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.
Multi-pollutant concentration measurements around a concentrated swine production facility using open-path FTIR spectrometry
Open-path Fourier transform infrared (OP/FTIR) spectrometry was used to measure the concentrations of ammonia, methane, and other atmospheric gases around an integrated industrial swine production facility in eastern North Carolina. Several single-path measurements were made over an 8-day period from 11 to 22 January 1999. Nine different monitoring paths were configured to determine the concentration ranges of ammonia and methane throughout this facility, with an emphasis on isolating the emissions from the farrowing/nursery barns, the finishing barns, and the waste lagoon. A series of sequential measurements was made on 13 January 1999, to estimate the target gas concentrations downwind from each of these sources and at an upwind background site under similar meteorological conditions. The path-averaged concentration (mean±standard deviation) of ammonia during these measurements was below the estimated method detection limit of 0.003 ppm at the background site, 0.328±0.044 ppm between the farrowing/nursery and finishing barns, 2.063±0.140 ppm perpendicular to the airflow from the exhaust fans of the finishing barns, 0.488±0.110 ppm along the western berm of the lagoon, and 0.722±0.659 ppm along the eastern berm of the lagoon. The mean-path-averaged concentration of methane during this same time period was 1.89±0.03 ppm at the background site, 2.58±0.11 ppm between the farrowing/nursery and finishing barns, 2.70±0.05 ppm perpendicular to the airflow from the exhaust fans of the finishing barns, 2.27±0.06 ppm along the western berm of the lagoon, and 11.02±9.69 ppm along the eastern berm of the lagoon as the prevailing westerly winds died down. The concentration measurements made along different monitoring paths during this study indicate that the confinement barns can be a significant source of ammonia, while the lagoon is a major source of methane. Attempts to apply tracer-based dispersion modeling techniques to the single-path OP/FTIR data to estimate emission rates of ammonia and methane from the different sources present at this facility were met with limited success.
Evaluation of emissions from remedial activity at a former manufactured gas plant by open-path Fourier transform infrared spectroscopy
Open-path Fourier Transform Infrared Spectroscopy (OP-FTIR) was used to conduct an air monitoring survey at a Fourier manufactured gas plant (FMGP) superfund site. This survey was performed in support and at the request of the Waste Management Division, U.S. EPA, Region VII. A three day study was conducted in which the OP- FTIR instrument was operated at several fenceline locations around the perimeter of the site in order to detect and quantify benzene emissions. Results of the survey indicated that benzene emissions correlate very closely with site excavation and soil processing activities. Varying concentrations of benzene were detected were and quantified in the field in near-real time. Laboratory analysis of the field data also indicated concentrations of ammonia and toluene at levels above the instrumental detection limit.