(Photo courtesy of EPA)

A tool developed originally to find unobstructed paths for wireless networks has been tuned up in a new version to serve homeland security.

VexLink, from Vexcel Corp., Boulder, Colo., is a multi-purpose geographic information system tool. It now has functions to model atmospheric propagation of gas and other contaminants. Users can apply data on air flow patterns and winds to track dispersal through landscapes of 3D building and terrain data.

The U.S. Environmental Protection Agency has used the tool to study the air pollution that spread across New York City as a consequence of the Sept. 11, 2001, terrorist attacks. The software also can find optimum locations for sirens and emergency loudspeakers. More information is at www.vexcel.com.