Reconstruction of Air Contaminant Concentration Distribution in a Two-dimensional Plane by Computed Tomography and Remote Sensing FTIR Spectroscopy

Abstract

This research combined open path FTIR (OP-FTIR) technique and computed tomography (CT) to reconstruct air contaminant concentration distribution in a two-dimensional plane. Remote sensing FTIR instrument was used to scan radial beam geometry and obtain path integrated concentration (PIC) data of acetone gas in the measuring plane. Smooth basis function minimization (SBFM) algorithm was adopted to reconstruct gaseous concentration distribution. For the purpose of finding out the preferable number of Gaussians used in SBFM algorithm, single-Gaussian, double-Gaussian, and three-Gaussian models were used respectively. Experimental results showed that the reconstruction result of acetone concentration distribution by SBFM algorithm with double-Gaussian model agreed with real distribution more qualitatively and quantitatively than single-Gaussian and three-Gaussian. Also, it has been proved that simulated annealing algorithm used in the optimization process of SBFM reconstruction was feasible and effective. Although computed tomography and remote sensing FTIR technique (CT-RS-FTIR) is still at the laboratory study stage, with further improvement of SBFM algorithm and beam geometry, it promises to be used in air pollution monitoring widely.

Combination of Neural Network and SBFM Algorithm for Monitoring VOCs Distribution by Open Path FTIR Spectrometry

“…A double bi-variant Gaussian [10] was chosen as the Basis function, and the detailed algorithm was described in previous studies. [2,5,10] s ray,j was used to evaluate the overall agreement between the predicted gaseous distribution and the reconstruction profile for the jth component. [2] The smaller s ray , j was, the better the reconstruction result was.…”

Children’s Health Risk Assessment of Lead Exposure

“…For example, it is reported that children's exposure to low Pb concentrations can affect its neural development [3]. So researchers worldwide generally agreed that Pb does not exist reference concentration (RfD) at current status (RfD means the recommended safety concentration which the health risk can be avoided) [4].…”