Michael R. Kemme

Field Evaluation of Digital Optical Method to Quantify the Visual Opacity of Plumes

Abstract Visual Determination of the Opacity of Emissions from Stationary Sources (Method 9) is a reference method established by U.S. Environmental Protection Agency (EPA) to quantify plume opacity. However, Method 9 relies on observations from humans, which introduces subjectivity. In addition, it is expensive to teach and certify personnel to evaluate plume opacity on a semiannual basis. In this study, field tests were completed during a “smoke school” and a 4-month monitoring program of plumes emitted from stationary sources with a Method 9 qualified observer to evaluate the use of digital photography and two computer algorithms as an alternative to Method 9. This Digital Optical Method (DOM) improves objectivity, costs less to implement than Method 9, and provides archival photographic records of the plumes. Results from “smoke school” tests indicate that DOM passed six of eight tests when the sun was located in the 140° sector behind one of the three cameras, with the individual opacity errors of 15% or less and average opacity errors of 7.5% or less. DOM also passed seven of the eight tests when the sun was located in the 216° sector behind another camera. However, DOM passed only one of the eight tests when the sun was located in the 116° sector in front of the third camera. Certification to read plume opacity by a “smoke reader” for 6 months requires that the “smoke reader” pass one of the smoke school tests during smoke school. The average opacity errors and percentage of observations with individual opacity errors above 15% for the results obtained with DOM were lower than those obtained by the smoke school trainees with the sun was located behind the camera, whereas they were higher than the smoke school trainee results with the sun located in front of the camera. In addition, the difference between plume opacity values obtained by DOM and a Method 9 qualified observer, as measured in the field for two industrial sources, were 2.2%. These encouraging results demonstrate that DOM is able to meet Method 9 requirements under a wide variety of field conditions and, therefore, has potential to be used as an alternative to Method 9.

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.

A Novel Method to Quantify Fugitive Dust Emissions Using Optical Remote Sensing

Abstract : This paper describes a new method for retrieving path-averaged mass concentrations from multi-spectral light extinction measured by optical remote sensing (ORS) instruments. The light extinction measurements as a function of wavelength were used in conjunction with an iterative inverse-Mie algorithm to retrieve path-averaged particulate matter (PM) mass distribution. Conventional mass concentration measurements in a controlled release experiment were used to calibrate the ORS method. A backscattering micro pulse lidar (MPL) was used to obtain the horizontal extent of the plume along MPLs line of sight. This method was used to measure concentrations and mass emission rates of PM with diameters smaller or equal to 10 microns (PM(sub 10)) and PM with diameters smaller or equal to 2.5 microns (PM(sub 2.50) that were caused by dust from an artillery back blast event at a location in a desert region of the southwestern United States of America.

Open burning and open detonation PM10 mass emission factor measurements with optical remote sensing.

Emission factors (EFs) of particulate matter with aerodynamic diameter ≤10 µm (PM10) from the open burning/open detonation (OB/OD) of energetic materials were measured using a hybrid-optical remote sensing (hybrid-ORS) method. This method is based on the measurement of range-resolved PM backscattering values with a micropulse light detection and ranging (LIDAR; MPL) device. Field measurements were completed during March 2010 at Tooele Army Depot, Utah, which is an arid continental site. PM10 EFs were quantified for OB of M1 propellant and OD of 2,4,6-trinitrotoluene (TNT). EFs from this study are compared with previous OB/OD measurements reported in the literature that have been determined with point measurements either in enclosed or ambient environments, and with concurrent airborne point measurements. PM10 mass EFs, determined with the hybrid-ORS method, were 7.8 × 10−3 kg PM10/kg M1 from OB of M1 propellant, and 0.20 kg PM10/kg TNT from OD of TNT. Compared with previous results reported in the literature, the hybrid-ORS method EFs were 13% larger for OB and 174% larger for OD. Compared with the concurrent airborne measurements, EF values from the hybrid-ORS method were 37% larger for OB and 54% larger for OD. For TNT, no statistically significant differences were observed for the EFs measured during the detonation of 22.7 and 45.4 kg of TNT, supporting that the total amount of detonated mass in this mass range does not have an effect on the EFs for OD of TNT. Implications: Particulate matter (PM) in the atmosphere affects the health of humans and ecosystems, visibility, and climate. Fugitive PM emissions are not well characterized because of spatial and temporal ubiquity and heterogeneity. The hybrid-ORS method is appropriate for quantifying fugitive PM emission factors (EFs) because it captures the spatial and temporal dispersion of ground level and elevated plumes in real time, without requiring numerous point measurement devices. The method can be applied to provide an opportunity to reduce the uncertainty of fugitive PM EFs and readily update PM emissions in National Emission Inventories for a range of fugitive PM sources.

Digital Photographic Technique to Quantify Plume Opacity During Daytime and Nighttime

United States Environmental Protection Agency (USEPA) developed opacity standards for sources of visible emissions to protect the visual quality of ambient air. Method 9 is USEPA’s standard method to quantify plume opacity by visual observations from qualified human observers during daytime. These observers are required to be certified twice a year at a “smoke school”. “Smoke school” is more formally referred to as “Visible Emissions Training”, which generally consists of a lecture session and a certification event where observers are field tested for their ability to determine the opacity of plumes. However, the use of observations by humans to quantify plume opacity introduces subjectivity, and is expensive due to semi-annual certification requirements of the observers. In addition, sources may emit plumes during nighttime that also need to be monitored to determine compliance for those sources. Digital Optical Method (DOM) was developed to quantify plume opacity from digital photographs for both daytime and nighttime conditions. Daytime field campaigns were completed during smoke schools with the Illinois Environmental Protection Agency (IEPA) and with industrial stacks during daytime. Field campaigns were also completed during nighttime with a smoke generator operated by IEPA. The field tests demonstrated that DOM has advantages when compared to Method 9 by its lower cost, improved objectivity, and availability of photographs of the visible emissions and their environments. Errors in results from DOM when compared to a reference in–stack transmissometer or a Method 9 observer are within USEPA’s error limits for Method 9. These encouraging results indicate that DOM has the potential to serve as an alternative method to Method 9 to determine the opacity of plumes for regulatory compliance of stationary sources.