Emissions of particulate matter (PM) from anthropogenic sources are regulated by federal and state authorities to protect human health and welfare. The United States Environmental Protection Agency (USEPA) developed both mass standards and opacity standards for a wide range of sources that discharge visible plumes of PM. This study is focused on developing innovative optical remote sensing (ORS) techniques to quantify the opacity of plumes from stationary point sources and mass emission factors from unique military operations generate PM that is emitted into the atmosphere. The USEPA developed Method 9 to describe how plume opacity is quantified by humans.

However, use of observations by humans introduces subjectivity, and is expensive because semiannual certifications are required for the observers. During the first stage of this research, a Digital Optical Method (DOM) was developed to quantify plume opacity at lower cost, with improved objectivity, and to provide an archival image for possible legal action. A mechanistic approach was taken by deriving algorithms, namely, the contrast and transmission models, to describe how plume opacity is determined, starting from the fundamental theories of aerosol optics, atmospheric physics, and digital imaging principles. These algorithms were applied to interpret the pixel values from digital photographs to quantify the plume’s opacity.

A series of tests were designed and conducted at both Method 9 smoke schools and an industrial site to evaluate the applicability of DOM in the field during both daytime and nighttime. Results from DOM were then compared to results from an in-stack transmissometer, the smoke school trainees, and a Method 9 qualified observer. The daytime field results demonstrated that DOM met the USEPA requirements of individual and average opacity errors under a wide range of meteorological and field conditions as long as the sun was located within the 200° sector to the back of the camera. Statistical analyses showed that DOM yielded more accurate results than the smoke school trainees. The results generated by DOM were consistent with those obtained by a Method 9 qualified observer when monitoring plume opacity in the field with a mean difference between those two methods of 2.2%. The opacity values obtained by different digital cameras with different technical specifications were also compared. The mean difference in opacity values for the different cameras was 3%, which suggested that DOM is able to be implemented using different cameras under the condition that the cameras were calibrated by quantifying the response curves. In addition, measurements of plume opacity during nighttime with the contrast model met USEPA’s requirements for the full range of opacity values from 0 to 100%. However, the transmission model satisfied the USEPA requirements for opacity values < 50%.

During the second stage of this research, a novel ORS technique was developed to obtain in-situ measurements of PM mass emissions for the dust plumes generated from unique military activities. This ORS system consisted of one ground-based Micro-Pulse Lidar (MPL) mounted on a positioner, two Open Path-Fourier Transform Infrared (OP-FTIR) spectrometers, and two Open Path-Laser Transmissometers (OP-LTs). An algorithm was formulated to compute PM extinction profiles along each of the plume’s cross-section from the MPL signals. Size specific PM mass emissions were then calculated by integrating the MPL’s extinction profiles with particle mass distributions determined by the OP-FTIR, OP-LT, and the dust’s particle density and refractive index. In addition, this method is able to quantify the spatial and temporal variability of the plume’s PM mass concentration across each of the plumes’ cross-sections. Two field studies were completed to test this new method in measuring the dust emissions emitted from military activities at desert regions in southwestern and northwestern U.S. Both the back blasts of artillery firings and movements of tracked vehicles were studied. The data collected from both field campaigns were analyzed by employing the method developed as part of this research. The dust mass emission factors were determined for the activities, and correlations were determined between the emission factor values and the types of activities under a range of operational and terrain conditions. Dust plumes were also characterized by developing contour maps that describe the plumes’ horizontal and vertical dimensions, light transmittance, and temporal variability of size specific PM mass concentrations.