Applications of Open-Path Fourier Transform Infrared for Identification of Volatile Organic Compound Pollution Sources and Characterization of Source Emission Behaviors
Abstract An open-path Fourier transform infrared spectroscopy (OP-FTIR) system was set up for 3-day continuous line-averaged volatile organic compound (VOC) monitoring in a paint manufacturing plant. Seven VOCs (toluene, m-xylene, p-xylene, styrene, methanol, acetone, and 2-butanone) were identified in the ambient environment. Daytime-only batch operation mode was well explained by the time-series concentration plots. Major sources of methanol, m-xylene, acetone, and 2-butanone were identified in the southeast direction where paint solvent manufacturing processes are located. However, an attempt to uncover sources of styrene was not successful because the method detection limit (MDL) of the OP-FTIR system was not sensitive enough to produce conclusive data. In the second scenario, the OP-FTIR system was set up in an industrial complex to distinguish the origins of several VOCs. Eight major VOCs were identified in the ambient environment. The pollutant detected wind-rose percentage plots that clearly showed that ethylene, propylene, 2-butanone, and toluene mainly originated from the tank storage area, whereas the source of n-butane was mainly from the butadiene manufacturing processes of the refinery plant, and ammonia was identified as an accompanying reduction product in the gasoline desulfuration process. Advantages of OP-FTIR include its ability to simultaneously and continuously analyze many compounds, and its long path length monitoring has also shown advantages in obtaining more comprehensive data than the traditional multiple, single-point monitoring methods.
Characterization of Volatile Organic Compounds in the Vicinity of an Optoelectronics Industrial Park in Taiwan
Abstract This study aimed to determine the concentration of volatile organic compounds (VOCs) and investigate the impacts of traffic and industrial activities on the concentration of VOCs near the Central Taiwan Science Park (CTSP) in Taiwan during 2005. Twelve-hour canister sampling was performed at 10 sites near CTSP every season. Samples were analyzed by gas chromatography with a mass-selective detector. The traffic ﬂow rate, industrial production rates, and meteorological information were also collected to assess their impacts on VOC concentrations using multiple linear regression models. The major components determined in the atmosphere were toluene (29.4–218.8 μg m−3), acetone (30–71.3 μg m−3), m/p-xylene (7.8–51.7 μg m−3), and ethanol (16.4–47.8 μg m−3); only ethanol revealed a pattern of increasing concentration from spring to winter. The log-transformed mean concentrations of toluene, acetone, and ethanol were significantly associated with the production rates of the optoelectronic companies after adjustment for traffic ﬂow and meteorological factors (P < 0.05). There was no significant association between the total traffic ﬂow rate and any log-transformed mean concentrations of VOCs. Each $1 million (U.S.) increase in optoelectronic sales was significantly associated with increasing mean concentrations of 1.29 ±1.08 μg m-3 for toluene, 1.13 ±1.05μg m-3 for acetone, and 1.25± 1.09μg m-3 for ethanol. The authors’ findings suggest that optoelectronic industrial activities are still the predominant source for VOC emissions surrounding this industrial park.
Simulation study for gaseous fluxes from an area source using computed tomography and optical remote sensing
This paper presents a new approach to quantify emissions from fugitive gaseous air pollution sources. We combine Computed Tomography (CT) with Path-Integrated Optical Remote Sensing (PI-ORS) concentration data in a new field beam geometry. Path integrated concentrations are sampled in a vertical plane downwind from the source along several radial beam paths. An innovative CT technique, which applies the Smooth Basis Function Minimization (SBFM) method to the beam data in conjunction with measured wind data, is used to estimate the total flux from an area source. We conducted simulation study to evaluate the proposed methodology under two beam geometry and configurations. This approach was found to be robust for a wide range of fluctuating wind directions. In the very sparse beam geometry we examined (5 beam paths), successful emission rates were retrieved over a 70 degree range of wind directions.