ASTM International, headquartered in West Conshohocken, PA, on June 22, 2010, announced a new approved test method for determining the opacity of a plume in an outdoor ambient atmosphere. ASTM D7520 was developed by Subcommittee D22.03 on Ambient Atmospheres and Source Emissions, part of ASTM International Committee D22 on Air Quality.
Currently, regulators, industry and government facilities use human observers to quantify the opacity of plumes, using EPA Method 9. The new method uses digital cameras and software to determine plume opacity while providing a digital image of the plume and its surrounding environment.
Air permits from regulatory agencies such as the EPA often require the measurement of a plume's opacity as the plume is emitted from a stationary point source (for example, smokestacks) in an outdoor ambient environment. While such opacity is often visually measured by human observers as "certified smoke readers," an approved opacity measurement method has long been sought by regulators and industry to take human subjectivity out of the equation.
Note that the cost of required six-month Method 9 retraining could potentially be avoided by use of this new ASTM opacity determination method, if ASTM D7520 is accepted by the environmental regulators as a replacement for Method 9. The recurring cost of the so-called “Smoke School” training is a significant operating expense for many regulated facilities. However, there is likely to be some type of requirement for ASTM D7520 training, although that is unknown at the present time.
"This is a great story about how innovative technologies and techniques are developed with Department of Defense-supported research and they result in the development of new methods like ASTM D7520," said Mark J. Rood, Ph.D., a professor of Environmental Engineering, University of Illinois, and a D22 member. "The development of this new method to determine plume opacity with low-cost digital still cameras was initially described in peer-reviewed journals and conference proceedings and is now an approved ASTM standard to assist USEPA in improving air quality at lower cost and with less subjectivity."
Scope of ASTM D7520-09
ASTM provides the following scope of use for ASTM D7520-09:
1.1 This test method describes the procedures to determine the opacity of a plume. The aforementioned plume is caused by particulate matter emitted from a stationary point source in the outdoor ambient environment using digital imagery and associated software and hardware.
1.2 The opacity of emissions is determined by the application of a Digital Camera Opacity Technique (DCOT) that consists of a Digital Still Camera, Analysis Software, and the Output Function’s content to obtain and interpret digital images to determine and report plume opacity.
1.3 This method is suitable to determine the opacity of plumes from zero (0) percent to one hundred (100) percent.
1.4 This test method is not applicable to stacks with internal diameters greater than 7.0 ft.
1.5 Conditions that shall be considered when using this method to obtain the digital image of the plume include the plume’s background, the existence of condensed water in the plume, orientation of the Digital Still Camera to the plume and the sun (see Section 8).
1.6 This standard describes the procedures to certify the DCOT, hardware, software, and method to determine the opacity of the plumes.
Recommendations
The author recommends that affected sources closely watch for EPA, state and local environmental agencies potential future adoption and use of ASTM D7520-09, which could provide a preferable alternative to using EPA Method 9 for opacity compliance determinations.
For further details on ASTM’s new opacity determination standard, see the following web sites:
ASTM D7520 - 09 Standard Test Method for Determining the Opacity of a Plume in the Outdoor Ambient Atmosphere
http://www.astm.org/Standards/D7520.htm
This article was partially excerpted from publically available information, and was compiled by Rick Wilson, Acacia Environmental Group LLC. Any opinions expressed in this article are those solely of the author, and are not intended as legal or professional guidance to any specific readers. For more information on the author see here.
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