ASTM International, W. Conshohocken, Pa., on Tuesday, 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.

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.

"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."

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.

SOURCE: ASTM Press Release