Robert H. Kagann

Optical Remote Measurement of Toxic Gases

Enactment of the Clean Air Act Amendments (CAAA) of 1990 has resulted in increased ambient air monitoring needs for industry, some of which may be met efficiently using open-path optical remote sensing techniques. These techniques include Fourier transform spectroscopy, differential optical absorption spectroscopy, laser long-path absorption, differential absorption lidar, and gas cell correlation spectroscopy. With this regulatory impetus, it is an opportune time to consider applying these technologies to the remote and/or path-averaged measurement and monitoring of toxic gases covered by the CAAA. This article reviews the optical remote sensing technology and literature for that application.

Long-path FTIR Measurements of Volatile Organic Compounds in an Industrial Setting

A long-path Fourier transform spectrometer was used to make measurements of volatile organic compounds in an industrial complex in New Castle, Delaware as part of the Superfund Innovative Technology Evaluation (SITE) program. These data are compared to data taken with a whole-air canister technique. To provide an effective comparison the canisters were transported along the path for a 32-min period. For each FTIR spectrum, 256 interferograms were co-added over a 4-mln period. Eight individual spectra were then co-added to obtain the comparison data.

Probing emissions of military cargo aircraft: description of a joint field measurement Strategic Environmental Research and Development Program.

Abstract To develop effective air quality control strategies for military air bases, there is a need to accurately quantify these emissions. In support of the Strategic Environmental Research and Development Program project, the particulate matter (PM) and gaseous emissions from two T56 engines on a parked C-130 aircraft were characterized at the Kentucky Air National Guard base in Louisville, KY. Conventional and research-grade instrumentation and methodology were used in the field campaign during the first week of October 2005. Particulate emissions were sampled at the engine exit plane and at 15 m downstream. In addition, remote sensing of the gaseous species was performed via spectroscopic techniques at 5 and 15 m downstream of the engine exit. It was found that PM mass and number concentrations measured at 15-m downstream locations, after dilution-correction generally agreed well with those measured at the engine exhaust plane; however, higher variations were observed in the far-field after natural dilution of the downstream measurements was accounted for. Using carbon dioxide-normalized data we demonstrated that gas species measurements by extractive and remote sensing techniques agreed reasonably well.

An Advanced Test Method forMeasuring Fugitive Dust Emissions Using a Hybrid System of Optical Remote Sensing and PointMonitor Techniques

A new test method for measuring fugitive dust emissions has been developed. This method includes one open path laser transmissometer (OPLT) extended to a path of several undred meters to measure ground-level extinction coefficients across an entire plume combined with one tower with at least two vertically distributed and time-resolved dust monitors (DM) (in the middle of the OP-LT path) to measure vertical gradients of PM10 and PM2.5 concentration. At least two wind monitors are mounted on the tower at the same elevation as the DM instruments to measure wind speed and wind direction for input into the PM flux calculations. The extinction data from the OP-LT (from a specific dust source) are calibrated to the PM10 concentration data from calibrated DM instruments. We found that such calibration is mainly a function of dust type and its typical airborne particle size distribution. The performance of this method is demonstrated through comparison to a more traditional upwind-downwind method that deploys three towers with five DM instruments on each tower to define the flux plane with multiple measurements. It is shown that the new hybrid method (one tower with two or three DM instruments and OP-LT) provides comparable flux calculation to the traditional method.

Use of a Fourier transform spectrometer as a remote sensor at Superfund sites

A Fourier transform infrared remote sensor (FTIR-RS) has been used at a Superfund site to make measurements of the concentrations of various gases. An attempt was made to measure benzaldehyde and benzonitrile along with methane and carbon monoxide. The results of these measurements are discussed. We also attempted to compare the FTIR-RS results with those from canister samples, and this comparison is also discussed.

Extractive sampling and optical remote sensing of F100 aircraft engine emissions.

Abstract The Strategic Environmental Research and Development Program (SERDP) has initiated several programs to develop and evaluate techniques to characterize emissions from military aircraft to meet increasingly stringent regulatory requirements. This paper describes the results of a recent field study using extractive and optical remote sensing (ORS) techniques to measure emissions from six F-15 fighter aircraft. Testing was performed between November 14 and 16, 2006 on the trim-pad facility at Tyndall Air Force Base in Panama City, FL. Measurements were made on eight different F100 engines, and the engines were tested on-wing of in-use aircraft. A total of 39 test runs were performed at engine power levels that ranged from idle to military power. The approach adopted for these tests involved extractive sampling with collocated ORS measurements at a distance of approximately 20–25 nozzle diameters downstream of the engine exit plane. The emission indices calculated for carbon dioxide, carbon monoxide, nitric oxide, and several volatile organic compounds showed very good agreement when comparing the extractive and ORS sampling methods.