气候变化领域集成服务门户(CCPortal): Estimation of atmospheric total organic carbon (TOC) - Paving the path towards carbon budget closure

CCPortal

DOI	10.5194/acp-19-459-2019
	Estimation of atmospheric total organic carbon (TOC) - Paving the path towards carbon budget closure
	Yang M.; Fleming Z.L.
发表日期	2019
ISSN	16807316
起始页码	459
结束页码	471
卷号	19 期号:1
英文摘要	The atmosphere contains a rich variety of reactive organic compounds, including gaseous volatile organic carbon (VOCs), carbonaceous aerosols, and other organic compounds at varying volatility. Here we present a novel and simple approach to measure atmospheric non-methane total organic carbon (TOC) based on catalytic oxidation of organics in bulk air to carbon dioxide. This method shows little sensitivity towards humidity and near 100 % oxidation efficiencies for all VOCs tested. We estimate a best-case hourly precision of 8 ppb C during times of low ambient variability in carbon dioxide, methane, and carbon monoxide (CO). As proof of concept of this approach, we show measurements of TOC + CO during August-September 2016 from a coastal city in the southwest United Kingdom. TOC + CO was substantially elevated during the day on weekdays (occasionally over 2 ppm C) as a result of local anthropogenic activity. On weekends and holidays, with a mean (standard error) of 102 (8) ppb C, TOC + CO was lower and showed much less diurnal variability. TOC + CO was significantly lower when winds were coming off the Atlantic Ocean than when winds were coming off land if we exclude the weekday daytime. By subtracting the estimated CO from TOC + CO, we constrain the mean (uncertainty) TOC in Atlantic-dominated air masses to be around 23 (± ≥ 8) ppb C during this period. A proton-transfer-reaction mass spectrometer (PTR-MS) was deployed at the same time, detecting a large range of organic compounds (oxygenated VOCs, biogenic VOCs, aromatics, dimethyl sulfide). The total speciated VOCs from the PTR-MS, denoted here as Sum(VOC), amounted to a mean (uncertainty) of 12 (± ≤ 3) ppb C in marine air. Possible contributions from a number of known organic compounds present in marine air that were not detected by the PTR-MS are assessed within the context of the TOC budget. Finally, we note that the use of a short, heated sample tube can improve the transmission of organics to the analyzer, while operating our system alternately with and without a particle filter should enable a better separation of semi-volatile and particulate organics from the VOCs within the TOC budget. Future concurrent measurements of TOC, CO, and a more comprehensive range of speciated VOCs would enable a better characterization and understanding of the atmospheric organic carbon budget. © Author(s) 2019.
语种	英语
scopus关键词	aerosol; atmospheric chemistry; carbon budget; estimation method; human activity; oxidation; total organic carbon; volatile organic compound; United Kingdom
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/144725
作者单位	Plymouth Marine Laboratory, Plymouth, United Kingdom; National Centre for Atmospheric Science (NCAS), Department of Chemistry, University of Leicester, Leicester, United Kingdom; Center for Climate and Resilience Research (CR2), Departamento de Geofísica, Universidad de Chile, Santiago, Chile
推荐引用方式 GB/T 7714	Yang M.,Fleming Z.L.. Estimation of atmospheric total organic carbon (TOC) - Paving the path towards carbon budget closure[J],2019,19(1).
APA	Yang M.,&Fleming Z.L..(2019).Estimation of atmospheric total organic carbon (TOC) - Paving the path towards carbon budget closure.Atmospheric Chemistry and Physics,19(1).
MLA	Yang M.,et al."Estimation of atmospheric total organic carbon (TOC) - Paving the path towards carbon budget closure".Atmospheric Chemistry and Physics 19.1(2019).