University of Washington

Arcadis G & M Inc.

Atmosfir Optics Ltd.

Ram Hashmonay

Robert Howard Kagann

Michael G Yost

Yair Shpitzer

Michael James Chase

Gilad Shpitzer

Robert H Kagann

The subject matter discloses a method for detecting concentration of air contaminants, comprising obtaining an average sample single beam value, the average sample single beam value comprises a first set of single beam measurements obtained from a detector; obtaining an average background single beam value, the average background single beam value comprises a second set of single beam measurements obtained from the detector; comparing the average sample single beam value to the average background single beam value to determine the concentration of air contamination; continuously updating the averages upon detection of new single beam measurements; wherein the second set of single beam measurements comprises a plurality of single beam measurements that were detected by the detector prior to the detection of the single beam measurements included in the first set of single beam measurements. In some cases, the first set partially overlaps with the second set.

Method for open path detection of air contaminants

Methods, systems, and computer program products for the fenceline monitoring of air contaminants. More particularly, methods, systems, and computer program products for correlating temporal variations between simultaneous measurements of at least one point monitor and an optical remote sensing (ORS) monitor to estimate the peak concentration of one or more air contaminants along a line of measurement, e.g., a fenceline.

Fenceline monitoring of air contaminants

Path Integrated Optical Remote Sensing (PI-ORS) instruments are used to provide Path Integrated Concentration (PIC) data corresponding to a particulate concentration in region scanned by a sequence of optical beams. Prior art methods of developing spatial concentration maps using PIC data have required a relatively large number of intersecting beam paths. The present invention can produce spatial concentration maps using considerably fewer optical beams. Preferably, a non-overlapping radial beam geometry is used to produce PIC data that are processed to produce a spatial concentration map. The PIC data are indicative of the cumulative spatial concentration distribution of the contaminant in the sampling region. Once the PIC data are obtained, a specifically developed reconstruction algorithm is applied to the PIC data to create a map of concentration or contaminants or other constituents in the sampling region. Any of several different reconstruction algorithms can be employed. In general, a method for fitting or interpolating is used to estimate the cumulative distribution function of the contaminants or constituents of interest over the sampling region from the observed PIC data. Continuous or spline functions can be used in the reconstruction algorithm. Preferably, a smooth basis function minimization (SBFM) algorithm is used to fit a superposition of the integrated basis functions to the PIC data. The evaluation of the directional derivatives for the fitted integrated (cumulative) basis functions provides the desired map of concentration values over the sampling region. Using far fewer sources and detectors than the prior art, reasonably accurate concentration mappings can be achieved.

Mapping air contaminants using path-integrated optical remote sensing with a non-overlapping variable path length beam geometry

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Chapel Hill, NC, United States of America

Ram Hashmonay