Uptake of gaseous formaldehyde by soil surfaces: a combination of   adsorption/desorption equilibrium and chemical reactions

doi:10.5194/acp-16-10299-2016

CORC > 北京大学 > 环境科学与工程学院

	Uptake of gaseous formaldehyde by soil surfaces: a combination of adsorption/desorption equilibrium and chemical reactions
	Li, Guo ; Su, Hang ; Li, Xin ; Kuhn, Uwe ; Meusel, Hannah ; Hoffmann, Thorsten ; Ammann, Markus ; Poeschl, Ulrich ; Shao, Min ; Cheng, Yafang
刊名	ATMOSPHERIC CHEMISTRY AND PHYSICS
	2016
关键词	MARINE BOUNDARY-LAYER OBSERVATORY PHOTOCHEMISTRY EXPERIMENT VOLATILE ORGANIC-COMPOUNDS VAPOR-PHASE SORPTION CARBONYL-COMPOUNDS RELATIVE-HUMIDITY CLAY-MINERALS NITROUS-ACID TRICHLOROETHYLENE VAPOR ATMOSPHERIC CHEMISTRY
DOI	10.5194/acp-16-10299-2016
英文摘要	Gaseous formaldehyde (HCHO) is an important precursor of OH radicals and a key intermediate molecule in the oxidation of atmospheric volatile organic compounds (VOCs). Budget analyses reveal large discrepancies between modeled and observed HCHO concentrations in the atmosphere. Here, we investigate the interactions of gaseous HCHO with soil surfaces through coated-wall flow tube experiments applying atmospherically relevant HCHO concentrations of similar to 10 to 40 ppbv. For the determination of uptake coefficients (gamma), we provide a Matlab code to account for the diffusion correction under laminar flow conditions. Under dry conditions (relative humidity = 0 %), an initial gamma of (1.1 +/- 0.05) x 10(4) is determined, which gradually drops to (5.5 +/- 0.4) x 10(5) after 8 h experiments. Experiments under wet conditions show a smaller gamma that drops faster over time until reaching a plateau. The drop of gamma with increasing relative humidity as well as the drop over time can be explained by the adsorption theory in which high surface coverage leads to a reduced uptake rate. The fact that gamma stabilizes at a non-zero plateau suggests the involvement of irreversible chemical reactions. Further back-flushing experiments show that two-thirds of the adsorbed HCHO can be re-emitted into the gas phase while the residual is retained by the soil. This partial reversibility confirms that HCHO uptake by soil is a complex process involving both adsorption/desorption and chemical reactions which must be considered in trace gas exchange (emission or deposition) at the atmosphere-soil interface. Our results suggest that soil and soil-derived airborne particles can either act as a source or a sink for HCHO, depending on ambient conditions and HCHO concentrations.; Max Planck Society (MPG); National Natural Science Foundation of China [41330635]; China Scholarship Council (CSC); Max Planck Society; SCI(E); ARTICLE; mshao@pku.edu.cn; yafang.cheng@mpic.de; 15; 10299-10311; 16
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/491583]
专题	环境科学与工程学院
推荐引用方式 GB/T 7714	Li, Guo,Su, Hang,Li, Xin,et al. Uptake of gaseous formaldehyde by soil surfaces: a combination of adsorption/desorption equilibrium and chemical reactions[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2016.
APA	Li, Guo.,Su, Hang.,Li, Xin.,Kuhn, Uwe.,Meusel, Hannah.,...&Cheng, Yafang.(2016).Uptake of gaseous formaldehyde by soil surfaces: a combination of adsorption/desorption equilibrium and chemical reactions.ATMOSPHERIC CHEMISTRY AND PHYSICS.
MLA	Li, Guo,et al."Uptake of gaseous formaldehyde by soil surfaces: a combination of adsorption/desorption equilibrium and chemical reactions".ATMOSPHERIC CHEMISTRY AND PHYSICS (2016).