan University in Thailand, and Associate Professor Surat Bualert from Kasetsart University, conducted a regional monitoring study on the BB biomarkers and POPs in the atmosphere of the Indochina Peninsula, based on the polyurethane foam passive atmospheric sampling (PUF-PAS) technique. The PUF-PAS samples were collected from 43 sampling points in major countries of the Indochina Peninsula, including Thailand, Vietnam, Cambodia, Laos, Myanmar, etc., covering three seasons: BB season (January-April), pre-rainy season (April-June) and rainy season (June-September). This study identified the regional distribution and seasonal characteristics of BB marker (levoglucosan), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Statistical analysis showed that the levoglucosan collected by PUF-PAS was significantly positively correlated with the concentrations of 16 PCBs and two OCPs. The results indicated that BB could promote the secondary emission of surficial POPs. The research team further analyzed the source of POPs by Positive Matrix Factorization (PMF) model and identified that the contribution of BB to PCBs and OCPs was 9.3%. Finally, the regionally temporal-spatial distribution of BB to PCBs and OCPs was further calculated through factorization, which was affected by terrain and urban-rural distribution.

The passive air sampling technique adopted here has been highly recognized by the Thai side, which agreed that it is economical and efficient. They also proposed to further promote and apply the passive air samplers to the Ministry of Natural Resources and Environment of Thailand. For the first time, this study quantified the contribution of secondary POP emissions caused by regional biomass combustion. The research results are helpful for environmental managers to formulate effective source control strategies for toxic pollutants, improve regional air quality, and serve the major livelihood needs of clean air-life and health.

Source: Dr. ZHAO Shizhen, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (GIGCAS)

论文信息：Haoyu Jiang（蒋昊余）, Jun Li（李军）, Ruijie Zhang ,* Wanwisa Pansak, Guangcai Zhong,（钟广财）, Kechang Li（李可昌）, Shizhen Zhao（赵时真）,* Surat Bualert, Onanong Phewnil, and Gan Zhang（张干）, (2023) Mapping the contribution of biomass burning to persistent organic pollutants in the air of the Indo-China Peninsula based on a passive air monitoring network. Environmental Science & Technology, 57(6), 2274-2285. (Supplementary Cover)