title: Emission Flux Measurement Error with a Mobile DOAS System and Application to NOxFlux Observations.
abstract: Mobile differential optical absorption spectroscopy (mobile DOAS) is an optical remote sensing method that can rapidly measure trace gas emission flux from air pollution sources (such as power plants, industrial areas, and cities) in real time. Generally, mobile DOAS is influenced by wind, drive velocity, and other factors, especially in the usage of wind field when the emission flux in a mobile DOAS system is observed. This paper presents a detailed error analysis and NOx emission with mobile DOAS system from a power plant in Shijiazhuang city, China. Comparison of the SO₂ emission flux from mobile DOAS observations with continuous emission monitoring system (CEMS) under different drive speeds and wind fields revealed that the optimal drive velocity is 30-40 km/h, and the wind field at plume height is selected when mobile DOAS observations are performed. In addition, the total errors of SO₂ and NO₂ emissions with mobile DOAS measurements are 32% and 30%, respectively, combined with the analysis of the uncertainties of column density, wind field, and drive velocity. Furthermore, the NOxemission of 0.15 ± 0.06 kg/s from the power plant is estimated, which is in good agreement with that from CEMS observations of 0.17 ± 0.07 kg/s. This study has significantly contributed to the measurement of the mobile DOAS system on emission from air pollution sources, thus improving estimation accuracy.
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. fcwu@aiofm.ac.cn.
authors.forename: Fengcheng
authors.initials: F
authors.lastname: Wu
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. angli@aiofm.ac.cn.
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. phxie@aiofm.ac.cn.|Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China. phxie@aiofm.ac.cn.|School of Environmental Science and Optoeclectronic Technology, University of Science and Technology of China, Hefei 230026, China. phxie@aiofm.ac.cn.
authors.forename: Pinhua
authors.initials: P
authors.lastname: Xie
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. hchen@aiofm.ac.cn.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. zkhu@aiofm.ac.cn.
authors.forename: Zhaokun
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. zhangqiong@aiofm.ac.cn.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. jgliu@aiofm.ac.cn.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. wqliu@aiofm.ac.cn.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Liu
keywords: DOAS; NOx; emission flux; error; mobile measurements; spectrophotometer