title: Path concentration distribution of toluene using remote sensing FTIR and one-dimensional reconstruction method.
abstract: A one-dimensional mapping technique coupled with Open-Path remote sensing FTIR was presented in this article. This technique was applied to one of the air toxic volatile organic compounds (VOCs)-toluene. The Path Integrated Concentrations (PICs) of toluene in different path lengths along one beam path were fitted by polynomial fitting method with degrees from 3 to 7. The 6th degree polynomial fitting showed the best fitting result. Moreover, the methods of reconstructing path concentration distribution along the beam path by applying a Gaussian model and the derivative of 6th degree polynomial fitting function were established in this article. The reconstructed concentrations of toluene along the beam path by the two methods were experimentally close. Results showed that the concentration peaks were at 1.05 and 2.40 m from the instrument by applying the Gaussian model with the maximum concentration of 0.85 and 3.19 ppm, and at 0.99 and 2.49 m from the instrument with the maximum concentration of 0.78 and 2.80 ppm by applying the 6th polynomial fitting function. It was obvious that the reconstruction results by these two methods were very close. This approach could be appreciated for its fast calculation, exact peak location orientation and concentration flow tendency mapping. In can be concluded that this method can provide the path concentration distributions of much more releasing gases in a briefly and intuitionistic way. The remote sensing FTIR coupled with these mathematical reconstruction techniques can be applied to the real world environmental and industrial hygiene monitoring, thus works as an alert system for the VOCs pollution.
authors.affiliation: Laboratory of Advanced Spectroscopy, Nanjing University of Science and Technology, Nanjing, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Houqian
authors.initials: H
authors.lastname: Xu
authors.forename: Rui
authors.initials: R
authors.lastname: Xue
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Wang
authors.forename: Yibo
authors.initials: Y
authors.lastname: Ren
authors.forename: Lianjun
authors.initials: L
authors.lastname: Wang
authors.forename: Junde
authors.initials: J
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D008962:Models, Theoretical; D017550:Spectroscopy, Fourier Transform Infrared; D014050:Toluene / Q000032:analysis*; D014054:Tomography; D014835:Volatilization
chemical_list: D000393:Air Pollutants; D014050:Toluene